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Riyad S. Aboutaha, PhD, F-ACI Associate Professor Syracuse University NYSDOT Syracuse University University at Buffalo NYSDOT Syracuse University University.

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Presentation on theme: "Riyad S. Aboutaha, PhD, F-ACI Associate Professor Syracuse University NYSDOT Syracuse University University at Buffalo NYSDOT Syracuse University University."— Presentation transcript:

1 Riyad S. Aboutaha, PhD, F-ACI Associate Professor Syracuse University NYSDOT Syracuse University University at Buffalo NYSDOT Syracuse University University at Buffalo

2 Introduction and Classification of Post-EQ Repair Introduction and Classification of Post-EQ Repair Post-EQ Retrofit of Bridge Elements Post-EQ Retrofit of Bridge Elements Field Guide for Post-EQ Retrofit of Bridge Elements Field Guide for Post-EQ Retrofit of Bridge Elements Summary and Conclusions Summary and Conclusions

3 OBJECTIVE Provide field inspectors and engineers with a quick guide for post-earthquake retrofit of bridges CLASSIFICATIONS Immediate Action / Retrofit Immediate Action / Retrofit Short-Term Retrofit Short-Term Retrofit Long-Term Retrofit Long-Term Retrofit

4 IMMEDIATE ACTION/RETROFIT Intended to stabilize the bridge and reduce the likelihood of further damage or progressive collapse, particularly during after-shocks Make the site safer for safer for further detailed inspection and retrofit

5 SHORT-TERM RETROFIT Intended to make the bridge safer for light emergency traffic (police cars, and ambulances, etc.), heavy emergency traffic (fire trucks) at limited speed, or allow ALL traffic. Immediate and short term retrofits may overlap, where the immediate-retrofit may serve as short-term retrofit.

6 LONG-TERM RETROFIT Intended to restore the bridge to its original strength, and possibly strengthen the bridge to improve its seismic resistance It may involve detailed seismic analysis of the bridge, as well as detailed design of the retrofit system by a structural engineer

7 Deck Failure

8 Superstructure Joint Failure

9 Pounding Damage

10 Column Damage (Flexure / Shear)

11 Column Failure

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13 BASIC ASSESSMENT Identify the purpose of the element /sub-element Identify the purpose of the element /sub-element SHEAR FAILURE SHEAR FAILURE Purpose of stirrups Purpose of stirrups Resist shear Resist shear Confine column Confine column Prevent buckling of longitudinal bars Prevent buckling of longitudinal bars

14 MATERIALS Steel: structural shapes, prestressing strands/bars, plates, and cables. Steel: structural shapes, prestressing strands/bars, plates, and cables. Fiber Reinforced Polymer (FRP) Composite Fiber Reinforced Polymer (FRP) Composite Polymer concrete Polymer concrete Polymer modified concrete / Non-shrink Grout Polymer modified concrete / Non-shrink Grout Special tools: flat jacks, chains, etc. Special tools: flat jacks, chains, etc.

15 External Post-tensioning Application of External Prestressing strands/bars

16 Application of Structural shapes/cables

17 Uniform confining pressure produced by circular steel jacket Uniform Confining Pressure Steel jacketed circular column 1.0 inch thick non-shrink grout Min. ½ thick Steel jacket Application of Structural Steel Plates

18 Assembly detail of a circular steel jacket 4.0 long steel angle with hole for assembly of steel shells spaced 3 feet center-center Steel bolt Application of Structural Steel Plates

19 Steel back plate for field welding. It is welded to one steel shell in shop, and field welded to the other shell. Details of the circular steel jackets shells Application of Structural Steel Plates

20 Non-uniform confining pressure produced by rectangular steel jacket Non-Uniform Confining Pressure Shear retrofit of rectangular column section using rectangular steel jacket Application of Structural Steel Plates

21 Lap splice retrofit of rectangular column section using elliptical steel jacket

22 FRP Diagonal anchor (a) Straight FRP sheet along with diagonal FRP anchors. Application of FRP Composites

23 (b) Isometric view of a strengthened beam with straight FRP system on the tension side, along with diagonal FRP anchors. Uniaxial FRP Composite strip/sheet Uniaxial Diagonal FRP anchor Application of FRP Composites

24 Uniform confining pressure produced by circular FRP jacket Uniform Confining Pressure FRP repaired circular column section Application of FRP Composites

25 Approach Roadways Approach Roadways Bridge Decks Bridge Decks Bridge Abutments Bridge Abutments Bridge Piers and Column Bridge Piers and Column Bridge Girders Bridge Girders Foundation Foundation

26 Retrofit of Damaged Approach Roadway In general, the level of damage is classified based on amount of settlement In general, the level of damage is classified based on amount of settlement For minor settlement (d<2), it is not a critical structural damage, however, it may pose serious driving hazard, that may affect traffic safety (use warning signs) For minor settlement (d<2), it is not a critical structural damage, however, it may pose serious driving hazard, that may affect traffic safety (use warning signs) For major settlement (d>6), must check abutment and its wing walls For major settlement (d>6), must check abutment and its wing walls Retrofit: refilled/repaved Retrofit: refilled/repaved

27 Retrofit of Damaged Approach Roadways

28 Retrofit of Damaged Bridge Decks MinorModerate Severe

29 Retrofit of Damaged Bridge Decks

30 Retrofit of Damaged Bridge Abutment EQ

31 Retrofit of Damaged Bridge Abutment

32 Retrofit of Damaged Bridge Pier Columns Typical Seismic Deficiencies

33 Retrofit of Damaged Bridge Pier Column (Shear Failure) MinorSevere

34 Retrofit of Damaged Bridge Pier Column (Shear Failure)

35 Retrofit of Damaged Bridge Pier Columns Typical Seismic Deficiencies

36 Retrofit of Damaged Bridge Pier Column (Flexural Failure) MinorSevere

37 Retrofit of Damaged Bridge Pier Column (Flexural Failure)

38 Retrofit of Damaged Prestressed Concrete Girders

39 Retrofit of Damaged Steel Girders

40 (a) Pile Overload (e) Rebar Flexural Yielding (b) Shear Failure(c) Anchorage Failure (d) Pile Pullout (f) Pile Shear Failure Foundation Failure

41 Check Deformations (rotation, level), and concrete distress Check Deformations (rotation, level), and concrete distress Requires extensive structural evaluation and retrofit measures Requires extensive structural evaluation and retrofit measures Retrofit of Damaged Foundation

42 Strategies page 1

43 Strategies page 2

44 Good understanding of the behavior of bridge elements helps identify the load path, and consequently the best retrofit system to ensure the continuity of the load path Good understanding of the behavior of bridge elements helps identify the load path, and consequently the best retrofit system to ensure the continuity of the load path A retrofit system is intended to serve the role of the damaged element or sub-element A retrofit system is intended to serve the role of the damaged element or sub-element Pay attention to the overall stability of the bridge system Pay attention to the overall stability of the bridge system Last but not least: SAFETY COMES FIRST! Last but not least: SAFETY COMES FIRST!

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