上海标准推荐的预制桩极限承载力分项系数研究

提出了获得上海市标准预制桩推荐表格统计特性的一种新方法,在运用该方法求得桩侧摩阻力和桩端阻力统计特性后,利用可靠度理论对上海地区31个场地进行了计算,并对计算结果进行统计分析,得到了可靠度指标的统计特性。在此基础上,按完全可靠性分析方法,求出了上海地区由标准推荐公式确定单桩竖向抗压承载力的分层桩侧摩阻力分项系数和桩端阻力分项系数,并对上海地区31个场地在利用分项系数设计方法的基础上反算了安全系数,结果说明所研究方法可作为规范过渡时的参考。

ON PARTIAL FACTORS OF LIMIT BEARING CAPACITY OF PRECAST PILE IN SHANGHAI CODE

The partial factors of limit bearing capacity formula recommended by Shanghai Foundation Design Code are explored in this paper. With the statistical properties of pile tip resistance and shaft frictional resistance, the reliability indexes of precast piles on thirty-one (31) construction sites are calculated by JC method and the statistical properties of the reliability indexes are derived accordingly. Based on these results and the complete reliability theory, the partial factors of pile tip resistance and layered shaft frictional resistance of vertical load limit bearing capacity formula of Shanghai Foundation Design Code are obtained, and the back calculation method is employed to compute the safety factors of the aforementioned thirty-one (31) construction sites. Results indicate that the new method can serve as a reference duing the intergrade of foundation design code.