1- Instructor, Civil Engineering Group, University of Kurdistan
2- Postdoctoral researcher, Civil Engineering Group, University of Kurdistan
3- Professor, Civil Engineering Group, University of Kurdistan , a.yazdani@uok.ac.ir
Abstract: (1533 Views)
The estimation of seismic demand that connects the ground motion intensity measure and the damage measure of structures is one of the most important components in the performance-based design. In the seismic demand model, the relationship between the structural response and a seismic parameter that expresses the random nature of earthquake is expressed in the mathematical form. Therefore, proper choice of earthquake intensity measure as a seismic parameter and identifying how it is related to structural damage can play an important role in reducing errors in seismic assessments. In many studies, the first mode spectral acceleration (Sa (t1)) or maximum ground acceleration (PGA) has been introduced as an appropriate intensity measure. However, some recent studies indicate that these IMs are insufficient in some circumstances. On the other hand, choosing a suitable method for measuring the sufficiency of intensity measures due to the existing uncertainties and also examining the performance of single-line demand model is of particular importance and should be considered. In this study, the suitability of different intensity measures of ground motion is quantified by using information theory and relative entropy concepts and Sa (t1) is used as the base IM. For this purpose, several concrete moment frame structures with different number of floors and heights have been considered and time history dynamic analysis has been performed using pulse-like earthquake records by IDARC software. The Park-Ang damage index, which has many applications, especially in concrete structures, has been used for structural response. Given that there is a possibility of different behavior of intensity measures at different damage levels, the discussion of multilinear demand models is proposed and the performance of several multilinear models has been evaluated by statistical tests. The results show that velocity-based intensity measures are sufficient for moderate damage level under pulse liked records. At these damage levels, the use of first mode spectral acceleration or acceleration-based intensity measures such as maximum ground acceleration can cause errors. Also, studies conducted in this paper have shown that the use of single-linear model is not suitable for all damage levels and the use of a three linear model with respect to damage levels can reduce errors in seismic assessments.
Article Type:
Original Research |
Subject:
Earthquake Received: 2022/02/5 | Accepted: 2022/06/15 | Published: 2022/10/2