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The Study on Lateral Reinforcement for 32m Simply Supported PC Double T.Beam

Author: WangXinGang
Tutor: WangQiCai
School: Lanzhou Jiaotong University
Course: Bridge and Tunnel Engineering
Keywords: Prestressed Reinforcement Concrete Simply supported T Beam Lateral Reinforcement Modality Base frequency
CLC: U445.72
Type: Master's thesis
Year: 2008
Downloads: 162
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Abstract

The massive prestressed reinforcement concretes simply supported T beam bridge presents the lateral stiffness insufficient and the lateral oscillation ultra to limit on the existing track line, after six times railroad increased speeds in our country. These majority of the bridge be designed in the 1980s, which are two piece prestressed reinforcement concrete simply supported T beam bridge, and two piece of T beam longitudinal separates which is only connected in the cross slab. The lateral relation between two pieces of T beam is weak, the traffic load and the speed already were greatly higher than the original design value, also passed through more than 20 years, some of the bridge disease appears and develops rapidly, it reflected prominently ultra limited in the bridge crosswise oscillation amplitude.The emphasis studies in this article is the 32m prestressed reinforcement concrete two piece simply supported T.beam’s lateral reinforcement technology. Analysis simply supported T.beam’s vibration characteristic from T beam transverse vibration mechanism we can find out the dynamic performance parameter which manifests the rigidity of the beam. Exploration the basic reason of the prestressed reinforcement concretes simply supported T beam lateral stiffness insufficient. It can be find out through theoretical analysis that the lateral stiffness of beam is correlational with base frequency of beam; Moreover, the primary cause of the beam crosswise rigidity insufficient is the weakly relation between two pieces of T beam. Therefore, the reinforcement plan should start from strengthen two piece of T beam crosswise relation.In order to seek the practical effective reinforcement measure, it takes two piece 32m prestressed reinforcement concrete simply supported T beam as the study object in this article, the modality analysis model is established according to the beam body actual size with large.scale finite element analysis software ANSYS, carries on the space vibration characteristic analysis to the beam body. It mainly adopts increases the original cross slab thickness and the addition of horizontal cross slab to increases crosswise relation between two piece of T beam, and according to different parameter value of the crosswise relation to establish the ANSYS model and carry on the modality analysis separately, calculates the beam body crosswise and the vertical first step base frequency. Analyzes the change of crosswise and the vertical rigidity to the beam body according to crosswise and the vertical first step base frequency value change, which provides the theory basis for the determination reasonable reinforcement plan.The modal analysis result indicated that, the crosswise relation which is increased between two pieces of T beam can increase the lateral stiffness of the beam body effectively, but the vertical rigidity of the beam body will reduce with the increase of crosswise relation. Therefore, the reasonable reinforcement plan should be the crosswise rigidity enhances most and at the same time vertical rigidities reduce least to beam body.Two kinds of reinforcement plans have been determined in this article, which in foundation of analysis massive calculation data, and overall evaluation crosswise and vertical rigidity change. The No.2 reinforcement plan apply in Longhai track line increased speed road section 32m the prestressed reinforcement concretes simple support T beam bridge reinforcement improvement project. The bridge examination result indicated that, Beam body crosswise first step base frequency distinct enhancement. Beam body base frequency and cross crosswise maximum oscillation amplitude in Railroad Bridge Examination Standard in goods car or machine with load usual value scope. The practice proved this article proposed the crosswise reinforcement plan is successful. This reinforcement plan definite mentality also may provide the reference to other spans two piece the prestressed reinforcement concrete simply supported T beam’s crosswise reinforcement plan determination.

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