Study on Some Technical Difficulties of Tianjin Haihe Bengbu Bridge

摘要

Tianjin Haihe Bengbu Bridge is built in CBD of Tianjin city and cross the Haihe river, it is dissymmetrical steel bridge of three dimensions Beam-Arch Combination System. Its bearing capacity depends upon two groups of spatial structures which consist of longer on, crossbeam, longitudinal arches and transverse arches. The bridge is complex for mechanical and tectonic consideration. In this paper, some technical difficulties in the bridge design and construction process was introduced , including the following:(1) The load-bearing behaviour of the supports of Tianjin Haihe River Bengbu Bridge are instinctive from each other. The 2nd support of 1st and 6th abutment are designed specially for carrying tensile and shearing load, compression and hearing load, alternatively. The 3rd supports of the 2nd and 5th piers are designed specially for carrying large-tonnage shearing as well as compression loads. The full-scale model was established, two loading project s of loading combinations were adopted, and the static behavior of the supports of abutment was analyzed. The full scale test revealed the rule of loading-vertical displacement and loading-lateral displacement . The reliability and safety of the bearings were verified. Some of the issues that needed to be considered in the real bridge const ruction were also discussed. The analysis result s can be used as reference for practical engineering.(2) The bracing member of abutment 1st and 6th are designed specially, which connect the main girder of the bridge and the rubber bearing of abutment. These buttress braces are designed uniquely in the world. , in order to transfer large-tonnage axial load, including compressive force and tensile force, to bearings. The loading behavior of them are significant effect to the security of the bridge and need to be analyzed specially. In this paper, a 1: 2.5-scale model is made, destructive experiment of experimental member is done. Through experiment, stress distribution of experimental member is detected, and work status at tension and compression load is also researched. Through analysis of experimental data the reliability and safety of the bearings are verified, this structure of bracing member is doable.(3) The Application of aluminum alloy bridge deck has no precedent in China. Tianjin Haihe Bengbu bridge firstly uses the aluminum alloy bridge in domestic, so we need the special test to study on it, for ensuring the safety. Through the static loading test of two kinds of decks in different size, we can determine the static bearing capacity of bridge deck and verify the performance of connecting part. The line friction test of standard specimens was adopted, and the aluminum alloy bridge deck's wear life is calculated by a model proposed in this paper. The electrochemical test was conducted to get the corrosion rate and etching figures in the simulating atmospheric environments. The result shows that the bridge deck has good static bearing capacity and the connecting part meets the quality requirements. Finite element analysis calculation also verifies the reliability of the test result. In summary, the test indicates that the bridge deck and connecting part both meet the requirement of the static loading, moreover, it also further explores the performance of the aluminum alloy, a kind of new building material.By experimental research, safety of the rubber bearing of abutment and the bracing member of abutment are verfied,Applicability of aluminum alloy bridge deck is verified.