体内张拉成形空间网格结构静力试验研究

与传统桁架结构不同,体内张拉成形空间网格结构通过张拉下弦管内钢索使结构成形,成形后结构上弦弯曲,呈现自平衡状态。完成了体内张拉成形空间网格结构1∶10缩尺模型的成形及静载试验,研究结构在受荷过程中杆件应力和节点位移的变化规律,结构成形阶段以弯曲应变为主,受荷阶段以轴向压应变的增加为主。结果表明分次分批张拉方案切实可行,面向工程实际的张拉方法可为该类结构的设计施工提供指导。荷载作用下结构整体竖向位移很小,预应力的施加提高了结构的刚度。确定上弦截面最不利杆件位置,建议在设计中采取加强措施。

Experimental study of space lattice structure formed via internal tensioning

Comparing with conventional steel truss,the internal tensioning space lattice structure is erected into the final position by tensioning pre-stressing cables passing through the bottom chord.As a result of the post-tensioning process,the top chords become curved.A test program is conducted on a 1∶10 scale model subjected to vertical load.Comparing the test and numerical results,a series of structural responses are obtained,including stress and join displacement.Bending strain is the main deformation in the erection stage and the increase of axial strain is the main deformation in loading stage.The results show that the tensioning method is feasible.The overall displacements are very small under vertical load because the structural stiffness is increased by applying pre-stress.The position of critical-members is confirmed,and the behavior and strength of the highly curved top chord in completed configuration are discussed.