钢衬钢筋混凝土管外包混凝土裂缝宽度计算公式安全度水平研究

通过引入等效保证率概念,对现有不同钢衬钢筋混凝土管外包混凝土结构裂缝宽度计算公式的计算精度以及安全度水平进行了分析比较。结果表明,前苏联П-780—83公式和董哲仁公式计算精度相对较高,其等效保证率分别达到了80.54%和92.38%。提出了两套钢衬钢筋混凝土管外包混凝土结构裂缝宽度计算建议方案:方案一为采用前苏联П-780—83中裂缝宽度计算公式计算,将计算值乘以增大系数1.2;方案二为采用董哲仁建议的裂缝宽度计算公式计算,其中平均裂缝间距改用国茂华公式。

Study on Reliability Level of Crack Width Calculation Formula for Outer Wrapped Concrete Structures of Steel Lined Reinforced Concrete Penstock

By introducing the concept of equivalent guarantee rate,the analysis and comparison of both the accuracy and safety level were conducted among different crack width calculation formulas for outer wrapped concrete structures of steel lined reinforced concrete penstock.The results show that the accuracy of formula given by design code П-780—83 of Former Soviet Union and Dong Zheren are relatively high and the equivalent guarantee rate of these two formulas are respectively 80.54% and 92.38%.Then two schemes of crack width calculation method were proposed for outer wrapped concrete structures.The first scheme is to apply the formula given in design code П-780—83 of Former Soviet Union and the calculation results gotten from this formula should be multiplied with factor 1.2.The second scheme is to apply the formula given by Dong Zheren while the average crack spacing should be calculated by the formula proposed by Guo Maohua.