The base isolation systems are among the passive control devices that have been used over the last three decades to limit the seismic-induced response of structures. In this regard, the Uniform Building Code provisions (UBC) has incorporated a special section for the seismic design of base isolated structures since its 1991 edition. Due to the importance of the behavior of these structures unde...

response modification factor (r-factor) is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake. relying on this, many seismic design codes led to reduce earthquake loads imposed to the structure. the present paper tries to evaluate the r-factors of conventional concentric braced frames (cbfs) and special moment frames (mrfs) in ...

Many exploration and drilling applications would benefit from a robust method of integrating vertical seismic profile (VSP) and seismic data to estimate interval velocity. In practice, both VSP and seismic data contain random and correlated errors, and integration methods which fail to account for both types of error encounter problems. We present a nonlinear, tomography-like least-squares algo...

The base isolation systems are among the passive control devices that have been used over the last three decades to limit the seismic-induced response of structures. In this regard, the Uniform Building Code provisions (UBC) has incorporated a special section for the seismic design of base isolated structures since its 1991 edition. Due to the importance of the behavior of these structures unde...

The unanticipated brittle fracture of connection of the steel moment resisting frame (SMRF) occurred in 1994 the Northridge earthquake. Since then, the researches for the vulnerability of connection of the existing SMRF and for rehabilitation of those buildings were conducted. This paper suggests performance-based optimal seismic retrofit technique using connection upgrade. For optimal design, ...

Hexagrid structural system is an innovated system with structural behavior which is similar to a tubular system. In this paper, a numerical study is conducted to estimate the seismic performance of horizontal hexagrid concerning the combined horizontal and vertical hexagrid, tubular and diagrid structural systems. First 30 and 50 story buildings are modeled using ETABS, then pushover and nonlin...

Non-linear dynamic time history analysis is considered as the most advanced and comprehensive analytical method for evaluating the seismic response and performance of multi-degree-of-freedom building structures under the influence of earthquake ground motions. However, effective and accurate application of the method requires the implementation of advanced hysteretic constitutive models of the ...

Most of oil and gas offshore platforms are located in the seismic regains. So, Seismic vulnerability evaluation of the offshore platforms is one of the most important and vital issues in the structural systems. In this study, jacket type offshore platforms are studied by incorporating the pushover analyses and nonlinear time history analyses, in such a way that, first some push over analyses ar...