Post-tensioned and shaped space truss is introduced in this paper. The basic structural module of new type of prestressing space structure is the single chord space truss (SCST), which is composed of a single layer of chords, together with outof-plane web members. Initially assembled on the ground level, the test space truss can be deformed into hypar shape by posttensioning the diagonal bottom layer strand. Vertical ultimate load test was carried out on the shaped model. Top joints were applied by concentrated load step by step. Stresses and vertical deflections were measured in the test. According to the load-deflection curve, the actual vertical ultimate load was gained. The test results show that the necessary prestress is in a less degree and the shape formation is attributed to the flexural deflection of top chords. Structural failure was attributed to plasticity and fracture of some top joints, but not to overall unstability, therefore, structural stiffness should be emphasized in the design.%介绍了一种新型预应力网壳一后张拉预应力成形网壳,其基本结构形式是单弦杆网架,由单层弦杆和平面外腹杆组成.试验网架在地面拼装,预应力索布置于下弦层,张拉得到鞍形网壳.在前人研究的基础上,对网架模型进行了预应力成形试验研究,测试了应力和变形.对一后张拉预应力成形鞍形网壳模型进行竖向加载试验,静载施加于上弦节点,分级加载.测试了各级荷载作用下的杆件应变和上弦节点挠度.得到荷载挠度曲线,从而得出该结构模型的竖向极限承载力.试验结果表明,施加较小的预应力,网架即由平面成为马鞍形曲面.马鞍形的形成主要是上弦杆的弯曲变形所致.该结构的主要破坏形式不是整体失稳,破坏主要原因是部分上弦节点进入塑性进而发生断裂,结构刚度是设计计算的重点.
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