拉索预应力空间网格结构的索张力计算及张拉全过程分析

Pretensioning calculation and whole-process analysis of prestressed space reticulated structure

实际工程中,对于拉索预应力空间网格结构的索张拉是一个需要反复调整的繁琐过程。对此,提出了一种针对多阶段多批次张拉施工全过程分析的计算方法,用以提高索张拉施工的效率。该法通过不断减小拉索实际张力与目标张力的差值来求解各索在张拉过程中应该产生的初始应变,最后只要利用计算结果并按照预定的顺序张拉,便可使所有索只经过一次张拉就能最终达到各自的目标张力值。对一个150 m跨度的拉索预应力球面巨型网格结构进行了计算,并利用计算结果,对结构的杆件内力和最大节点位移进行了张拉全过程跟踪分析。结果表明,在实际工程中采用上述方法进行计算与张拉是切实可行的,另外,在张拉过程中进行跟踪分析十分必要。

It is a complicated process to adjust the tensile forces of cables to their target forces in the practical tensioning construction of prestressed space reticulated structure.Therefore a calculation method for the whole-process analysis of the multi-stage and multi-batch tensioning construction is presented,so that the efficiency of tensioning could be improved.This method calculates the required initial strains of cables in the tensioning construction through gradually diminishing the difference between subsistent tensile forces of the cables and their target values.Thus all the cables can reach their target tension stresses with only once stretch if they are stretched to the calculated strains in the predetermined tensioning sequence.A prestressed spherical reticulated mega-structure with the span of 150 m was calculated using the proposed analysis results,and the member＇s internal forces as well as the maximal nodal displacement were tracked in the whole pretensioning process.Results indicate that this method is feasible in practice.Also it is essential to do tracing analysis in the whole process of construction.