预应力混凝土T梁桥端部锚固区拉压杆模型及配筋设计  

Strut-and-tie models for end anchorage zones in prestressed concrete T-section girder bridges and reinforcement design

作　　者：林波[1] 刘钊[1] 郑和晖[1] 王景全[1] 

机构地区：[1]东南大学混凝土及预应力混凝土结构教育部重点实验室,南京210096

出　　处：《东南大学学报（自然科学版）》2009年第S2期118-125,共8页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(50778038);教育部博士点基金资助项目(20070286097)

摘　　要：根据有限元应力分析结果,抽象出力流传递路径,提出了T梁端部锚固区拉压杆模型的构形方法.通过对劈裂应力的数值积分,计算合力作用点位置,并将其作为拉杆位置确定的依据.分析表明,由于T梁端部锚固力的合力对截面形心的偏心距不大,劈裂应力合力作用点至锚固端的距离与梁高的比值,基本不受锚下预加力大小、梁高以及翼板宽度变化的影响,大小稳定在0.67~0.69之内.最后,应用该构形方法,得到了跨度为20~50m的T梁端部锚固区拉压杆模型,将由拉压杆模型计算出的劈裂力大小与精细化有限元分析结果进行了比较,其比值分布在1.16~1.34范围之内,由此可见,由拉压杆模型给出的劈裂力计算值与有限元分析结果之间相差不大,且偏于安全.According to the results of the finite element analysis,load paths were drawn and strut-and-tie models(STMs) for end anchorage zones in T-section girder bridges were proposed.Through integrating the bursting stresses along the tendon axis,the location of the resultant bursting force was obtained,which was taken as a basis to determine the location of ties.The results show that because the eccentricity of the resultant anchoring force from the center of the girder section is not great,the ratio of the space between the resultant bursting force and the anchor to the girder height is in the range of 0.67 to 0.69 and almost not influenced by parameters such as the magnitude of the tendon force,the girder height and the flange width.Finally,the STMs for end anchorage zones in T-section girder bridges with span varying from 20 to 50 m were constructed.At the same time,to evaluate the precision of the STMs for bursting forces presented in this paper,a comparison was carried out between the results from the STMs and those of the finite element solutions.The results indicate that the magnitudes of bursting forces obtained by the STMs are close to those obtained by finite element analysis and the ratios between them are in the range of 1.16 to 1.34.

关 键 词：拉压杆模型 劈裂力 端部锚固区 配筋设计 有限元分析 

分 类 号：U448.35[建筑科学—桥梁与隧道工程]