摘要
西宁海湖新区财富天街项目商业C3段地上结构平面尺寸大于规范规定的现浇钢筋混凝土框架结构设置伸缩缝的最大间距,通过计算以及裂缝控制措施来分析商业C3段结构超长不设缝是可行的。采用PMSAP软件,进行升温30℃和降温30℃两种工况的应力分析,控制混凝土X向与Y向的平均拉应力均不超过混凝土抗拉强度标准值;根据应力分析结果,对楼板进行加厚、双层双向拉通配筋、提高楼板配筋率;适当提高梁的纵筋配筋率,所有梁的腰筋直径加大一级,保证梁受拉不开裂。采用粉煤灰混凝土,严格控制水灰比在0.50以下,减少水泥用量和用水量,降低水化热和收缩变形;在普通混凝土内滲入水泥用量10%~12%的UEA、HEA等类似膨胀剂,减轻混凝土的开裂。要求施工单位认真做好混凝土的养护,采取有效措施,确保混凝土在湿润的条件下硬化;加强浇水养护,浇水养护时间宜在14d以上。
Xining Haihu New District Fortune Plaza Project commercial C3 building was an overlong concrete structure.The structural plane dimension exceeded the maximum size of code requirement,which the plane dimension of cast-in-situ reinforced concrete frame structure should set expansion and contraction joint. Commercial C3 building without the joint is feasible by calculation analysis and crack control measures. A brief description is given on design of overlength structure measure. PMSAP software was adopted to make stress analysis of two operating condition on heating 30℃ and cooling30℃,average tensile stress of concrete in X and Y direction were controlled not to exceed the value of characteristic value of concrete tensile strength. According to the result,pointed thickening of slab,spreading reinforcement in both two layers and two ways and increasing ratio of reinforcement should be made in slab. In order to ensure no cracks when tension force act on the beam,ratio of longitudinal reinforcement of beam should be increased and diameter of side bar of all the beam be add a level. Fly ash concrete is adopted,water/cement ratio is strictly controlled not to exceed 0. 5,decrease cement and water content,and reduce heat of hydration and shrinkage deformation. In order to reduce cracking,expansive admixture as UEA,HEA with a dosage of 10% ~ 12% of cement content. Construction units are requested to do a well concrete maintenance,effective measures should be adopted for concrete hardening under humid conditions; strengthen water curing and time of water curing should be above 14 days.
出处
《建筑结构》
CSCD
北大核心
2016年第S2期107-110,共4页
Building Structure
关键词
平面结构超长
温差效应
裂缝控制
plane overlength structure
temperature variation effect
crack control
