分块预制改整体现浇空心板病害成因分析及其承载能力评定

摘要

Fabricated hollow slab is one-way place,but integral cast-in-situ hollow slab is two-way place.If the two-way slab reinforce by fabricated hollow slab,it will be transfinite vertical cracking.This paper analysis on disease of these hollow slab by theory,finite element analysis on it by beam,plate and solid,and study on calculation method of internal force and carrying capacity.Then this paper list out the ratio of vertical moment and horizontal moment with three integral cast-in-situ hollow slab.%将原设计为分块预制安装空心板改为整体现浇施工,板的受力状态由单向板转变为双向板。改变了施工方式却仍按原设计配置横向钢筋的空心板,往往容易出现超过规范限制的纵向裂缝,导致裂缝间的板块出现＂单板受力＂现象。对一座实际桥梁原设计为分块预制而施工时改为整体现浇的空心板病害原因进行理论分析;并应用MIDAS-Civil软件的梁单元和板单元,及ANSYS软件的Solid45单元分别建立了平面杆系模型、板单元模型及三维实体单元模型进行有限元分析;对内力及承载力计算方法进行研究,得出建立板单元模型计算内力既简便又可靠,及可采纳＂荷载有效分布宽度＂概念及初等梁理论公式计算承载力的结论;最后列出了3座空心板纵、横向弯矩的比例（约11.5%～16.1%）供工程人员参考。