气膜钢筋混凝土结构施工过程有限元模拟研究

Construction Process Finite Element Simulation of Reinforced Concrete Structures Using Inflated Forms

混凝土喷射过程中结构变形的准确预测和有效控制是决定气膜钢筋混凝土结构施工技术应用的前提。采用结合分层壳单元的多步骤非线性阶段施工有限元分析方法,考虑施工过程中混凝土龄期的增长及结构荷载、结构截面组成不断变化的复杂动态过程,对大海则气膜钢筋混凝土壳的混凝土喷射过程进行模拟。结果表明,随着施工过程的进行,结构变形趋势分为整体下沉、下部结构下沉的同时上部结构抬升、再次整体下沉3个阶段;在曲壁段首层混凝土喷射时出现几处局部变形突变;施工过程中膜应力下降值在膜初始应力的25%以内。施工变形随膜材、聚氨酯和早期混凝土弹性模量的增加有不同程度的减小;通过减小首层混凝土的喷射厚度和每次喷射范围,能有效减小施工变形。

Accurate prediction and control of structural deformation during concrete spraying is crucial to the application of the construction technology of reinforced concrete structures using inflated forms.Using the multi⁃step nonlinear staged construction finite element analysis method combined with layered shell elements,considering the increase of concrete age and the complex dynamic process of structural load and structural section composition during the construction process,the concrete spraying process of the reinforced concrete shell using inflated forms named Dahaize is simulated.The results show that the structural deformation contains three stages:overall subsidence,subsidence of substructure with the uplift of superstructure,and overall subsidence again.Furthermore,local deformation mutation occurs when spraying the first layer concrete of the curved wall part,and the unloading of fabric stress during construction is within 25%of the initial stress.The construction deformation declines with the increase of elastic modulus of fabric,polyurethane and early concrete,and also significantly decreases by reducing the thickness of first layer constructional concrete and the range of each spraying.