单箱多室波形钢腹板PC组合梁桥动力特性试验研究

摘要

为了研究单箱多室波形钢腹板PC组合梁桥动力特性,参照南昌市朝阳大桥非通航孔桥,制作了三跨单箱两室PC连续波形钢腹板试验梁,并对模型桥和实桥进行动力测试.分别利用自互功率谱法和传递率法对动力特性进行分析,识别了试验梁前四阶模态参数和实桥前七阶模态参数;同时利用ANSYS程序建立实桥和模型桥的有限元分析模型,并进行动力特性分析;研究结果表明,除因实桥两幅之间横向工字钢连接,导致实桥理论和实测扭转1阶频率相差较大外,实桥各阶理论与实测频率相差较小,振型一致;试验梁低阶频率理论值与实测值能较好吻合.研究设计制作的波形钢腹板缩尺试验梁及测试结果正确,试验梁能较好体现实桥动力特性;传递率法可较好识别该类桥梁结构的模态参数.%To study the dynamic characteristics of a multi-cell single-box continuous box girder bridge with corrugated steel webs,a scale-size test model beam was set up based on a non-navigable span bridge of Chaoyang Bridge in Nanchang Jiangxi province.The modal analysis methods of cross-power spectrum density method and transmissibility method were used to analyze the model beam and the real bridge.The first four order modal parameters of the model beam and the first seven order modal parameters of the real bridge were identified;The software ANSYS was used to build up the spatial finite element model of the model beam and the real bridge and analyze their dynamic characteristics.Compared the test results and finite element calculation results of the real bridge,the error was small and vibration modes were consistent,excepted for the first order torsional vibration of the real bridge,because the dense beams between the south bridge and the north bridge were equipped to connect the two bridges,which led to the big errors.Compared the test results and finite element calculation results of the model beam,the error was small at low frequencies.The methods to set up the model beam and modal analysis results were effective,and at the same time the transmissibility method could be precise to identify the modal parameters of a bridge with corrugated steel webs.