南京江北地区PHC桩竖向承载力可靠度分析

Reliability analysis of vertical bearing capacity of PHC piles at north bank of Yangtze River,Nanjing

引入无量纲随机变量的极限状态方程,利用收集到的南京江北地区预应力管桩的试桩资料,采用"校准法"计算了现行地基规范关于桩基设计的总体可靠度水准和可靠指标,分析了总安全系数、荷载效应比和荷载组合形式对可靠指标的影响,并计算了相应的抗力分项系数。研究结果表明,可靠指标与总安全系数、荷载效应比和荷载组合形式有关,而且总安全系数对可靠指标的影响较大。荷载组合形式只对抗力分项系数产生较小的影响。

Based on the test data of prestressed high strength concrete（PHC） pile at north bank of the Yangtze River in Nanjing and the limit state equation of dimensionless random variables, the standard of the integral reliability level in the current Specifications of Foundations is calculated with the method of calibration, and the reliability index is calculated. Further more, the influence of general assurance coefficient, loading effect ratio and different load compositions on the reliability index is investigated. Finally, the partial coefficient of the resistance is calculated. It is shown that the reliability index is related to general assurance coefficient, loading effect ratio and different load compositions. In addition, it is also indicated that the influence of general assurance coefficient on the reliability index is remarkable, whereas the influence of different load compositions on the partial coefficient is weak.