工业建筑楼面活荷载概率模型及楼板可靠度分析

Probability model of the live load and reliability analysis of the industrial building floor

参考规范中对工业建筑楼面活荷载标准值的取值规定和原始统计资料,提出了荷载的概率模型。针对设备区楼面活荷载,考虑其与已有规范规定分级标准的一致性,采用级差超越概率反推标准差,不考虑时间的影响,建议任意时点值和设计基准期最大值的概率模型均为极值I型,均值系数均为1,对级差为1kN/m2、2kN/m2、5kN/m2的楼面活荷载,标准差分别为0.40kN/m2、0.80kN/m2、2.00kN/m2。针对无设备区操作荷载,考虑与民用建筑临时性楼面活荷载的同质性,建议任意时点值和设计基准期最大值的概率模型均为极值I型,均值系数和变异系数分别为0.35、0.66和0.70、0.37。通过对比JCSS给出的楼面活荷载建议模型和统计参数得出,文中模型更精确且便于可靠度的校准计算。根据文中荷载模型,对钢筋混凝土楼板设计进行了初步校准,设备区楼板平均设计可靠度水平为4.37,无设备区楼板平均设计可靠度水平为3.21,均满足规范对安全性的要求。

According to the code specification standard values and the statistical data of the live loads for industrial building,a probability model of the load for reliability analysis is proposed.For the live loads in the equipment area, with the consistency of the grading standard in the TJ9-74 code,which may determines the standard deviation with the transcendence probability of the grading difference values.Without considering the time influence,it is suggested that the extreme value type-I distribution as the probability model of the any-time point load and the maximum load during the design reference period,with the mean coefficient as 1 for conservative,and the statistical parameters as 0.40kN/m^2,0.80kN/m^2,2.00kN/m^2 for the grading difference values of 1kN/m^2,2kN/m^2, 5kN/m^2,respectively.For the operating load in the non-equipment area,considering its homogeneity with the live loads of the civil building,the extreme value type-I model is recommended.The mean coefficients and the variation coefficients of the any-time point load and the maximum load during the design reference period are 0.35, 0.66 and 0.70,0.37,respectively.By comparing with the load model and statistics parameters in JCSS,this model is much more accurate and reliable.With the above model,the design code of the reinforced concrete slab can be initially calibrated.The average design reliability in the equipment area is 4.37,and the non-equipment area is 3.21, they are all satisfied with the safety requirements.