European Bridge Conference15th International Conference

8th - 9th July 2014Edinburgh, Scotland

ISBN No: 0-947664-76-8Editor: Professor M C Forde, PhD, FREng, FRSE, FACI, CEng

Carillion Chair, University of Edinburghm.forde@ed.ac.uk

Keynote Papers (K)

1354 EVALUATING SERVICE LIFE OF LONGSPAN BRIDGE CABLES

Dr K Mahmoud, Bridge Technology Consulting Inc, New York, NY, USA

Bridge cables are subject to different degradation processes such as corrosion pitting, stress corrosion cracking, corrosion-fatigue and hydrogen embrittlement. In the last three decades, many suspension bridge cables have demonstrated signs of degradation with different degrees of severity resulting in reduced load carrying capacity. This necessitates a quantitative rationale for the assessment of remaining strength and safe service life of bridge cables. The quantitative methodology must utilize inspection findings and laboratory test results for condition assessment and reliability criteria, similar to LRFD approach. With that in mind, random sampling and reliability-based analytical techniques are required for the assessment of remaining cable service life. The wire mechanical properties and findings of broken and cracked wires must be defined as probabilistic quantities. If an evaluation is conducted using these criteria, the results can be used to establish the tempo of bridge cable inspection and further evaluations in the future. Once probability distributions for wire mechanical properties, such as strength and strain, and loads are established, it’s possible to develop a cable failure mechanism and assess the serviceability of the cable. Use of probabilistic analysis in this approach is similar to the LRFD probabilistic analysis employed in the current AASHTO standards. This paper presents the BTC method, a probability-based methodology for the evaluation of remaining strength and service life of bridge cables. The BTC method is patented and has been published in two reports sponsored by the U.S. Federal Highway Administration (FHWA). Currently, the BTC method is being applied at the Forth Road Bridge in Scotland, and has been applied at the Bronx-Whitestone and Mid-Hudson Bridges in the United States.

1315 SUSPENSION BRIDGES – DESIGN, MAINTENANCE & INSPECTION OF MAIN CABLES B Colford, Forth Road Bridge, Edinburgh, UK

This paper reviews issues with long span suspension bridges. Two well known and publicised closures of suspension bridges due to cable deterioration, the US Grant Bridge and the Waldo-Hancock Bridge, are salutary lessons for all those involved in long span bridges. They highlight the absolute need for properly funded and well organised maintenance of these assets and that a programme of regular investigations, including internal inspections, of the main cables must be carried over the full service life of the bridges. These investigations cost time and resources but the engineering profession has a duty to ensure they are carried out.

1150 MANAGEMENT OF M4 ELEVATED SECTION SUBSTRUCTURES

CR Hendy & CT Brock, Atkins & ADJ Nicholls, Connect Plus (M25) Ltd Epsom, S El-Belbol, Highways AgencyUK

The M4 Elevated Section in West London is a 1.9 km concrete viaduct structure providing a major arterial route into London. An intervention model bringing together structural assessment and forecast deterioration, corrosion modelling and cracking has been developed to prioritise structural rehabilitation of the substructure crosshead beams. To evaluate residual strength an initial assessment of crossheads was undertaken, which identified a deficiency in tensile capacity at the ends of the crosshead cantilevers compared to current demands. Further assessment has been undertaken, including three dimensional strut and tie, non-linear finite element analysis and plastic analysis, to confirm public safety with continued trafficking of the structure, and to determine the need for strengthening.Additionally extensive monitoring of the crossheads has been implemented including mapping of all cracks, and remote crack monitoring to safeguard the substructures and allow early interventions. The long term maintenance strategy brings together strengthening and cathodic protection concrete preservation methods with removal and repair of concrete delamination.This paper discusses the development of the prioritisation process including deterioration modelling, together with the extended structural analysis to formulate a strengthening programme for these substructures.

1218 FLEXIARCH’ – A VERSATILE & SUSTAINABLE BRIDGE SYSTEM

Prof AE Long, Dr S Nanukuttan, Queen's Univ Belfast, A Gupta & D Courtenay, Macrete Ireland, Toomebridge, UK

Concrete bridges built during the 1960s/1970s were largely based on precast girders with an in situ deck slab, as these bridges could be installed rapidly. However, many have deteriorated as a result of corrosion of reinforcement and have had to be replaced. The resulting traffic congestion has cost £ billions. A range of approaches have been adopted to counter thedeterioration caused by the ingress of chlorides including increased cover, surface coatings, cathodic protection but with limited success. One solution is to avoid the use of corrodible reinforcement for elements exposed to aggressive environments.In this context it has been found that highly sustainable bridges can be developed from the arch concept. Conventional arch bridges have the benefit of being aesthetic, strong and durable as steel reinforcement is not necessary. However, cost and time to prepare the centring and accurate voussoirs render them non competitive against precast girder and slab systems. Apatented system, which uses precast concrete voussoirs and does not require centring, has overcome these problems and over 40 ‘FlexiArches’ have been constructed in the UK/Ireland. These can be installed rapidly, days rather than months, are cost competitive and have all the attributes of masonry arches. They have been extensively tested at full scale, used for shortspan bridges and for the rehabilitation/strengthening of deteriorated bridges. Comparative studies have demonstrated that they are significantly more sustainable than alternative systems.

Bridge Management

1200 3R’S APPROACH TO BRIDGE MANAGEMENT: RETAIN, REPAIR & REPLACE

D Dunne, AECOM, P McKenna, D Barnett & A White, CH2M HILL, Glasgow & Worcester, UK

Deterioration of reinforced concrete structures, such as bridges, is over time a normal and to a certain degree an expected process. When these processes become abnormally advanced before a structures design life is attained, this poses

challenges both economically and technically. As a result, the condition of such structures and the cause of any deterioration must be accurately determined by visual assessment, monitoring and testing, for safety and operational requirements are to be achieved. Ombersley Bridge carries the A449 over the A4133 approximately 6 miles north of Worcester in the UK. The bridge was originally constructed in 1974. A regular inspection programme established that the bridge abutments were cracking and that the bridge was moving. This paper, from a consultant’s perspective, outlines aspects of the investigation and subsequent retention, repair and replacement intervention works. Findings of the experimental investigations are presented. Thereafter, overviews of the works which were undertaken are discussed. The paper ends with conclusions taken after the works concluded.

1175 BALANCING EXTENDED SERVICE LIFE AND SUSTAINABLE CONCRETE MATERIAL USAGE IN MISSOURI BRIDGE A7957

E.S. Hernandez, A. Griffin and Prof J.J. Myers, Missouri Univ of Science & Technology, Rolla MO, USA

Because of its unique nature, self-consolidating concrete (SCC) has the potential to significantly reduce costs associated with transportation-related infrastructure, benefiting both MoDOT and the residents of Missouri. SCC is a highly flowable, non-segregating concrete that can be placed without any mechanical consolidation, and thus has the following advantages over conventional concrete:

decreased labor and equipment costs during concrete placement, decreased potential for and costs to repair honeycombing and voids, increased production rates of precast and cast-in-place (CIP) elements, and improved finish and appearance of cast and free concrete surfaces.

In addition to SCC, innovative materials such as High Volume Fly Ash Concrete (HVFAC) also provide a significant potential to produce more cost effective mix designs for CIP concrete. Since the 1930’s, fly ash – a pozzolanic material – has been used as a partial replacement of portland cement in concrete to improve the material’s strength and durability, while also limiting the amount of early heat generation. From an environmental perspective, replacing cement with fly ash reduces concrete’s overall carbon footprint and diverts an industrial by-product from the solid waste stream (currently, about 40 percent of fly ash is reclaimed for beneficial reuse and 60 percent is disposed of in landfills). The objective of this research is to provide an implementation test bed and showcase for the use of sustainable and extended service life concrete. In this implementation study for Missouri Bridge A7957, a level of 50% fly ash to cement proportions was utilized as well as SCC and high-strength self-consolidating concrete (HS-SCC) in the load carrying elements to showcase the use of these innovative materials.

1350 OPTIMIZING A BRIDGE RESPONSE MODIFICATION APPARATUS

A Schultz, Univ of Minnesota, Minneapolis, A Gastineau, KPFF Engineers, Seattle & SF Wojtkiewicz, Clarkson Univ, Potsdam, NY, USA

Given the plurality of bridges in the United States that are classified as deficient and in need of replacement or repair, methodologies to help avoid the substantial costs of replacing these bridges simultaneously are important. This paper presents a synthesis of work conducted to develop a structural response modification approach employing a mechanical amplifier and supplemental stiffener and damper to extend the fatigue life of existing steel bridge structures. The optimal cross-sectional area for apparatus members and response modification device stiffness and damping characteristics for these apparatuses are investigated to reduce local stresses as a means to increase bridge life. A reduced order numerical model of an existing finite element bridge model is developed for the purpose of optimizing the apparatus. The study indicates that for

the apparatus employing the mechanical amplifier, small dampers are optimal for maximal safe life extension. The study also suggests that improvements in performance can be obtained from the apparatus using semi-active control.

Longspan Bridges

1305

ANALYSIS & FATIGUE TESTING OF FULL SIZE BRIDGE HANGER CONNECTION TO DEVELOP INSTRUMENTATION SYSTEM & DETECTION CRITERIA FOR IN SERVICE MONITORING

P Plemic & R E Lindenberg, Wiss, Janney, Elstner Associates Inc, Northbrook, IL, USA

To address the complex in-service behavior of a bridge platform welded hanger connection, modeling and laboratory studies were conducted to develop an instrumentation plan for monitoring and detecting of crack initiation and propagation. The purpose of the work was to understand the anticipated test behavior and to robustly measure the accelerated 400,000 lbf (1700kN) cyclic fatigue test to failure.

The primary objective of the laboratory testing was to develop the detection criteria, to demonstrate the effectiveness of Acoustic Emission (AE) sensors for potential crack detection and to optimize the number of required sensors and AE system for the detection and monitoring of the crack growth. The secondary objective of the experimental testing was to estimate the fatigue resistance life cycle of the fillet weld between the hanger connection and kicker gusset plate. Testing was conducted on four samples, two simple plate connections models and two full-scale hanger connection using Universal Test Machine with a 400,000 lbf (1700kN) capacity equipped with a controller that allows cyclic or fatigue testing of samples. During testing a visual examination as well as Magnetic Particle Testing of the test specimen was conducted. At the conclusion of the cycling, Ultrasonic Testing was performed on each test specimen. The testing was performed at the structural laboratory of the Jack R. Janney Technical Center at Wiss, Janney, Elstner Associates, Inc. (WJE) in Northbrook, Illinois

Prior to testing a finite element analysis (FEA) was performed to identify high stress locations for each test sample, and to allow for visualization and animation of the sample response to the applied loads.

1342 REVIEW OF "ADA BRIDGE" LOAD TEST PROJECT D Kovacevic, V Radonjanin, M Malešev & D Lađinović, Univ of Novi Sad, & S Ranković, Univ of Niš, Serbia

This is brief presentation of "Ada Bridge" load test project. Things that stand out this project are scale, status and importance of the structure. In this sense, this load testing is, if not the biggest, probably until now, the most complex structure testing in this (ex-YU) region. This fact emphasizes the amount and type of load used for testing, number and type of load configurations, number and type of performed measurements and assortment of used measuring equipment.

Load test of "Ada Bridge" was done according to our SRPS U.M1.046 regulation respecting the special demands set by investor, contractor and manager in corresponding parts of the technical documentation.

The goal of testing was to get experimental proof of bridge's capacity for taking and transferring design loads and actions, namely the proofs that bridge structure satisfies the criteria of bearing capacity, stability and serviceability.

1236 PRACTICAL STRUCTURAL MONITORING OF LONG-SPAN BRIDGES - THE STRAINSTALL 2014 UPDATE

J St Leger, S Babin, M Anderson, A Scullion, Strainstall Monitoring, Royston, UK

This paper considers the following from a practical perspective:

1. Bridge management - how appropriate structural health monitoring systems help the bridge owner.2. Current effective monitoring systems and how new sensor technology and future developments will help.3. The fast moving world of web based applications for the delivery of structure information – the changing picture.4. Derivation of meaningful and timely information from structural health monitoring systems to enable effective bridge management and informed decision making.5. An overview of state-of-the-art structural health monitoring systems for bridges.

1267 NEW TEST METHODS FOR STAY CABLE SYSTEMS AW Gutsch, M Laube, T Nolte, TU Braunschweig, Germany

In cable bridges the cables are subjected to different kind of loading scenarios during their lifetime. Before the installation of stay cables the systems have to proof their sustainability in tests. The different types of tests are mentioned in several national and international accepted recommendations [1 – 5]. Up to now the most common loading tests for stay cable systems are the axial fatigue loading test and subsequently a static loading test to determine the ultimate breaking load (UBL).Experience showed that bending effects due to installation tolerances of the anchorages and other sources of bending like sag, wind-rain induced vibration or flexural deformation of the bridge deck are fatigue relevant in practice, too. For the investigation of these effects in tests the anchorages are usually installed with a specific angle in the axial test set-up or recently specific bending fatigue tests were performed. Here different test set-ups for bending fatigue tests with constant axial forces and with synchronized axial dynamic forces will be shown.Saddles must be designed such as to ensure a safe transfer of vertical forces and of differential forces of stay cables from opposite sides of the pylon. The simulation of a saddle in a stay cable test results in a complex test set-up. Here a modified test set-up for a saddle test with fatigue load will be presented.Finally the test set-up for fire resistance tests for qualification test of stay cables with fire resistance characteristics will be shown here.

1213 ACCESS SOLUTIONS FOR SUSPENSION BRIDGE CABLE MAINTENANCE R Burgess & J Mawson, C Spencer Ltd, Hull, UK

Access provision to undertake construction and remedial works to structures is an increasingly demanding consideration for the execution of bridge projects worldwide. Both temporary and permanent access solutions provide engineers with opportunities to undertake projects in challenging locations whilst satisfying the concerns of multiple stakeholders, not least the bridge users. With many structures operating above capacity and subsequently demanding regular maintenance and enhancement, options to limit or mitigate disruption to the infrastructure whilst utilising cutting edge construction and maintenance techniques frequently demand extensive innovation in access provision alone, just to allow staff and equipment safe and adequate passage to the final work site.

Regardless of the structure type, age, usage and location, access provision to undertake construction, remedial, maintenance and enhancement projects is a constant consideration for Bridge Engineering globally. With ongoing changes to intended maintenance plans, design life and asset management technologies, few structures were designed and built with adequate access to facilitate the types of projects typically seen around the world today, as such facilitating access alone can occupy a disproportionate amount of the design and construction approach to any bridge project.

The paper will discuss current issues in today’s industry and how new-build bridge projects can be designed with future-proof access in mind, whilst of course considering the capital expenditure implications of such provisions. The paper will focus upon the project-specific requirements for some typical and specialist remedial & maintenance projects and why access alone frequently becomes the pinnacle consideration in today’s market. Finally the paper will consider variations in the working cultures and legislation of international markets and how this can impact upon the chosen access methodology for a given scheme.

1356 BRIDGE WINDSHIELD DESIGN TO AVOID AEROELASTIC PHENOMENA

M Ogueta-Gutierrez & S Franchini, Universidad Politecnica de Madrid, Spain

Since in 1940 the Tacoma Narrows Bridge was destroyed by the wind, aeroelastic instabilities have been recognized as one of the most challenging aspects of bridge design. They can produce long-term fatigue failure through vortex induced vibrations, or sudden collapse through self-excited flutter. These vibrations may also cause discomfort for the users and temporary closure of the bridge.Wind tunnel studies are a very helpful tool to understand these phenomena. By means of them, the critical wind speed at which vortex induced vibration and flutter appear can be precisely determined and the design of the bridge can be reconsidered in the early steps of the process.In this paper, an optimum design of the bridge section is sought. One of the most relevant parameters that influence the stability of a certain deck is the porosity of the barriers. Section model tests have been carried out to find whether an

optimum value of the porosity of the barrier exists. This value or range of values must present neither vortex induced vibration nor flutter.

Steel & Iron Bridges

1151 FATIGUE MANAGEMENT OF THE MIDLAND LINKS STEEL BOX GIRDER DECKS C Hendy, Atkins, Epsom & S Chakrabarti, Consultant UK,

The Midland Links Motorway Viaducts, carrying M5 and M6 around Birmingham, have been subject to a regular programme of assessment, repair and strengthening since 1989 after corrosion problems, primarily due to chloride contamination, were first detected in 1979. A number of the longer spans comprise multiple steel and concrete composite box girders and some of these superstructures are supported by steel box girder cross beams. Assessment showed areas of very high overstress in the web plate at the locations of internal bracings. These overstresses affected ultimate, serviceability and fatigue limit states and arose because of poor detailing of the cross braces and stiffeners.

The greatest concern was the fatigue stresses produced in the web at the end of the transverse stiffeners at the internal bracing locations. This was caused by the distortional stiffness of the bracing coupled with the termination of the transverse stiffener in the web. Acoustic emission sensors were installed to determine if the predicted fatigue activity was actually occurring and elastic shell finite element modelling was undertaken for an improved determination of stresses. Plastic redistribution was considered to demonstrate adequate ULS performance and an analysis was undertaken with potential fatigue damage modelled to prove the structure would not collapse with such damage at the ultimate limit state. In-situ strain monitoring was undertaken both under known test vehicle loading and under normal traffic conditions to derive more accurate fatigue stress spectra. These results were used not only to calibrate the finite element results but also to improve the predicted fatigue life and allow preparation of a long-term strategy for managing and monitoring fatigue activity using a damage tolerant approach.

1183 NEW REPAIR METHOD USING CFRP SHEET FOR CORRODED STRUCTURAL STEEL MEMBERS

D Wakabayashi, Nippon Expressway Research Inst., T Miyashita & M Nagai, Nagaoka Univ of Tech, Niigata, Y Okuyama, Nagano Nat College of Tech, N Koide, Kawasaki Heavy Industries Ltd, Y HIdekuma & A Kobayashi, Nippon Steel, W Horimoto, Kurabo Industries, Ltd, Japan

Loss of cross section owing to corrosion is a primary factor in the deterioration of steel bridges. Therefore, carbon fiber-reinforced plastic (CFRP) has attracted attention as a material for repairing and reinforcing steel bridges because of its light weight, high strength, and superior durability. Although many studies have been published relating to this topic, previous studies have primarily focused on the application of CFRP to axial or bending members. However, most of the corrosion is found on the webs or columns at the ends of the main girders. Few investigations have examined repairing corroded webs or columns using CFRP. In this research, a shear buckling test for steel girders and a uniaxial compression test for cruciform columns are conducted to develop a repair method for corroded steel girder ends using CFRP sheets. In this method, low elastic putty layers are inserted between steel and CFRP sheets to improve the performance of out-of-plane deformation.

1343STEEL BRIDGE RENEWAL TECHNICAL SOLUTION ASSESSMENT OF WELDED SUPERSTRUCTURE FATIGUE & STEEL GRADE SELECTION

G Lagoda, Warsaw Univ of Technology, M Lagoda & T Wierzbicki, Road & Bridge Research Inst. Warsaw, Poland

The paper treats on assessment of the Warsaw Grot Rowecki Bridge across Vistula river renovation design. The bridge after renovation is to carry both local and transit traffic. The main goal of the renovation is adopting the structure to carry five lanes each direction (two for the S type road and three for local traffic) with regard to the claimed loads and government law regulations. Moreover, the bridge will be used by the pedestrian and bicycle traffic.The steel investigation result analysis, including fatigue aspects, was necessary to assess the designed solution. The structural material ageing was taken under consideration, through the examination steel samples taken from the highest stress amplitudes deck area.

1345 DYNAMIC INTERACTION BETWEEN RAILS AND STRUCTURE IN A COMPOSITE BRIDGE OF 120 M LENGTH C Jurado Cabanes, Politecina de Madrid, Spain

The new steel composite bridge over Verdugo river for the line of high-speed trains in Galicia (Spain) is has been placed between the localities of Arcade and Pontesampaio. The total length of the viaduct is 120.00 m with a central pillar arranged in the middle of the river, dividing the total length of the bridge in two spans with 60.00 m each one.

The structure consists of a composite deck with two metallic main trusses of 1.80 m of height, on both sides of the platform. The composite slab deck has metallic transverse girders of 0.90 m of height arranged every 5.0 m, where are disposed the pre-slabs, that support the pouring concrete of the deck. The foundation has 6 reinforced concrete piles of 1.75 m of diameter and 21 m of length under the central pillar and 9 of 22 m of length under each abutment.The project velocity of the line is 200 km/h. Under the rails and over the deck there is ballast and according with the owner, it was needed to study, if it was necessary to dispose expansion devices for the rails.

A 3D finite element model with 7265 nodes, 6569 elements type FRAME and 2003 elements type SHELL has been made, which comprises all the elements of the structure: deck, trusses, girders, central pillar, abutments, mat foundations and concrete piles.According with the European and Spanish Regulations it is needed to make an extensive model in order to verify three aspects: Maximum tensions in rails. Maximum displacements. Maximum rotations at the ends of spans.

The paper presents all the aspects of the study, compare the different Rules and finally exposes the conclusions.

1287 REPAIR OF DISTORTION INDUCED FATIGUE DAMAGE IN STEEL GIRDERS USING COMPOSITE MATERIALS

SH Bun, E Bonet, A Matamoros, C Bennnett, RB Gonzalez, ST Rolfe, Univ of Kansas, Lawrence, KS, USA

This paper is focused on the development of modular shallow trapezoidal boxes fabricated from cold-bent structural steel plate using standard mill plate widths and thicknesses. This concept was developed by a technical working group within the Steel Market Development Institute’s (a business unit of the American Iron and Steel Institute) Short Span Steel Bridge Alliance (SSSBA), led by the current authors. This working group consists of all stakeholders in the steel bridge industry, including mills, fabricators, service centers, industry trade organizations, universities, and bridge owners. The goal was to develop innovative and economical modular solutions for the short-span steel bridge market. The proposed system meets the needs of current industry trends of accelerated bridge construction, while offering an economical solution. This paper will provide an overview of experimental testing currently being conducted and further parametric analysis and design studies focused on assessing behavior and ultimate capacity of the proposed system.

1291SKEWED STEEL BRIDGES: EFFECTS OF CROSS-FRAME LAYOUT ON FLANGE LATERAL BENDINGS STRESSES DURING CONSTRUCTION

J Zhou, C Bennett, A Matamoros & ST Rolfe, Univ of Kansas, Lawrence, KS, USA

Lateral flange bending stresses can arise from a number of sources, such as wind loading or eccentric concrete placement, but of particular interest are lateral flange bending stresses, fl, that occur due to skew. Lateral flange bending stresses that occur in skewed bridge systems tend to develop due to lateral forces transferred through cross-frames which may connect adjacent girders at different span points. In lieu of a refined analysis, the AASHTO-LRFD Bridge Design Specifications currently permit engineers examining bridges skewed more than 20° to use a minimum value of fl = 10 ksi for an interior girder and fl = 7.5 ksi for an exterior girder. The estimates for fl provided within the AASHTO-LRFD Bridge Design Specifications are based on a limited data set for skewed bridges. Additionally, since the AASHTO-LRFD Design Specifications state that cross-frames or diaphragms should be placed in a staggered configuration when a bridge is skewed more than 20°, the approximate values provided for fl should not be expected to be indicative of the lateral flange bending stresses experienced when cross-frames are instead carried parallel to the skew in bridges skewed beyond 20°. Carrying cross-frames and diaphragms parallel to the skew angle in bridges skewed more than 20° is a practice implemented by some state DOTs, and is primarily done to minimize problems with cross-frame fit-up during erection.

The authors have performed a study to investigate the effects of cross-frame orientation and skew angle upon lateral flange bending stresses, by examining lateral flange bending stresses in a suite of detailed 3D, solid finite element analyses of skewed bridge systems, in which cross-frame layout, spacing, and skew angle were varied. Skewed bridge systems with cross-frames placed parallel to the skew angle as well as systems with cross-frames arranged in a staggered configuration were considered. The models included both material and geometric nonlinearities to assess the lateral flange bending stresses in the different bridge systems.

The findings of this study showed that cross-frames placed parallel to the angle of skew produced significantly lower values for fl than cases in which cross-frames were placed perpendicular to the girder line and staggered. Both reducing the skew angle and decreasing cross-frame spacing were found to reduce lateral flange bending stresses. The values of lateral flange bending stress for all configurations were greater than the bounds of the approximate values suggested by AASHTO. Moreover, the minimum values for fl provided in the AASHTO-LRFD Bridge Design Specifications were found to be significantly lower than the results obtained from this study.

1314 VIBRATION-BASED FE MODELING AND STRUCTURAL ANALYSIS OF THE PADERNO IRON ARCH BRIDGE (1889) Dr C Gentile & Dr A Saisi, Politecnico di Milano, Italy

The San Michele bridge (1889), one of the most important monuments of XIX century iron heritage, has been studied by Politecnico di Milano since 2009. The first part of the investigation, aimed at the assessing the state of preservation of the historic infrastructure, included preliminary dynamic tests in operational conditions as well as the design and installation (late November 2011) of a continuous dynamic monitoring system in the bridge. More recently, a FE model of the bridge was implemented, and accurate visual inspection and local survey of the corrosion state on the bridge members began, in order to obtain a dynamics-validated model including also the information on the actual local state of preservation of the main structural members of the bridge. After a brief description of the first part of the investigation, the paper describes the FE model, the correlation between the actual dynamic characteristics of the infrastructure and the model prediction, and the results of the numerical calculations carried out to evaluate the effects of present loading conditions.

1341A PROPOSAL TO INCREASE WELD PENETRATION TO IMPROVE THE FATIGUE STRENGTH OF RIB-TO-DECK WELDED JOINTS IN ORTHOTROPIC STEEL BRIDGE DECKS

V Dung Cao & E Sasaki, Tokyo Inst of Technology, Tokyo, & K Tajima & T Suzuki, Hiroshima, Japan

For rib-to-deck welded joints in orthotropic steel bridge decks, a partial joint penetration with 75% and 80% penetration ratios is required by specifications in Japan and USA, respectively. The effectiveness of the proposed 100% penetration on enhancing the fatigue strength of rib-to-deck welded joints was evaluated by both fatigue tests and finite element analysis using the effective notch stress method. Four full-scale orthotropic deck specimens were subject to laboratory fatigue testing. Each specimen consists of a 12-mm-thick deck plate and one closed 6-mm-thick rib. The rib-to-deck joints of the specimens were fabricated with 75% and 100 % weld penetration ratios. Fatigue test results show that fatigue cracks initiated from the weld toe inside the rib in the 100% penetration specimens, but from weld root inside the rib in the 75% penetration specimens. To investigate this fatigue behavior, strain measurements were taken at 5 mm from the rib-to-deck weld line during the fatigue tests. Results of the finite element analysis indicate that a deeper partial penetration results in a slightly higher effective notch stress at the weld root of the partial penetration weld. The effective notch stress at the crack initiation location with 100% penetration is lower than that obtained with partial penetration. The open angle appears to have a significant effect on the effective notch stress at the upper weld toe inside the rib of the specimens with 100% penetration. An open angle of 1350 at the upper weld toe is a possible recommendation to further improve the proposed weld configuration. The proposed 100% penetration may enhance the fatigue strength of rib-to-deck welded joints.

1299 RESEARCH ON THE NEW CFRP PRESTRESSING SYSTEM FOR METAL BRIDGE STRENGTHENING

TW Siwowski & P Pasko, Rzeszow Univ of Technology, Poland

The use of CFRP prestressed strips in strengthening work has gone through a big development during the past 20 years. It has been revealed that the bending strength and stiffness of steel beams can be considerably enhanced with this technique. The main problem of strengthening with prestressed strips has been the anchor zones. Without mechanical anchorages there have been peeling failures at the ends. Therefore the still development in CFRP strips anchorage systems has been recently observed. The paper briefly describes the research on the new prestressing system for CFRP strips with special steel anchorages. The initial testing has revealed that the concept might be used for strengthening. The steel anchors developed in

the frame of the project ensure to sustain the prestressing force up to 70% of the ultimate tensile strength of CFRP strips. The first on-site application of the new system for a composite steel – concrete bridge strengthening is shortly described as well. The presented case study has revealed the effectives of the new prestressing system, which seems to be reliable for steel bridge applications.

NDT of Bridges

1261 IMAGE-BASED INSPECTION SYSTEM FOR ROUTINE VISUAL INSPECTIONS OF UK HIGHWAYS BRIDGES,

S McRobbie & A Wright, TRL, Wokingham, M Burrow, Univ of Birmingham, UK

Concrete overlays of concrete bridge decks are common practice for many transportation authorities and are expected to increase the service life of the underlying concrete deck on the order of 20 years. Nonetheless, many authorities do not permit the overlay to be accounted for in the structural load rating of the repaired deck. This effectively restricts overlays to being relatively thin thereby limiting the utility of overlays as a tool for maintaining a sustainable bridge infrastructure. The authors challenge the assertion that overlays must remain non-structural. The objective of this work is to provide laboratory-based experimental verification and assessment of the performance of reinforced concrete bridge deck slabs rehabilitated by means of hydrodemolition (HD) followed by the application of a latex modified concrete (LMC) overlay. The fundamental objective is to determine whether the overlay may be considered composite with the residual deck and under what conditions composite behaviour may be assumed in eventual load rating of the rehabilitated deck.

Tests of ten full-scale laboratory specimens and four decommissioned bridge slabs (having marked existing damage) are presented. The principal parameter investigated is the depth of HD and subsequent LMC overlay. Depths ranging from 7% to 50% of the original slab depth are considered and, in all but the thinnest cases, the overlay does not increase the overall depth of the slab (an important consideration on existing bridges that must be compatible with existing roadway elevations). Results are considered in terms of overall slab performance including cracking, moment-curvature response and, importantly, behaviour and performance of the LMC-concrete interface. In all cases, LMC-repaired slabs demonstrated analytically-predictable behaviour marginally superior to control monolithic slabs. The results clearly demonstrate that not only is composite action between the overlay and residual slab established and maintained, the interface, when constructed correctly, does not affect slab behaviour.

1196 ANALYSIS OF REINFORCED CONCRETE STRUCTURES USING STIFFNESS ADAPTATION

GMA Schreppers, TNO DIANA BV, Delft, A de Boer, Utrecht, The Netherlands, & D Begg, Univ of Portsmouth

Many bridges in the Netherlands have been built during the 1970’s and as such were not designed for today’s traffic. As a consequence the Dutch Ministry of Infrastructure and the Environment has initiated a program in which existing bridges are inspected and re-examined and in selected cases the load-capacity is assessed by performing numerical analyses. One such bridge is the Heteren Viaduct. The concrete structure is a 17-span double-box girder Rhine Bridge with a length of 974 meters and width of 16.85 meters. During inspection of this viaduct shear cracks were observed in the webs. This bridge has subsequently been analysed using a newly developed “Stiffness Adaptation” method in the DIANA Finite Element program. The method allows the calculation of crack patterns, crack widths and onset of reinforcement yielding. A new and efficient modelling and analysis strategy has also been developed for the assessment. In this strategy a 3D solid model is generated, based on a CAD-model of the bridge. Automatic mesh generating procedures are used so that all details can be modelled in a reasonable time. This paper shows a new approach for both designing and re-assessment of structures using a 3D finite

element analysis to perform non-linear analysis using the Stiffness Adaptation method. It can be seen this can be used for very detailed models while significantly reducing run times with improved confidence in the results therefrom.

1152EVALUATION OF QUASI-STATIC TEMPERATURE EFFECTS ON THE CLEDDAU BRIDGE FROM CONTINUOUS MONITORING

R Kromanis, P Kripakaran, Univ of Exeter, W Harvey, Bill Harvey Assoc, Exeter, UK

Many bridges in the Netherlands have been built during the 1970’s and as such were not designed for today’s traffic. As a consequence the Dutch Ministry of Infrastructure and the Environment has initiated a program in which existing bridges are inspected and re-examined and in selected cases the load-capacity is assessed by performing numerical analyses. One such bridge is the Heteren Viaduct. The concrete structure is a 17-span double-box girder Rhine Bridge with a length of 974 meters and width of 16.85 meters. During inspection of this viaduct shear cracks were observed in the webs. This bridge has subsequently been analysed using a newly developed “Stiffness Adaptation” method in the DIANA Finite Element program. The method allows the calculation of crack patterns, crack widths and onset of reinforcement yielding. A new and efficient modelling and analysis strategy has also been developed for the assessment. In this strategy a 3D solid model is generated, based on a CAD-model of the bridge. Automatic mesh generating procedures are used so that all details can be modelled in a reasonable time. This paper shows a new approach for both designing and re-assessment of structures using a 3D finite element analysis to perform non-linear analysis using the Stiffness Adaptation method. It can be seen this can be used for very detailed models while significantly reducing run times with improved confidence in the results therefrom.

1272DEVELOPMENT OF BRIDGE INSPECTION TECHNOLOGY WITH SUPER HIGH RESOLUTION DIGITAL IMAGE AND IMAGE PROCESSING TECHNOLOGY FOR CRACK DETECTION

T Yamamoto, Y Maeda, Y Fukunaga, T Matsui & M Ohara, West Nippon Expressway Co. Ltd, Osaka, Japan

The importance of inspections is getting increased in maintenance of concrete structures of expressways, as the amount of aged structures is increased. In order to increase accuracy and reliability of general structure condition assessments, we, NEXCO-West, one of the operators of expressways in Japan, developed an innovative inspection method using super high resolution digital image and image processing technology to obtain qualitative data of cracks on concrete surface, location, width and length. With this method, we can acquire a super high resolution digital image for each span of bridges, and detect cracks. The data are provided to engineers for their subsequent structural diagnosis and rehabilitation planning. A historical record of cracks for use in monitoring crack propagation over time can also be acquired. It is expected that with this technology, the reliability of inspection is increased and the decision making of owners becomes more effective. This paper reports the outline, status and perspectives of development of the technology.

1177APPLICATION OF ACOUSTIC EMISSION MEASUREMENTS IN THE EVALUATION OF PRESTRESSED CAST IN-BETWEEN DECKS

P van Hemert, SAAM Fennis, DA Hordijk, TU Delft, The Netherlands

A large number of concrete structures, that is built in the sixties and seventies of the twentieth century, need to be re-evaluated. It should be judged whether their capacity is still sufficient for the increased traffic loads. Acoustic emission (AE) is a non-destructive technique that can possibly be used to get a better insight in the structural state of these concrete structures. However, interpretation the AE measurements is challenging and is even more difficult when the concrete is cracked by for example alkali–silica reaction. Due to the existing cracks the wave attenuation affects the acoustic emission measurements. For an investigation into the capacity of pre-stressed cast in-between decks a 1:2 scale bridge was loaded in

the Stevin laboratory of Delft University of Technology under two-way shear. In this preliminary research it was investigated whether AE-measurements can be used to get an idea about the structural condition of a structure, or more precise, to what extent the ultimate capacity is reached. For testing the concrete in-between decks a cyclic loading procedure is applied. It appeared that cyclic loading resulted in a lower capacity in comparison with the previously performed static loading experiments. There was no AE indication of early failure due to cyclic loading. Usually applied parameters, like ‘Kaiser Effect’ and ‘Calm Ratio’ are investigated. Furthermore, it was investigated whether the location of cracks could be determined by the emitted sound during the fracture process and applying a relatively large numbers of AE-sensors (so-called source location). In this article the performed AE measurements are reported and results discussed.

1227IMPACT ELASTIC-WAVE METHODS FOR DETECTION OF GROUTING CONDITION IN POST-TENSIONING TENDON DUCTS OF PC MEMBERS USING ADAPTIVE NOISE CANCELLER

S Hattori, T Kamada, Osaka Univ, S Uchida, Ritsumeikan Univ, Japan

Recently, non-destructive testing methods of pre-stressed concrete (PC) structure with post-tensioning steel are considered to be highly important, because the corrosion of steel components, such as steel bars or steel strands, finally, will possibly cause degradation of a whole bridge. Though the grouting of duct inside sheaths prevents corrosion, it was reported that serious corrosion actually happened in many PC bridges in service. Thus, precise and quantitative non-destructive evaluation methods are highly required for effective repair or strengthening work of them.Feasibility of impact-elastic wave method using adaptive noise canceller has been investigated for this purpose. In this method, simultaneous multi-point responses activated by a single-shot impact is used. Generally, surface wave propagates dominantly on the surface of concrete and prevents receiving the reflection between concrete surface and ducts. For receiving the signal of grouting condition, transfer functions between the measured points are processed and tuned adaptively to cancel the surface wave. Consequently, each of extracted waves reflected from the ducts is piled and accumulated to form grouting condition visibly. Evaluation of this method was carried out by three reinforced concrete specimens where both grouting portion and non-grouting portion were artificially set in tendon ducts.

1359 BRIDGE WEIGH IN MOTION WEB AXLE DETECTOR E Salem, Al-Azhar University, Cairo, Egypt

As a result of the collapse of a composite steel bridge on a major highway in Egypt, an investigation was launched to determine the main cause of the collapse. Prior to this investigation, there was no available data about traffic volume and truck gross weights. From early investigation, it was argued that the main cause of the collapse was a result of illegal heavy trucks. Others argued that the bridge collapsed as a result of fatigue. To determine which argument is closer to reality, it was decided to develop a new system for Bridge Weigh-In-Motion (BWIM), for the first time in Egypt. With the hope that the information gathered from this study, on an existing bridge on the same highway at which the bridge collapsed, could help in determining the main cause of the collapse.

To develop the new system for BWIM, a preliminary finite element analysis was performed to provide guidance for instrumentation plan. For axle detection, it is important to select a location which has the largest sensitivity to axle presence. Four concentrated loads were applied to the bridge model and the analysis was performed for this simple case of loading. Searching through all straining actions developed in the steel girder as a result of this simple case of loading, it was clear that as the axle load is transferred from the deck slab to the steel girder, vertical axial stresses in the girder web are developed. Another case of loading was applied to the finite element model: two concentrated loads near support representing a vehicle axle. As it is expected, the maximum shear stress occurs at the

composite section center of gravity. In this method, instead of measuring the shear strain, the diagonal tensile strain, oriented 45o from the pure shear plane, is measured. The conclusion from the preliminary finite element analysis is to instrument the web at midway between transverse stiffeners by placing the strain gauges oriented vertically near the top flange at a distance equals 15% of the web height. With regard to vehicle axle load and detection, the web is instrumented with a strain gauge oriented 45o at the composite section center of gravity near the bridge support. From this study, a new system for BWIM emerged. It is called Bridge-Weigh-In-Motion Web Axle Detector (BWIM-WAD). All the information required are gathered through instrumenting the girder web at two different locations along the girder span. This new system is simple, yet accurate, and provides all necessary information; axle load and spacing, vehicle speed and gross weight.

Concrete Bridge Investigation & Repair

1340EMERGENCY FOUNDATION REPAIRS TO THE LEO FRIGO MEMORIAL BRIDGE: QA/QC CHALLENGES AND SOLUTIONS

B Hertlein, GEI Consultants Inc, Libertyville, IL, J Dohlby, URS Corp, Milwaukee, WI & T Buchholz, Wisconsin DoT, Green Bay, WI, USA

The Leo Frigo Memorial Bridge carries Interstate Highway 43 over the Fox River near its mouth into Lake Michigan’s Green Bay, just north of the city of the same name, in Wisconsin, USA. Construction started in 1977, and the bridge opened to traffic in 1980. On September 25, 2013, motorists reported to authorities that a section of the bridge appeared to have sunk a foot or more. Immediate investigation revealed that a pier within a 400-foot long portion of the bridge had indeed settled more than 2 feet, and the bridge was immediately closed to traffic.The bridge is a critical link in both a major urban arterial route for the city of Green Bay, and the Midwest interstate highway network, so the economic consequences of closure were significant to both the city of Green Bay, and the States of Wisconsin and Michigan. The Wisconsin Department of Transportation responded with an emergency assessment and repair plan that involved the construction of a total of 20 drilled shafts adjacent to the original foundations of the five piers in the affected part of the bridge, with a very tight construction schedule that required work shifts around the clock. Adverse ground, access and weather conditions along with 24-hour shifts created a highly challenging environment in which to construct the new foundations, and the QA/QC program for the new foundations was a critical component in meeting the accelerated construction schedule.The outcome of the project was that the bridge was reopened to traffic 102 days after it was closed. This paper focuses on the challenges met and overcome by both the foundation contractor and by the testing team that was tasked with verifying the quality of the new foundations under such challenging conditions, and recommending repairs for the surprisingly few construction issues that were uncovered by the QC program.

1277 SEISMIC VULNERABILITY OF BRIDGES OF ITALIAN MOTORWAY NETWORKS

G Pasqualato, C Bafaro, Sineco S.p.A., Milan, P Crespi, Politecnico di Milano, N Giordano, N Longarini, M Zucca, CIS-E Consortium, Milan, Italy

In recent years, Italian technical-scientific community has increased its interest on the evaluation of the seismic vulnerability of existing structures. Among this wide range of structures, motorway viaducts stand out for their strategic relevance and technical complexity. Most of these structures were built between ’60 and ’70 years, according to design procedures which ignored nowadays knowledge in seismic engineering.Thus, the necessity to evaluate the real strength capacity of these structures with modern analysis techniques has become essential, leading to the determination of their safety level in case of an earthquake. For the assessment of several bridges of

a motorway network, a multi-modal pushover analysis approach has been considered. This analysis technique allows considering the nonlinear behaviour and the complex dynamic response of such a structures without exceeding in high computational costs.Some basic rules were defined (constitutive laws of materials, finite element type, plastic hinge models, etc.) for the modelling of viaducts in a commercial FEM software, in order to guarantee homogeneous comparable results among the large number of bridges of a network. Furthermore, a specific software routine was implemented. This routine starts from the pushover results of a FEM commercial software and executes the modal combinations and the safety verifications, reducing the time cost and the possibility of errors, following in the evaluation of the seismic vulnerability indexes.These risk indexes are then reported in seismic vulnerability forms collected by the Italian Hazard Management Agency (Italian Civil Protection) for risk management purposes.

1285EXPERIMENTAL EVALUATION OF AS-BUILT & RETROFITTED TWO-COLUMN BRIDGE BENTS UNDER VEHICULAR COLLISION FORCE AT THE BENT COLUMN

N Wehbe, South Dakota State Univ, Brookings, SD, B Tigges, Raker Rhodes Engineering, Des Moines, IA USA

Current AASHTO-LRFD Bridge Design Specifications require a bridge column to be designed for a collision load of 600 kips (2680 kN) applied laterally at 5 ft (1525 mm) above ground. This requirement is set to prevent bridge collapse under the extreme event of a semi tractor-trailer collision with the bridge column. The majority of overpass bridges on the interstate system and other major highways in the United States were designed and constructed prior to the development of the collision load design requirements. In non-seismic regions where the lateral seismic loads on bridge columns are negligible, and in the absence of other significant lateral load requirements such as ice or collision loads on bridge piers, bridge columns were designed for low lateral load demands that did not govern the design of the columns. Therefore, the confinement/shear reinforcement in such columns was kept to the minimum transverse steel requirements specified in the prevailing codes at the time. In the case of a heavy truck collision incident, columns that lack sufficient shear strength and ductility capacity due to inadequate transverse reinforcement would be vulnerable to catastrophic failure and may consequently lead to bridge collapse. A companion study on collision hazard risk analysis in South Dakota identified a two-column bridge bent type to be economically critical and vulnerable to collapse. This paper presents an experimental evaluation of the structural performance of the vulnerable two-column bridge bent type when subjected to the AASHTO’s collision load. Two one-third scale bridge bents were tested in the laboratory. One specimen represented the vulnerable prototype bent. The other specimen was retrofitted with a “crash strut” that the State of Minnesota is implementing to prevent bridge collapse under collision loads. In this paper, the test results are analyzed and the effectiveness of the crash strut is evaluated.

1328 REPAIR & STRUCTURAL STRENGTHENING OF OVERHEAD R.C. BRIDGES FOR PETROLEUM PRODUCTS CONDUITS

Prof A Shilin & Dr D Kartuzov, ZAO “Triada-Holding”, Moscow, Russia

A new approach is analyzed to repair of overhead bridges for petroleum products conduits, reinforced concrete structures of which are subject to negative impact from leakages. The approach combines refurbishment of structural damage and subsequent strengthening of the repaired structures with CFRP products.The core element of the strengthening system is a high-adhesion polymer cement matrix which, on one hand, protects structural reinforcement from further corrosion and, on the other hand, provides strong bond between composite products and structural concrete.The repair was done without interruption of petroleum conduit functioning. As a result, structural service life was extended

substantially.

1365 INSPECTION AND CONDITION EVALUATION OF GREEK OLD CONCRETE RIVER ROAD

I Papayianni, E Anastasiou & M Papachristoforou, Aristotle Univ of Thessaloniki, P Panetsos, Egnatia Odos S.A, Thermi, Greece

A great number of river bridges in Greece were constructed after the Second World War. Nowadays, their age exceeds 40 years and they are still in operation. The Laboratory of Building Materials at the Aristotle University of Thessaloniki in cooperation with Department of Bridge Maintenance of Egnatia Odos S.A. and relevant sectors of the local Prefecture has undertaken a survey of concrete members of the bridge structural system. This survey includes:- A systematic visual observation of concrete members.- The production or update of the geometry of the bridge structure “as designed”.- The pathology maps concerning cracks, spalling/swelling, efflorescence pop-outs, calcium leaching, surface water abrasion and locations of reinforcement exposition and corrosion.- The identification of the actual mechanical characteristics of the bridge (elastic modulus of elasticity etc), based on the evaluation of site material and laboratory tests and on other inspection findings that are used to reconstruct the analytical static model of the bridge. Non-destructive methods and drilled cores have been used for this puprpose.- The determination of porosity, PH, carbonation depth of concrete, as well as chloride and other salt content. Microstructural observation with stereoscopic methods was also used to complete or help with the recognition of the deterioration mechanism.The results from three surveyed bridges are presented and commented. The topography of damage and the mechanisms of corrosion or any other concrete deterioration have been recognized. In addition, comparing our results with those of the archives of Egnatia Odos S.A., it seems that there are some areas in bridges which are more prone to damage. These areas could be protected more in order to prolong the service life of concrete bridges. Technical faults associated with the drainage system cause failures and premature corrosion repeatedly. Although most of the concrete bridges are near the sea (at a distance of 1 km) the concrete does not show relatively high content of chlorides, while carbonation depth is generally low. Taking into account the results and remarks from the survey, the repair of bridges (materials and techniques) is expected to be more effective.

1278 EVALUATION OF STRUCTURAL BEHAVIOR OF CORROSION DAMAGED REINFORCEMENT CONCRETE BRIDGES J Nepal & H P Chen, Univ of Greenwich, Chatham, UK

Corrosion of reinforcement is one of the major causes of deterioration of reinforced concrete (RC) structures exposed to aggressive environments, such as highway bridges. The serviceability and durability of the RC bridges are often challenged by reinforcement corrosion. As a result, they cannot serve for the full service life as they are designed for. The increasing number of aging and deteriorating RC bridges has caused great loss in infrastructure management industry. Therefore deterioration of the corrosion affected RC bridges is of greater challenge both technically and economically. The damage caused by corrosion occurs in the form of cracking, eventual spalling of concrete cover and reduction in cross-section of reinforcement bars. If the corrosion continues it affects the bond mechanism between the reinforcement and concrete which consequently influences the overall behaviour of the structures in terms of both ultimate and serviceability limit states. Assessment of structural behaviour of corrosion damaged RC bridges is essential to estimate the residual capacity of the structure which ultimately aids in making decisions for reliable and cost effective infrastructure management. Conventional

design methods do not provide procedures to predict the structural behaviour of corrosion damaged RC structures. This paper investigates the different types of defects caused by reinforcement corrosion and its impact on the structural behaviour of these corrosion damaged RC structures.

1325 REDUCING THE RISK OF POTENTIAL FAILURES OF HIGHWAY STRUCTURES

Dr D Pearson-Kirk, M S Lever & I S Motyl, Mouchel Limited, Exeter, UK

Despite the use of design procedures and construction practices that have been developed over many years, the failure and unexpectedly early deterioration of structures has become a matter of considerable concern in many countries. One effect of this problem is that significant expenditure has to be diverted from capital works to the management of existing structures.

The paper contains a review of the performance of structures and the benefits of inspections of higher risk structures being accompanied by targeted testing. A phased approach is described that enables higher risk structures to be identified and prioritised for investigation. Investigations need to be carried out by well-qualified dedicated technical staff, with results being interpreted by experienced engineers. The condition of structures can then be accurately assessed, the extent, severity and causes of any deterioration determined, and any appropriate management actions identified with confidence.

Case studies from Europe and the United States are presented that cover the identification of higher risk structures, determining the causes, extent and severity of defects, avoiding mis-diagnoses and determining appropriate courses of action. Subsequent changes may then be made to design standards, specifications, construction procedures and to the training of staff that will assist in maintaining the best value of the assets.

Certain of the ideology currently used in the management of structures needs to be changed in order to avoid failures and unexpectedly early deterioration of structures in the future. Design and maintenance engineers need to be educated as to the benefits of condition monitoring in the identification of causes of deterioration, together with an improved understanding of the assessment and control of deterioration.

Cathodic Protection

1283 CATHODIC PROTECTION OF CONCRETE BRIDGES, KJ Bennett, Freyssinet Limited, Telford, UK

It is well known that steel corrodes and, when embedded in concrete, this expansive reaction cracks the concrete and forces the cover concrete to spall away. Stopping this process is more complex than chipping back the loose concrete and replacing it. Whilst this may fix the direct area of repair it does nothing to improve the situation in adjacent parts of the structure and may even make matters worse. This paper will look at the basic electro-chemical corrosion mechanism with steel embedded in concrete and examine the impressed current cathodic protection systems which have been implemented on three recent contracts to arrest further rusting.

1202 HYBRID ELECTROCHEMICAL TREATMENT OF PASTON INTERCHANGE BRIDGES, UK

A Higson, D Dudeney, M Burrows, Balvac, Sutton Weaver, N Davison, S Holmes, M Davison CP-Tech, Nottingham, UK

Chloride induced corrosion on bridge structures is well documented. Common options to deal with the corrosion attack are to repair spalled concrete and/or utilise electrochemical treatments. Paston interchange comprises two over-bridges that carry the A47 over the A15 in Peterborough: both of which have suffered extensive concrete damage from chloride induced corrosion. This paper details the installation of a hybrid electrochemical treatment system to offer long term protection to the two bridges. The hybrid treatment system utilises a discrete anode in an initial short term impressed current re-passivation phase, then a galvanic phase to offer long term protection. The design of the hybrid system, installation procedure and monitoring data obtained following installation are detailed.

NDT & Repair of Bridge Decks

1367 EXPERIENCE WITH EVALUATING BRIDGE DECK DETERIORATION WITH GROUND PENETRATING RADAR

A P Annan & J D Redman, Sensors & Software, Mississauga, ON, Canada

Ground penetrating radar (GPR) has been promoted as an effective means for assessing the state of concrete deterioration in bridge decks for several decades. The method has met with mixed success and is still not adopted widely. Constant development is making high speed GPR mapping more affordable and systems more widely available and easier to deploy. For the many years, we have developed highway speed ground coupled GPR surveying platforms with one of the main applications being rapid examination of bridge decks. American Society for Testing and Materials (ASTM) standards proscribe a procedure that should be followed. The standard was written primarily for air launched GPR measurements and then modified to ground coupled GPR. Our experience indicates the much higher resolution ground coupled enable more exact analysis incorporating both velocity and attenuation properties. Further, the proscribed process ignores the impact of depth and other variables in the analysis which advanced practitioners know are major limitations.

Using both the high speed ground coupled GPR system as well as small scale surveys using cart mounted and handheld GPR’s, we have extensively tested ground coupled measurements and evolved processing to provide cost effective deck deterioration mapping. In this paper, we will describe the work flow we have evolved and demonstrate successful application of the methodology.

1368USING 3D GPR, LASER SCANNER AND HIGH PRECISION THERMAL CAMERA TECHNIQUES IN CONCRETE BRIDGE DECK CONDITION SURVEYS

A Leppala, T Saarenketo, P Varin & P Maijala, Roadscanners Oy, Tampere, Finland

Ground penetrating radar (GPR) has been promoted as an effective means for assessing the state of concrete deterioration in bridge decks for several decades. The method has met with mixed success and is still not adopted widely. Constant development is making high speed GPR mapping more affordable and systems more widely available and easier to deploy.

For the many years, we have developed highway speed ground coupled GPR surveying platforms with one of the main applications being rapid examination of bridge decks. American Society for Testing and Materials (ASTM) standards proscribe a procedure that should be followed. The standard was written primarily for air launched GPR measurements and then modified to ground coupled GPR. Our experience indicates the much higher resolution ground coupled enable more exact analysis incorporating both velocity and attenuation properties. Further, the proscribed process ignores the impact of

depth and other variables in the analysis which advanced practitioners know are major limitations.

Using both the high speed ground coupled GPR system as well as small scale surveys using cart mounted and handheld GPR’s, we have extensively tested ground coupled measurements and evolved processing to provide cost effective deck deterioration mapping. In this paper, we will describe the work flow we have evolved and demonstrate successful application of the methodology.

1138STRUCTURAL EVALUATION OF SLAB REHABILITATION BY METHOD OF HYDRODEMOLITION AND LATEX MODIFIED OVERLAY

MJ McCabe, Beaudette Consulting Engineers, Missoula, MT KA Harries & M Sweriduk, Univ of Pittsburgh PA, USA

Concrete overlays of concrete bridge decks are common practice for many transportation authorities and are expected to increase the service life of the underlying concrete deck on the order of 20 years. Nonetheless, many authorities do not permit the overlay to be accounted for in the structural load rating of the repaired deck. This effectively restricts overlays to being relatively thin thereby limiting the utility of overlays as a tool for maintaining a sustainable bridge infrastructure. The authors challenge the assertion that overlays must remain non-structural. The objective of this work is to provide laboratory-based experimental verification and assessment of the performance of reinforced concrete bridge deck slabs rehabilitated by means of hydrodemolition (HD) followed by the application of a latex modified concrete (LMC) overlay. The fundamental objective is to determine whether the overlay may be considered composite with the residual deck and under what conditions composite behaviour may be assumed in eventual load rating of the rehabilitated deck.

Tests of ten full-scale laboratory specimens and four decommissioned bridge slabs (having marked existing damage) are presented. The principal parameter investigated is the depth of HD and subsequent LMC overlay. Depths ranging from 7% to 50% of the original slab depth are considered and, in all but the thinnest cases, the overlay does not increase the overall depth of the slab (an important consideration on existing bridges that must be compatible with existing roadway elevations). Results are considered in terms of overall slab performance including cracking, moment-curvature response and, importantly, behaviour and performance of the LMC-concrete interface. In all cases, LMC-repaired slabs demonstrated analytically-predictable behaviour marginally superior to control monolithic slabs. The results clearly demonstrate that not only is composite action between the overlay and residual slab established and maintained, the interface, when constructed correctly, does not affect slab behaviour.

1274 GPR ANALYSIS OF BRIDGEDECK CONSTRUCTION AND THE DETECTION OF DELAMINATION

E Carrick Utsi & V Utsi, Utsi Electronics Ltd, Cambridge, A Birtwisle, Atlas Geophysical Ltd, Rugby, UK

Ground Penetrating Radar (GPR) is a commonly used investigation technique for examining the structure and potential structural faults in bridgedecks. In order to detect delamination at an early stage, it is useful to deploy a very high frequency GPR. Although this limits the depth of penetration, since the upper asphaltic layers tend to be thin, the finer target resolution is very useful.

Simulations and the practical results of commercial GPR surveys are used to illustrate the detection of delamination within the first 200mm of surface using a 4GHz antenna. Potential problems such as the limitations of frequency and the use of materials unsuited to GPR are briefly discussed.

It can be useful to carry out this type of survey at speed although this requires the antenna to be lifted off the bridgedeck surface. In theory horn antennas are more efficient than other types of antenna for this mode of operation as they should not require ground coupling. The effect of increasing antenna height above the surface is described and illustrated with reference to a 4GHz horn antenna used to detect the position and depth of bridgedeck reinforcement. The conclusions reached are that good ground coupling is essential for optimum detection unless a very high frequency horn antenna is used; that it is important to select the right frequency for the task; and that very high frequency antennas are useful for examining delamination in the wearing course, allowing such surveys to be completed at traffic speeds.

1168REPAIR AND MAINTENANCE OF DELAMINATED REINFORCED CONCRETE DECKS CAUSED BY DEICING SALTS IN HOKURIKU EXPRESSWAY IN JAPAN

Y Ishikawa & N Arima, Central Nippon Highway Engineering, Ishikawa, Kanazawa, M Nagai & E Iwasaki, Nagaoka Univ of Technology, M Moriyama, Central Nippon Expressway, Ishikawa, Japan E Iwasaki,

The use of deicing salt has dramatically increased in the Hokuriku expressway in Japan because of the studded tires banned in 1990. The use of deicing salt is able to keep the safety condition of icy road. However, as an opposite result, the highway structures will be significantly damaged by salt attack. Especially, reinforced concrete bridge decks and bridge girder ends have been damaged by deicing salt. In this paper, the field investigations are carried out at 5 cases of the delaminated reinforced concrete bridge deck in the Hokuriku Expressway. In order to evaluate the condition of reinforced concrete bridge decks, the various non-destructive examinations, hereinafter NDE, are used in the field. NDE are able to detect the delaminated areas in slight condition. In addition, we propose the evaluation of reinforced concrete bridge decks at the top with NDE and at the bottom surface with visual survey is proposed. However, that investigation results aren’t always accurate. Thus, it becomes necessary to cover the inaccuracy of NDE results. In order to cover NDE inaccuracies, we develop a fast accelerate set concrete named as FACET. FACET is concrete mixed directly with chemical powder in a mixer truck. FACET is a low cost concrete which has a flexible supply system that can cover shortage of NDE results. In addition, we carried out feasibility study on FACET in a total area of about 1,000m2. In result, it becomes possible to evaluate the condition and implement comprehensive repairing works for the reinforced concrete decks in the Hokuriku Expressway.

1313 BRIDGE REHABILITATION AND STRENGTHENING WITH CONCRETE OVERLAYS

Jakob Kunz & Camiel de Smet, Hilti Corp, Liechtenstein + Norbert Randl, Hilti Development, D-86916 Kaufering, Germany

The placing of concrete overlays has gained in importance as a result of the more frequent need to strengthen existing structures. In order to obtain monolithic structures, the shear transfer between the concrete layers must be guaranteed. The state of the art connecting procedures and design method are briefly introduced. From an analysis of the load-bearing behaviour of the interface, optimization criteria concerning the static behaviour of connectors are derived. Numerical models which allow to simulate a splitting test and a shear test have been set up and calibrated. By simulating various connector geometries in the splitting test, an optimized shape could be defined. Simulation of the shear test confirmed the improved behaviour of the new shape compared to traditional connectors. An analysis of the placing procedures has shown that the

new shape also offers a clear advantage in terms of time required for setting the elements.

1275 EUROPEAN GPR ASSOCIATION: ITS PRESENT & FUTURE ROLES IN ENGINEERING, E Carrick Utsi, Utsi Electronics Ltd, Cambridge, UK

The European GPR Association (EuroGPR) grew up originally from the UK based Impulse Radar Users Association (IRUA). The change of name and extension across the continent resulted when it became evident that a licensing framework for the use of a transmitting technology would be required not only within the UK but also across Europe.The initial focus of the organisation on licensing issues has resulted in a workable frame of reference for all of the major GPR manufacturers, EN302 066 01 and the adoption of the Association’s own Code of Practice as an European Telecommunications Standards Institute official document.Standards and guidelines for all types of GPR survey including utility detection and engineering investigations are becoming of increasing concern both to GPR surveyors and to the engineers who employ them. The Association has contributed to the issue of the Survey Association guidelines, the formation of the Utility Mapping Association, and the drawing up of PAS128, due to be issued in Spring 2014. It also issues its own guidance on the use of GPR.Even for those not based within Europe, the Association welcomes collaboration, technical input and continues to hold its members accountable for their expertise.

FRP Bridge Strengthening

1326 LONG-TERM DURABILITY ASSESSMENT OF PRESTRESSED CONCRETE GIRDERS WITH FRP SHELL,

M Shafqat Ali, M Saeed Mirza & L Lessard, McGill Univ, Montreal, Canada

This paper presents the results of a preliminary study on design of FRP-reinforced bridge girders for durability over a long service life, when subjected to an aggressive environment. This system of three materials - FRP composites, concrete and prestressing steel, have their individual durability problems and the associated deterioration mechanisms, which can range from superficial surface problems to disintegration of the FRPs, concrete and prestressing steel within the member. The FRP composite shell, acting as a barrier, showed significant resistance against chloride ingress by significantly slowing down the chlorides ingress rate and the total amount of chloride ions. Based on Fick’s second law of diffusion, the predicted profiles for a prestressed concrete girder without FRP shell showed that chloride ingress from the exterior surface can reach the prestressing steel strands within a period of about 45 years. For a prestressed concrete girder with an FRP composite shell, the accumulated time for chloride ions reaching the level of prestressing steel strands was predicted to more than 135 years. These results suggest that the FRP shell can be quite effective in improving the durability characteristics of prestressed concrete girders and can significantly extend their service life.

1303TESTS OF CRACKED, R.C. BEAMS STRENGTHENED WITH NEAR-SURFACE-MOUNTED FIBER-REINFORCED POLYMER STRIPS

EA. Bertolotti, Hartzell Engine Technologies, Montgomery, AL, R Barnes, WB Childs & AK Schindler, Auburn Univ, AL, USA

A standard State of Alabama (USA) reinforced concrete highway bridge type has been judged to have deficient negative-moment capacity under current loading standards. A near-surface-mounted fiber-reinforced polymer (NSM FRP)

strengthening system was proposed to repair the deficiency. A survey of relevant literature regarding the intermediate-crack (IC) debonding of NSM FRP revealed only tests with reinforcement ratios and concrete compressive strengths greater than those present in the deficient bridge; furthermore, few previous tests involved flexural specimens that were cracked prior to strengthening. To generate experimental data for direct correlation with this standard bridge type, a series of laboratory tests was conducted to study the performance of the proposed NSM system.Eight specimens were designed to represent realistic ranges of (a) existing steel reinforcement and (b) newly installed NSM FRP. In order to mimic actual bridge conditions, the specimens were fabricated with 50 ksi [340 MPa] steel reinforcement and 3000 psi [20 MPa] concrete, pre-cracked, and then repaired with NSM FRP strips. Flexural tests included service-load cycles, followed by monotonic loading until failure. A nonlinear, layer-by-layer flexural analytical model—to account for strain hardening in the steel, and the cracked nature of the specimens during repair—was developed to compute expected performance data for comparison to the experimental results. Results were also compared to the strength predictions resulting from the limiting design values recommended by ACI 440 (2008), Standards Australia (2008), and others.Analysis of the data obtained from both the service-load cycles and the monotonic loading showed no evidence of bond degradation; examination of the specimens after failure and all experimental results indicated functional bond until achievement of ultimate strength. The capacities predicted according to the evaluated design methods proved conservative. The viability of the recommended design was confirmed.

1269SHEAR STRENGTHENING OF PRESTRESSED CONCRETE BEAMS UNDER CYCLIC LOADING WITH TEXTILE REINFORCED CONCRETE,

M Herbrand & J Hegger, RWTH Aachen Univ, Germany

A large part of the existing highway bridges in Germany exhibits calculative shear capacity deficits under static and cyclic loading. More structures are expected to demand refurbishment and strengthening within the next years, especially due to the current conditions of many older road bridges in Europe. Since a reconstruction of the respective bridges is not reasonable or financially feasible in many cases, the assessment and development of effective strengthening methods becomes more important.Many strengthening methods have proven to be suitable for the shear strengthening of bridges, e.g. additional external prestressing, additional concrete layers, additional steel reinforcement in slots or glued CFRP-stripes (Carbon Fibre Reinforced Polymer). However, the applicability and effectiveness of these methods are also influenced by some disadvantages. Besides these common strengthening methods, the use of textile reinforced concrete (TRC) offers an innovative alternative for strengthening measures by combining the advantages of lightweight glued CFRP-stripes and additional concrete layers, which possess better bond characteristics and lower temperature sensitivity. As the textile reinforcement does not require protection against corrosion, thin layers of reinforcement are possible.For the above reasons, two full scale tests on I-shaped prestressed concrete beams (h = 0,7 m, l = 6,5 m) under cyclic shear loading were carried out at the Institute of Structural Concrete at RWTH Aachen University. Previous tests on identical non-strengthened beams served as a reference for the tests on members strengthened with textile reinforced concrete. The paper presents the test results with regard to the effectiveness, advantages and possible fields of application of this innovative strengthening method.

1322 RETROFITTING OF BRIDGES FOR SEISMIC VULNERABILITY REDUCTION

SP Stefanidou, Aristotle Univ of Thessaloniki, Greece & Prof AJ Kappos, City University, London, UK

The key objective of this paper is to quantify the effect of retrofitting a bridge using different retrofit techniques in terms of probabilistic seismic vulnerability curves (fragility curves). To this purpose, an analytical, component-based methodology is developed. The capacity of different bridge components (piers, bearings, abutments), retrofitted using alternative techniques, i.e. reinforced concrete (R/C) and fibre-reinforced polymer (FRP) jackets, and replacement of old bearings with high-damping ones, is analytically estimated, using global engineering demand parameters; hence threshold values are defined for different limit states. A key point is the correlation of global engineering demand parameters (displacement, drift) to local ones (curvature, material strain), taking into consideration different failure modes of the bridge components. The effect of the degree of retrofitting on the performance of bridge components (piers having various geometric properties) is evaluated and closed-form correlation equations are derived for the piers, based on a parametric investigation; aleatory and epistemic uncertainties are quantified using a reduced sampling technique (LHS). Fragility curves are generated for a retrofitted bridge (case study), using a probabilistic seismic demand model based on the results of inelastic dynamic response history analysis for appropriately selected earthquake ground motions, and combining the individual component fragility (series or parallel connection). The results can be further expressed in terms of cost-related parameters and be used to identify the optimum retrofit solution.

Post-Tensioned Concrete Bridges

1279 CABLE IMPREGNATION FOR POST-TENSION GROUTING PROBLEMS

D Whitmore, D Simpson & H Liao, Vector Corrosion Technologies, Winnipeg, Canada, I Lasa, Florida DoT, Gainsville FL, USA

Thousands of bridge structures utilize grouted high-strength post-tension strands. Problems with grouting techniques and grout materials has resulted in bridges with deficient grout including voids, chloride contaminated grout and soft grout. These problems have promoted corrosion and failure of post-tension tendons, some within 6 to 17 years of service. The Florida Department of Transportation (FDOT) has spent more than $55 million (USD) repairing 11 post-tension bridges to date. A cost-effective corrosion mitigation technique has been developed to minimize the corrosion of post-tension bridges which have grouting issues. This paper describes the development and implementation of this technique including application to grouted tendons of the Ringling Bridge (Sarasota, FL) and the I-95 / I-295 Interchange in Jacksonville, FL.

1266INVESTIGATIONS OF P-T BRIDGES WITH CRITICAL PRESTRESSING STEEL REGARDING HYDROGEN-INDUCED CRACKING (HIC),

A W Gutsch & M Walther,TU Braunschweig, Germany

In Germany there are about 120,000 road bridges. Due to consistent increase of traffic loads in the last decade, the bearing capacity of about 2,000 of them has to be carefully checked. In this group, several of the bridges were built between 1960 and 1978. During this period the new construction type of prestressing steel was used in many bridges. Already in the construction phase the first damages on the prestressing steel occurred. Only a few hours after finishing the tensioning of the tendons, single wires failed without advance notice, still before the ducts had been injected with grouting mortar. In other cases wire breakage was detected several years after completion and designated use.The analyses of several cases of damage revealed that the wires and strands had collapsed due to hydrogen-induced stress corrosion cracking (HIC). After a closer look to the observations, single manufactures and batches could be named. Today the

prestressing steel used in those days is classified into two groups: the old type of potentially critical prestressing steel produced between 1960 and 1965 and the new type of potentially critical prestressing steel produced between 1965 and 1978. Wires for prestressing steel were mostly produced with an oval, or less often also with a round, cross-section, of 30 mm2 to 40 mm2 surface area. The critical prestressing categories are generally classified to the strength class St 145/160 (new classification St 1420/1570) [1, 2].

1195EFFECT OF FREQUENCY RANGE ON SIBIE FOR IDENTIFYING PARALLEL ARRAY OF PRE-STRESSING DUCTS

M Kira & M Ohtsu, Kumamoto Univ, Y Masahiko & T Tokumitsu, Fuji P.S Co., Ltd, Tokyo, Japan

In Germany there are about 120,000 road bridges. Due to consistent increase of traffic loads in the last decade, the bearing capacity of about 2,000 of them has to be carefully checked. In this group, several of the bridges were built between 1960 and 1978. During this period the new construction type of prestressing steel was used in many bridges. Already in the construction phase the first damages on the prestressing steel occurred. Only a few hours after finishing the tensioning of the tendons, single wires failed without advance notice, still before the ducts had been injected with grouting mortar. In other cases wire breakage was detected several years after completion and designated use.The analyses of several cases of damage revealed that the wires and strands had collapsed due to hydrogen-induced stress corrosion cracking (HIC). After a closer look to the observations, single manufactures and batches could be named. Today the prestressing steel used in those days is classified into two groups: the old type of potentially critical prestressing steel produced between 1960 and 1965 and the new type of potentially critical prestressing steel produced between 1965 and 1978. Wires for prestressing steel were mostly produced with an oval, or less often also with a round, cross-section, of 30 mm2 to 40 mm2 surface area. The critical prestressing categories are generally classified to the strength class St 145/160 (new classification St 1420/1570) [1, 2].

1268DIFFERENT WAYS TO INVESTIGATE AND TO REPAIR THE DAMAGES OF A POST-TENSIONED DECK OF A HIGHWAY BRIDGE AFTER A FIRE INCIDENT DUE TO A TRAFFIC ACCIDENT

Dr AW Gutsch, TU Braunschweig, Germany

Due to a traffic accident on a highway a truck started to burn just under a post-tensioned reinforced concrete bridge. The rapid development of the fire caused significant damages like concrete spallings of the concrete cover at the underside of the bridge deck. The question was whether the degree of damages was so critical that a repair of the bridge deck was possible or not. In this report the systematic way to investigate the bridge and to classify the damages after the fire incident will be presented. New methods were used to estimate the temperature exposure of the pre-stressing steel during the fire. Only by these methods the decision to repair the bridge was possible. Finally the applied repair concept with different steps, methods and materials will be shown.

Joint Details & Bearings

1149 PERFORMANCE OF PRECAST CONCRETE BEARINGS ON STEEL STRINGERS FOR AN ELEVATED LIGHT RAIL

J Pearson & R Lindberg, Wiss, Janney, Elstner Associates, Inc., Northbrook, IL, E La Guardia, Michael Baker Corporation, Philadelphia PA, USA

Reconstruction of the Frankford elevated light rail line, originally constructed beginning in 1915, was completed in 1997. As part of the reconstruction, removal of portions of the existing structure and installation of new structural elements was

performed. The original foundation, steel columns and cross girders remained while the deck and its support substructure were replaced. The new rail deck consisted mainly of precast concrete panels. Those portions of the precast concrete deck panels, which bear on and are attached to the supporting structural steel stringers, are referred to as haunches. The intent of certain haunch connection details was to allow the concrete deck panels to be free to move or slip when loaded. In 1998, Southeastern Philadelphia Transit Authority (SEPTA) identified several haunch locations where concrete spalled at the bearings. By 2007, it was found that the number of distressed haunches had grown to over 5,000. An investigation was performed to review existing haunch conditions, investigate the precast concrete haunch distress, identify the cause of distress and recommend repairs. This work consisted of a document review of previous studies, field investigation and testing, laboratory testing, haunch distress inspection, and repair prototype constructability and testing. The investigation, testing, and analysis of data were performed to determine the extent and cause(s) of haunch distress, and determine options for repairing delaminated and spalled haunch concrete. This paper will describe the observed behavior of the haunch connections in the field and the lab in order to understand the causes for the precast concrete spalling. The haunch reinforcement repair to resist the unintentional partial composite action is described.

1262 BEHAVIOUR OF ECC LINK SLABS FOR JOINT-FREE BRIDGE CONSTRUCTION K Hossain, Ryerson Univ, Toronto, ON, Canada

The expansion joints are a major source of deterioration of multi-span bridges in Canada and North America. Expansion joints can be replaced by flexible link slabs forming a joint-free bridge. The high strain capacity while maintaining low crack widths makes engineered cementitious composite (ECC) an ideal material for the link slab construction. The use of ECC link slab in joint free bridge construction isan emerging technology and very few research has been conducted to date on this novel form of construction. This paper presents the results of an experimental investigation on behaviour of volcanic ash based ECC (VAECC) link slabs under monotonic loading. The performance of VAECC link slab compared to its normal concrete (NC) counterpart is described based on load-deformation response, crack development, and stress-strain characteristics in reinforcement and concrete.

Composite Bridges

1254 USE OF INNOVATIVE “COMPOSITE DOWELS” IN PREFABRICATED COMPOSITE BRIDGES

J Gallwoszus, J Hegger, M Kopp, M Gundel & M Feldmann, RWTH Aachen, Germany

Composite dowels are known as powerful shear connectors in steel-concrete-composite girders. More and more they are used in practice especially for prefabricated composite bridges. Advantages over headed studs are in particular the increased strength, the sufficient deformation capacity even in high strength concrete and the simple application in steel sections without upper flange. However, missing provisions in standards for composite dowels with the economic clothoid and puzzle strip have led to retentions of clients and delays in the approval process. Hence, the aim of the recently finished German research project P804 (P804, 2014) founded by FOSTA- Research Association for Steel Application was to solve open questions concerning these innovative shear connectors and to prepare a general technical approval available for any design office and construction company. In this paper design concepts for ultimate limit state and fatigue limit state, structural design principles and instructions for production and construction are presented and background information are given.

1174 HYBRID COMPOSITE BEAM (HCB) BRIDGE IMPLEMENTATION & FIELD MONITORING,

MA Abeol Seoud & , JJ Myers, Missouri Univ of Science & Technology, Rolla MO, USA

This project involves the field evaluation of three Hybrid-Composite Girder Bridges in Missouri, USA. These hybrid composite beams (HCB)s are comprised of three main sub-components: a composite shell, compression reinforcement, and tension reinforcement. The shell is comprised of a fiber reinforced polymer (FRP) box beam. The compression reinforcement consists of self-consolidating concrete (SCC) which is pumped into a profiled conduit within the shell. The tension reinforcement consists of galvanized steel tendons anchored at the compression reinforcement ends. Due to the novelty of the HCB and its unclear behavior, an integrated study is under implementation to evaluate the recently constructed hybrid bridge superstructures. To achieve the goals of this study, a series of load tests was applied to the three bridges and the HCBs deflections were measured. HCB elements have been instrumented with various sensors and the induced strains were recorded at several stages and under the applied test loads. Finite element models (FEM)s were constructed via ANSYS and SAP2000 commercial softwares. Mathematical calculations were performed to predict the deflections and the strains using the existing design methodology. The study showed that the new HCB is a promising technique in the bridge applications. The HCB unique configuration optimizes its performance and leads to lightweight, cost-effective, and durable member. The existing design procedure is simple and suites the bridge designers. However, it needs some refinements. This paper presents briefly the work achieved to date and highlights the concluded remarks. The fabrication and construction sequencing of the HCB is also presented.

1264 A PEDESTRIAN BRIDGE MADE OF TEXTILE REINFORCED CONCRETE

S Rempel & J Hegger, RWTH Aachen Univ, C Kulas, Groz-Beckert KG, Solidian, Germany

The present paper exposes the project and construction of one of the most singular viaducts in Spain which crosses above the existing motorway M-31, with a very acute angle of 20º. Due to the obliquity of the crossing, the solution of the bridge has been made as a skewed bridge (“in pérgola”) with a length of 153 m.

Rail Bridge Investigation & Repair

1316 NEW BRIDGE “IN PÉRGOLA” FOR HIGH SPEED TRAINS TO THE NORTHWEST OF SPAIN

Dr C Jurado Cabanes, Polytechnic University of Madrid, Spain

The present paper exposes the project and construction of one of the most singular viaducts in Spain whichcrosses above the existing motorway M-31, with a very acute angle of 20º. Due to the obliquity of thecrossing, the solution of the bridge has been made as a skewed bridge (“in pérgola”) with a length of 153 m.

Masonry Arch Bridges & Bridge Scour

1251 MASONRY ARCH STRENGTHENING OF EDEN BRIDGE (LATHRISK)

P McKenna, D Dunne, CH2M HILL, Glasgow & Worcester, F Ratcliffe, Fife Council, Glenrothes, UK

Located by Lathrisk in Fife, Scotland, Eden Bridge is a two span masonry arch which dates from the 1800’s. The structure is frequently trafficked and is deemed a Grade B listed structure by Historic Scotland. As a consequence of its age, condition and humped back profile the northern span across the River Eden was subject due to the northern span to a weight restriction of 7.5 Tonnes Gross Vehicle Weight, following previous assessment.This paper will outline the steps taken to enhance the structural capacity by means of a simply supported reinforced concrete relieving slab in line with BA 16. This solution for the northern arch spanned between the north abutment and central pier

below springing level, thus relieving the existing arch of all applied loads. In addition to some minor works, an unreinforced slab was also laid over the southern dry (flood) span arch. Collectively these works facilitated an increase in the load carrying capacity to full HA loading and 30 Units of HB.The paper will also demonstrate that the stringent requirements of an historic structure can with due consideration and collective consultation be achieved, whilst remaining sympathetic to the aesthetics of the original structure and realising the goal of increasing the structures functionality.

1247 UPDATE OF MANUAL ON SCOUR AT BRIDGES & OTHER HYDRAULIC STRUCTURES

A Kitchen & S Dusting, JBA Consulting, Skipton, AM Kirby & J Chesterton, Mott MacDonald, M Roca & M Escarameia, HR Wallingford, P Charles, CIRIA, London, UK

Bridges over water can be at risk of failure due to scour and flooding. However, bridge owners and managers face conflicting demands between the need to ensure public safety and commercial pressures to keep bridges open to minimise disruption and avoid penalties.

Guidance on scour risk management is currently provided by the Manual on scour at bridges and other hydraulic structures (May et al, 2002). The Manual touches on risk management, with comprehensive advice on scour processes, scour assessment and the design and installation of scour countermeasures.

Recent bridge failures have highlighted the importance of the scour risk management cycle, from asset identification and scour assessment to mitigation, inspection and monitoring. Furthermore, recent research has improved our understanding of scour for the purposes of design, mitigation and maintenance. The Manual is therefore being updated with new guidance on scour risk management, including emergency planning, inspection, monitoring, debris management, revised equations for the prediction of scour and updated advice on scour countermeasures. The new Manual, due in 2014, will also provide lessons learnt with case studies such as Lower Ashenbottom viaduct (2004), River Crane, Malahide viaduct and Cumbria (all 2009) and a summary of methods for the assessment of hydrodynamic forces.