performance based design for bridge piers impacted by

Performance Based Design for Bridge Piers Impacted by Heavy Trucks

Anil K. Agrawal, Ph.D., P.E., Ran Cao and Xiaochen XuThe City College of New York, New York, NY

Sherif El-Tawil, Ph.D.University of Michigan, Ann Arbor, MI

1

Research in this presentation has been sponsored through a FHWAcontract on Hazard Mitigation Team with Mr. Waider Wong as theTask Manager.

ObjectivesDevelop bridge design guidelines to achieve desired

performance levels during heavy vehicular impact.

A methodology to predict impact loads based onweight and velocity

Definition of performance levels

Approach to achieve desired performance level

Step by step examples illustrating performance baseddesign and

Demonstration of effectiveness of the design throughnumerical simulations validated through physical largescale tests. 2

Outline of the Presentation

Introduction

Material Model

Large Scale Testing and Simulation

Heavy Vehicle Simulation

Performance-based Design For Heavy Vehicle

Simulation3

Highway Bridges o designed to resist

• Gravity Load• Live Load

o expected to experience extreme events• Hydraulic• Overload• Collision• Earthquake

Bridge Failures

Introduction

Introduction

Hydraulic57%

Collision13%

Overload12%

Fire3%

Earthquake1%

All Other14%

Causes of failure of bridges.

5

Presenter

Presentation Notes

Based on bridge failure data compiled by New York State Department of Transportation, figure 1 shows causes of bridge failures in United States during 1969 and 2006. It is observed that collision, both caused by vessel and vehicles, is the second leading cause of bridge failures after hydraulic.

Major ProblemMinor Problem

Introduction

Introduction

Introduction

Truck Impact on Piers of Tancahua Street Bridge over IH-37, Corpus Christi, Texas on May 14, 2014.

11

Introduction

Truck impact on Bridge on 26 ½ Road over IH-70, Grand Junction, Colorado

12

Introduction

Truck impact on Mile Post 519 Bridge over IH-20, Canton, TX

13

Introduction

Truck impact on FM 2110 bridge over IH-30, Texarkana, Texas on Aug. 8th, 1994.

14

Introduction

Truck impact on SH-14 Bridge Over IH-45, Corsicana, Texas

15

Experimental Test

Inertial restraints by the superstructures can produce the column design forces

that are more than 200% larger than those calculated by the static procedure

prescribed in AASHTO.

Introduction

Truck Impact on Bollards

Test of anti-ram bollards based on truck collision conducted by Hunan University, 2009.

Introduction

Truck Impact on Bollards

High capacity of the steel tube filled with concrete, the column didn’t go large

deformation.

Test of anti-ram bollards based on truck collision conducted by Hunan University, 2009.

Introduction

IntroductionFull-Scale Testing at TTI

19

• Tests based on impact by truck on rigid piers.• Results don’t apply to concrete piers that are damaged, resulting in

significant loss of energy.• Test results don’t provide a basis for performance based approach.

FHWA / TTI Test

The peak impact force reached 900 kips from the contact between the engine and

the pier; there is no damage in the rigid pier; 600 kips is recommended to update

AASHTO guideline.

Test of tractor-trailer and rigid steel pier collision by TTI, 2010.

Introduction

FHWA / TTI Test

The peak impact force reached 900 kips from the contact between the

engine and the pier; there is no damage in the rigid pier; 600 kips is

recommended to update AASHTO guideline.

Introduction

Medium Weight Truck

Truck FEM Model:

Weight: 15,000 pound (66 KN)

Dimension: 27 FT×8 FT×10 FT

Material Model Truck Component

Elastic Material Models Engine, Transmission, Radiator

Rubber Material Model Mounts between the cabin and rails, engine and rails,

etc.

Rate-dependent Isotropic Elastic-plastic Material Model Chassis components and the body shells

Miele, C.R., Plaxico, C. A., and Kennedy, J.C.(2005). Heavy Vehicle-infrastructure asset interaction andCollision. Heavy Vehicle Research Center, Oak Ridge National Laboratory.

TRUCK MODELS FOR THEORETICAL RESEASRCH

Truck FEM Model:

Weight: 80,000 pound (360 KN)

Dimension: 66 FT×9 FT×13 FT

Chuck A. Plaxico (2015). FEA vs TTI Test 429730-2, Preliminary Validation Analysis. Roadsafe LLC.

TRUCK MODELS FOR THEORETICAL RESEASRCH

• Heavy Weight Trucks• 80,000 lb weight

IntroductionDamage modes during vehicular impacts

24Texas I45 Bridge Accident in 2014.

Primarily shear failure mode dominant during accidents.

Presenter

Presentation Notes

For example, Liu (2012) investigated the impact of a single unit truck model in LS-DYNA on piers of a three span bridge with three column pier bent. The numerical model of the bridge with the truck is shown in figure 6.

Material ModelsConcrete and Steel Material Models in LS-DYNA

25

Mat ID Mat Name Characteristics and ImplementationMat 17 Isotropic Elastic-Plastic With

Oriented CracksDoes not consider the pressure hardening effect, strainrate effects, and damage softening effect. Potentialapplications include brittle materials such as ceramics aswell as porous materials such as concrete in cases wherepressure hardening effects are not significant.

Mat 72 MAT_CONCRETE_DAMAGE Widely used for simulating blast and impact in concretestructures.

Mat 96 Brittle Damage Model Mainly used to simulate cracks due to tensile stress.

Mat 111

Johnson-Holmquist Concrete Model

Used for concrete subjected to large strains, high strainrates, and high pressure.

Mat 159

Continuous Surface Cap Model

Developed to simulate the deformation and failure ofconcrete in roadside safety structures impacted byvehicles

Mat 3 Plastic Kinematic This model is widely used to simulate isotropic andkinematic hardening plasticity considering rate effect.

Material ModelMat 3: Kinematic Plasticity Model for Steel Rebars

26

Elastic-plastic behavior with kinematic and isotropic hardening.

Material ModelCALIBRATION OF CONTINUOUS SURFACE CAP MODEL

Impact Test by Fujikake et al. (2009)

27Geometry and rebar detailing of the RC beam specimen.

28

RC beam hammer impact test setup.


Impact Test by Fujikake et al. (2009)

29


Default CSCM Parameters

30


Parameters Gf 0.4_1_0.4

31


Parameters Gf 0.4_1_0.4

32

Details of shear test setup. (Priestley et al. 1994)


Shear Failure Simulation

33

Column Damage Levels.


Shear Failure Simulation

Large Scale Testing and Simulation

34

Conceptual model of the pier-bent structure for testing and pendulum test frame system.

35

Generation of impact force time history of the impactor.

Large Scale Testing and SimulationDesign of the Impactor

36

Setup of field test.

Large Scale Testing and SimulationTest Setup

Impact Test

38

Permanent crack pattern on four sides of weak pier

Cracks on Impacted Weak Pier

Large Scale Testing and SimulationTest Results

39

Crack evolution for the weak pier impact.

Crack Development on Impacted Pier


40Permanent crack pattern of four sides of strong pier.


Cracks on Impacted Weak Pier

41

Finite element model with mesh size 1.5 inch (38 mm).

Large Scale Testing and SimulationFinite Element Validation

42

Computational model of pendulum impactor.


43

Pendulum nose crash process.

Impactor Crash Process

Large Scale Testing and SimulationEXPERIMENTAL VS. COMPUTATIONAL RESULTS

44

Test result of impact force and velocity of point A.


45

Critical points displacement for the impacting into the weak and strong column scenario.

Displacement Time History



46

FE model of tractor-semitrailer in LS-DYNA.

Truck Model

47

Engine impacts with the rigid steel pier during test and simulations.

Trailer impacts with pier during test and LS-DYNA simulation.

Heavy Vehicle SimulationTruck Model

48

Impact force time histories during the test and FEM simulation in LS-DYNA.


49

Whole Bridge Pier bent Model

Heavy Vehicle SimulationModeling of Pier

Displacement time history at impact point

50

Heavy Vehicle SimulationModeling of Pier

Fixed-FixedModel of piersufficient

51

Heavy Vehicle SimulationNumerical Simulation Setting

52

Heavy Vehicle SimulationExample Piers

53

Pulse model for impact force time history for impact by single unit truck on bridge piers.

Single Unit Trucks

Heavy Vehicle SimulationModelling of Vehicular Impact Force

54

Time history for impact force by the tractor-semitrailer on a rectangular concrete pier.

Heavy Vehicle SimulationVehicular Impact Force for Tractor-Semitrailers

55

Proposed triangular pulse model for heavy vehicle impacts on bridge pier.


56Contours of impact force distribution along the height of the pier for case

P36_V50_M40 (unit: kips).

Points of Application of Pulse Impact


57

Application of impact pulse loading function of the pier.

Points of Application of Pulse components


58


Damage Modes and Displacement time-histories for P3_V50_M40 case.

Heavy Vehicle SimulationParametric Study: Effect of Impact Velocity

59

0

200

400

600

800

1000

1200

20 40 60 80

Impa

ct fo

rce

(Kip

s)

Velocity (mph)

F1

0

100

200

300

400

500

600

20 40 60 80

Impa

ct fo

rce

(Kip

s)Velocity (mph)

F2

0

400

800

1200

1600

2000

20 40 60 80

Impa

ct fo

rce

(Kip

s)

Velocity (mph)

F3

050

100150200250300350

20 40 60 80

Impa

ct fo

rce

(Kip

s)

Velocity (mph)

F4

0

200

400

600

800

1000

20 40 60 80

Impa

ct fo

rce

(Kip

s)

Velocity (mph)

F5

60

0

0.005

0.01

0.015

20 40 60 80

Tim

e (s)

Velocity (mph)

T1

0.000

0.010

0.020

0.030

0.040

20 40 60 80

Tim

e (s)

Velocity (mph)

T2

0.000

0.010

0.020

0.030

0.040

0.050

20 40 60 80

Tim

e (s)

Velocity (mph)

T3

0.000

0.020

0.040

0.060

0.080

0.100

20 40 60 80

Tim

e (s)

Velocity (mph)

T4

Heavy Vehicle SimulationParametric Study: Effect of Impact Velocity

61

0

200

400

600

800

1000

1200

28 33 38 43

Impa

ct fo

rce

(Kip

s)

Pier size (in)

F1

30 mph

50 mph

70 mph

0100200300400500600700

28 33 38 43

Impa

ct fo

rce

(Kip

s)Pier size (in)

F2

30 mph

50 mph

70 mph

0200400600800

10001200140016001800

28 33 38 43

Impa

ct fo

rce

(Kip

s)

Pier size (in)

F3

30 mph

50 mph

70 mph

050

100150200250300350400

28 33 38 43

Impa

ct fo

rce

(Kip

s)

Pier size (in)

F4

30 mph

50 mph

70 mph

0

200

400

600

800

1000

1200

28 33 38 43

Impa

ct fo

rce

(Kip

s)

Pier size (in)

F5

50 mph

70 mph

Heavy Vehicle SimulationParametric Study: Effect of Pier Size

62

0.000

0.005

0.010

0.015

0.020

28 33 38 43

Tim

e (s)

Pier size (in)

T1

30 mph

50 mph

70 mph0.0000.0050.0100.0150.0200.0250.030

28 33 38 43

Tim

e (s)

Pier size (in)

T2

50 mph

70 mph

0.0000.0100.0200.0300.0400.0500.060

28 33 38 43

Tim

e (s)

Pier size (in)

T3

30 mph

50 mph

70 mph0.0000.0200.0400.0600.0800.1000.120

28 33 38 43Ti

me (

s)Pier size (in)

T4

30 mph

50 mph

70 mph

Heavy Vehicle SimulationParametric Study: Effect of Pier Size

63

0200400600800

10001200

10 30 50

Impa

ct fo

rce

(Kip

s)

Truck weight (US ton)

F1

30 mph

50 mph

70 mph

0200400600800

10 30 50

Impa

ct fo

rce

(Kip

s)


F2

30 mph

50 mph

70 mph 0

500

1000

1500

2000

10 30 50Impa

ct fo

rce

(Kip

s)


F3

30 mph

50 mph

70 mph

-100

100

300

500

10 20 30 40 50Impa

ct fo

rce

(Kip

s)


F4

30 mph

50 mph

70 mph 0200400600800

1000

10 30 50Impa

ct fo

rce

(Kip

s)Truck weight (US ton)

F5

50 mph

60 mph

70 mph

Heavy Vehicle SimulationParametric Study: Effect of Truck Weight

64

0.000

0.005

0.010

0.015

0.020

10 20 30 40 50

Tim

e (s

)


T1

30 mph

50 mph

70 mph0.000

0.010

0.020

0.030

0.040

0.050

10 20 30 40 50

Tim

e (s

)


T2

30 mph

50 mph

70 mph

0.000

0.010

0.020

0.030

0.040

0.050

0.060

10 20 30 40 50

Tim

e (s

)


T3

30 mph

50 mph

70 mph

0.000

0.020

0.040

0.060

0.080

0.100

10 20 30 40 50

Tim

e (s

)


T4

30 mph

50 mph

70 mph

Heavy Vehicle SimulationParametric Study: Effect of Truck Weight

65

Heavy Vehicle SimulationPulse Parameters Based on Nonlinear Regression

66

Heavy Vehicle SimulationTruck Impact Versus Pulse Loading

67

Distribution of impact force pulse around the diameter of a circular pier

Heavy Vehicle SimulationCircular Piers

68

Heavy Vehicle SimulationCircular Piers

Performance-Based Design ApproachHeavy Vehicle Impacts

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Concept developed primarily in earthquake engineering.

Performance-based design philosophy entails estimation ofseismic demands in the system and its components andchecking to see if they exceed the capacity associated with arequired performance objective for a given hazard intensitylevel.

Commonly accepted performance levels:

Immediate Occupancy (IO)

Collapse Prevention (CP)

Only preliminary development in PBD for vehicular impacts.

70

Capacity Design of Bridge Piers

Capacity design is the process whereby plastic hinge mechanisms arepromoted by providing over strength in shear at critical locations. Plastichinging is a more ductile mechanism than shear failure and can lead toincreased collapse resistance.


71

Shear Failure Versus Ductile Failure


Shear failure of bridgepiers: Not Preferred

Flexure failure of bridgepiers: PreferredCapacity design reducesthe occurrence of shearfailure

72


Reduction in shear deformation

(a) (b) (c)Circular section

Non-capacity designed

Capacity designed

*NC – non capacity design, *C – capacity designed PR: Plastic rotationSD: Shear distortion

• Effect of capacity design

73

(a) Minor damage. (b) Moderate damage. (c) Severe damage.

Examples of the various modes of failure by the heavy truck impact

Performance-Based Design ApproachDesign Framework

Direction of impact

Minor cover damage

Some plastichinging

Some sheardistortion, but core intact

Zone with shear cracking and largeshear distortion

Well developed plastichinge region

Shear cracks and deteriorations in core

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Impacts by Tractor-Semitrailer

Performance-Based Design ApproachDesign Framework

Minor damage

Moderate damage

Severe damage

Minor damage

Moderate damage

Severe damage

Max(D1, D2)/C

• D1: base shear from bumper impact.• D2: base shear from engine impact.• C: shear capacity of the full section.

• D3: base shear from trailer impact.• Cs: shear capacity of the stirrups.

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Performance-Based Design Procedure

STEP 1Strength/service

design.

STEP 3Select D/C.

STEP 4Try a pier size.

STEP 5Find D1, D2, D3

using pulse model.

STEP 6Stirrups check.

C = Max(D1, D2)/(D/C)

STEP 7Check plastic hinge.

2*Mdesign / 5 (ft) < Cdesign

STEP 2Select V and W.

STEP 8Check performance.Max(D1, D2)/Cdesign

D3/Cdesign or D3/Csdesign

76

Selected cases for validation of proposed method.

Case Truck characteristics

Columnsize

Columnheight D2/Cdesign

D3/Cdesign(D3/Csdesign)

Predicted damage

level

Max(SD, PR)

Actual damage

level

1 50mph_80kips 39in-circular 20 ft 1.40 0.64 Minor 0.003 Minor

2 60mph_80kips 33in-square 20 ft 2.22 1.31 Severe 0.161 Severe

3 60mph_40kips 33in-square 18 ft 2.25 0.78 Moderate 0.030 Moderate

4 60mph_60kips 33in-square 20 ft 2.22 1.10 Moderate 0.059 Moderate

5 40mph_80kips 33in-square 20 ft 1.85 0.55 Minor 0.003 Minor

Performance-Based Design Procedure

• D2: base shear from engine impact.• D3: base shear from trailer impact.• C: shear capacity of the full section.• Cs: shear capacity of the stirrups.

• SD: Shear distortion• PR: Plastic rotation

600 Kips AASHTO Versus Actual Impact

• Design 36” pier for 600 kips• Tractor-semitrailer (80,000 lb)

77

70 mph 50 mph 30 mph

Direction of impact

78

AASHTO PBD (moderate)

Concrete 36”x36”x192” 36”x36”x192”

Longitudinal rebar

12 #11 12 #11

Stirrups #6 @12” #6 @6”

AASHTO design Performance-based design (moderate)

600 Kips AASHTO Versus Performance-based design

• Tractor-semitrailer: 70 mph, 80,000 lb

Table. Design comparison

SUMMARY & CONCLUSIONS A performance based framework for design of piers against vehicular impacts has

been developed using calibrated models of piers and tractor-semitrailer truckbased on available test data.

A three-triangular pulse model was proposed for simulating impact by a tractor-trailer on bridge piers for design purposes.

A performance based approach for the design of bridge piers was developed byquantifying damage in terms of plastic rotation and shear distortion and theperformance in terms of demand / capacity (D/C) ratios.

The approach is simple enough for design office use and proposes three levels ofperformance immediate use, damage control and near collapse. Applicability ofthe proposed design approach was demonstrated through several cases that werenot included in the calibration of the proposed design method.

Limitations: Characteristics of the cargo: sand ballast. Pulse model parameters based on a single type of truck that had given

bumper characteristics and engine weight. Limited test data for calibration. No full scale performance verification.

79

80

Thank you Very Much.

performance based design for bridge piers impacted by

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