结构设计地震力的确定

资料简介：

　　Determination of structural design seismic forcesEarthquake is sudden and has very low predictability, to the serious loss of human society, is the most serious types of natural disasters, the disasters. According to the current level of science in China and economic conditions, Seismic proposed "three levels" of fortification goal, known as "minor earthquake, the earthquake can repair, earthquake did not fall." Usually about a small earthquake, the earthquake, earthquake, respectively referring to the probability of exceedance in 50 years, 63%, 10%, more than 2 to 3% of the earthquake, seismic fortification intensity, strong earthquake. A structure designed to determine the earthquake forces 1.1 The feasibility of low seismic force values Twentieth century, the eighties, both countries recognize the design of such a fact that in the earthquake, structural failure in the real before, there is a large plastic deformation capacity (ductility), namely the structure of a smaller earthquake in or close to the yield potential under the state; in larger earthquakes, the structure of certain positions will have moved into post-yield inelastic deformation, and with the seismic force increases, the structure of the site into plastic deformation increased first enter the site of plastic deformation of yield increase. Dissipation through deformation of the structure of this earthquake came more energy to convert it into heat.
　　结构设计地震力的确定
　　地震灾害具有突发性，至今可预报性很低，给人类社会造成的损失严重，是各类自然灾害中最严重的灾害之一。我国根据现有的科学水平和经济条件，对建筑抗震提出了“三个水准”的设防目标，即通常所说的“小震不坏，中震可修，大震不倒”。通常所讲的小震、中震、大震分别指的是50年超越概率为63%，10%，2~3%的多遇地震、设防烈度地震、罕遇地震。 1 结构设计地震力的确定1.1 低地震力取值的可行性到二十世纪八十年代，各国设计规范都承认这样一个事实，就是在地震作用下，结构在真正失效前，有一个较大的塑性变形能力（结构延性），即结构在一个较小的地震下可能达到或者接近屈服状态；而在较大的地震下，结构的若干部位将陆续进入屈服后的非弹性变形状态，并且随着地震力的增大，结构中进入弹塑性变形的部位增多，先进入屈服的部位弹塑性变形也增大。结构通过这种变形耗散较多的地震传来的能量，将其转换成热能。