载荷重新分担对膨胀式自应力灌浆卡箍防滑和防撬设计影响

Effects of the load redistribution on the anti-slip and anti-prying designs for the expansive stressed grouted clamp

传统的卡箍设计方法是通过建立海洋平台有限元模型并在强度分析基础上提取受损单元处完好时的最大载荷,将此载荷作为卡箍设计的初始条件。而卡箍实际承担的是平台安装上卡箍之后载荷重新分担下相应受损处承受的载荷,一般会比初始设计载荷大。着重研究载荷重新分担对膨胀式自应力灌浆卡箍防滑设计和防撬设计的影响,针对渤海湾中主要承受冰载荷作用的一个典型平台结构,提出了在线单元平台有限元模型上近似模拟卡箍的方法,提取载荷重新分担下的卡箍设计载荷进行了分析。结果表明载荷重新分担对卡箍防滑设计影响较小,但对防撬设计有着显著影响,并对此提出了在螺栓设计时增加螺栓预紧力安全系数的应对措施。

The traditional design method for the expansive stressed grouted clamp is to establish the finite element model of offshore platform and to extract the largest load of the damaged element when it is intact based on the strength analysis. Then the load is used as the initial condition in the process of the clamp design. But the actual load exerted to the clamp is the load of the damaged element under the load redistribution after the clamp is installed on the platform. It is usually larger than that of the initial load. In this paper,emphasis is placed on the effects of the load redistribution on the anti-slip and anti-prying designs for the expansive stressed grouted clamp. For a typical platform structure which is under the ice load in the Bohai Bay,an approximate method to simulate the clamp structure in the platform model which consists of line elements is proposed. Then the load for clamp design under load redistribution is extracted and analyzed. The analysis result shows that the load redistribution has little effects on the anti-slip design,but has significant effects on the anti-prying design. Then advice is given that the safety coefficient of bolt pre-tightening force would increase for the process of bolts design.