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一、新规范中σ0的两种取值方法新编《钢筋混凝土工程施工及验收规范》(GBJ204-83)中第4.2.2条对施工单位混凝土标准差的历史统计水平σ0的取值问题规定如下: 1.施工单位如具有30组以上混凝土试配强度的历史资料时,σ0可按下式求得:式中:R_i——第i组的试块强度; R_n——n组试块强度的平均值。 2.施工单位如无历史统计资料时,σ0可按表1取值: 新规范(GBJ204-83)业经城乡建设环境保护部批准颁发,从1984年7月1日正式实施。据了解,在实施过程中,有相当部分施工单位在确定σo值时都直接取方法2(以下简称表格法)。
First, the new specification of σ0 two value methods New “construction and acceptance of reinforced concrete engineering” (GBJ204-83) in Section 4.2.2 of the construction unit standard deviation of the historical statistical level σ0 value of the issue As follows: 1. If the construction unit has more than 30 sets of historical data of concrete test strength, σ0 can be obtained by the following formula: where: R_i—the strength of the test block of the i-th group; R_n—the strength of the n test block average of. 2. If the construction unit does not have historical statistics, σ0 may be based on the value given in Table 1: The new specification (GBJ204-83) was approved by the Ministry of Environmental Protection of Urban and Rural Development and was formally implemented on July 1, 1984. It is understood that in the implementation process, a considerable number of construction units directly adopt Method 2 (hereinafter referred to as the table method) when determining the σo value.