预应力正放四角锥组合网架结构试验研究

预应力组合网架是一种基于组合网架和预应力技术发展起来的由钢和钢筋混凝土组合而成的空间结构,它可以充分发挥钢材抗拉,混凝土抗压的特点。当采用分批张拉时,后批索张拉必然会造成前面所有批索实际张力发生改变。本文对一3m×3m(网格数为3×3)的试验模型的三根预应力下弦拉索,采用了三种张拉次序(依次张拉、先张拉两边索再张拉中间索和先张拉中间索后张拉两边索)进行张拉,测出了索内预应力及结构内力的变化,并与基于张力松弛法的索-杆-梁-板系有限元法分析结果进行对比,结果表明,采用张力松弛法可以考虑不同张拉次序对索内预应力的影响。

Experimental study on prestressed orthogonal square pyramid composite space truss

Prestressed composite space truss is developed on the basis of com po site structure and prestress cables. It is a new type of steel-concrete space s tructures in which the steel is in tension and the concrete is in compression. D ifferent tensioning sequences in batches may lead to different stress distributi on and cable controlling forces. In this paper, the test of a 3m×3m (3×3grids) orthogonal square pyramid composite space truss model with prestressing three b ottom cables by three different prestressing sequences in batches were carried o ut, namely tensioning the cable in order from one side to other side; tensioning the two exterior cables first, then the middle one; tensioning the middle cable first, then the exterior ones. Based on the experimental research of the prestr essed square pyramid composite space truss,the internal forces of each element u nder prestress and loads were analyzed. In comparison with the cable-truss-b eam- plate complicated finite element method,it shows that the release tension tech nology has the merit of considering the effect of different tensioning sequences on the prestresses of cables, so it is more reasonable in calculating the cable controlling forces and internal stresses.