灌浆圆钢管压陷极限承载力试验研究

Experimental research on cave-in ultimate bearing capacity of grouted-round-steel tube

通过9个灌浆圆钢管压陷承载力试验,考察了支杆与弦杆直径比、弦杆所受轴力的性质与大小等参数对灌浆圆钢管压陷承载力的影响。由试验得出:随着灌浆圆钢管支、弦杆直径比的增大或弦杆上轴向压力的施加,其压陷承载力也相应增大;对弦杆施加轴向拉力,灌浆圆钢管压陷承载力提高程度不明显,灌浆圆钢管压陷破坏属于延性破坏,具有良好的的强度储备。有限元数值模拟分析除考察了模型试验所考察的参数之外,还考察了弦杆尺寸、弦杆壁厚、水泥石强度、弦杆钢材强度等参数对灌浆圆钢管压陷承载力的影响,在模型试验和仿真试验的基础上,分析了灌浆圆钢管压陷机理,建立了灌浆圆钢管压陷极限承载力公式,为推广内置钢桁架混凝土组合梁提供了基础性素材。

Experiment on cave-in beating capacity of 9 grouted-round-steel tube was carried out. Influence of some factors on cave-in bearing capacity of grouted-round-steel tube was analyzed, such as ratio of branch tube diameter to main tube diameter, characteristic and value of axial force acting on chord. The experiment result shows ： the cave-in bearing capacity of grouted-round-steel tube will be strengthened by increasing the ratio of branch tube diameter to main tube diameter or axial pressure acting on the main tube; but axial tension has little effect on the cave-in bearing capacity, and failure of grouted- round-steel tube is ductile, which has great safety margin. In addition to these factors in model experiment, influence of dimension of chord, thickness of chord＇s wall, strength of hardened cement pastes and strength of chord steel on cave-in bearing capacity were analyzed by finite element numerical simulation analysis. Based on model experiment and simulated experiment, mechanical property of grouted-round-steel tube in cave-in failure mode was analyzed, then, the formula of cave- in ultimate bearing capacity of grouted-round-steel tube was established. It provides basic data for spreading encased steel truss concrete composite beam.