Study On Structural Reliability Of Concreete Girder Bridge In High Speed Railway

In recent years, the advancement of science and engineering promotes the rapid development of high-speed railway around the world. In China, it has basically formed the4vertical and4horizontal backbones by the end of2013, and the national high-speed railway mileage will reach more than18000km by2015. The rapid improvement of world-wide high-speed rail promotes the railway engineering design methods finer. The current domestic railway bridge design codes are still carried out in accordance with the allowable stress method. And the railway department currently and actively promotes the scientific research and revision of the railway engineering design codes, which is based on the theories of probability, statistics, reliability, and structure limit state. Therefore, it is necessary to study and discussion the reliability of high-speed railway bridges.Firstly, it has a discussion about structure reliability theories, structural reliability calculation methods, and ANSYS probabilistic FEM design technology, calculation methods of reliability and procedures, etc. Secondly, it introduces the characteristics and types of high-speed railway bridges at home and abroad, and summaries the probabilistic distribution of resistances and loads and their statistical parameters. On this basis, it derives the reliability simplified formula based on flexural ultimate limit state in the mid-span section of prestressed concrete simply supported beam. Besides, taking simply supported beam with common spans of24m and32m, and continuous beams of (32+56+32) m,(40+56+40) m and (48+80+48) m as the engineering backgrounds, it conducts a comparison and analysis of differences of reliability indexes by a second order method and ANSYS probabilistic FEM, as well as the correlation, sensitivity, performance function fitting etc. Finally, by the comparing the ZK loading and China Railway Standard Live loading (CR Live loading), the reliability indexes of ultimate and serviceability limit state have been checked in the middle section of side-span and mid-span of the (40+56+40) m continuous beam bridge.. As a result, the reliabilities on the main midspan section in stress of ultimate limit state under ZK loading and China Railway Standard Live loading are greater than4.7; and that of serviceability limit state greater than t the recommended value of1.0to3.0.It conducts the reliability analysis of often-used pre-stressed concrete girder bridges and has summaries of results, which can provide a reference for the revise and reform of the high speed railway bridge design code.