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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。
Section C3, Fortune Street, Hai Lake New District, Xining Commercial C3 section of the ground structure is larger than the standard size of the cast-in-situ reinforced concrete frame structure to set the maximum expansion joints, through the calculation and crack control measures to analyze the structure of commercial C3 feasible. The PMSAP software was used to analyze the stress in two conditions of 30 ℃ and 30 ℃, and the average tensile stress in X and Y direction of concrete was controlled not to exceed the standard value of tensile strength of concrete. According to the stress analysis results, Thick and double biaxially drawn reinforcement to improve the rate of floor reinforcement; appropriate to increase the longitudinal reinforcement of the beam rate, all beam waist diameter increased by a level to ensure that the beam is not pulled by cracking. Using fly ash concrete, strictly control the water-cement ratio below 0.50, reduce the amount of cement and water consumption, reduce heat of hydration and shrinkage deformation; infiltration of ordinary concrete 10% to 12% of the cement content of UEA, HEA and other similar expanders , Reduce the cracking of concrete. Require the construction unit to do a good job of concrete conservation, to take effective measures to ensure that concrete hardening under humid conditions; strengthen watering conservation, water conservation time should be 14d or more.