experimental study on seismic performance of laminated-...

Experimental Study on Seismic Performance of Laminated-Rubber Bearings as Structural Fuses

Department of Bridge Engineering, Tongji UniversityNailiang Xiang

The 7th Kwang-Hua Forum on Innovations and Implementations

in Earthquake Engineering Research9-11 December 2016, Shanghai, China

xiangnailiang@gmail.com

Introduction1

Quasi-static testing2

Shake-table testing3

Conclusions4

1 Introduction

Introduction

Ø Support length in longitudinal direction

Ø Concrete shear keys in transverse direction

Ø Without any connection except friction

Ø Directly placed between the superstructure and the substructure

Typical installation details of laminated-rubber bearings in China

Introduction

Sliding of laminated rubber

bearings

Concrete shear keys failure

Expansion joints damage

Ø 2008 Wenchuan earthquake

Ø Small to medium-span bridges

Ø Damage investigation

Ø Typical earthquake damages

Introduction

Bridge span collapse due to inadequate pier-girder support

length

Detail A Detail B

Introduction

Sliding of laminated rubber

bearings

Excessive girder displacements

Damage of shear keys, abutments, expansion joints due to pounding

Minor damage of substructures

Excessive pier-girder relative displacements

Bridge span collapse due to

inadequate support length

Typical Damage Process of Highway Bridges in Wenchuan Earthquake

2 Quasi-static testing

9

Quasi-static testing

Vertical Loading ArmTop Steel Plate

Bearing Specimen

Displacement Gage

Bottom Steel PlateHorizontal Loading Arm

Rollers

Testing apparatus Testing setup

Cyclic loading protocol Testing process

10

Quasi-static testing

Monotonic force-displacement curves Cyclic force-displacement curves

11

Quasi-static testing

Effect of normal pressure and loading velocity on the friction coefficients of bearings

3 Shake-table testing

13

Shake-table testing

Setup of a quarter-scale bridge model Installation of laminated-rubber bearings

A Northridge earthquake wave A response spectrum-compatible artificial wave

14

Shake-table testing

Hysteretic force-displacement curves of laminated-rubber bearings subjected to Northridge wave

15

Shake-table testing

Hysteretic force-displacement curves of laminated-rubber bearings subjected to artificial wave

16

Shake-table testing

Peak measured strains in longitudinal steel bars in piers

4 Conclusions

18

Conclusions

1

4

2

3

The coefficient of friction is inversely related to normal pressure, while positively related to velocity;

The sliding of laminated-rubber bearings can act as fuses, dissipating large amounts of earthquake energy and providing an isolated response for substructures;

Design strategy considering the sliding of laminated-rubber bearings is simple and cost-effective, compared with some conventional isolation bearings;

Future research will mainly focus on the calibration of the proposed design strategy.

Thanks for your attention!

Department of Bridge Engineering, Tongji UniversityNailiang Xiang

The 7th Kwang-Hua Forum on Innovations and Implementations

in Earthquake Engineering Research9-11 December 2016, Shanghai, China

xiangnailiang@gmail.com