LNG储罐混凝土外罐竖向预应力筋的张拉顺序

Tension sequence of vertical prestressing reinforcing steel bar in concrete shell of LNG storage tank

针对某50 000m3 LNG储罐(液化天然气储罐)外罐竖向预应力筋张拉顺序,根据混凝土和预应力钢绞线的本构关系,应用ANSYS有限元软件,建立LNG储罐混凝土外罐和预应力钢绞线有限元模型.通过等效降温法模拟预应力筋的张拉,实现四点、三点、二点对称张拉模拟实验,在不同张拉方法下得到储罐外罐应力、位移及其变化规律.结果表明:二点对称张拉应力普遍偏小,应变与三点对称张拉相似且低于四点对称张拉,二点对称张拉优于其他张拉方式.建议实际LNG储罐设计、施工时采用二点对称张拉竖向预应力筋.

This paper deals with the tension sequence of Vertical prestressing reinforcing steel bar in concrete shell of a 50 000 m3 LNG storage tank. Based on the constitutive relation of concrete and steel, we established finite element model of LNG storage tank prestressed steel strand with finite element software ANSYS. Through the equivalent cooling method simulation tendons drawing, we have realized four, three, two point symmetric tension simulation test. Under different drawing method, we can obtain the tank’s stress and displacement value and its changes. Through comparing the stress and displacement relationship, two point symmetric tension stress is generally smaller than others. Its strain is similar to three tension and lower than four tension. Thus two point symmetric tensioning of tension is superior to other ways. So we suggest that actual LNG tank design and construction should adopt two point symmetric tensioning of vertical tendons.