大连体育馆弦支穹顶结构张拉成形及静载试验研究

大连体育馆屋盖采用了弦支穹顶结构,为探索不同张拉方案的优劣及可行性,校核结构数值分析时数值模型和计算结果的准确性,研究结构在施工、设计荷载下的受力特性,对大连体育馆缩尺模型结构进行张拉成形和静力加载试验,结合有限元软件ANSYS对试验进行全过程模拟。结果表明:撑杆的内力和节点位移的试验值与理论值吻合较好,以撑杆内力为张拉控制目标,达到了张拉要求;撑杆顶升成形方法在试验中需进行反复调试,可控性较差,且需要对索进行精确下料,难度高;斜索张拉法可控张拉点较多,且斜索索力相对较小,索力可控性好,成形精度更高,故在施工中建议采用斜索张拉方案;在静力加载试验中,弦支穹顶上部网壳节点的位移、撑杆轴力和杆件应变与荷载基本满足线性关系,表明结构整体竖向刚度在设计荷载范围内未出现弱化,网壳杆件整体应力水平在设计范围内,结构满足设计要求。

Study of the tension formation and static test of a suspendome for Dalian Gymnasium

The roof of Dalian Gymnasium is a suspendome.It is necessary to investigate the characteristics and feasibility of different tension schemes,and in addition,to check the accuracy of numerical model and calculation results in structure analysis and to investigate the mechanical performance under construction and design loading.A 1∶ 10 scaled model test of the suspendome was conducted.The results show that the internal force of the strut and the displacement of the joint in theory are in good agreement with test results.Therefore,the demand of the cable tension can be achieved when taking the internal force of the strut as the tension aim.The lift-up method of strut needs to be adjusted continuously and the blanking of the cable needs to be accurate when conducting the test,which indicates that the method is relatively difficult.However,the diagonal cable force can be effectively controlled due to the sufficient controllable tension points and relative smaller cable force,and more importantly,the forming accuracy of tensioning diagonal cables is higher,therefore,this method is suggested during construction.The displacement of the joint in the upper reticulated shell of the suspendome,the axial force of strut and the stress of the members present basically a linear variation with the test load,which indicates that the vertical stiffness of overall structure is well in the range of design load and the overall level of stress in the members of reticulated shell is lower than design value.