Performance of Pipe Extender–Shear Key at In-Span Hinges of Multiframe Bridges

Abstract

In multiframe bridges, shear keys are elements located at in-span hinges. They preserve the transverse integrity of adjacent frames during seismic events. In-span hinges must simultaneously accommodate longitudinal and transverse seismic deformations to prevent unseating and collapse. The California Department of Transportation has standardized a shear key detail known as the pipe extender–shear key (PE-SK). In some cases, cable restrainers pass through the PE-SK. This detail serves three functions: (a) it acts as a shear key for transverse motion, (b) it provides cable restraint to prevent unseating, and (c) it is a backup against unseating if the cables rupture. The transverse capacity and stiffness of this detail have not been fully investigated. In this paper, findings from finite element analyses performed to study the load–deformation behavior of the PE-SK with varying longitudinal gap sizes are discussed. A refined three-dimensional finite element model of the detail was developed with Abaqus. The model was validated by using data from previously conducted push-off experiments. The analyses demonstrated that (a) the pipe shear key detail is ductile under lateral loading and maintains its resistance under large transverse displacements, (b) the lateral capacity and stiffness of the pipe shear key vary with the size of the longitudinal gap, and (c) cyclic loading may significantly reduce the lateral stiffness of the element. Stresses and deformation in the concrete suggest that a steel collar may be useful in preventing concrete crushing at the contact surface. Tensile force in the cable restrainers has no effect on the transverse performance of the detail.

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References

Hube

M. A.

, and Mosalam

K. M.

. PEER 2008/103: Experimental and Computational Evaluation of Current and Innovative In-Span Hinge Details in Reinforced Concrete Box-Girder Bridges. Pacific Earthquake Engineering Center, Berkeley, Calif., 2008.

DesRoches

, and Fenves

G. L.

. Design Procedures for Hinge Restrainers and Hinge Seat Width for Multiple-Frame Bridges. Technical Report MCEER-98-0013. Multidisciplinary Center for Earthquake Engineering Research, University of California, Berkeley, 1998.

Yashinsky

Recent Change to Seismic Design Practice in California. Office of Earthquake Engineering, California Department of Transportation, Sacramento, 2013.

Mehrraoufi

Seismic Transverse Response of Multi-Frame Bridges. PhD dissertation. University of Connecticut, Storrs, 2015. http://digitalcommons.uconn.edu/dissertations/762/.

Nutt

R. V.

Comprehensive Design Example (California Bridge). Multidisciplinary Center for Earthquake Engineering Research, 2005. https://mceer.buffalo.edu/research/HighwayPrj/Workshops/Portland/IVa-5-Nutt.pdf.

Restrepo

J. I.

, and Panagiotou

. BART Aerial Guideway Shear Key Tests. University of California, San Diego, 2005.

Zaghi

A. E.

, and Saiidi

M. S.

. Seismic Design of Pipe–Pin Connections in Concrete Bridges. Center for Civil Engineering Earthquake Research, Reno, Nev., 2010.

Zaghi

A. E.

, and Saiidi

M. S.

. Bearing and Shear Failure of Pipe–Pin Hinges Subjected to Earthquakes. Journal of Bridge Engineering, Vol. 16, No. 3, 2011, pp. 340–350. https://dx-doi-org.web.bisu.edu.cn/10.1061/(ASCE)BE.1943-5592.0000160.

XS7-070: Restrainer Details for Pipe Extender/Shear Key (New). Bridge Standard Detail Sheets. Division of Engineering Services, California Department of Transportation, Sacramento, July 2014.

10.

Hipley

Bridge Retrofit Construction Techniques. Presented at 2nd National Seismic Conference on Bridges and Highways, Sacramento, Calif., 1997.

11.

Restrainer Material Properties and Design. Bridge Design Aid 14-1A. California Department of Transportation, Sacramento, July 2008.

12.

Abaqus 6.11-1 User’s Manual. Dassault Systems, Paris, 2011.

13.

Zaghi

A. E.

, and Saiidi

M. S.

. Seismic Performance of Pipe–Pin Two-Way Hinges in Concrete Bridge Columns. Journal of Earthquake Engineering, Vol. 14, No. 8, 2010, pp. 1253–1302.

14.

Popovics

A Numerical Approach to the Complete Stress–Strain Curve of Concrete. Cement and Concrete Research, Vol. 3, 1973, pp. 583–599.

15.

Steel Construction Manual, 14th ed. American Institute of Steel Construction, 2011.

16.

Baltay

, and Gjelsvik

. Coefficient of Friction for Steel on Concrete at High Normal Stress. Journal of Materials in Civil Engineering, Vol. 2, No. 1, 1990, pp. 46–49.

17.

Rabbat

B. G.

, and Russell

H. G.

. Friction Coefficient of Steel on Concrete or Grout. Journal of Structural Engineering, Vol. 111, No. 3, 1985, pp. 505–515.

18.

Choo

Y. S.

, Quah

C. K.

, Shanmugam

N. E.

, and Liew

J. Y. R.

. Static Strength of Plate Trunnions Subjected to Shear Loads—Part I: Experimental Study. Journal of Constructional Steel Research, Vol. 58, No. 2, 2002, pp. 301–318.