Alexander M. Vaysburd

1

Alexander M. Vaysburd45 years

experience

in concrete

research,

engineering and

practice

Pièce COM-71

Education

1961 M.Sc.A. (Civil Engineering) Kiev Civil Engineering Institute Kiev, USSR

1974 Ph.D. (Concrete Technology) ZNEEP Selstroi Aprelevka, USSR

Thesis title: “Polystyrene concrete for agricultural buildings”

2

Professional experience

(…)

1961-1964 Laboratory Engineer

Precast Concrete Plant, Kiev (USSR)•Concrete testing and production quality control

1964-1974 Chief Technologist

Kievorgtehstroy, Development and Research Company, Kiev (USSR)•Design research and field development of precast concrete elements for industrial construction

3

4


(…)

1974-1979 Chief Engineer

Tashorgtehstroy, Development and Research Company, Tashkent (USSR)•Design, research and development of prefabricated concrete structures

1974-1979 Professor

Polytechnical Institute, Tashkent (USSR)•Concrete technology

5


(…)

1980-1981 Engineer

Precast Concrete Plant, Lourel, MD (USA)•Quality control and shop drawings

6


(…)

1981-1992 Senior Structural / Concrete Materials Engineer

Greiner Engineering Inc., Baltimore, MD (USA)•Structural and materials engineering expertise•Bridge design and specifications•Inspection and supervision of condition evaluation•Design of bridge repair and rehabilitation* Greiner Engineering Inc. is now named URS

7


(…)

1992-2000 Director of Research & Development

Structural Preservation Systems Inc., Baltimore, MD (USA)•Performed engineering consulting services in the field of condition evaluation, cement-based repair materials, concrete repair and strengthening•Principal Investigator for Research Projects in the field of concrete repair for U.S. Army corps of Engineers, US Navy

8


(…)

Since 2000 Principal

Vaycon Consulting, Baltimore, MD (USA)•Concrete engineering consulting services & trouble shooting of concrete problems•Office at the Structural Preservation Systems, Inc. (Structural Group) Headquarters, Hanover, MD (USA)

9

Professional affiliations

Fellow

of

the

American

Concrete

Institute

(ACI)

Member

of

ACI Technical

committeesACI 546 – Concrete RepairACI 364 – RehabilitationACI 213 – Lightweight ConcreteACI 365 – Service Life

10


(…)

Since 2002 Adjunct Professor, Concrete Technology

Université Laval, Québec (Canada)•Cementitious Materials behavior, concrete deterioration and reinforcing steel corrosion mechanisms, condition evaluation of existing concrete structures prior to repair

Laval is among the few universities in North America with courses in the field of condition evaluation and repair technology of concrete structures

11

Professional affiliations (…)

Member

of

Regroupement International des Laboratoires d’Essais sur les Matériaux (RILEM)

Member

of

RILEM Technical

committeeTC 193-RLS – Concrete Overlays

12


Member of the ACI International Committee which developed the “Concrete Repair Manual”, 2002Compilation of standards, guidelines and technical reports in the field of concrete repair• American Concrete Institute• Concrete Society of UK• British Research Establishment• International Concrete Repair Institute• AASHTO• NACE• (…)


Other members of the“Concrete

Repair Manual”, 2002 taskgroup

Hywel Davies (UK)Frank Dyton (UK)Peter Emmons (USA)Jim Maker (UK)Stuart Matthews (UK)Jay Paul (USA)Randall Poston (USA)Peter Robery (UK)Roel van Es (UK)Mike Walker (UK)Lech Czarnecki (Poland)Jean-Philippe Fuzier (France) 13


Chairman of the International Cooperative Research Program CREEP (Concrete Repair Engineering Experimental Program)

consortium US Bureau of Reclamation - US Navy - BASF

Master Builders - Conproco - Sika Structural Group Vaycon - Laval University

14


Development of cementitious

repair materials performance test methods and performance criteria for selection of crack resistant repair materials

Member of the National Association of Corrosion Engineers (NACE)

15

Honors

and

awards

1972 Gold Medal

USSR National Exposition Development of technology of manufacturing “sandwich” panels for agricultural buildings

1993 Innovation Award

International Conference, Structural Faults and Repair – 93, Edinburgh, United Kingdom Most meritorious paper on concrete materials

16

Honors

and

awards

(…)

1996 The ACI Wason

Medal

American Concrete Institute Best paper award on concrete repair by ACI

2000 ACI Fellowship

American Concrete Institute

17

18

Honors

and

awards

(…)

2000The ACI Cedric-Willson

Award

American Concrete Institute Significant contributions to the concrete industry in design, production and use of structural LWAC

2000The ACI Construction Practice Award

American Concrete Institute Paper on strenghtening of concrete structures

19

Related

experience

• Cement-based materials

• Concrete technology

• Inspection and Condition evaluation of existing structures

• Durability and corrosion protection

• Repair of concrete

• More than 45 years of experience in Europe, Asia, North Africa and North America

Related

experience

(…)

• Numerous condition evaluation and testing projects of bridges, concrete structures in marine environment and industrial buildings- Walt Whitman Bridge in Pennsylvania- Harry W. Nice Memorial Bridge in Virginia- I-83 bridges- Runways and taxiways- Baltimore Martin State Airports- BWI- Cleveland- Pittsburgh- Washington National- Toyota pier in Port of Baltimore- etc. 20

Related

experience

(…)

• Technical supervision of condition evaluation and concrete repairs of the fire damage Roseton Power Generating Plant in Newburgh, New York (1996)

• Technical consultant on condition evaluation and troubleshooting concrete problems U.S. Army Chemical Weapons Demilitarization Facilities, Aniston, Alabama (1998)

21

Principal investigator

and

consultant

Inspection, condition evaluation and repair of the elevated road bridge and overpass bridge Baltimore Washington International Airport, 1987

Study on cement-based materials and techniques for structures in marine environments

U.S. Navy, 1997

Research project “Performance Criteria for Selection of Cement-based Repair Materials”

U.S. Army Corps of Engineers, 1993-199822


and

consultant (…)

Development of Concrete Repair Guide Specifications

Mobile Oil Corporation, 1998

Developing crack-resistant cementitious repair materials

Conproco Corporation, Dover, N.H., 2003

WHARFER (Engineered management system (EMS) for waterfront facilities) - Condition evaluation and rating U.S. Navy Structures, 2004

23


and

consultant (…)

Condition evaluation and recommendations for remediation

Ford Island Bridge, Pearl Harbor, Hawaii, 2005

Selective condition inspection of piers at U.S. Navy bases (SBIR Project)•U.S. Navy•San Diego (CA), Pearl Harbor (HA) and Point Loma (CA), 2003•Pearl Harbor (HA), 2005

24


and

consultant (…)

Selective condition inspection of piers at U.S. Navy bases (SBIR Project)

25


and

consultant (…)

26

Condition evaluation and recommendations for remediation

Grand Mosque Hassan II, Casablanca, Morocco, 2002-2006

27

Participation in development

of technical

documents

ACI/ICRI Concrete

Repair

Manual

(2 volumes), 2nd Ed.,

American Concrete Institute (ACI), Farmington Hills, MI, International Concrete Repair Institute (ICRI), Des Plaines, IL, 2093 pp., 2003.

ACI 213R-03 Guide for Structural Lightweight-Aggregate

Concrete

28


of technical

documents (…)

ACI 364 Guide for condition assessment of concrete structures (in preparation)

ACI 364.2007 Materials Data Sheet Protocol and Commentaries

ACI 546.2R-98 Guide to Underwater Repair of Concrete

ACI 546R-04 Concrete Repair Guide

29


of technical

documents (…)

ACI 546.3R-06 Guide for the Selection of Materials for the Repair of Concrete (in publication)

ACI SDC Vision 2020: Strategic development plan for the concrete repair industry

RILEM TC RLS-193 –

Concrete Overlays State-of-the-art

report (in publication)

30


of technical

documents (…)

RILEM TC RLS-193 –

Concrete Overlays State-of-the-art

report (in publication)

RILEM TC RLS-193 Concrete Overlays Recommendations (in preparation)

Publications and

presentations

Authorship / co-authorship in the field of concrete construction

• 2 monographs• 201 papers• 12 patents

31

Inspection

32

Mandate

1. Examination of different versions of the inspection guidance documents prepared by the MTQ over the past 30 years

2. Review of inspection guidance documents developed by other agencies in North America

3. Review and analysis of the inspections performed on the de la Concorde bridge between 1977 and 2005

4. Development of recommendations for improvement of inspection practices at MTQ

33

Outline

Comments on MTQ bridge inspection documents

Condition evaluation de la Concorde bridge design vs. inspection

Comments on de la Concorde bridge inspection history

Necessity to perform condition evaluation of de la Concorde bridge

Conclusions

34

Sources of

information

For the purpose of the mandate, translated excerpts or summaries of the subsequent French-written documents were provided and discussed with Dr. Bissonnette, ing. and Ms. M-J Houde, ing., M.Sc.

35

Sources of

information (…) De la Concorde bridge file

• Bridge design drawings (1969)

• De la Concorde Bridge inspection reports (period: 1977-2005)

• Documents related to the request for technical assistance from the Laval Territorial Direction (2004-2005)

• Remedial work estimate (Étude d’opportunité) (2003)

• Photograph file of the repair works in 199236

Sources of

information (…) MTQ documents

• Bridge maintenance guide (Guide d’entretien des structures) - 1978 ed. updated until 1987

• Structures Inspection (Inspection des ouvrages d’art) - 1987 ed.

• Summary of MTQ training courses intended for bridge inspectors

37

Sources of

information (…) MTQ documents

• Manual of bridge inspection – Evaluation of distresses (Manuel d'inspection des structures – Évaluation des dommages)- 1993 ed. updated in 1996- 2004 ed. updated in 2005

• Manual of bridge maintenance (Manuel d'entretien des structures)- 2001 ed. - 2004 ed.I focussed on:- chapter 3: intervention methods

(« méthodes d’intervention ») - chapter 4: damage evaluation

(« relevés de dommages ») 38

Sources of

information (…) Other relevant documents

Bridge Preservation Management(Gestion de la conservation des ponts (2003)), Rapport à l’Assemblée Nationale pour l’Année 2002-2003 Tome II, Vérificateur Général du Québec)

Inspection system (Power point presentation) (Ministère des Transports du Québec), Guy Richard, Toronto (february 2007)

39

Sources of

information (…) Other relevant documents

US National Bridge Inspection Standards (2004)

AASHTO Manual for Condition Evaluation of Bridges (2000)

National Highway Institute Training Course – Safety Inspection of Highway Bridges (2004)

Ontario Structure Inspection Manual (2000)

UK Concrete Society Technical Report No. 54 – Diagnosis of Deterioration in Concrete Structures (2000)

40

Sources of

information (…) Translation of testimony transcripts

Mr. Gilbert Bossé, eng.Mr. Claude Leclerc, eng.Mr. Christian Mercier, eng.Mr. Guy Richard, eng.Mr. Tiona Sanogo, eng.Mr. Draco Simic, eng.

41

Sources of

information (…) Reports

• Report Desjardins Sauriol & Associés - F. Légeron *

• Report MTQ - B. Massicotte et coll. *

• Report MTQ - R. Ellis

• Report MTQ - Direction des Structures

• Rapport synthèse sur les politiques, procédures et pratiques du ministère des Transports du Québec relativement aux ponts et viaducs

* Translated summaries

42

Sources of

information (…)

• Meetings with Dr. Jacques Marchand

and Dr. Denis Mitchell to discuss the content of their report on the causes of de la Concorde Bridge collapse

43

44

Additional comments

on MTQ bridge inspection documents

MTQ bridge inspection documents

Before

1993• Bridge maintenance guide

(Guide de l’entretien des structures,1978)• Structures inspection

(Inspection des ouvrages d’art,1987)

From

1993• Manual of bridge inspection – MBI Manual

(Manuel d’inspection des structures)

45

Manuel d’inspection des structures

In 1993•implementation of the Manuel d’inspection des structures (MBI Manual)

Substantial progress was achieved in comparison to previously issued inspection guides

Comprehensive state-of-the-art document

Compares well with documents developed by other agencies - AASHTO / NBIS - OSIM

46

Manuel d’inspection des structures (…) (1993, including

1996, 2004 and

2005 amendments)

Outline of comments

• Inspection objectives• Adaptability of the Manuel• Condition evaluation• Manuel updates

47

Manuel d’inspection des structures (…) Inspection objectives

Some important inspection objectives are not defined in the manual

48


AASHTO Manual for Condition Evaluation of Bridges

“Inspections should not be confined for searching for defects which may exist, but should include anticipating incipient problems. Thus, inspections are performed in order to develop both preventive, as well as corrective maintenance programs.”

49

50


An adequate attention has to be given in the manual to the critical importance of establishing the diagnosis of defects• Cause• Extent

This will allow to pay attention and effectively address the causes, and not only the symptoms of the deficiencies


Significant attention in the Manual given to:the different structural elements of the bridgesthe variety of material distress / deterioration

However, little information provided on:•guidance on the diagnosis of material defects•possible effects on performance

51

Manuel d’inspection des structures (…) Adaptability of the inspection system

There is no guidance on how to deal with bridges with unusual elements and/or details

52


AASHTO Manual for Condition Evaluation of Bridges

Inspection plan and techniques should consider:•Unique structural characteristics and special problems• Current technology and practice

Intensity and frequency of inspection consistent with:• Type of structure and details• Potential for failure

Inspectors are assigned in accordance with their qualifications 53


Requirement

“Defects found in various portions of the structure will require thorough investigation to determine and evaluate their cause. The cause of most defects will be readily evident; however, it may take considerable time and effort to determine the cause of some defects and to fully assess their seriousness. (…)

Unusual or unique bridges may require special considerations, and these should be defined in the inspection plan for the bridge.” 54

Manuel d’inspection des structures (…) Condition evaluation

The engineering task

of thorough investigation to determine the cause of the defects and fully assess their seriousness is called condition evaluation

This critical topic should be considered with more details in the manuals

55

56

Manuel d’inspection des structures (…) Updates of the manual

Regular updates of the manual over the years

• Inspection frequency• Inspector qualifications and training • Procedures

CEM ou CEC Manuel 1996 Manuel 2004

6 Aucun travaux requis Aucun travaux requis

5 s’ici 6 à 10 ans dans plus de 10 ans

4 d’ici 3 à 5 ans d’ici 6 à 10 ans

3 d’ici 1 à 2 ans d’ici 3 à 5 ans

2 d’ici l’an prochain d’ici 1 à 2 ans

1 Travaux prioritaires Travaux prioritaires 57

Manuel d’inspection des structures (…) Updates of the manual

In 2004, the suggested timeframe for actions to be taken (repair work priority) has been significantly increased

Manuel d’inspection des structures

(…) Updates of the manual

• It is difficult to understand such a relaxation in the requirements, especially considering the fact that:

“Between 1998-99 and 2002-03, the relative number of deficient bridges in the province of Quebec has increased from 36 to 42 %.” (Vérificateur Général of Quebec Report, 2003)

Conclusion on MTQ bridge inspection documents

Overall good documents

Main areas for improvement• Emphasis to be put on causes

of distresses

• Condition evaluation protocol

59

Condition evaluation

60

Condition evaluation U.K. Concrete

Society*

Objectives of

condition evaluation

Determine or confirm the cause of observed deterioration distress

Determine the extent of deterioration/distress

Evaluate the impact of the problems discovered on the current serviceability, durability and structural integrity of the structure

* “Diagnosis of deterioration in concrete structures”, Technical Report No. 54, UK Concrete Society 2000

61

62


Society

(…)

Objectives of


Assess future performance (of deteriorated and apparently sound areas)

Determine (if necessary) what immediate measures are needed to maintain serviceability and safety

Establish means to maintain or restore structural integrity

Minimize current and future maintenance costs

63


Society

(…)

Requirements of a condition evaluation

In-depth review of existing conditions Observing the deficiencies

Performing selective semi-destructive and non- destructive testing

Analysis of field survey and laboratory testing data collected reviewed by both:•Material specialist •Structural engineer

64


Society

(…)

Complementary character of inspection and condition evaluation

Many types of deterioration lead to characteristic visual traits, such as particular forms of cracking

Visual inspection of a structure therefore plays a part in:

the early stages of the diagnosis and assessment process influencing decisions about an appropriate investigation scheme

65


Society

(…)

Stages of a condition evaluation process

Investigation of the current condition of the structure• Diagnosis of the causes of deterioration/distress• Selection of an appropriate solution


Society

(…)

Initial phase of condition evaluation process

66

Routine inspection

Preliminary

inspection

Preliminary

desk study

Initial diagnosis

Plan main investigation


Society

(…)

Detailed phase of condition evaluation process

67

Sampling In situ testing Structural assessment/ Design study

Desk studyMapping

Appraisal

and

evaluation

Laboratory testing


Society

(…)

Final phase of condition evaluation process

68

Interpretation

Prediction

Options

Prediction

Principle (“approach”)

Repair and protection methods

Cost

Condition evaluation Ontario (OSIM 2000)

Criteria

for undertaking

a condition evaluationCondition survey type

Description Condition survey trigger

Concrete Deck(Asphalt or Concrete surface)

Involves the testing of various core samples, sawn samples and the delineation of delaminated areas and areas of high corrosion potential (using half-cell survey)

5 % of element in “Poor” Condition State

Concrete Substructure

Involves the testing of various core samples, etc., and the delineation of delaminated areas and areas of high corrosion potential (using half-cell survey)

10 % of element in “Poor” Condition State

69


-

MTQ

Addressed

in the

Manual

of

Bridge Maintenance

Bridge slab

/ superstructure only(«

Expertise de dalle / tablier

»)

70


-

MTQ (…)

In the

manuals, two

operations

form

part of

a condition evaluation

process

Slab / superstructure condition evaluation («Expertise de dalle / tablier»)

Condition evaluation prior to repair «Relevé de dommages»

71


-

MTQ (…)

What is a condition evaluation?Comparative description found in Manuel d’entretien des structures

72

General inspection Condition evaluation(Inspection générale) (Relevé de dommages)

MTQ Manuel d’inspection des structures

MTQ Manuel d’entretien des structures

Continuous process One-time eventVisual observations More sophisticated means

Damages are recorded Damages evaluated in-depthAll elements are addressed For elements to be repaired

Filed in the system Requires a written report

Conclusion on condition evaluation

To successfully address the deficiencies, both causes and extent must

be clearly established

Condition evaluation implies using available means for identifying these causes and assessing the extent of deficiencies• Non-destructive testing• Sampling and testing • Exploratory windows

73

Conclusion on condition evaluation

(…)

The scope should be extended to the substructure elements

Condition evaluation objectives and procedures should be more explicitly defined

74

75

CONSENSUS 1.12.1:Inspection manuals

The

quality

of

the

MTQ inspection manuals is

comparable to that

of

similar

documents

used

elsewhere

in North

America.

Les manuels d’inspection du MTQ sont d’une qualité comparable à des documents similaires applicables en Amérique du Nord

Additional

comments

The MTQ bridge manual and practice would nevertheless benefit from more comprehensive guidance on the following basic issues:

•Protocol for inspection of bridges with regards to unusual details and components

•Condition evaluation

•Causes and mechanisms of concrete deterioration

76

De la Concorde bridge design as related

to inspection

77

Bridge design as related

to inspection

MTQ is

responsible

for the

management of

9200 structures and

owns

more than

half

of

them

• 50 different types of structures

• Quebec has a harsh climate

78


to inspection Bridge inspection is

a complex

task

Broad

knowledge

is

required

in many

fields• bridge engineering• material behavior• evaluation and testing techniques• remediation practices

Considerable

level

of

responsibility

on the

part of

the

professionals

involved

79


to inspection Bridge inspection is

a complex

task

North American experience has demonstrated that design-related problems and deficiencies concerning accessibility and maintainability of the critical bridge elements are of paramount importance for the service life and safety of the bridge structure

See: NCRHP Synthesis 123, Transportation Research Board, National Research Council, Bridge designs to reduce and facilitate maintenance and repair, 1985

80

81


to inspection

Presently, it

is

recognized

that

a quality

bridge design should

anticipate

for:

• Inspection• Maintenance • Repair• Replacement


to inspection

Lack

of

access

to some

critical

bridge elements

can

substantially

affect:

• Reliability of inspection• Accuracy of the engineering judgement• Bridge maintainability• Service life of the bridge• Public safety

82

83


to inspection

Elements

of

de la Concorde bridge not accessible for inspection and

maintenance

• Beam seats / joints• Box girders• Diaphragms


to inspection Beam seats/joint detail: problem-prone

Even adequately designed bridge joints are a problem

United States (Purvis & Berger, 1983):“More than half of the problems reported on concrete deck bridges are related to the expansion joints, or are caused by leakage through the joints.”

84


to inspection Beam seats/joint detail: problem-prone (…)

Italy (Manning and Ryell, 1981) “79 % of special maintenance and repair operations on bridges arise due to poor sealing of the expansion joints.”

85

86


to inspection de la Concorde bridge

The joint leaked and moisture, deicing salts, abrasives and debris through the leaking joint, piled up on beam seat area and penetrate into the concrete

With freeze-thaw cycles, this condition led to progressive concrete deterioration

The situation was amplified by the absence of effective drainage system


to inspection de la Concorde bridge (2006)

87N-E joint


to inspection BWI Bridge

Vaysburd, A.M. (1990) Deterioration and Rehabilitation of the Elevated Road Bridge at Baltimore/Washington International Airport, Concrete International, No. 9, September, pp. 45-50.

88


to inspection BWI Bridge (…)

Elevated Roadway Bridge at Baltimore/Washington International Airport

In-span joints

similar to those found on de la Concorde bridge

89

90





91

Distresses in the joint areas



92

de la Concorde bridge (1992) BWI bridge (1986)

EAST joint

BWI Bridge Joint repair details

93

94


to Inspection BWI Bridge

Investigation of the problems

95

Bridge design vs. inspection

Conclusion on de la Concorde bridge design shortcomings

Unusual or unique portions of the bridge structure required special considerations (procedures, frequency, etc.)• Inspection• Maintenance

Comments

on de la Concorde bridge inspection history

96

Summary of inspections

Regularly

inspected

between

1977 and

2005

23 filed reports• Routine inspections• General inspections

Complied with the frequency requirements

97

Comments

on de la Concorde bridge inspection historyAddressed issues

• Reporting rigor & precision

• Information consistency

• File keeping

98

Reporting

rigor

and

precision

Lack of rigor / precision in most of the reports

99

Reporting

rigor

and

precision

(…) Examples of lack of rigor / precision

1986 Routine Inspection Report first time documented “deterioration of the concrete slab”

“Deterioration” is a broad and generic term

The report does not indicate:• the type of deterioration• the location of deterioration• the extent of deterioration

100

101

Reporting

rigor

and

precision

(…)

For instance, US NHI document “Safety Inspection of In-Service Bridges”

requires:

• defect specific types • defect qualification• defect quantification • defect location

102

Reporting

rigor

and

precision

(…) Examples provided in the NHI document

Defect Qualification crack sizes record lengths, widths, depth

section loss record the remaining section dimensions

deformation record amount of misalignment

Defect Quantification spalling 2’ x 3’ x 2’’ deep

scaling 4’ high by full abutment widthdelamination 1’ x 6’

103

Reporting

rigor

and

precision


Defect Location 2210 mm from fixed bearing on Beam 3 at

Abutment 1940 mm from west corner of Abutment 2760 mm below bridge seat on south face of column 1, pier 2

Reporting

rigor

and

precision


1991 Routine Inspection Reports “Cracking under the bridge longitudinal joint over an

area of 2,5 m2.”

There is no indication of crack width, length, pattern, and possible causes for the cracks

104

Reporting

rigor

and

precision


1997 Routine Inspection Report

“Many vertical and diagonal cracks in the west abutment and few vertical and diagonal cracks in the east abutment.”

What “many” and “new” mean in relative terms?No exact locations, no length, no width and no attempt to characterize the type of crack

105

106

Reporting

rigor

and

precision


1997 Routine Inspection Report

“Repair of questionable quality.”

No indication of which repair, what repair material was used, size of the repairWhat does “questionable quality” mean?

Reporting

rigor

and

precision


2003 Routine Inspection Report“Cracked pavement.Leaking joint.Concrete delamination at the North corner of the West abutment.Beam seat concrete (north-east corner) is severely deteriorated.Under the exterior side, concrete is delaminated in some areas («en certains endroits»). ”Location of «some areas» are not provided, nor is the size and number of these defects

107

108

Reporting

rigor

and

precision


Inaccurate use of the technical terms in the description of the defects

For instance, regular use of “delamination” in lieu of “spalling”• Delamination («délaminage») – separation along

a plane parallel to a surface (splitting, cracking)• Spalling («éclatement») – detachment from a

larger mass

109

Information consistency

Appraisal of the bridge condition over time

Terminology used in the reports with respect to the rating system


(…) Examples of inconsistency

May 12, 1999 General InspectionWhile CECS = 4

(acceptable

condition)

Nevertheless, overall condition appraisal is qualified as good (“bon”)

110

111



2002 General Inspection Report

“The overall condition was found acceptable.”

2003 Routine Inspection

“The overall condition was found good.”

112



June 10, 2004 Routine Inspection

“The overall condition was found good.”

June 17, 2004 Alarming letter from DT to DS

113



May 18, 2005 General Inspection

While CECS = 3 (mediocre

condition)

Nevertheless, overall condition appraisal is qualified as acceptable

114



Misunderstanding on how the unusual abutments («culées») of the bridge were described and categorized• Until 1999

the bridge structure was qualified as a single span, without consideration to the abutment cantilever slabs (usual abutment form)

• From 1999 3-span bridge, the cantilever («porte-à-faux») of each abutment being treated as a separate span

115

Information consistenc


In the same time, the beam seats were still being treated and rated in the standard abutment form –

as secondary elements in

the MTQ rating system

File keeping Flaws in file keeping

The bridge record file was incomplete

Examples of missing records

Concrete properties and characteristics• In-place at the time of construction• At any other time

1992 joint replacement and repair project

116

117

Conclusions on de la Concorde bridge inspection recordsTo a certain degree, the inspection practice was characterized by:• lack of rigor• inconsistency • incomplete records

This obviously did not contribute to the timely identification of deficiencies

118

Consensus 1.12.3:Compliance

with

manual

requirements

Some

inspection manual

requirements

were

not fully

satisfied

with

regards to:

•the attribution of rating index values•the detailed content of inspection reports•the prescribed in the Manual allowable time before repair works

Certaines exigences prévues dans les manuels d’inspection du MTQ n’ont pas été entièrement respectées quant:•à l’attribution de certaines cotes d’évaluation•au contenu détaillé des rapports d’inspection•aux délais prescrits par le manuel pour les travaux d’entretien

119

Comments

It should be stated that, based on the information available for review, no slab / superstructure condition evaluation has ever been performed on de la Concorde bridge, whereas it was required on a few occasions.

Need for performing condition evaluation of de la Concorde bridge

120

121

Need

for condition evaluation

Note: Based on the information available for review, it

appears that no condition evaluation (including sampling and testing) was ever requested and performed during the service life of the bridge.

Need


(…)

Condition evaluation, including concrete sampling and testing, was justified and necessary on a number of occasions

•1992 joint replacement and repair project

•Based on the 1999, 2002, 2005 General Inspection results

•Based on the observed cantilever slab abutment condition in 2004

122

Need


(…)

1992 joint replacement and repair project• Repair work should have been preceded by a


123S-E joint

Need


(…)

1999 General Inspection• Bridge deck CEM = 4

• Starting in 1999, the cantilever slabs were categorized as individual spans

• According to the MBI manual, slab / superstructure condition evaluation («Expertise de dalle / tablier») was required no later than 2003 124

CEM Condition evaluation4 Required within 2 to 4 years

MBI manual (1996) (p. 2-18)

Need


(…)

1999 General Inspection• Beam seats CEC = 3

(based on the N-E seat condition)

• According to the manual, repair should have been performed no later than 2001

125

MBI manual (1996) (p. 2-15)

CEM or CECRepair should be performed within 1 to 2 years

Suggested

delay

3

Need


(…)

• Starting in 1999, the cantilever slabs were categorized as individual spans

• Prior to repair, a slab / superstructure condition evaluation («Expertise de dalle / tablier») of the bridge deck would have been required as per article 4.2.3 of the manual

126

Need


(…)

1999General Inspection• Reported CECS = 4

Abutment seats CEC = 3 Should have been categorized as slab ends (primary elements) Would they have rightly been categorized: CECS = 3

• According to the MBI manual, with appropriate rating, actions would have been required

127

CECS

3 Special inspection is necessary Possible load limitation

Suggested

actions MBI manual (1993) (p. 2-17)

Need

for in-depth

investigation

2002General Inspection• Bridge deck CEM = 3

• In 2002, the cantilever slabs were categorized as individual spans

• According to the MBI manual, slab / superstructure condition evaluation («Expertise de dalle / tablier») was required no later than 2004

CEM Condition evaluation

3 Required within 1 to 2 yearsMBI manual (1996) (p. 2-18)

Need


2004 Request for assistance from the Direction of Structures by the Laval DT

Instead of recommending that a condition evaluation be performed, the response transmitted to the DT was to take no remedial action until deterioration got worse

«Nous recommandons à la direction territoriale d’attendre l’apparition de dommages plus importants au niveau des assises (…) ou au-dessous des tabliers avant de procéder aux travaux de réparation (…)»

129

Need


(…)

2005 General Inspection

• Bridge CECS = 3• No condition evaluation was requested

130

Need


(…)

Condition evaluation was necessary• To establish the cause and extent of concrete

deterioration and its effect on the integrity and future performance of the structure

• To evaluate the condition of the concrete superstructure members

• To determine the nature of the diagonal cracks on the sides of the cantilever slabs and if internal moisture transport mechanism (crack network) is present

• To evaluate the concrete condition in non-accessible beam-seat areas 131

Need


(…)

Engineer delegated to address specific problems or concerns with a structure

• Similar to a doctor seeing a patient

132

Need


(…)

Diagnosis and treatment of a disease• The symptoms must be observed and discussed

• The medical history has to be reviewed

• The doctor has to have a thorough knowledge in his field

• To diagnose the illness, tests must be carried out blood test, ETG, X-ray, colonoscopy, etc.

• An accurate diagnosis can be made

• Effective remedies can be prescribed133

Need


(…)

Once causes of the defects are well established, appropriate remedial strategy can be implemented • Strategy addressing causes and not symptoms

Remedial

action alternatives

• Do nothing and monitor• Repair• Replace

134

Need


(…)

Causes of de la Concorde bridge collapse

• According to Marchand & Mitchell (2007), South- East portion of the bridge collapsed due to a brittle shear failure in the East cantilever

• The shear failure was caused by the development of horizontal crack initiated in the zone of weakness, just above the hooks of the # 8 hanger rebars in the top portion of the member, near the beam seat

135

Need


(…)

Conclusion

It is the opinion of the reviewers that if the necessary condition evaluation (including sample observation and testing) of the bridge element experiencing significant deterioration & distress had been conducted on a timely basis, it is likely that the problems which led to the bridge collapse, as described in Marchand & Mitchell’s report, could have been detected.

136

Conclusion

Without inferring that the collapse would have been predicted, the internal zone of concrete weakness could have been detected with cores taken

as part of a


137

138

What

would

you

do? BWI Bridge

139

What

would

you

do? S-E abutment

(side

view)

140

What

would

you

do?

What

would

you

do?

Example

of

how

I would

approach

the

problem of

cracking observed

on the

sides

of

the

abutment

cantilever slabs

• Removing asphalt locally• Identifying core locations with a pachometer• Core extraction

141

142

What

would

you

do? S-E abutment

(side

view)

143

What

would

you

do? S-E abutment

What

would

you

do? S-E abutment

(plan view)

144S-E

N-E

≈

0,5≈

1,0

≈

1,0

≈

1,5

[m]

145

What

would

you

do? S-E abutment

≈

1,0[m]

≈

1,0 ≈

0,5≈

0,4

≈

0,4

What

would

you

do? Cracking on the

abutment

cantilever slabs

(…)

Core

extraction

Visual

observations• Cores• Core holes

Based

on the

observations, appropriate laboratory

tests should

be

carried

out, such

as

• Compressive strength test• Petrographical analysis• Determination of air-entrainment characteristics• Determination of chloride ion content

146

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