The Italian code requires spectrum compatibility with mean spectrum for a suite of accelerograms selected for time-history analysis. Although these requirements define minimum acceptability criteria, it is likely that code-based non-linear dynamic analysis is going to be done based on limited number of records. Performance-based safety-checking provides formal basis for addressing the record-to-record variability and the epistemic uncertainties due to limited number of records and in the estimation of the seismic hazard curve. “Cloud Analysis” is a non-linear time-history analysis procedure that employs the structural response to un-scaled ground motion records and can be directly implemented in performance-based safety-checking. This paper interprets the code-based provisions in a performance-based key and applies further restrictions to spectrum-compatible record selection aiming to implement Cloud Analysis. It is shown that, by multiplying a closed-form coefficient, code-based safety ratio could be transformed into simplified performance-based safety ratio. It is shown that, as a proof of concept, if the partial safety factors in the code are set to unity, this coefficient is going to be on average slightly larger than unity. The paper provides the basis for propagating the epistemic uncertainties due to limited sample size and in the seismic hazard curve to the performance-based safety ratio both in a rigorous and simplified manner. If epistemic uncertainties are considered, the average code-based safety checking could end up being unconservative with respect to performance-based procedures when the number of records is small. However, it is shown that performance-based safety checking is possible with no extra structural analyses.

意大利语法规要求为选择用于时间历史分析的一组加速度计的频谱与平均频谱兼容。尽管这些要求定义了最低可接受标准，但是基于代码的有限数量的记录可能会进行基于代码的非线性动态分析。基于性能的安全检查为解决记录之间的差异和由于记录数量有限而造成的认识不确定性提供了正式基础，并为地震危险曲线的估算提供了基础。“云分析”是一种非线性的时间历史分析程序，它采用对未缩放的地面运动记录的结构响应，可以直接在基于性能的安全检查中实施。本文解释了基于性能的密钥中基于代码的规定，并将进一步的限制应用于旨在实现云分析的频谱兼容记录选择。结果表明，通过乘以一个封闭形式的系数，可以将基于代码的安全比转换为简化的基于性能的安全比。可以看出，作为概念上的证明，如果代码中的部分安全系数设置为1，则该系数平均将略大于1。本文为严格限制和简化方式，将由于样本量有限以及在地震危险曲线中基于性能的安全比传播认识不确定性提供了基础。如果考虑到认知上的不确定性，当记录数量很少时，基于代码的平均安全检查可能最终与基于性能的过程不相关。但是，这表明基于性能的安全检查是可能的，而无需进行额外的结构分析。