Apply To New Live Load Standard Railway Bridge Power Factor

The train live load mode of our high-speed railway is ZK live load. Their corresponding dynamic coefficients are quoted from the UIC load. With high-speed railway operational mileage large increasing in our country, it is necessary to further analysis dynamic coefficient formula of ZK live load. This paper takes part of some existing and under construction simple supported beam bridges, continuous girder bridges and continuous rigid-frame bridges as the research objects, analyses the rationality of dynamic coefficients of existing bridge codes, so as to provide reference for establishing the dynamic coefficients for ZK live load. The major work are as follows:(1) The research history and status of bridge dynamic coefficients at home and abroad in recent years are summarized, the bridge dynamic coefficient calculation methods of some countries'standards are briefly introduced, and the necessity of the study of dynamic coefficients of ZK live load applicable in our country is expounded.(2) Beam segment element and space beam element are used to establish numbers of typical bridges'dynamic space finite element analysis model, and the vibration characteristics of these bridges are analyzed and calculated; also the train-bridge system dynamics analysis mode is established for simulation calculation and analysis of bridge operation dynamic coefficients.(3) Through the simulated calculation and analysis of various typical bridges'train-bridge system space dynamic response when the high-speed train passes by, bridge operation dynamic coefficients under various operating conditions are obtained; peak speed along variation trend and theoretical resonance speed are analyzed and compared, which is shown that the two results coincide with each other well.(4) According to the contrast analysis of the equivalent linear load of train loads and ZK live load which have multiplied by operation dynamic coefficients and design dynamic coefficients separately, the rationality of dynamic coefficients of existing bridge codes are studied. The results show that the current calculation formula for dynamic coefficients of bridge rules tends to be conservative in bridge design, and the continuous girder bridge tends to be more conservative than simply supported beam bridge and continuous rigid-frame bridge, so it is necessary to further perfect the dynamic coefficient calculation formula for current specification.