ECC材料对混凝土框架结构倒塌安全储备的提升作用

Enhancement on Collapse Safety Margin of Concrete Frame Structures Using Engineered Cementitious Composite Materials

结构的倒塌安全储备能力不仅与结构设计规范、施工方式以及场地地震风险等因素有关,而且还与结构所选用的材料密切相关.由于普通混凝土的低延性特点,地震中结构的破坏多发生于梁柱构件的端部,考虑到ECC材料超高韧性的特点,本文采用ECC材料少量替换梁柱构件端部的普通混凝土,以减小地震中结构的损伤.通过对普通框架和ECC材料局部替换后框架结构的抗震性能对比,研究局部使用ECC材料对结构倒塌安全储备能力的提升作用.分析表明,少量ECC材料替换混凝土后构件其它部位的混凝土得到了充分的利用,结构的倒塌安全储备能力较普通框架有较为明显的提升;并且,少量ECC替换后对结构的振动特性影响很小.

Structural collapse safety margin is not quality control, site seismic risk, etc, but also only associated with design codes, construction closely associated with materials that have been used in structures. As a result of low ductility in ordinary concrete, failures generally occur at the ends of components,i, e. beams and columns in structures subjected to earthquakes. In view of ideal ductility capacity of engineered cementitious composite（ECC） materials ,seismic damage of concrete structures excited by earthquakes could be alleviated through replacing small amount of ordinary concrete at the end zone of structural components by these materials. Comparison between ordinary and modified concrete frame structures is carried out to reveal enhancement in local replacement with ECC materials. The results indicated that concrete in rest part of structural components could be more fully utilized. Therefore, structural collapse safety margin was dramatically enhanced with small amount of replacement. Most important, such small amount of replacement exerts negligible impact upon dynamic properties of structures.