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A Research On The Mechanical Behavior Of Partially Concrete-Filled Steel Box-Section Bridge Piers

Posted on:2012-07-12Degree:MasterType:Thesis
Country:ChinaCandidate:Y D WangFull Text:PDF
GTID:2132330338483997Subject:Structural engineering
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With the accelerating pace of our modernization development, highway bridge construction is becoming a very important factor which influences the rapid development of society and economy. In recent years, the earthquake occurred frequently, which has caused great destruction to the bridge facilities in the earthquake areas. During these big disasters, a large quantity of the damages to the bridges is due to the invalidation of the lower part of the bridges, which eventually leads to the failure of the whole structures, especially for those reinforced concrete piers because of its heavy self-weight and poor ductility. Compared with reinforced concrete piers, steel piers have higher strength and better seismic performance, and with their characteristics of convenience as well as less area-taking, they have been extensively constructed in many developed countries. However, the steel piers are still likely to suffer from local deformation failure when the earthquake occurred. It has been proved that filling concrete into the steel piers is an efficient method to improve the ductility behavior of steel bridge piers.When the concrete is filled into the steel piers, the interaction behavior between steel plate and concrete can efficiently improve the strength and ductility of steel piers. Although the finite element formulation has been proposed by some researchers, they didn't account for the slide and un-bonding behaviors between steel plate and concrete. On the basis of previous researches on the partially concrete-filled steel piers, the main contents of this thesis include the following four parts.(1) By employing the finite element program DIANA to carry out a series of numerical analyses, the influence of some parameters on the mechanical behavior of partially concrete-filled steel box-section piers has been investigated. The results show that with the increase in the filled-in concrete, the ultimate strength and ductility of the piers are greatly improved. And the ductility of the piers decreases as the increase in width-thickness ratio of flange plate and the slenderness ratio of the piers.(2) The effect of interface behavior between steel plate and concrete on the ductility behavior of the piers has been studied by adopting numerical analysis method. It is concluded that the ductility behavior of the piers can be greatly improved by completely bonding the steel plate with concrete in the case of a 50% height of filled-in concrete.(3) The hysteretic behavior and failure modes of the piers subjected to a constant vertical load as well as a cyclic horizontal loading have been investigated through experiments. The experimental results indicate that concrete-filled steel piers have good hysteretic behavior, and the height of filled-in concrete and flange plate width-thickness ratio have great effects on the hysteretic behavior of the piers. After consolidating the steel plate and concrete with some welded nails between them, energy-absorption capacity of the piers can be obviously improved.(4) The numerical analytical results coincide well with the experimental results, which indicate that the proposed finite element formulation can be used to predict the mechanical behavior of the partially concrete-filled steel piers with great accuracy.The mechanical behavior of partially concrete-filled steel box-section piers subjected to a constant vertical load and a monotonic or cyclic horizontal loading are investigated by combining the accurate finite element formulation with related experiments in this thesis. However, further studies on some issues are still required in the future.
Keywords/Search Tags:partially concrete-filled steel bridge pier, numerical analysis, experimental study, ductility behavior, hysteretic behavior, failure mode
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