单层K6型球面胶合木网壳结构受力性能试验研究

Experimental investigation on mechanical performance of K6 single-layer reticulated glulam shells

为分析不同节点刚度、矢跨比对单层K6型木网壳结构受力性能的影响,设计了4个跨度为4 m,矢跨比分别为1/10、1/5,连接节点分别为单列、双列螺栓的缩尺比1∶10网壳试件,进行了全跨、半跨以及破坏荷载作用下的试验。研究结果表明:在不同加载阶段,试件节点位移基本呈顶点位移最大,1环其次,2环最小的趋势,矢跨比对试件的初始刚度影响较大;半跨加载阶段,矢跨比对试件刚度的影响比全跨加载阶段更明显;破坏荷载作用阶段,矢跨比对提高试件跨中挠度达到l/400(l为跨度)时的加载值的影响更大,节点刚度对提高杆件出现第2条裂缝时的加载值的影响更大;矢跨比越大,试件由于节点处应力集中而易发生开裂,节点刚度提高有利于抑制第2条裂缝的发生,并减缓试件刚度的退化;矢跨比大的试件易发生承载力破坏,矢跨比较小的试件易发生失稳破坏。

In order to study the effect of stiffness and rise-span ratio on the mechanical performance of K6 single-layer glulam reticulated shells, the experiments, including load cases of full-span and half-span loading, and inner-ring failure load, were conducted on four models with a span of 4 m, rise-span ratios of 1/10 and 1/5 and two kinds of joints with single and double row bolts. The results show that the top nodal displacements are the largest, then the inner ring, and the second ring is the smallest in different loading stages. The rise-span ratio has a great influence on the initial stiffness of the model. Compared with full-span loading, rise-span ratio has an higher impact on the stiffness under half-span loading. Under the action of failure load, the rise-span ratio has more influence on the loading value when the deflection reaches//400 （ 1 is the length of span）, and the joint stiffness has more influence on the increase of loading value when the second crack occurs. The larger the rise-span ratio is, the easier the specimen will crack due to the stress concentration at the joint. But the increase of the joint stiffness will be beneficial to restrain the occurrence of the second crack and slow down the stiffness degradation of the specimen; the specimens with large rise-span ratio can be easily damaged, and specimens with small rise-span ratio can occur instability destruction.