摘要
以黑龙江省林泉公路通河松花江大桥锚下处理为依托,选取最大悬臂长时的施工阶段为计算分析对象,通过建立等高、等厚、等长的节段模型,设置相同的钢束,只考虑最不利状态下腹板悬浇束与顶板悬浇束间的合成作用,得到应力、应变数据,结合模型分析,总结出大跨径箱梁腹板、顶板大吨位锚下受力特性及规律:张拉顶板预应力束时,在距离锚垫板范围约25 cm处,混凝土横向和竖向拉应力较大,此处受力最不利;腹板束薄腹板处锚下竖向拉应力为其主要控制应力。在设计中,锚下混凝土在大吨位预应力作用下,除了布置螺旋箍筋,还必须增加横向连接钢筋使螺旋箍筋与腹板两侧钢筋网片形成封闭箍筋笼,且应加密。由此既能提高锚下混凝土承压的能力,又能提高腹板混凝土保护层的抗裂性能。
Based on Tonghe Songhua River bridge anchor processing of Linquan highway in Heilongjiang province, the maximum cantilever construction stage was selected as the object of analysis to get the stress and strain data through the establishment of equal height, equal thickness, and equal length section model with consideration of the synthesis of web cantilever beam and the roof canti- lever beam under the most adverse conditions. Combined with the numerical and model analysis, the characteristics and rules of the large-span box girder webs and roof under large tonnage anchor stress are summarized ： （1） The horizontal and vertical tensile stress of concrete about 25 cm from the scope of the anchor plate is larger which is the worst place（2）The anchor vertical tensile stress of the thin web beam is the main control stress. Therefore, in design, anchor concrete under the effect of large-tonnage pre-stressed, in addition to decorate a spiral stirrups, it is also necessary to increase the lateral connection on both sides of steel spiral stirrups and the web forms a closed stirrup reinforcement fabric piece cage, and should be encrypted. This can not only improve the ability of anchor con- crete confined, but also improve the anti-cracking performance of the web cover concrete.
出处
《森林工程》
2015年第4期140-143,共4页
Forest Engineering
关键词
大跨径箱梁
大吨位
锚下
局部应力
large-span box girder
large tonnage
anchor
local stress
