在役混凝土简支梁有效预应力计算 - 交通运输工程学报 - 长安大学.pdf

第5 卷　第3 期 交 通 运 输 工 程 学 报 Vol.5　No.3 2005 年9 月 Journal of T raffic and Transportation Engineering Sept. 2005 :1 71-1 37(2005)0-3 004-7 05 刘龄嘉, 贺拴海, 赵小星 ( , 　7100 4) 　:为了对在役混凝土桥 结构永存预应力和实际承载能力进行评估,用后张法测试混凝土简支 在不同预应力值作用下的自振频率和在相同预应力值、不同竖向力值作用下的挠度, 以混凝土简支 的振动基频随预应力作用值的增大而有规律地增大为基础, 回归出简支 的有效刚度与预应力函 数表达式, 计算出PC 简支 的挠度计算值, 并与试验测试挠度值进行了比较。结果表明, 在混凝土受 拉区开裂前, T 型 和实心板 的计算结果误差均不超过10%, 其中实心板 有80%的测试数据误 差在±5%以内;空心板 的计算结果误差不超过15.71%, 有73.3%的误差不超过10%;用实测简支 基频和挠度可推算出简支 的有效预应力, 可进行预应力混凝土结构的安全评估。 :桥 工程;预应力混凝土简支 ;振动频率;挠度;有效预应力;试验 :U441.5　　　:A Effective prestress computation of existing PC simply-supported beam Liu Ling-jia, He Shuan-hai, Zhao Xiao-xing (Key Laboratory for Bridge and Tunnel of Shaanxi Province, Chang an University, Xi an 7100 4, China) Abstract:In order to evaluate the permanent prestress and structure loading capability of existing prestressed concrete bridge, the longitudinal pretensioning force w as enforced on the simply- supported concrete beam to gain its natural frequency and deflection by pos-t tensioning structure method. Based on the relation of its fundamental frequency increasing w ith its pretension force s increasing, a regression analysis of the data w as conducted to develop an equation of its effective stiffness, the computation value and the measure value of its deflection w ere compared. The analysis results show that the deflection errors of T and rectangular beams are w ithin 10%, the errors of hollow slab beam are w ithin 15.71%, w hich indicates that using the tested fundamental frequency and deflection can calculate simply-supported beam s effective prestress. 3 tabs, 4 figs, 11 refs. Key words:bridge engineering;PC simply-supported beam ;vibration frequency;deflection; ef