2016 PTI CONVENTION 18 40 years 1 9 7 6 - 2 O 1 6 ™ Technical Sessions Monday, April 25—Pike II & III Opening Session Session Moderator: eodore L. Neff, Executive Director, Post-Tensioning Institute 8:00 a.m. – 8:05 a.m. Session Introduction 8:05 a.m. – 8:30 a.m. Celebrating 40 years of Advancing the PT Industry Bob Sward, PTI President, VSL Over the past 40 years, PTI has filled a critical role in the development of new and innovative applications of post-tensioning. From slabs-on-ground to rock and soil anchors, segmental and cable supported bridges, containment structures, and buildings, all have benefited from the leadership provided by the Institute and its members. e Institute has provided guidance and recommendation to Owners, Engineers, Contractors, and Material Suppliers through the development and distribution of technical specifications, guides, and recommendations, and interacting with other Trade and Code writing organizations. To maintain its relevance, the Institute needs to have a clear vision and plan for the future. Over the past year, a select task group has worked to develop a strategic plan to propel the Institute into the coming years. e key elements of the plan will be presented during this session. 8:30 a.m. – 8:55 a.m. e High Cost of (a Lack of ) Education eodore L. Neff, Executive Director, Post-Tensioning Institute Having a trained and qualified work force is essential to the future success of the post- tensioning industry. However, designers, contractors, suppliers, and even associations are struggling to find competent people. Many experienced personnel have retired or will retire soon; combined with the cutbacks that many organizations had to make as a result of the recession, the result is high demand and low supply that has made it very competitive for the qualified workers that are available. is situation has been aggravated at the university level as well, where relatively few colleges currently teach post-tensioning. is presentation will examine some of the costs and impacts on the industry’s profitability, efficiency, safety, competitiveness, and image from not having a highly skilled work force, and will highlight PTI’s strategic efforts to counter these trends. 8:55 a.m. – 9:20 a.m. PTI Technical Committees: Reflecting on 40 Years as We Plan for the Future Don Kline, TAB Chair, Kline Engineering & Consulting, LLC is presentation will reflect on the achievements and advancements in the PT industry over the past 40 years through the lens of TAB and PTI technical committees. e author presents a case for building on this foundation to propel us forward as the international technical leader for PT.
Transcript
2016 PTI CONVENTION
18
40years
19
76 - 2
O1 6
™
Technical SessionsMonday, April 25—Pike II & III
Opening SessionSession Moderator: Theodore L. Neff, Executive Director, Post-Tensioning Institute
8:00 a.m. – 8:05 a.m. Session Introduction
8:05 a.m. – 8:30 a.m. Celebrating 40 years of Advancing the PT Industry Bob Sward, PTI President, VSL
Over the past 40 years, PTI has filled a critical role in the development of new and innovative applications of post-tensioning. From slabs-on-ground to rock and soil anchors, segmental and cable supported bridges, containment structures, and buildings, all have benefited from the leadership provided by the Institute and its members. The Institute has provided guidance and recommendation to Owners, Engineers, Contractors, and Material Suppliers through the development and distribution of technical specifications, guides, and recommendations, and interacting with other Trade and Code writing organizations. To maintain its relevance, the Institute needs to have a clear vision and plan for the future. Over the past year, a select task group has worked to develop a strategic plan to propel the Institute into the coming years. The key elements of the plan will be presented during this session.
8:30 a.m. – 8:55 a.m. The High Cost of (a Lack of) Education Theodore L. Neff, Executive Director, Post-Tensioning Institute
Having a trained and qualified work force is essential to the future success of the post-tensioning industry. However, designers, contractors, suppliers, and even associations are struggling to find competent people. Many experienced personnel have retired or will retire soon; combined with the cutbacks that many organizations had to make as a result of the recession, the result is high demand and low supply that has made it very competitive for the qualified workers that are available. This situation has been aggravated at the university level as well, where relatively few colleges currently teach post-tensioning.
This presentation will examine some of the costs and impacts on the industry’s profitability, efficiency, safety, competitiveness, and image from not having a highly skilled work force, and will highlight PTI’s strategic efforts to counter these trends.
8:55 a.m. – 9:20 a.m. PTI Technical Committees: Reflecting on 40 Years as We Plan for the Future
Don Kline, TAB Chair, Kline Engineering & Consulting, LLC
This presentation will reflect on the achievements and advancements in the PT industry over the past 40 years through the lens of TAB and PTI technical committees. The author presents a case for building on this foundation to propel us forward as the international technical leader for PT.
2016 PTI CONVENTION
19
40years
19
76 - 2
O1 6
™
9:20 a.m. – 9:45 a.m. PTI Certification Programs—A Reflection Larry Krauser, CAB Chair, General Technologies, Inc.
A reflection of the history of the PTI Certification Programs—how they started, how they have transitioned, and where they are going.
Session #2: PT Bridges ISession Moderator: Ken Black, VSL
10:15 a.m. – 10:20 a.m. Session Introduction
10:20 a.m. – 10:45 a.m. 32 Years of PTI’s Development of Recommendations for Cable-Stayed Bridges
David Goodyear, T.Y. Lin International
The East Huntington Bridge was one of the early U.S. projects with detailed stay cable specifications that focused on fatigue and performance testing. The detailed requirements were tailored for Hi-Am cables. The success of strand cables for Brotonne and the general interest of the Post-Tensioning Institute in the stay market were motivation for assembling what was (at the time) an ad-hoc committee to write the industry’s first comprehensive recommendations for stay cable design and supply. Beginning with the first edition, the presentation will chronicle the development of the PTI Recommendations over the years of efforts from the beginning committee meeting in 1984 to the present 6th Edition of the Recommendations.
10:45 a.m. – 11:10 a.m. FHWA DTFH611D00048 - Task 5009; Development of FHWA Guidance for Monitorable Replaceable and Assessable PT Tendons Trey Hamilton, PhD, University of Florida Antonio Ledesma, WSP Parsons Brinckerhoff Ian Hubbard, WSP Parsons Brinckerhoff
Many recent improvements have been made in the design, construction, and inspection practices of post-tensioned (PT) bridges in the United States. However, our industry should continue to develop new means and methods to advance the state of practice for PT bridges to improve quality and durability and to ensure they meet the intended service life. Tasks 2 and 3 of this research project focus on new technologies in the United States, such as EIT monitor-ing and replaceable external PT, and provides recommendations for implementation, standard details, and draft specifications. Task 4 includes an industry-critical assessment of the current construction, inspection, and testing practices and provides recommendations on areas for further improvement.
The research effort is ongoing and the presentation provides an update and current status.
Opening Session, cont.
2016 PTI CONVENTION
20
40years
19
76 - 2
O1 6
™
11:10 a.m. – 11:35 a.m. Experiences and Reflections on EIT Post-Tensioning Tommaso Ciccone, Tensa International
Increasing demand for long-lasting and highly protected PT tendons is now leading the way to further developments of electrically isolated tendons (EITs). The presentation goes through experiences and notes taken from a massive project completed with EIT tendons.
11:35 a.m. – 12:00 p.m. Current State of the Art in the Design and Construction of the Complex Interchange Projects Using Spliced Precast Girders
Gregg Reese, Summit Engineering Group, Inc.
The design of spliced precast girder bridges has expanded into complex medium- to long-span urban interchange projects. The development of this technology combines modern precast girder cross sections, post-tensioning, and spliced construction to extend span ranges while accommodating complex and curved alignments. Interchange projects constructed over the last 12 years using this design approach have proven to be an economical and constructible solution that has been successfully implemented on numerous projects in different parts of the United States. This paper will describe the development of the design processes and details and will describe the latest projects where this type of construction has been successfully used.
Session #3: Bridges II Session Moderator: Tommaso Ciccone, Tensacciai srl
1:30 p.m. – 1:35 p.m. Session Introduction
1:35 p.m. – 2:00 p.m. Sulfate Limits for Corrosion of Steel Strand in Deficient Grout Krishna Vigneshwaran Konda Krishnamurthy,
Florida International University
Despite all the major advantages of post-tensioning tendons, there have been severe corrosion problems in PT tendons in several Florida bridges. Significant portions of those tendons exhibited segregated grout that was often associated with severe corrosion of the strand that sometimes resulted in tendon failure. Those deficient grouts in the tendons showed low chloride content below commonly assumed threshold limits for corrosion initiation, but they showed higher concentrations of sulfate ions, high pore water pH, and high moisture content. Nationwide, there were cases where significant chloride contamination in similar prepackaged grout product and reported results from research indicated chloride threshold limits as low as 0.2%. However, the adverse role of deficient grout (including combined presence of sulfates) on chloride-induced corrosion had not been elucidated. To address the problems, different laboratory tests (including large-scale casting) were carried out. The casting was carried out with various adverse conditions including expired grout, 15% excess mix water, and with varying level of sulfates and chlorides. The role of pH (12.5 < pH < 13.3 pH) in solution was addressed. The objectives of the research were to verify the role of sulfates but also to quantify sulfate content and introduce possible sulfate limits for corrosion development in various grout conditions.
Session #2: PT Bridges I, cont.
2016 PTI CONVENTION
21
40years
19
76 - 2
O1 6
™
2:00 p.m. – 2:25 p.m. Effect of Exposure to Humidity and Temperature on the Fresh Properties of Cementitious Post-Tensioning Grout
Trey Hamilton, PhD, University of Florida
This paper summarizes ongoing research for the Florida Department of Transportation, which is focused on understanding the effect of environmental exposure on the performance of freshly mixed prepackaged post-tensioning grout and in particular on bleed or segregation, or both. Results will be presented of experimental work using a number of methods that measure the mass change of the portland cement powder after exposure to elevated heat and humid-ity. This testing was focused on understanding the effect of topochemical hydration of the portland cement that can occur under elevated humidity. It is believed that the chemical and physical changes caused by this “pre-hydration” results in adverse effects on the bleed and segrega-tion properties of the freshly mixed grouts, potentially leading to the formation of soft grout.
Session #3: Bridges II, cont.
2016 PTI CONVENTION
22
40years
19
76 - 2
O1 6
™
2:25 p.m. – 2:50 p.m. Project Updates on the St. Croix and Lesner Segmental Bridge Projects
Drew Micklus, Freyssinet, Inc.
Project Updates on the St. Croix and Lesner Segmental Bridge Projects. This presentation will introduce two significant bridges and explain their main features.
2:50 p.m. – 3:15 p.m. Gerald Desmond Replacement Bridge - Long Beach, CA Ken Black, VSL
The Gerald Desmond Bridge is a key link connecting the Port of Long Beach terminals to the surrounding area of Long Beach and the 710 Freeway. It is a busy route with approximately 15% of the nation’s containerized water cargo transported across the bridge. The existing steel arch bridge, which was built in 1968, has become unable to accommodate the much larger container ships underneath its span and the greater traffic across its deck. The clearance is being increased from the existing 155 ft to 205 ft with an elegant cable stay design. The main span will be 410 ft. In addition to the stay cables, the structure also uses post-tensioning. Besides the improved traffic flow, safer access, and accommodating of larger ships, the bridge will also feature a bicycle path with three scenic overlooks. The design-build contact was awarded to the joint venture team of Shimmick Construction Co. Inc., FCC Construction S.A. and Impregilo S.p.A. (SFI) in 2012. Structural Technologies LLC (VSL) is providing the stays. The bridge is currently under construction with completion expected in 2018. The presentation will cover the history of the bridge, current progress and schedule, construction methods and highlighting the post-tensioning and stay cable portions of the project.
Session #4: PT Buildings ISession Moderator: Thomas Kang, PhD, Seoul National University
3:45 p.m. – 3:50 p.m. Session Introduction
3:50 p.m. – 4:15 p.m. Post-Tensioned Concrete in U.S. Buildings Ken Bondy, Consultant
A 50-year overview of the use of post-tensioned concrete in U.S. building construction as seen through the eyes of the author.
Session #3: Bridges II, cont.
2016 PTI CONVENTION
23
40years
19
76 - 2
O1 6
™
4:15 p.m. – 4:40 p.m. Design, Modeling, and Monitoring Considerations for PT Building Structures
Thomas Kang, PhD, Seoul National University
In this presentation, recent advances in design, modeling, and monitoring considerations for PT building structures will be introduced. For architectural reasons, PT buildings often have an irregular and asymmetric plan layout of multiple vertical elements (columns and bearing walls) and two-way slabs. For such cases, modeling the right boundary condition and the right restraint effects is a challenging task and should be carefully considered. Three different modeling schemes are compared in terms of pre-compression, deflection, and applied concrete stress. During the construction of multi-story PT flat plate buildings, shoring and unshoring or reshoring procedures are complicated, and construction loads associated with cumulative shoring could be significant, particularly for the floor below which shoring is removed. Because improper construction procedures could make the service load design invalid and cause substantial cracking and long-term deflection, the construction sequence should be an important part of the design process and are considered in design. Finally, monitoring of long-term tendon stresses at various points along the length is something that has never been done before. Prof. Kang’s research team has been successfully monitoring the unbonded tendon stresses from an actual PT building structure in Korea and will share the research results with PTI Convention participants.
4:40 p.m. – 5:05 p.m. Key Aspects of 2-D and 3-D Finite Element Solutions for Serviceability and Strength Requirements of Post-Tensioned Beams and Slabs
Spencer Lee, ADAPT Corporation
The design of two-way unbonded or bonded post-tensioned two-way flat slab and flat plates, one-way slabs, and beams oftentimes relies on computer models and analysis for checking compliance of code-specific serviceability requirements and strength design. Two common software approaches are the use of a simplified two-dimensional (2-D) frame program employing the Equivalent Frame Method or an advanced three-dimensional (3-D) finite element program for continuum slabs with and without integrated beams.
The use of 3-D finite element software has gained wide acceptance and use, especially for two-way slabs of complex geometry and irregularity like podium or transfer slabs. However, the use of simplified 2-D frame software continues to be a popular and widely used method for more linear, repetitive geometric layouts like parking structures. There are clear advantages to the use of both methods for specific slab and beam configurations.
Key design drivers that are stipulated by design codes are often compared between both methods. These include precompression (P/A), balanced loading, tensile and compressive stresses, long-term deflections, secondary PT effects, flexural reinforcement for minimum and strength requirements, and punching shear. Differences exist in these key results between both methods of analysis as a result of underlying programmatic assumptions and methodol-ogy. While results of both methods may satisfy code requirements, understanding these key differences is critical to design confidence and adoption.
Session #4: PT Buildings I, cont.
2016 PTI CONVENTION
24
40years
19
76 - 2
O1 6
™
5:05 p.m. – 5:30 p.m. Design and Construction Issues in Post-Tensioned Mat Slab Foundations
Bryan Allred, Seneca Structural Engineering, Inc.
The presentation will cover several topics related to the successful design of the post-tensioned mat foundations. Post-tensioned detailing, use of available software, and engineering concepts will be addressed in addition to construction photographs, which will show what elements to “look out” for during structural observations.
Tuesday, April 26—Pike II & III
Session #5: PT Buildings II Session Moderator: Edgar Zuniga, Dywidag-Systems International USA, Inc.
Lateral force-resisting systems using well-designed ductile concrete walls offer inherent advantages for the seismic performance of buildings. The strength and stiffness of concrete walls naturally serve to reduce seismic movements to better protect the structure and building systems. While traditional seismic design’s emphasis on ductile yielding, transient movement, and energy dissipation is effective in protecting building occupants or preventing collapse, there is little regard to the effects of permanent deformations or post-earthquake functionality. A structural system that has the ability to recenter the building provides an added measure of resiliency that can protect and maintain the function of important building components such as cladding, elevators, and interiors.
Post-tensioned concrete walls, which combine unbonded high-strength steel tendons with conventional mild-steel reinforcement, offer the opportunity to meaningfully enhance the seismic resiliency of structural wall systems in a cost-effective and practical way. The defining feature of the post-tensioned cast-in-place wall system is its self-centering ten-dency, which can minimize or virtually eliminate permanent deformations following a major earthquake. In this combination, the tendons remain elastic to provide restoring force, while the reinforcement yields to dissipate seismic energy for controlled inelastic response. The post-tensioning provides increased flexural strength with reduced quantities of mild rein-forcement, resulting in more efficient design and improved constructability. The system has broad application for mid- and high-rise structures and can be adapted for retrofit and new construction.
The presentation will explain the concepts and principles underlying the design of the system and illustrate its application through case studies highlighting a number recent projects in the SF Bay Area.
Session #4: PT Buildings I, cont.
2016 PTI CONVENTION
25
40years
19
76 - 2
O1 6
™
8:30 a.m. – 8:55 a.m. Shear Nonsense: A Critique of the ACI Code Shear Design Procedure for Post-Tensioned Beams
Dirk Bondy, Seneca Structural Engineering, Inc.
This paper criticizes the ACI Code procedure for shear design in post-tensioned concrete beams, a procedure that has remained substantially unchanged for more than 50 years since it first appeared in ACI 318-63. The primary criticism is that the ACI 318 shear equations mismatch demand and capacity, consistently requiring more shear reinforcement away from the supports (like at quarter points) than they do at the supports where the shear is highest. That flies in the face of actual post-tensioned concrete beam behavior, and common sense. The current ACI 318 procedure also, in many typical cases, predicts concrete shear capacities Vc in prestressed beams that are substantially less than those in otherwise identical nonpre-stressed beams. Additional criticisms involve the definitions and use of the d and dp terms, and the procedure for minimum shear reinforcement. A new logical equation for shear design of post-tensioned beams is proposed that will greatly simplify shear design and remedy all the cited anomalies.
Session #5: PT Buildings II, cont.
2016 PTI CONVENTION
26
40years
19
76 - 2
O1 6
™
8:55 a.m. – 9:20 a.m. Advancing Anchorage Performance Technology Thomas Mathews, Precision-Hayes International
Research and development regarding the efficiency of anchorage assemblies has been accelerated in recent years to provide substantive value to the industry. These efforts continue to progress beyond dimensional considerations to other factors that contribute to optimized tendon performance. Decades of manufacturing, design, and testing experience specific to anchorage development have contributed to unique improvements that offer dependable, superior performance. This presentation provides some historical perspective and details significant advances.
9:20 a.m. – 9:45 a.m. Anchorage Zone Reinforcement: How Important and Whose Responsibility Is It?
Edgar Zuniga, DYWIDAG-Systems International USA, Inc.
The reinforcement in both the general and local anchorage zones is critical for the proper performance of a post-tensioning tendon anchorage. However, what these two zones are, how they interact with each other, what the main solicitations in each of them are, and who is responsible for their design is not always well understood. The ACI and AASHTO code requirements for unbonded and bonded post-tensioning anchorage zones are presented along with typical applications. Also, the differences between basic or normal versus special anchorage devices are discussed.
Session #6: PT Solutions Session Moderator: Don Illingworth, Don Illingworth & Associates, Inc.
10:15 a.m. – 10:20 a.m. Session Introduction
10:20 a.m. – 10:45 a.m. Slab-on-Ground Conversion to Suspended Foundation Don Illingworth, Don Illingworth & Associates, Inc.
The presentation will discuss the construction methods and engineering involved in converting a typical ribbed post-tensioned slab-on-ground to a pier-supported foundation.
The method is compliant with IBC and ACI and the appropriate section of the codes will be discussed. Tunneling under the foundation provides access to the interior of the foundation and steel push piles are driven to refusal to raise the foundation. The foundation is no longer in contact with the soil and future soil movement will not affect the foundation. This repair was done in Texas, where excessive deferential soil movement has caused problems and minor adjustments are not appropriate.
1000 Museum Place, Downtown Miami, FL - The new 1000 Museum Place will be a unique and innovative building located in downtown Miami near Museum Park. Designed by the famous architect Zaha Hadid, this 62-story work of art with its spiraling and flowing columns will prove to be one of the most beautiful structures in Miami. A unique post-tensioning layout was used to overcome the challenges presented by the building concrete exoskeleton.
Grove and Grand Bay, Coconut Grove, FL - Grove and Grand Bay Project consist of two unique twisting tower buildings designed by the Danish Architect Bjarke Ingels. To achieve the twists, inclined columns were incorporated into the design. A bonded post-tensioning roof frame was used to overcome the torsion forces generated by the tower’s inclined columns.
2016 PTI CONVENTION
28
40years
19
76 - 2
O1 6
™
11:10 a.m. – 11:35 a.m. Project Update on the Hebron Gravity-Based Structure Drew Micklus, Freyssinet, Inc.
The main features of this significant structure will be addressed in this presentation.
11:35 a.m. – 12:00 p.m. Innovative Use of Bonded, Post-Tensioned Bars and Precast Segmental-Concrete Foundations
Cory Brett, Simpson Gumpertz & Heger, Inc.
As part of a radar facility being constructed for the U.S. Government in the remote Arctic, several logistical challenges confronted the project team. Procurement of construction materials in the United States, delivery to Greenland, limited availability of construction equipment, and a restrictive two-and-a-half-month construction season all contributed to a complex engineering and construction project.
For foundation construction, traditional cast-in-place concrete construction was not possible given the lack of batch plants near the remote site. Precast segmental-concrete ele-ments were the alternative, including a mat foundation for the radar tower and deep footings for an ancillary support structure. To accelerate the erection schedule, the design engineers engaged a domestic concrete precaster to cast elements in Massachusetts and truck them to a port in Norfolk, VA. From there, segments were loaded onto a boat that carries supplies to the project site once a year. The segments had to be small enough to fit into shipping containers, be light enough for site cranes to manipulate, and act as a cohesive foundation system once in-stalled. Using a combination of grouted splice sleeves and bonded post-tensioning techniques, the contractor completed foundation construction within the short construction season. This case study shows how the U.S.-based design engineers worked creatively and successfully with a domestic precaster and foreign contractor to provide a solution that satisfied the project’s many technical and logistical challenges.
1:05 p.m. – 1:30 p.m. Considerations in Designing Post-Tensioning Repairs Tracy Naso, Wiss, Janney, Elstner Associates, Inc.
Designing repairs for existing post-tensioning systems requires consideration of unique conditions beyond basic repair techniques. Common challenges will be introduced and discussed, such as accommodating the post-tensioning force flow in the structure, avoiding unintentional damage as a result of repairs, repair phasing, shoring requirements, stressing procedures, and repair durability.
Paper-wrapped post-tensioning was used widely in bridges, buildings, parking garages, and stadiums from late 1950 to the early 1970s. This early post-tensioning system has unique characteristics and can be difficult to evaluate and repair. This presentation discusses various evaluation techniques that can be applied to evaluate paper-wrapped post-tensioning effectively, which include visual inspection, test pit, corrosion potential, continuity, conductivity, and tension tests. Case studies will be presented. Once the conditions of tendons are well-understood, cost-effective solutions can be prescribed to repair and rehabilitate this early post-tensioning system.
2016 PTI CONVENTION
30
40years
19
76 - 2
O1 6
™
2:00 p.m. – 2:30 p.m. Structural Strengthening Using External PT Michelle Haughey, Schwager Davis, Inc.
Many of our nation’s existing structures have outlived their expected design life. With the increased cost of construction, many owners have resorted to structural renovations and strengthening to extend the life of their structures in lieu of replacement. The success of these renovation projects is largely dependent on the systems and details used. This presentation will highlight how post-tensioning can be an effective solution for such projects.
2:30 p.m. – 3:00 p.m. Corrosion Mitigation Using Impregnation on Bonded PT Garth Fallis, Vector Corrosion Technologies
Two new case studies and further research of this promising technique will be presented.
Session #8: Panel Discussion on Repair/Open Paper Session Moderator: Sivakumar Munuswamy, Thornton Tomasseti, Inc.
4:00 p.m. – 4:25 p.m. Post-Tensioning - Codes vs. Practices; A Need for Trained Engineering Professionals
Sivakumar Munuswamy, Thornton Tomasseti, Inc.
Lately, post-tensioning design is delegated to the specialty engineers due to lack of trained engineers, as only very few universities teach prestressed concrete, and some of the universities do not even have two-way slab design in their reinforced concrete design courses. Some believe that the liability and responsibility can be divested, contrary to many professional engineering boards’ requirements. As an institution, PTI needs to take an initiative to convince the universities through ABET the urgency to include this fundamental design topic as part of the undergraduate structural engineering curriculum. This paper presents how the industry could benefit from having well-trained engineers from the universities.
4:25 p.m. – 4:50 p.m. TENDON - New Educational Free Software for Post-Tensioned Structures
Fábio Albino de Souza, EBPX
The TENDON is an educational free software, aiming to help in the learning of post-tensioned structures such as beams and one-way and two-way slabs. The working platform is the Android and IOS suitable for tablets due to better visualization and manipulation of data
Session #7: Strengthening & Repair, cont.
2016 PTI CONVENTION
31
40years
19
76 - 2
O1 6
™
Session #8: Panel Discussion on Repair/Open Paper, cont.beyond mobility. Because it is a very intuitive software, the teacher can be more dynamic in their teachings, causing the student to visualize faster results, arousing interest and interaction with the class. Designed to be a universal software, it provides basic elements and unknowns that the user fills in and can later edit the code according to their country. The application will be available in April 2016 to download. We hope to contribute to the knowledge of prestressed concrete and that it can be spread worldwide, mainly in Latin America.
4:50 p.m. – 5:15 p.m. Forty Years of PT Construction Asit Baxi, Baxi Engineering, Inc.
This presentation will reflect on the construction aspects of post-tensioning over several decades. The evolution of the PT systems will be discussed, with the changing specification re-quirements. Ease of post-tensioning construction will be illustrated as well. A future outlook will show how PT is integrated into BIM and what advantages it brings.
![POST-TENSIONING INSTITUTE S · Post-Tensioning Institute’s “Design of Post-Tensioned Slabs-on-Ground”, (PTI Design Procedure) 3rd Edition [13]. The PTI Design Procedure is used](https://static.documents.pub/doc/80x56/5e7408aed0e09073b07aeb48/post-tensioning-institute-s-post-tensioning-instituteas-aoedesign-of-post-tensioned.jpg)
