Verification research on inelastic seismic behavior of soil-foundation-structure system

本课题的研究目的是通过现场观测试验、SSI分析和理论验证土-基础-结构体系地基地震运动的输入耗能，重点研究土的邻域非弹性行为。观测研究包括2004年10月新泻-中越地震后的余震观测和震后损害评估，具体研究目标是识别基础和邻近土壤的基底运动输入损失。在K-net Ojiya台站，主震期间记录到一次频谱强度非常高的强运动。使用记录作为结构的基础输入运动，计算了大的非弹性位移响应，尽管钢筋混凝土建筑物的观测损伤似乎普遍小于计算中的损伤。在K-net附近的一个自由场地和一所学校建筑中观察到余震。更多的信息可以识别这些地点的差异。得到了相对较高的余震，达到了《建筑标准法》设计运动的2级，其中建筑物的输入运动比自由场和K-net站的输入运动明显减小，这可能是由于输入损失或邻近基础的土-结构相互作用所致。假设K-net台站和JMA台站记录的主震动可能是结构的基础运动输入，并将结构的观测损伤与计算响应进行比较。从分析中可以看出，进入结构的主冲击强度明显小于K-net，也可能小于JMA。并对Ojiya某学校建筑进行了现场静力推覆试验，确定了基础水平侧阻力的非弹性行为。建立了能较好地模拟这些观测和试验数据的解析模型。由这些影响引起的输入损失用一般实用形式来近似表示

The objective of the research project is to verify the input energy dissipation of earthquake motion at the base in soil-foundation-structure systems by on-site observation and test, SSI analysis and theory, with specific focus on the neighborhood inelastic behavior of soil. The observation research includes aftershock observation and the post-earthquake damage evaluation after Niigata-Chuuetsu Earthquake, October 2004, which was conducted with a specific research objective on identification of input loss of base motion at the foundation and neighborhood soil. A strong motion with very high spectral intensity was recorded during the main shock at K-net Ojiya station. Using the record as the base input motion to structures, large inelastic displacement responses were calculated, although the observed damages to reinforced concrete buildings seemed to be generally less than those in the calculation. The aftershocks were observed at a free field and in a school building nearby the K-net s … More tation to identify the difference at these sites. Relatively high aftershock up to the level 2 of the design motion in the Building Standard Law was obtained, where the input motion into the building was obviously reduced from those at the free field and the K-net station, which might be due to the input loss or soil-structure interaction at the neighborhood foundation. The main shocks recorded at the K-net and the JMA stations were assumed as possible input base motions to the structure, while the observed damages to the structure were compared with the calculated responses. It may be concluded from the analysis that the intensity of the main shock into the structure was obviously much less than that of K-net and probably also less than that of JMA. An on-site static pushover test on a school building in Ojiya was also conducted, from which inelastic behavior in lateral resistance at foundation level was identified. Analytical model is developed which fairly simulates these observation and test data. Input losses due to these effects are approximated in a general practical form Less