施工过程中隔震层钢筋砼梁变形初步分析

Preliminary Analysis on Deformation of Reinforced Concrete Beam of Isolation Layer during Construction Process

摘要:

以某隔震工程隔震层梁出现裂缝为研究背景,运用有限元分析软件SAP2000对隔震结构和非隔震结构进行了施工过程模拟,分析对比了两种结构在施工过程中隔震层钢筋砼梁的内力和变形规律,对隔震层梁裂缝形成的原因进行了分析,并运用有限元分析软件ANSYS对该原因下梁的裂缝进行了数值模拟。结果表明隔震层梁出现的裂缝是由施工荷载、温度变化和混凝土收缩共同作用引起的:建筑物施工期间结构刚度尚处在成长阶段,受到支撑变形、温度变化和混凝土收缩等不利作用对结构长期性能和耐久性产生负面影响。对于两种结构,常规算法由于不考虑框架的生成和加载历史,算得的内力值均偏小;而隔震结构偏小的幅度更大,因而更危险。计算同时表明,在结构施工过程中,各层梁当拆除其支撑、模板和浇筑其上一层时,其内力达到最大值;其中隔震层梁内力最大,为隔震结构在施工中的薄弱部位。给出了对其加强保护的施工建议。

Abstract:

This paper simulated the construction process of isolated and traditional seismic-resistant structures.The internal force and deformation law of the girder in the isolation layers were analyzed in the two types of structures during construction.In addition,the reason for girder cracking in the isolation layers was examined by using the finite element method（FEM） to simulate cracking.The results show that girder cracking in the isolation layers is caused by construction loads,temperature fluctuation,and concrete shrinkage.During the period of construction,structural stiffness develops,which causes adverse reactions of shore deformation,temperature fluctuation,and concrete shrinkage to produce negative effects on long-term performance and durability of the structure.Such factors significantly affect both isolated and traditional seismic resistant structures.Compared with the traditional seismic resistant structure,the isolated structure,which has larger load effects,is more likely to encounter safety issues during the construction period.Each floor＇s internal forces reach the maximum when the templates of the floor beam are removed and concrete is poured on the structure.The isolation layers are the weakest parts and should therefore be given sufficient attention.