Saber Moradi

Western University | UWO · Department of Civil and Environmental Engineering

Steel moment-resisting frames are prone to extensive damage in seismically active zones. Large permanent deformations in structural members following strong earthquakes can be mitigated using smart materials such as shape memory alloys. In this article, three-dimensional finite element analyses are conducted to study the seismic performance of beam...

The objective of this study is to identify the significant parameters that influence the lateral load–drift response of steel posttensioned (PT) connections. In particular, the effects of variations in beam section size are included in the study. First, three-dimensional finite-element models are developed to simulate the monotonic lateral load beh...

Endplate moment connections with shape memory alloy (SMA) bolts provide self-centering for the seismic resilience of structures. Predicting the self-centering response of these new beam-column connections, which have not been codified yet, requires conducting experimental tests or detailed continuum finite-element simulations. Computationally effic...

Link to Download: https://doi.org/10.1016/j.jobe.2024.108607 OpenAccess Paper Rocking structural systems have been proposed as a promising solution for designing resilient building structures. These low-damage systems can prevent significant economic losses associated with repair, demolition, and business downtime following earthquakes. The impor...

Shape memory alloys (SMAs) have found several applications in earthquake‐resilient structures. However, because of high material costs, their implementation on industry projects is still limited. Developing design approaches that minimize the use of expensive SMAs is critical to facilitating their widespread adoption in real structures. This paper...

Performance-based design optimization (PBDO) aims to design safe, resilient, and cost-effective structures. Methods used for PBDO have evolved by integrating numerical modeling, performance-based design principles, and optimization algorithms. The PBDO framework enables the design of structures with optimal performance and cost. This paper provides...

Past research efforts have developed several self-centering beam-to-column connections for minimizing structural damage in steel moment frames after severe earthquakes. However, less focus has been on low-damage column base connections. Severe damage at the base of columns in conventional steel structures with moment frames is likely during an inte...

Steel plates with openings are used to provide energy dissipation in earthquake-resistant structures. Shear-acting steel plates with butterfly-shaped or straight links are particularly used as easily replaceable fuses in low-damage design of structures. Sensitivity analyses have shown that the cyclic response of steel plate fuses varies depending o...

This paper presents the development of predictive equations for the self-centering response of moment-resisting connections equipped with Shape Memory Alloy (SMA) bolts and steel angles. First, three-dimensional finite element models are developed in ANSYS. The analysis is validated using experimental results for seven beam-column connections. Usin...

This paper proposes a performance-based seismic design (PBSD) method for self-centering moment-resisting frames with shape memory alloy (SMA)-bolted endplate connections. PBSD can be used to achieve different performance objectives, resulting in several benefits, such as cost-effectiveness and customization of the design. This study develops a PBSD...

Steel beam-column connections with shape memory alloy (SMA) bolts provide self-centering behavior and eliminate permanent deformations in earthquake-resilient steel moment frames. This paper presents the development and frame modeling application of a freely available Graphical User Interface (GUI) for predicting the cyclic and self-centering respo...

Self-centering systems can prevent permanent damage to structures and reduce downtime and repair costs following a seismic event. This paper presents the development and experimental validation of detailed three-dimensional finite element (FE) models of two different types of self-centering beam-to-column connections using ANSYS Mechanical APDL. Th...

Self-centering systems are effective in minimizing residual deformations in structures and consequently reducing the repair costs following a seismic event. This paper proposes the procedure of developing surrogate models to characterize the cyclic response of new self-centering beam-to-column connections with Shape Memory Alloy (SMA) bolts and ste...

This paper presents the development of predictive equations for the self-centering response of moment-resisting connections equipped with Shape Memory Alloy (SMA) bolts and steel angles. First, three-dimensional finite element models are developed in ANSYS. The analysis is validated using experimental results for seven beam-column connections. Usin...

The paper is freely available through the following link: https://authors.elsevier.com/a/1f52E,3HWfELyS This paper proposes a self-centering rocking dual-core braced frame system with buckling-restrained fuses (SC-RDC-BRF). While providing low-damage design and improved seismic resilience, the proposed system prevents soft-story failure in steel b...

Full-text access: https://rdcu.be/cLd2G This paper presents a seismic topology optimization study of steel braced frames with shape memory alloy (SMA) braces. Optimal SMA-braced frames (SMA-BFs) with either Fe-based SMA or NiTi braces are determined in a performance-based seismic design context. The topology optimization is performed on 5-and 10-...

This paper performs a statistical sensitivity analysis of the cyclic response of self-centering column base connections equipped with shape memory alloy (SMA) bolts. Experimentally validated finite element models are first developed for self-centering column base connections with SMA bolts. The effect of fifteen potentially influential design facto...

Steel plate devices are widely used for providing energy dissipation in earthquake resistant structures. Recent development of self-centering structures, such as controlled rocking frames, which offer minimized downtime and repair costs following severe earthquakes, relies on the energy dissipation capability of steel plate fuses. The cyclic respon...

Free access to the paper (until Oct 22, 2021): https://authors.elsevier.com/a/1dgkj,3HWfAYLN This paper presents the development and validation of moment-rotation backbone curve parameters for self-centering steel endplate connections with superelastic SMA bolts. In terms of influential design factors, surrogate models of response parameters are...

The main objective of this study is to develop predictive equations for characterizing the cyclic response of steel beam-to-column connections with superelastic Shape Memory Alloy (SMA) bolts and steel angles. High-fidelity continuum finite-element (FE) models are developed to simulate the cyclic behavior and limit states of steel beam-column conne...

Shape memory alloys (SMAs) are a class of metallic alloys that exhibit several unique characteristics, such as self-centering, which is the ability of the material to return to their original un-deformed position after experiencing large inelastic deformations. Several past studies have reported on the potential of using SMAs for providing self-cen...

Shape memory alloys have been used in developing self-centering steel moment connections. This article presents a numerical study aiming at evaluating the cyclic response sensitivity and limit states of extended endplate steel connections with shape memory alloy bolts. Three-dimensional finite element models are developed and validated against a re...

In modern architectural design, the use of non-orthogonal connections is inevitable, where the beam is connected to the column at an angle other than 90°. In this paper, a parametric study is performed to evaluate the cyclic behavior of sloped Reduced Beam Section (RBS) connections. A nonlinear finite element model is developed and verified using a...

https://authors.elsevier.com/a/1aU0vW4G4N8r4 Non-orthogonal structural framing is essential in modern architectural design; and sloping beams are often required in structures, particularly at the roof level. In this paper, a sensitivity study is conducted to statistically evaluate the effect of beam slope angle along with different design factors...

For downloading pdf: https://authors.elsevier.com/a/1aMKR_rUeEUTdy Steel plate devices are commonly used for the seismic energy dissipation and damage mitigation of structures. Particularly, butterfly-shaped steel plate fuses are essential components in controlled rocking frames, which have been shown as promising self-centering systems for minim...

In modern architectural design, the use of non-orthogonal connections is inevitable, where the beam is connected to the column at an angle other than 90°. In this paper, a parametric study is performed to evaluate the cyclic behavior of sloped Reduced Beam Section (RBS) connections. A nonlinear finite element model is developed and verified using a...

In modern architectural design, the use of non-orthogonal connections is inevitable, where the beam is connected to the column at an angle other than 90°. In this paper, a parametric study is performed to evaluate the cyclic behavior of sloped Reduced Beam Section (RBS) connections. A nonlinear finite element model is developed and verified using a...

This chapter seeks to determine the optimal structural design parameter values for a 6-story controlled rocking steel braced frame (CRSBF) building that minimizes the upfront (initial construction) and earthquake-induced economic and environmental impacts. The dead load on the rocking frame, initial post-tensioning force, fuse strength and frame as...

Guyed steel lattice towers (or guyed masts) are widely used for supporting antennas for telecommunications and broadcasting. This paper presents a numerical study on the static and dynamic response of guyed towers. Three-dimensional nonlinear finite-element models are used to simulate the response. Through performing static pushover analyses and fr...

Driven by a need to reduce repair costs and downtime in structures following a major earthquake, self-centering systems have been introduced. Post-tensioned high strength steel strands have shown promising results in providing self-centering capability in steel frames, where the beams are compressed to columns. This study aims at investigating the...

As an alternative to conventional seismic force resisting systems, controlled rocking steel braced frames (CRSBFs) can effectively eliminate permanent structural damage after earthquakes. Together with the rocking action in the braced frame, post-tensioning (PT) elements and fuse members are used to provide self-centering and energy dissipation, re...

Free access to the article: https://authors.elsevier.com/c/1XicjW4G4FefC Parameterized fragility functions are developed for a controlled rocking steel braced frame (CRSBF) system, which link the probability of exceeding system-level limit states to ground motion intensity and design parameters such as frame aspect ratio, the initial post-tensio...

This presentation gives a introduction about the seismic performance of self-centering moment resisting frame (SC-MRF). The whole presentation includes background introduction for why we need post-tensioned connection, the phenomenological model for post-tensioned connection, structural modeling for SC-MRF, nonlinear static and dynamic analysis, an...

Controlled rocking steel braced frames have been demonstrated recently as self-centering systems that can reduce permanent deformation of structural members in a major earthquake and thus minimizing repair costs. The design of these frames allows for rocking action at the base of columns, thereby limiting demands on frame members. The overturning r...

The use of posttensioning techniques in steel beam-column connections can improve the re-centering capability and reduce permanent deformation. Reliable finite element model can be used to investigate the load carrying capacity of the post tensioned (PT) steel beam column connection under cyclic loading, which is both time and cost saving. The opti...

Posttensioned (PT) elements in steel buildings can substantially mitigate permanent seismic damages and the associated post-earthquake repair costs during earthquakes. In this paper, a response surface methodology (RSM) is used to predict and optimize the lateral response characteristics of PT steel beam-column connections with top-and-seat angles....

Permanent deformations in a steel moment resisting frame can be eliminated by using post-tensioned (PT) elements. This paper presents the development of three-dimensional finite element models of PT steel beam-column connection subassemblies. Knowing that there is limited experimental data in the literature on PT steel connections with top-and-seat...

This paper evaluates the overstrength, ductility and response modification factors for low to mid-rise Buckling Restrained Braced Frames (BRBFs) designed as per the National Building Code of Canada (NBCC) 2010. In addition to nonlinear static pushover analyses, dynamic time history analyses are performed to assess the seismic performance of four-,...

Free Download Link: http://hdl.handle.net/2429/57480 As per current seismic design codes, steel buildings are designed to prevent collapse and loss of lives. Ductile steel structures, however, remain susceptible to earthquake-induced damage. The immediate occupancy of damaged buildings may not be possible. Large permanent deformations can make b...

Steel beam-column connections with posttensioned (PT) elements are proven systems that can provide adequate stiffness, strength, and ductility, while eliminating permanent deformations in a moment-resisting frame subjected to seismic loading. In this study, detailed three-dimensional finite-element (FE) models of steel beam-column connections with...

Through the use of post-tensioned (PT) elements in steel beam-column connections, steel buildings under seismic excitations can return to their plumb position, displaying negligible permanent deformation. The cyclic behavior of a PT connection is affected by several design parameters. This paper aims at identifying the significant factors which aff...

In the past earthquakes, steel moment resisting frames suffered damage. Earthquake-induced damage in the main structural members, such as beams, and columns, leads to permanent deformations in buildings. The resulting permanent damage following earthquakes substantially increases repair costs. The repair of damaged buildings with extensive permanen...

This paper determines the seismic performance of four-storey concentrically braced frames equipped with either steel buckling-restrained braces or buckling-restrained superelastic shape memory alloy (SMA) braces through incremental dynamic analysis. The incremental dynamic analysis technique is used to examine the behaviour of four-storey braced fr...

Incremental Dynamic Analysis (IDA) is a technique to determine the overall seismic performance of structures under varied intensities of earthquakes. In this paper, the seismic performance of four-story steel braced frames equipped with superelastic Shape Memory Alloy (SMA) braces is assessed by performing IDA. The seismic response of SMA-braced fr...

In this paper, the seismic performance of steel frames equipped with superelastic shape memory alloy (SMA) braces was investigated. Nonlinear time history analyses were performed using OpenSees for twenty-four shape memory alloy-braced frames of varyied heights and bracing types. To assess the efficiency of using this innovative material the seismi...