基于卡车加载和差分曲率的简支梁桥预警新指标

差分曲率指标在实际用于损伤识别时受到加载方式的限制.为此,首先采用了一种卡车加载方式,通过两次卡车加载可实现集中载荷的工况,并对简支梁桥建立起了相应的损伤识别方法,提出了新的"卡车载荷差分曲率指标(truck load difference curvature indicator,TLDCI)".基于实测的竖向位移数据得到的TLDCI图形可识别损伤的出现和位置信息,从而实现简支梁桥的状态预警.TLDCI方法的计算简单而且不需要与结构完好状态下的数据进行对比.所提出方法的有效性通过算例得到了证明,并最后讨论了提高其稳定性的措施.

NEW EARLY WARNING INDICATOR BASED ON TRUCK LOAD AND DIFFERENCE CURVATURE FOR BRIDGES OF SIMPLY-SUPPORTED BEAMS

The application of the difference curvature index for the damage detection is limited because of the loading mode.In this paper,a loading mode based on the truck is proposed.The working condition of the concentrated load can be obtained after the twice truck loading.A damage detection method for bridges of simply supported beams is established by a new indicator called the truck load difference curvature indicator (TLDCI).According to the measured vertical displacement data,a graph of the TLDCI can be established.The occurrence and the localization of the damage then can be identified and the early warning for the bridge damage can be realized.The TLDCI method involves a simple calculation and does not require the prior information of the intact bridge.Its effectiveness is validated by an example.Finally,how to improve the stability of this new method is discussed.