Quantification of Cracks in Concrete Bridge Decks in Ohio District 3

Size: px

Start display at page:

Download "Quantification of Cracks in Concrete Bridge Decks in Ohio District 3"

Elijah Johnston
6 years ago
Views:

1 Quantification of Cracks in Concrete Bridge Decks in Ohio District 3 Student Study Project State Job Number: Research Results Presentation ODOT Central Office, Columbus, OH questions to: Research@dot.state.oh.us Sai K. Ganapuram Michael A. Adams Anil Patnaik (PI) The University of Akron 1

2 Acknowledgments Mr. Perry Ricciardi, SME for the project (ODOT District 3 Construction Engineer) Mr. Marlin Wengerd, ODOT District 3 Bridge Engineer Mr. John Adamski, ODOT District 3 Testing Engineer Ms. Nancy Spencer, ODOT District 3 Administrative Assistant Ms. Vicky Fout, Mr. Brandon Perkins, and Ms. Jill Martindale, ODOT Research Section Srikanth Bajaj, Sudeep Adhikari, and Pragya Jai Kumar (graduate students of the University of Akron) 2

3 Overview Introduction Task List and Objectives Literature Review List of Surveyed Bridges Pre-Survey Preparation Methodology Database Crack Maps and Crack Densities Discussion Conclusions and Recommendations 3

4 Problem Statement Development of numerous cracks in bridge decks is a serious problem throughout the United States, including Ohio Ohio bridges constructed within the last ten years already display different levels of cracking Cracks provide passageway for aggressive agents into the concrete and facilitate initiation of corrosion of reinforcing steel 4

5 General hypothesis at District 3 Structural slab decks have greater degree of cracking relative to stringer supported bridge decks. Verify statement Quantify difference 5

6 Task List Review Literature on Development of Cracks in Reinforced Concrete Bridge Decks Study ODOT District 3 Inventory and Classify Bridge Decks Selection of Typical and Representative Bridge Decks Study the Extent and Pattern of Cracking of Selected Bridge Decks Establish Potential Correlation Between the Extent of Cracking and Bridge Deck Classification Establish Crack Minimization Strategies for New Bridge Decks Summarize the findings 6

7 Objectives Determine which superstructure type (structural slab or stringer supported) has a higher propensity for bridge deck cracking Develop insight that will be helpful in understanding the cracking behavior of structural slab and stringer supported concrete bridge decks Identify general areas where consideration should be given for future considerations Significance of Work ODOT Bridge Inspection Protocol 1 offers qualitative condition assessment Project provides a quantitative measurement of the tendency of cracking for the two types of bridge decks 7 1 ODOT Manual of Bridge Inspection, 2006

Literature Review Types of Cracking Transverse Diagonal Longitudinal Map/Pattern Causes of Cracking Cracking occurs due to the restraint of concrete Volumetric

8 Literature Review Types of Cracking Transverse Diagonal Longitudinal Map/Pattern Causes of Cracking Cracking occurs due to the restraint of concrete Volumetric movement is prevented by restraint Classification of Cracks 2 Cracking becomes visible when tensile strength of concrete is exceeded by tensile stresses 8 2 NCHRP Synthesis 333

9 Literature Review (Continued) Causes of Cracking (Cont.) Plastic, Drying, and Autogeneous Shrinkage, Thermal Stresses Design Parameters: Bridge design, boundary conditions, deck thickness Material Parameters: Cement content, strength, aggregates, w/c Construction Parameters: Placement sequence, curing, weather, concrete temperature Some Ways to Reduce Cracking Reduce thermal gradients between concrete deck and girders Control evaporation of water from concrete surface Use concrete mixes with low early strength, low water to cement ratios, and low cement content 9

10 All From: Evaluation of Crack-Free Bridge Decks Patnaik et al., Evaluation of LC HPC for Pennington County Bridges, Final Report: Evaluation of Crack Free Bridge Decks, June 2011

11 Literature Review (Continued) Evaluation of Crack-Free Bridge Decks SDDOT Report Compared constructability and cracking behavior of newly constructed bridge decks using: Low Cracking High Performance Concrete (LC-HPC) A45 Concrete SDDOT s existing concrete mixture design Performed detailed crack surveys at four different instances: Prior to bridges being open to traffic One year Two years Three years Performance assessed by measuring and comparing crack densities Followed University of Kansas Pooled Fund crack survey protocol 11

12 List of Surveyed Bridges Selection Basis Age of Bridge QC/QA Concrete No Interstates 12

13 Bridge Locations in District 3 13

Crack Survey Protocol Follow University of Kansas specification for crack survey 4 Station bridge in the longitudinal direction at 10 ft. intervals Mark 5 ft. x 5 ft.

14 Crack Survey Protocol Follow University of Kansas specification for crack survey 4 Station bridge in the longitudinal direction at 10 ft. intervals Mark 5 ft. x 5 ft. grid Trace cracks that can be seen while bending at waist ACI in 14 Typical Crack Survey Procedure 4 Pooled Fund Project Crack Survey Protocol, Construction of Crack-Free Bridge Decks, Kansas Department of Transportation

15 Pre-Survey Preparation Compile project plans for each bridge Produce a scaled drawing of each bridge deck with a scale: 1 in. = 10 ft. Example of Scaled Drawing of Typical Bridge Deck 15

16 Clearing of Bridge Deck of Debris Spraying Water on Bridge Deck 16

17 Wooden Frame 15 ft. x 20 ft. Grid composed of 5 ft. x 5 ft. sections 15 ft. x 20 ft. Grid 17

18 Methodology Plot crack profiles onto a scaled sketch of bridge deck Transfer crack profiles to a scaled computer drawing Typical Crack Map of a Bridge Deck 18

19 Methodology (Continued) Calculate the crack densities for the corresponding bridge decks using the crack maps 19

20 Methodology (Continued) Determine widths of cracks for each bridge deck classification at select locations Measure crack widths using a crack comparator card 20

21 Database ODOT Material and Inspection Reports for each bridge Concrete Properties of Surveyed Bridge Decks 21

22 Database (Continued) Study Concrete Cylinder Reports and Mixture Designs for each bridge deck Develop insight into any connection between the patterns of cracking and information established in literature review Establish any potential correlation between bridge deck classifications and severity of cracking 22

23 Crack Maps 23

24 ASD-SR Crack Density : ft/ft 2 Age : 17 months Class of Concrete : QC/QA 4500 Area : 2022 ft 2 Type of Bridge : Concrete Slab Continuous with 3 spans 24

25 ASD-US Crack Density : ft/ft 2 Age : 18 months Class of Concrete : High Performance Mix 4 Area : 6924 ft 2 Type of Bridge : Concrete Slab Continuous with 3 spans 25

26 LOR-SR Crack Density : ft/ft 2 Age : 20 months Class of Concrete : QC/QA 4500 Area : 4170 ft 2 Type of Bridge : Concrete Slab Continuous with 3 spans 26

27 LOR-SR Crack Density : ft/ft 2 Age : 36 months Class of Concrete : QC/QA 4500 Area : 2965 ft 2 Type of Bridge : Steel beam Simple 27

28 ASD-US Crack Density : ft/ft 2 Age : 17 months Class of Concrete : QC/QA 4500 Area : 6410 ft 2 Type of Bridge : Steel Beam Continuous with 3 spans 28

29 ASD-SR Crack Density : ft/ft 2 Age : 21 months Class of Concrete : QC/QA 4500 Area : ft 2 Type of Bridge : Steel Beam Continuous with 3 spans 29

30 CRA-SR Crack Density : ft/ft 2 Age : 35 months Class of Concrete : Class S Area : 5150 ft 2 Type of Bridge : Steel Beam Continuous 30

31 WAY-US Crack Density : ft/ft 2 Age : 48 months Class of Concrete : High Performance Mix 4 Area : 5365 ft 2 Type of Bridge : Steel Beam Continuous with 2 spans 31

32 ERI-US Crack Density : ft/ft 2 Age : 42 months Class of Concrete : QC/QA 4500 Area : ft 2 Type of Bridge : Steel Beam Continuous with 3 spans 32

33 MED-SR Crack Density : ft/ft 2 Age : 40 months Class of Concrete : HP Mix 4 MOD Area : 6765 ft 2 Type of Bridge : Prestressed Concrete Beam Supported 33

34 HUR-US Crack Density : ft/ft 2 Age : 24 months Class of Concrete : High Performance Mix 4 Area : 6765 ft 2 Type of Bridge : Prestressed Concrete Beam Supported 34

35 HUR-US Crack Density : ft/ft 2 Age : 24 months Class of Concrete : High Performance Mix 4 Area : 6765 ft 2 Type of Bridge : Prestressed Concrete Beam Supported 35

36 Summary of Crack Densities of Surveyed Bridges Bridge Number Date Placed Date of Crack Survey Age (Mon.) Concrete Type Deck Length (ft) Deck Width (ft) Deck Area (ft 2 ) Total Cracks (ft/ft 2 ) Crack Density Structural Cracks (ft/ft 2 ) Shrinkage Cracks (ft/ft 2 ) Concrete Slab Continuous ASD /1/09 3/8/11 17 QC/QA LOR /24/09 4/21/11 20 QC/QA ASD /23/09 3/22/11 18 HP Mix Average Prestressed Concrete Beam Simple Span HUR /26/09 9/15/11 24 HP Mix HUR /26/09 9/13/11 24 HP Mix MED /5/08 9/29/11 40 HP Mix 4 Modified Average Simply Supported Steel Beam LOR /30/08 4/28/11 36 QC/QA

37 Summary of Crack Densities of Surveyed Bridges (Continued) Crack Density Bridge Number Date Placed Date of Crack Survey Age (Mon.) Concrete Type Deck Length (ft) Deck Width (ft) Deck Area (ft 2 ) Total Cracks (ft/ft 2 ) Structural Cracks (ft/ft 2 ) Shrinkage Cracks (ft/ft 2 ) Steel Beam Continuous WAY /10/07 10/6/11 48 HP Mix ASD /21/09 4/7/11 17 QC/QA ASD /27/09 4/5/11 21 QC/QA CRA /15/08 9/20/11 35 Class S ERI /30/08 11/1/11 42 QC/QA Average

38 Crack Density (ft/ft 2 ) Concrete Slab Continous HUR HUR Steel Beam Continous Steel Beam Simple Prestressed Concrete Beam Simple ASD LOR CRA WAY LOR ASD ASD MED ERI ASD Age (Months) Plot of Total Crack Densities with Age 38

39 Crack Density (ft/ft 2 ) 0.3 Concrete Slab Continous Steel Beam Continous Steel Beam Simple Prestressed Concrete Beam Age (months) Shrinkage Crack Densities vs. Age for Different Types of Bridges 39

40 Crack Density (ft/ft 2 ) SD-DOT (Patnaik, et al., 2010) Concrete Slab Continous Steel Beam Continous Steel Beam Simple 0.4 Prestressed Concrete Beam Simple Age (months) Comparison of Shrinkage Crack Densities with Those from Previous Studies 40

Important Observations Structural Slab Bridge Decks Structural cracks were located over the supports Shrinkage cracks were perpendicular to the structural cracks Several

41 Important Observations Structural Slab Bridge Decks Structural cracks were located over the supports Shrinkage cracks were perpendicular to the structural cracks Several hairline cracks were located throughout the bridge decks Select crack widths measurements were between inches Structural cracks were as wide as inches 41

42 Important Observations Stringer Supported Bridge Decks Transverse cracks were located perpendicular to the longitudinal axis of the bridge at roughly 7 10 feet intervals Cracking concentrated over the supports at the negative moment regions Numerous small cracks were located throughout the bridge decks 42

43 Conclusions Structural slab bridge seems to have a higher tendency to crack than stringer supported bridge decks. QC/QA bridge decks measured smaller shrinkage crack densities. No direct correlation was found between the age of the bridge deck and the amount of cracking. Several large structural cracks were parallel to the intermediate supports, which were very wide and much greater than inch giving a reason for concern. The shrinkage crack densities of the bridge decks in Ohio were considerably lower than those of the bridge decks of some other states. 43

44 Recommendations The use of QC/QA 4500 concrete be continued to minimize shrinkage cracking. Cracks observed in continuous structural slab bridges are much wider than the ACI 224 report recommended limit. These non-shrinkage cracks need further investigation. Further crack surveys may be performed on the bridges of this study within a couple of years to investigate if the crack densities increase with time. 44

Comment The presence of railings at the end of the bridge deck (for example, # ERI-250-1138)

45 Comment The presence of railings at the end of the bridge deck (for example, # ERI ) seemed to reduce the cracks at the ends. This option may be further investigated by the Department. 45

46 Summary Review of Literature List of Surveyed Bridges Pre-Survey Preparation Methodology Database Crack Maps and Crack Densities Discussion Conclusions and Recommendations 46

47 questions to Final report is available online at: PR/Research/reportsandplans/Reports/2012/Stru ctures/134564_fr.pdf 47

Types of Cracking and Influencing Causes

Types of Cracking and Influencing Causes TRB Cracking Webinar May 25, 2016 R. Doug Hooton NSERC/ Cement Association of Canada, Senior Industrial Research Chair in Concrete Durability & Sustainability hooton@civ.utoronto.ca