摘要
研究目的:为控制大跨度箱梁桥腹板斜裂缝的出现,对腹板主应力的两项影响因素,竖向预应力筋的构造形式和腹板厚度变化方式进行了研究。研究方法:在腹板厚度的各种变化形式下,采用桥梁分析软件对腹板主拉应力进行了计算和分析。同时,针对普通形式竖向预应力筋的缺点,提出了另外两种竖向预应力筋的布置构想;并采用Ansys软件对竖筋各种构造形式下的腹板主应力进行了空间有限元对比分析。研究结果:得出了腹板厚度不同变化情况下的腹板主应力曲线;竖向预应力筋不同构造形式下腹板主应力变化曲线和局部梁段节点第一主应力云图。研究结论:(1)腹板厚度变化方式的取用是一个重要的裂缝控制因素,应尽量采用较为缓和的变化方式。(2)与普通型竖筋相比,U型竖筋的优势是可以使U型区域内的腹板混凝土受到整体预压应力作用,限制腹板主拉应力的出现和大小。新型竖筋构造形式对腹板主应力的影响分析,对连续体系箱梁的竖筋合理布置提供了参考意见。
Research purposes： For controlling the appearance of web inclined crack in large span box girder bridge, the paper researched on two influence factor of web＇ s principle stress, which involved the construction form of vertical prestressed reinforcement and web thickness change in different fashion. Research methods： Research method ： Using bridge analysis software, the paper calculated web principle tensile stress in different change fashion of web thickness. At the same time, aiming at disadvantage of general vertical prestressed reinforcement, other two layout imagination of vertical prestressed tendon was put forward in paper. Space finite element method was adopted to analysis web principle stress comparing each conformation form of vertical prestressed reinforcement by using Ansys software. Research results： Research result： The paper deduced principle stress curves in different change fashion of web thickness; principle stress change curve in different construction form of vertical prestressed reinforcement;and node＇ s first principle stress contour of local beam segment.Research conclusions ： Research conclusion ： （ 1 ） The adoption of web thickness change fashion was thought an important influence factor in crack control, and transitional change fashion should be used to the full. （2）comparing the general vertical tendon,the advantage of U type vertical tendon represent to bring monolithic precompression stress on web con- crete in the U region, which restrict the appearance and magnitude of web principle tensile stress. The influence analysis for new conformation form of vertical prestressed tendon offered referenced opinion for continuous system box girder in reasonable arrangement of vertical.
出处
《铁道工程学报》
EI
北大核心
2006年第6期34-38,63,共6页
Journal of Railway Engineering Society
基金
华东交通大学科研基金资助项目(2004年度)
关键词
竖向预应力筋
腹板
主应力
空间有限元
vertical prestressed reinforcement
web
principle stress
space finite element
