体外横张预应力加固布束方案的探讨  

Study of Prestressing Strand Layout for Strengthening with External Transversely-Tensioning Prestress

作　　者：秦晓东[1] 朱世峰[2] 钟继卫[2] 

机构地区：[1]江苏海通建设工程有限公司,江苏连云港222001 [2]中铁大桥局集团桥科院有限公司,湖北武汉430034

出　　处：《桥梁建设》2010年第3期71-74,共4页Bridge Construction

摘　　要：结合连续刚构桥后期挠度逐渐增大特点,提出首先采用纵向张拉、结构后期运营中采用横向张拉的技术调控连续刚构桥跨中后期挠度。通过分析体外横张预应力束张拉空间可知,伸长率随着预应力束上、下张拉角度的增加而线性增大,布束时应结合最小上、下张拉角选择下弯点位置。通过探讨3种预应力束布置方案可知,当所需调控主梁挠度较小且箱梁高度较高时,可在箱梁内布置预应力束;当所需调控主梁挠度较大且箱梁高度难以满足张拉要求时,可在箱梁腹板外侧或中跨锚固点至L/4(L/3)的箱梁内布置预应力束,但方案选择应以少损伤原结构为宜。In accordance with the characteristic of gradual increase of the late period deflection of continuous rigid-frame bridge,the technique of longitudinally tensioning only for the first time and then transversely tensioning in the late operation period is put forward for adjusting and controlling the late period midspan deflection of such type of the bridge.From the analysis of tensioning space of the external transversely-tensioning prestressing strands,it is known that the elongation ratio of the strands linearly increases with the increase of the upper and lower tensioning angles of the strands.When the prestressing strands are laid out,the draping point positions of the strands should be selected in consideration of the minimum upper and lower tensioning angles.Further from the study of three kinds of the prestressing strand layout schemes,it is known that the strands can be laid inside the box girder in case the deflection of the girder to be adjusted and controlled is little and the depth of the girder is great while in case the deflection to be adjusted and controlled is great and the depth of the girder can not meet the requirement of tensioning,the strands can be laid outside the web of girder or in the section from the central span anchor point to L/4（L/3） inside the girder,however,the selection of any layout schemes should cause as less damage to the original girder structure as possible.

关 键 词：体外预应力 横向张拉 布束方式 桥梁加固 探讨 

分 类 号：U445.71[建筑科学—桥梁与隧道工程] U448.23[交通运输工程—道路与铁道工程]