石板坡长江大桥钢混结合段局部应力分析

结合石板坡长江大桥的设计及施工特点,运用大型有限元软件ANSYS建立了石板坡大桥钢混结合段结构分析的空间有限元模型,钢箱梁用shell63壳单元模拟,混凝土箱梁用solid95实体单元模拟,预应力钢绞线用link8单元模拟,并采用约束方程模拟预应力筋和混凝土间的粘结作用.根据运营过程中的最不利荷载工况,分析了钢混结合段在4种工况下的应力状态,检验了设计的安全性与合理性.结果表明,除钢箱梁锚垫板下预应力管道支承钢板以及与混凝土箱梁结合面折角处存在应力集中现象、部分拉应力超出混凝土的抗拉强度外,结构总体受力合理,内部应力满足设计要求;鉴于钢混结合段的构造与受力都很复杂,建议在此部分的混凝土箱梁采用钢纤维混凝土作为加强措施.

Analysis on Local Stress of Steel-concrete Beam Linked Part of Shibanpo Bridge

According to particularity of the bridge in design and construction, the finite element space model of steel-concrete beam linked part is built, in which steel box girder, concrete box girder and prestressed tendon are simulated with shell63, solid95 and link8 element respectively, tension is loaded by falling temperature, and bond action between prestressed tendon and concrete is simulated with restriction equation.The local stress of steel-concrete beam linked part is analyzed according to four load cases.The safety and reasonable design is verified and the measure for meliorating stress of steel-concrete beam linked part is proposed.The results indicate that the forced performance of structure is reasonable and stresses meet all the requirements of design except the stress concentration occurs at supported steel plate of tendon pipe under anchored padding plate in steel box and at corner of linked plane of steel box and concrete box and tensile stress at a few station is beyond tensile strength of concrete. As the structure and stress of steel-concrete beam linked part are very complex, concrete box girder in steel-concrete beam linked part using steel fibre concrete is proposed to improve performance of structure.