Temporary Bearing Method in Construction of Continuous Beam Bridge Erected as Simply-Supported Beam

Mehadi Hassan Rabby,Miaoqiang Huang,Zhipei Guo

doi:10.4236/ojce.2018.84033

Abstract

The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are presently designed as simply-supported beam bridge. The main disadvantage of this type of bridges is that, the seismic resistance is weak, and under the external force beyond the design range, the bridges are more likely to fall in danger because of failure in girders. Also they have expansion joints for each span, which affects the comfort of driving and the overall integrity of the bridge deck is poor [1]. Therefore, design and construction of the bridges have been revised to establish continuity between girders of two adjacent spans and transform the bridge as simply supported continuous beam bridge [2]. Temporary bearing (sandbox) method is proposed in this paper to solve the system transformation of continuous beam bridges. Design of the temporary bearing is very simple and can be manufactured at site. This method has been proved in construction of Arial Kha Bridge and can be applied for other similar bridges in Bangladesh.

Highlights

IntroductionTo cast the end joint at site, the girders of adjacent two spans need to be placed at their desired position against the permanent bearing pad with the help of temporary support
The present practice in Bangladesh for erection of girders is placing the girder directly on the bearing pad and joining the adjacent two spans in deck slab level by adopting expansion joints, as the bridges are presently designed as -supported beam bridge
Construction of the bridge is very smooth and speedy compared to the present practice which has been proved in construction of Arial Kha Bridge

Summary

Introduction

To cast the end joint at site, the girders of adjacent two spans need to be placed at their desired position against the permanent bearing pad with the help of temporary support. After gaining the target strength at the “Cast-in-situ” girder joint section, and after completion of stressing and grouting for negative moment tendons, temporary bearing is released and the girder is placed on the permanent bearing pad [3]. When the temporary bearing is removed, the beam body can be uniformly and stably placed on the fixed bearing pad. Using this method, construction of the bridge is very smooth and speedy compared to the present practice which has been proved in construction of Arial Kha Bridge

Design and Calculation

Production and Application

Case Study

Conclusion and Recommendation