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    Seismic performance of stainless-steel built-up box columns subjected to constant axial loads and cyclic lateral deformations

    , Article Structures ; Volume 33 , 2021 , Pages 4080-4095 ; 23520124 (ISSN) Moghaddam, H ; Sadrara, A ; Jalali, S. R ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    The seismic behavior of stainless-steel built-up box columns subjected to constant axial loads and cyclic lateral deformation that are used in special moment frames (SMFs) has been investigated through finite element (FE) analysis. A total of 208 numerical models were conducted to cover a range of parameters affecting the seismic behavior of the columns. These include the web slenderness ratio, flange slenderness ratio, global slenderness ratio, axial load level, and lateral loading protocol. The performance indices of overstrength factor, axial shortening, out-of-plane deformation, plastic hinge length, and rotation capacity were calculated and compared. Local buckling of the columns also... 

    Evaluation of strong column-weak beam criterion in spliced columns of steel moment frames

    , Article Results in Engineering ; Volume 14 , 2022 ; 25901230 (ISSN) Shamszadeh, M. M ; Maleki, S ; Sharif University of Technology
    Elsevier B.V  2022
    Abstract
    In the seismic design of steel special moment frames, it is necessary to ensure that columns are generally stronger than beams. This reduces the probability of a weak story failure mechanism of the frame and ensures the formation of beams' plastic hinges earlier than the columns'. This criterion is known as strong column-weak beam (SCWB) in seismic design codes and is checked by a formula in the form of a ratio of total flexural strengths of columns to beams framing at each joint. It is common practice to ignore the column section change at the splice location and to use the flexural strength of the larger column section in evaluating this ratio. In this paper, several steel special moment... 

    Collapse Probability Assessment of Steel Special Moment Resisting Frames through Incremental Dynamic Analysis

    , M.Sc. Thesis Sharif University of Technology Dejan, Amir (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Abstract
    Assessment of the probability of collapse or exceeding other limit states is one of the major goals of Performance-Based Earthquake Engineering. Moreover, other beneficial materials such as estimation of loss of money and downtime, which make it convenient for decision makers to judge the condition of a structure and take wise steps about it, can be drawn from the results of such an assessment.Current work investigates the probability of collapse and also immediate occupancy limit states at three discrete hazard levels of 50%, 10% and 2% in 50 years and also by utilizing mean annual frequency approach for three archetypes of steel special moment-resisting frames of 4, 8 and 12 stories.Ten... 

    Seismic Demands on Gravity Only Steel Frames

    , M.Sc. Thesis Sharif University of Technology Tork, Reza (Author) ; Maleki, Shervin (Supervisor)
    Abstract
    Nowadays, using perimeter steel moment frames in combination with interior gravity frames have become common practice in structural building design. One of the key benefits of this system is the open space that it provides for the architects. In active seismic regions, special details are required in the design of the seismic force resisting systems to make these frames ductile. However, these details cause excessive displacement for the gravity force resisting system. Although the gravity frames are not designed to endure seismic forces, they collaborate in the system’s response as they are connected to the same floor diaphragm and withstand lateral displacements. Therefore, these systems... 

    Seismic performance of reduced web section moment connections

    , Article International Journal of Steel Structures ; Volume 17, Issue 2 , 2017 , Pages 413-425 ; 15982351 (ISSN) Momenzadeh, S ; Kazemi, M. T ; Hoseinzade Asl, M ; Sharif University of Technology
    Korean Society of Steel Construction  2017
    Abstract
    Seismic behavior of beam-to-column connections can be improved by shifting the location of inelasticity away from the column’s face. Such connections can be achieved by reducing the flange area at a specific distance from the beam-column connection, called reduced beam section (RBS), or by reducing web area by introducing a perforation into the web, called reduced web section (RWS). This paper presents a parametric study that is carried out on the effect of the perforation size, perforation location, and the beam span length in the RWS connections, using finite element modeling. Next, an interaction formula is derived for design purposes, and a step by step design method is developed.... 

    Surrogate SDOF models for probabilistic performance assessment of multistory buildings: Methodology and application for steel special moment frames

    , Article Engineering Structures ; Volume 212 , 2020 Vaseghiamiri, S ; Mahsuli, M ; Ghannad, M. A ; Zareian, F ; Sharif University of Technology
    Elsevier Ltd  2020
    Abstract
    This paper proposes a methodology for generating surrogate single-degree-of-freedom (SDOF) models that can be utilized to estimate the probability distribution of the roof drift ratio of multistory buildings at various ground motion intensity measures. The use of an SDOF model as a surrogate for multistory buildings can significantly alleviate the high computational cost for probabilistic seismic demand assessment considering both model uncertainty and record-to-record variability. The surrogate SDOF model generated herein explicitly accounts for model uncertainties and can be used as an alternative to the nonlinear dynamic analysis of detailed building structures. Applications for such... 

    The Application of Simplified MDOF Models for Estimating the Moment Resisting Frames Seismic Demands in Endurance Time Method

    , M.Sc. Thesis Sharif University of Technology Hosseini, Mojtaba (Author) ; Esmaeil Pourestekanchi, Homayoon (Supervisor)
    Abstract
    Modified Fish-Bone (MFB) Model and Consistent Generic (CG) Model are simplified Multi-Degrees-of-Freedom (MDOF) models, proven to be valuable tools in estimating seismic demands of moment-resisting frames, aimed to reduce the computational costs by decreasing the number of degrees of freedom. The preliminary expansion of these simplified models for steel moment resisting frames (SMRFs) were proposed by considering elastoplastic behavior and is not able to take into account stiffness and strength deteriorations in nonlinear dynamic behavior of structures. However, behavior deterioration affects seismic demands of SMRFs under intense earthquakes. For this reason, the present study is done to... 

    Evaluation of Seismic Performance Factors for a Dual Lateral Force Resisting System with Special Moment Frame and Ordinary Concentrically Braced Frame

    , M.Sc. Thesis Sharif University of Technology Bakhshivand, Ehsan (Author) ; Maleki, Shervin (Supervisor)
    Abstract
    Regarding available structural codes, for designing of buildings with dual lateral force resisting system which includes special moment frames and ordinary concentrically braced frames, we need to determine seismic performance factors. Seismic performance factors embraces of response modification (R), over strength (Ω0) and displacement amplification (Cd) factors. The goal of this research is to evaluate aforementioned factors using the method presented with FEMA P-695. This method represents a reliable framework to assess the seismic performance factors of various kinds of lateral force resisting systems. In this approach, first, archetypes are designed with assuming certain values for... 

    Risk-based Approach to Account for Soil-Structure Interaction in Seismic Design of Building Structures

    , Ph.D. Dissertation Sharif University of Technology Vaseghi Amiri, Shaghayegh (Author) ; Ghannad, Mohammad Ali (Supervisor) ; Mahsuli, Mojtaba (Supervisor)
    Abstract
    This paper proposes a novel probabilistic approach to account for soil-structure interaction (SSI) in the seismic design of building structures. In this approach, an SSI response modification factor, RSSI, is introduced to capture SSI effects on the seismic performance of structures. The proposed procedure quantifies RSSI such that the probability distribution of the collapse capacity of the structure designed to account for SSI concurs with that of the structure designed using the default fixed-base provisions. The proposed approach is employed for special steel moment frame buildings with surface foundation. A surrogate single degree of freedom (SDOF) system is developed in this study and... 

    Development of hysteretic energy compatible endurance time excitations and its application

    , Article Engineering Structures ; Volume 177 , 2018 , Pages 753-769 ; 01410296 (ISSN) Mashayekhi, M ; Estekanchi, H. E ; Vafai, H ; Mirfarhadi, S. A ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    The aim of this study is to develop a new simulation procedure of endurance time excitations in which hysteretic energy compatibility is included. Existing methods for simulating excitations consider only amplitude and frequency content of motions and disregard parameters related to cumulative damage of structures. Hysteretic energy consistency, as a cumulative damage-related parameter, is included in the process. The proposed method is applied to generate new excitations. Efficiency of the proposed method is examined in two ways: (1) comparing damage spectra of simulated excitations with recorded ground motions; (2) applying simulated excitations in seismic assessment of three concrete...