American Society of Civil Engineers


Cracking Mechanism and Simplified Design Method for Bottom Flange in Prestressed Concrete Box Girder Bridge


by Yiqiang Xiang, (Dept. of Civil Engineering, Zhejiang Univ., Hangzhou, Zhejiang 310058, China. E-mail: Xiangyiq@zju.edu.cn), Guobin Tang, (corresponding author), (Dept. of Civil Engineering, Zhejiang Univ., Hangzhou, Zhejiang 310058, China E-mail: tangguobin@foxmail.com), and Chengxi Liu, (Dept. of Civil Engineering, Zhejiang Univ., Hangzhou, Zhejiang 310058, China. E-mail: sd1207465@163.com)

Journal of Bridge Engineering, Vol. 16, No. 2, March/April 2011, pp. 267-274, (doi:  http://dx.doi.org/10.1061/(ASCE)BE.1943-5592.0000151)

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Document type: Journal Paper
Abstract: Serious cracking has occurred frequently in the bottom flange of box girders during construction in recent years. This paper aims at studying the cracking mechanism and countermeasures. The stress field in the bottom flange associated with the bottom continuity tendon is presented, and the propagation of cracks during tensioning is simulated by nonlinear analysis according to the actual construction sequence. A cracking mode, which is not easy to detect in field investigation, is illustrated through numerical and theoretical study. It is caused by the deficient shear strength of the bottom flange attributed to the void in tendon ducts. Based on numerical results and field investigation, four types of cracking in the bottom flange are proposed and discussed, and a simplified design method is recommended for control of cracking.


ASCE Subject Headings:
Girder bridges
Box girders
Concrete
Flanges
Cracking
Design

Author Keywords:
Bridge engineering
PC box girder
Bottom flange
Cracking mechanism
Simplified design method