虎门大桥跨越珠江干流狮子洋出海航道，为联系粤东、粤西、深圳与珠海两经济特区、香港与澳门两特区的交通枢纽，主航道采用主跨为888m的双铰简支悬索桥。为实时监测桥梁结构振动状况和记录大型桥梁真实地震反应，在虎门大桥悬索桥东西主塔、箱梁上架设了总计36通道的强震动监测系统。本文简要介绍了该监测系统的测点布置、系统构成和技术特点，并重点对系统在2013年2月22日河源4.8级地震中的强震动记录进行了分析，讨论了由于局部场地条件差异引起的多点地震动输入问题。

 Humen Bridge is located at the estuary of the Zhujiang (Pearl) River carrying the Guangzhou-Shenzhen-Zhuhai Superhighway which links up Guangzhou City to the Shenzhen and Zhuhai Special Economic Zones, Hong Kong and Macau. Its main channel is a long span steel suspension bridge with a main span of 888m. To monitor its real-time vibration and capture possible earthquake responses, a vibration monitoring system comprising 36-channel accelerometers has been set up at its main span. The location of sensors, equipments and technical features of the monitoring system are briefly introduced first in this paper. Then the strong motion records in Heyuan M4.8 earthquake on Feb. 22, 2013 are analyzed. The multi-supported input phenomenon caused by local site effect was identified and discussed.