求翻译：摘要: 为防止高层建筑结构的突然倒塌，在保证三水准设防要求的前提下进行第二阶段设计时，必须进行结构弹塑性变形分析，结合新抗震规范分析了弹塑性变形的影响因素和计算方法，以保证结构的安全可靠性。是什么意思？

Summary: to prevent tall building suddenly collapsed, on the premise of ensuring three-level security requirements during the second phase of the design must be elastic-plastic deformation analysis of structures, combined with the new seismic code analysis of the influence factors of elastic-plastic deformation and calculation methods, to ensure the security and reliability of structures.