钢-混凝土空间组合壳体结构静力破坏试验

STATIC DESTRUCTION TEST STEEL-CONCRETE SPACE COMPOSITE SHELL

为研究钢-混凝土空间壳体结构在静力荷载下内力响应、破坏过程与失效机理,以球面钢-混凝土组合肋壳为对象,设计并制作整体结构和组合肋网2个缩尺模型,节点施加集中荷载进行结构破坏性试验。加载初期,两个试件变形均很小,整体结构模型中薄壳主要承受薄膜压力,组合肋中为轴压力;随着荷载增大,在组合肋壳加载壳面区域附近出现微小裂缝,组合肋网中加载点附近区域的混凝土与钢肋间出现微开裂。当壳面顶部出现交叉型裂缝,在一个加载点混凝土壳面压碎,下部组合肋节点混凝土部分也被压碎,在加载点附近形成局部塌陷区时,结构发生破坏;组合肋网模型中加载点处出现组合肋节点混凝土压碎,钢肋板出现局部褶皱,与圈梁相交的组合肋中钢肋板与混凝土间出现裂缝。试验结果表明:组合肋壳发生局部强度破坏;组合肋网由于局部杆件失效而发生破坏,试验测得组合肋壳最大承载力约为组合肋网的3倍,两个试件的荷载-位移曲线都表现出较好的延性。

In order to study the structural response,the destruction process and failure mechanism of space shell structure,two scaled models of a spherical steel-concrete composite ribbed shell and a composite ribbed network were designed and fabricated separately,and the structure destruction test was conducted by concentrically loading on joints.At the initial stage,the deformation of two specimens was very small.The concrete shell was mainly subjected to membrane pressure,and the axial compression for composite ribs.As the load increasing,the microcracks appeared near the loading shell area,and appeared between the steel ribs and concrete near to the loading points in composite ribbed shell.The cracks on the top of the shell surface were crossed,the concrete shell was crushed at a loading point,the concrete part of the lower joint ribs was also crushed.When the local subsidence area was formed near the loading points,the structure was destructed.In the combined ribbed network model,the joints of composite ribs were crushed at the loading points,local folds were observed on the ribs,and cracks appeared between the concrete and the steel plate of ribs which intersecting on ring beams.The test results showed that the local strength of steel-concrete composite ribbed shell was reduced,the composite ribbed network was destructed due to the failure of local bars.The maximum bearing capacity of the composite ribbed shell was about 3 times that of the composite ribbed network,the load displacement curves of both models exhibited good ductility.