波形钢腹板预应力混凝土组合箱梁桥悬臂施工中钢腹板临时支撑方案比较

COMPARATIVE STUDY ON FALSEWORK SCHEME OF STEEL WEBS FOR PC COMPOSITE BOX-GIRDER WITH CORRUGATED STEEL WEBS DURING CANTILEVER CONSTRUCTION

在悬臂施工的波形钢腹板预应力混凝土(PC)组合箱梁桥中,为了施工安全,往往需要在钢腹板上设置一些临时性支撑结构。为了克服临时支架法需占用大量施工空间的缺点,提出一种由大刚度钢管组成的钢管支架法,该方法结构简单、空间占用小。对两种方案进行比较分析,采用三维有限元数值模拟法,分别进行静力分析和特征值计算。计算结果表明:虽然临时支架在钢-混组合箱梁桥的施工中有效,但在波形钢腹板(PC)组合箱梁桥的悬臂施工过程中并不能明显改善波形钢腹板的受力状态;而钢管支架能够有效地改善悬臂状态下波形钢腹板的受力状况。

Some temporary support structures are often installed on steel webs to ensure construction safety for PC composite box-girder bridge with corrugated steel webs during cantilever construction.To overcome the disadvantage of large space occupation for temporary frame,a new supporting structure consisted of strong stiffness steel tubs is presented.This supporting method has simple structure and small space occupation.In order to compare the two schemes,static analysis and eigenvalue calculation were conducted by using 3D finite element numerical simulation in view of these two schemes.The calculated results show that temporary frame can not improve mechanical performance in evidence of corrugated steel webs in spite of its validation in construction of steel-concrete composite box-girder bridge,but supports with steel tubes can increase buckling strength of corrugated steel webs in cantilever state efficiently.