Presentation Title
BRIDGE IMPACT DAMAGE: ALTERNATIVES TO REPLACEMENT Graham Bettis, P.E. TxDOT Bridge Construction & Maintenance Section
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
Bridge Impact Damage Minor damage? – Easy call. Repair it.
Severe or catastrophic? – Still easy. Partial or complete replacement. What about the inbetween?
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
2
Decisions, Decisions… Repair
Rehabilitate
Replace
The Good
The Good
The Good
Fast
Detours usually unnecessary
Capacity uncompromised
Least Expensive
Less expensive than replacement
Often more cost-effective than rehabilitation
Minimal impact to traffic
Can restore ultimate capacity The Bad
The Bad Unlikely to restore capacity
The Bad Restricted traffic lanes
Significant and prolonged impact to traffic
Altered load paths
Overall highest cost
Expensive on unit cost basis
Implications Important to ensure sufficient capacity, but being overly conservative can have significant consequences in terms of cost and traffic disruption National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
3
Immediate Response – Extreme Underreaction
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
4
Immediate Response – Overreaction
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
5
Traffic Disruption
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
6
Traffic Disruption
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
7
Minor Damage – The Easy Calls
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
8
Severe Damage – Still an Easy Call
But, check out the lack of displacement due to redundancy.
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
9
Severe Damage – Partial or Full Replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
10
Catastrophic Damage
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
11
Catastrophic Damage
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
12
Analysis Load Rating Individual Girder Line vs. Structural Continuity
– Multi-Beam = Load Path Redundancy – Superstructure Integrity: Continuity through beams, composite deck, transverse diaphragms
Redundancy – Difficult to quantify, especially in an emergency – Altered load paths
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
13
Difficult Decisions
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
14
Difficult Decisions
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
15
Something Missing?
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
16
Redundancy
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
17
Prestressed Concrete Beam Damage – Repair Options Patching – Does not restore capacity
– Falling debris Strand splicing – Can restore ultimate capacity
Glass or Carbon Fiber Reinforced Polymers (FRP) – Confinement – Strengthening Most repairs include some combination of these options
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
18
Rehab – Beam Replacement and Repair
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
19
Patching
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
20
Splice, Patch, Wrap, and Raise
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
21
Strand Splicing
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
22
Strand Splicing Installed Using Calibrated Torque Wrench
Strand Coupler
Anchor
Torque Wrench
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
23
Strand Splicing Mock-Up
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
24
Concrete Patching
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
25
CFRP Installation - Confinement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
26
The Finished Product
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
27
Prestressed Concrete Impact Damage Repair Recent repair performed by TxDOT maintenance crew.
28 National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
Substructure Impact Damage Repair
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
29
CFRP Strengthening per ACI ACI 440.2R-08 – Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures Minimum capacity without FRP – ΦRn ≥ 1.1SDL + 0.75SLL (Eq. 9-1) – Accounts for damaged FRP (especially fire) Increasing flexural strength (Chapter 10) – Increases of up to 160% documented (just because you can doesn’t mean you should)
– 40% is more reasonable Increasing shear strength (Chapter 11)
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
30
Anchored CFRP Center for Transportation Research (CTR) at The University of Texas at Austin (Report 0-6306) Substantially increases bond strength Improved ductility through redistribution of load New equations for shear strengthening (moment, too)
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
31
Anchored CFRP
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
32
Steel Repair Options Heat straightening Weld repair
Crack repair Strengthening Partial or full section replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
33
Heat Straightening
Vee Patterns
Direction of Movement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
34
Heat Straightening Considerations Not overly prescriptive. Apply pressure, then heat.
Certified welder only, even if only heating. No cold bending (700 °F minimum). Don’t overheat (1,200 °F maximum for most steel).
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
35
Composite Sections
Composite or non-composite?
Check the plans Look for separation between top flange and deck
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
36
Impact Damage to Composite Steel Girder
Girder replaced because shear studs pulled out of deck
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
37
Impact Damage to Non-Composite Steel Girders
Another difficult decision Minor repair, heat-straighten, or partial replacement?
5” displacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
38
Steel Superstructure Repair Options
Minor deformation doesn’t bother us much, but…
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
39
Steel Crack Repair
Cracks must be repaired. This is common at impact points.
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
40
Partial Girder Replacement – “Strongback” Supports
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
41
Half-Section Replacement “Strongback”
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
42
Half-Section Replacement
Strongback Support
Replacement Section
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
43
Full Section Girder Replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
44
Repeated Hits
FRP helps absorb and distribute load during subsequent impacts.
Steel is typically very forgiving. This girder has been repaired multiple times. National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
45
Repeated Hits
Poor quality patching creates potential for falling debris
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
46
Raising Vertical Clearance – Pedestal Installation
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
47
QUESTIONS? Graham Bettis, P.E. TxDOT Bridge Construction & Maintenance Section [email protected] 512-416-2526 National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
Bridge Impact Damage Minor damage? – Easy call. Repair it.
Severe or catastrophic? – Still easy. Partial or complete replacement. What about the inbetween?
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
2
Decisions, Decisions… Repair
Rehabilitate
Replace
The Good
The Good
The Good
Fast
Detours usually unnecessary
Capacity uncompromised
Least Expensive
Less expensive than replacement
Often more cost-effective than rehabilitation
Minimal impact to traffic
Can restore ultimate capacity The Bad
The Bad Unlikely to restore capacity
The Bad Restricted traffic lanes
Significant and prolonged impact to traffic
Altered load paths
Overall highest cost
Expensive on unit cost basis
Implications Important to ensure sufficient capacity, but being overly conservative can have significant consequences in terms of cost and traffic disruption National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
3
Immediate Response – Extreme Underreaction
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
4
Immediate Response – Overreaction
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
5
Traffic Disruption
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
6
Traffic Disruption
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
7
Minor Damage – The Easy Calls
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
8
Severe Damage – Still an Easy Call
But, check out the lack of displacement due to redundancy.
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
9
Severe Damage – Partial or Full Replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
10
Catastrophic Damage
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
11
Catastrophic Damage
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
12
Analysis Load Rating Individual Girder Line vs. Structural Continuity
– Multi-Beam = Load Path Redundancy – Superstructure Integrity: Continuity through beams, composite deck, transverse diaphragms
Redundancy – Difficult to quantify, especially in an emergency – Altered load paths
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
13
Difficult Decisions
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
14
Difficult Decisions
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
15
Something Missing?
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
16
Redundancy
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
17
Prestressed Concrete Beam Damage – Repair Options Patching – Does not restore capacity
– Falling debris Strand splicing – Can restore ultimate capacity
Glass or Carbon Fiber Reinforced Polymers (FRP) – Confinement – Strengthening Most repairs include some combination of these options
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
18
Rehab – Beam Replacement and Repair
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
19
Patching
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
20
Splice, Patch, Wrap, and Raise
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
21
Strand Splicing
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
22
Strand Splicing Installed Using Calibrated Torque Wrench
Strand Coupler
Anchor
Torque Wrench
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
23
Strand Splicing Mock-Up
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
24
Concrete Patching
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
25
CFRP Installation - Confinement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
26
The Finished Product
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
27
Prestressed Concrete Impact Damage Repair Recent repair performed by TxDOT maintenance crew.
28 National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
Substructure Impact Damage Repair
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
29
CFRP Strengthening per ACI ACI 440.2R-08 – Guide for the Design and Construction of Externally Bonded FRP Systems for Strengthening Concrete Structures Minimum capacity without FRP – ΦRn ≥ 1.1SDL + 0.75SLL (Eq. 9-1) – Accounts for damaged FRP (especially fire) Increasing flexural strength (Chapter 10) – Increases of up to 160% documented (just because you can doesn’t mean you should)
– 40% is more reasonable Increasing shear strength (Chapter 11)
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
30
Anchored CFRP Center for Transportation Research (CTR) at The University of Texas at Austin (Report 0-6306) Substantially increases bond strength Improved ductility through redistribution of load New equations for shear strengthening (moment, too)
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
31
Anchored CFRP
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
32
Steel Repair Options Heat straightening Weld repair
Crack repair Strengthening Partial or full section replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
33
Heat Straightening
Vee Patterns
Direction of Movement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
34
Heat Straightening Considerations Not overly prescriptive. Apply pressure, then heat.
Certified welder only, even if only heating. No cold bending (700 °F minimum). Don’t overheat (1,200 °F maximum for most steel).
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
35
Composite Sections
Composite or non-composite?
Check the plans Look for separation between top flange and deck
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
36
Impact Damage to Composite Steel Girder
Girder replaced because shear studs pulled out of deck
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
37
Impact Damage to Non-Composite Steel Girders
Another difficult decision Minor repair, heat-straighten, or partial replacement?
5” displacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
38
Steel Superstructure Repair Options
Minor deformation doesn’t bother us much, but…
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
39
Steel Crack Repair
Cracks must be repaired. This is common at impact points.
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
40
Partial Girder Replacement – “Strongback” Supports
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
41
Half-Section Replacement “Strongback”
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
42
Half-Section Replacement
Strongback Support
Replacement Section
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
43
Full Section Girder Replacement
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
44
Repeated Hits
FRP helps absorb and distribute load during subsequent impacts.
Steel is typically very forgiving. This girder has been repaired multiple times. National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
45
Repeated Hits
Poor quality patching creates potential for falling debris
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
46
Raising Vertical Clearance – Pedestal Installation
National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
47
QUESTIONS? Graham Bettis, P.E. TxDOT Bridge Construction & Maintenance Section [email protected] 512-416-2526 National Bridge Preservation Partnership
Bridge Impact Damage: Alternatives to Replacement
