弯桥存在损伤时的位移影响线研究  

Analysis on Displacement Influence Line of Damage in Curved Girder Bridges

作　　者：魏婷婷[1] 张延庆[1] 张刚[1] 李起航 

机构地区：[1]北京工业大学建筑工程学院,北京100124

出　　处：《科学技术与工程》2014年第32期79-83,共5页Science Technology and Engineering

摘　　要：鉴于弯桥的竖向位移便于测量,其影响线反映移动荷载沿某条车道移动时某一观测点的位移变化规律,利用位移影响线二阶导数可以对弯桥进行损伤检测分析。采用梁格法建立分析模型,通过研究同一模型的不同横截面位置、不同程度的损伤与同一车道纵桥向不同观测点的影响线二阶导数关系,验证了影响线二阶导数对弯桥损伤位置及程度检测的有效性。根据以上研究的影响线二阶导数特点,定义影响线二阶导数在损伤位置相邻荷载作用点的平均值与损伤位置的差值,取绝对值作为评价检测敏感度的指标,指标越大表示检测敏感度越高。又通过研究相同跨径时,曲率半径从R=30 m变化至R=220 m的20个有限元模型两条车道的40组影响线数据,发现随着弯曲程度的增大,外侧车道的检测敏感程度也随之增大,而内侧车道则呈现相反趋势,同一条件下内侧车道的检测效果要好于外侧车道。In view of the displacement influence line which can reflect the vertical displacement change rule ina observation points when moving load moves along for a lane line, can be directly measured in practical engineer-ing. Using displacement influence line of the second derivative to detect and analyze the local damage of curvedbridge. With the analysis of curved girder bridge model by comparing the second derivative of the vertical displace-ment influence lines corresponding to the different cross section positions, different extent of damage and differentobservation points in longitude direction of the same lane, it can be learned that such a method can detect the posi-tion and extent of local damage in curved girder bridge. According to the characteristics of second derivative of verti-cal displacement influence line when damage exists in curved girder bridge, the difference between the damage lo-cation＇ s second derivative and the mean value of that at the adjacent load points was calculated, then the differ-ence＇ s absolute value was defined as the magnitude to evaluate the sensitivity of damage detection. When the spanis a constant, contrastively analyzing 20 finite element models whose curvature radius R ranges from 30 m to 220 mand 40 groups of data of vertical displacement influence line, results show that the outer lane＇ s sensitivity to damage detection goes up with the increase of curved bridge＇ s degree of crook, while the inner lane shows the contrarytrend.

关 键 词：弯桥 位移影响线二阶导数 检测 梁格法 弯曲程度 

分 类 号：U448.42[建筑科学—桥梁与隧道工程]