Iman Hajirasouliha

Iman Hajirasouliha
The University of Sheffield | Sheffield · Department of Civil and Structural Engineering

BSc, MSc, PhD

About

264
Publications
106,311
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
5,993
Citations
Additional affiliations
October 2012 - December 2015
The University of Sheffield
Position
  • Lecturer in Structural Engineering
September 2010 - October 2012
University of Nottingham
Position
  • Lecturer in Structural Engineering
November 2015 - present
The University of Sheffield
Position
  • Lecturer

Publications

Publications (264)
Article
Full-text available
Earthquake induced soil liquefaction poses a significant threat to buildings and infrastructure, as evidenced by numerous catastrophic seismic events. Existing approaches of regional liquefaction hazard assessment predominantly rely on deterministic analysis methods. This paper presents a novel Probabilistic Liquefaction Hazard Analysis (PLHA) fram...
Article
The use of cold-formed steel (CFS) built-up sections for portal frames is gaining popularity due to their ability to provide sustainable solutions and more optimized section design opportunities. This paper presents an experimental and numerical investigation conducted on a novel unsymmetrical CFS built-up stiffened box beam. The sections are manuf...
Article
Full-text available
This paper examines the effects of near-field pulse-like earthquake ground motions (GMs) on the seismic resilience, repair cost and time, and structural collapse risk of low-to-high-rise selected multi-story RC structures with special moment-resisting frames (SMRFs) and shear walls. Selected 5-, 10-, and 15-story structures are designed based on a...
Article
This paper reports on an experimental investigation of the out-of-plane bending behavior and capacity of cold-formed steel (CFS) stud walls sheathed with wood-based boards [oriented strand board (OSB) or plywood] by means of four-point bending tests on a series of 10 specimens. The tests simulated outward wind loading (suction), which subjects the...
Article
Full-text available
While many railway viaducts still in use in Turkish railway networks are located on active fault zones that produced historical destructive earthquakes, they are not seismically designed in accordance to current standards. This study aims to provide a better understanding about the serviceability fragility of such systems by conducting detailed pro...
Article
Unlike influence lines, the concept of influence zones is remarkably absent within the field of structural engineering, despite its existence in the closely related domain of geotechnics. This paper proposes the novel concept of a structural influence zone in relation to continuous beam systems and explores its size numerically with various design...
Article
Full-text available
To reduce lateral drifts, the parameters of friction tuned mass dampers (FTMDs) need to be "tuned up" during the design process, which can be a challenging task for multi-storey buildings subjected to real ground motions. To address this issue, this article proposes a practical particle swarm optimisation (PSO) algorithm to optimise simultaneously...
Article
Full-text available
This article investigates numerically the seismic behavior of Multi-Degree-of-Freedom (MDOF) systems with novel 2-4 Direction and Displacement Dependent (2-4DDD) and 2-4 Displacement-Velocity Dependent (2-4DVD) Semi-Active (SA) controls. This study builds upon the novel SA 2-4DDD control system, in which the damper forces are controlled by inter-st...
Article
Full-text available
The design of bridges often overlooks the vertical component of earthquakes or considers it of secondary importance, despite compelling evidence indicating specific structural damage caused by primary earthquake waves. Conversely, during the operational phase, the combined influence of ground motion and moving loads from vehicles can significantly...
Article
Full-text available
Reinforced concrete (RC) frames are extensively used in construction of buildings worldwide. The conventional design of these buildings typically relies on a "trial and error" method, starting with initial dimensioning followed by validation of the preliminary design. This approach makes it difficult to calculate potential cost savings in materials...
Article
This paper aims to develop Machine Learning (ML) algorithms to predict the buckling resistance of cold-formed steel (CFS) channels with restrained flanges, widely used in typical CFS sheathed wall panels, and provide practical design tools for engineers. The effects of cross-sectional restraints were first evaluated on the elastic buckling behaviou...
Article
Full-text available
Failure of short columns in concrete buildings has been extensively reported during past earthquakes. Assessing the behaviour of short columns is challenging and often requires using time-consuming advanced numerical modelling. This article presents a new and practical Short Column Macro Element (SCME) that predicts accurately the behaviour of conc...
Conference Paper
Compared to a single cold-formed steel (CFS) channel beam, a built-up I-beam comprising of two such channels possesses a higher bending capacity and greatly increased stability. However, since CFS webs are typically slender elements, they are susceptible to web crippling under concentrated loading. Most of the previous research in this area has foc...
Article
Full-text available
This work develops a machine learned structural design model for continuous beam systems from the inverse problem perspective. After demarcating between forward, optimisation and inverse machine learned operators, the investigation proposes a novel methodology based on the recently developed influence zone concept which represents a fundamental shi...
Preprint
Full-text available
Most conventional seismic design approaches aim to provide solutions with sufficient strength to primarily ensure “life safety”, but cannot directly limit structural damage under different hazard levels. They generally lack provisions for determining whether structural configurations can be improved to achieve greater cost efficiency. This study ad...
Article
Full-text available
A new scenario-based method is proposed to determine the performance range of structural systems. The advantage of this method is using inter-storey drift as a damage index, while exploiting local damage indices of the main structural members without the need for detailed analytical models and computationally expensive non-linear dynamic analyses....
Article
The Newmark design spectra are commonly adopted in seismic codes to calculate design spectra, while these spectra generally differ from the statistically driven ones. This study endeavors to re-construct the Iranian design spectra by implementing a modified Newmark method on an extensive database of previous Iran earthquakes. To this end, three set...
Article
Full-text available
One of the main problems of nonlinear time history analysis is its high computational effort, especially in structures with large number of structural components, high-rise buildings and complex structural systems. The ground motions recorded in recent years also include more recorded points than in the past, which has also increased the required v...
Conference Paper
Full-text available
A comprehensive experimental program was designed to explore the bending behaviour and capacity of cold-formed steel (CFS) stud walls clad with wood-based boards. The investigation focused on several key design parameters, such as screw spacing, board material and thickness, stud and track thicknesses, board configuration (single-sheathed, double-s...
Article
This paper presents an experimental study of demountable steel-concrete composite reduced web section (RWS) connections for use in seismic areas. Four composite connection specimens were subjected to sagging and hogging moments to investigate the performance of RWS connections under reversible actions. For such purpose, a single web opening was cre...
Article
Full-text available
This paper presents an experimental study of demountable steel-concrete composite reduced web section (RWS) connections for use in seismic areas. Four composite connection specimens were subjected to sagging and hogging moments to investigate the performance of RWS connections under reversible actions. For such purpose, a single web opening was cre...
Article
Although previous attempts for enhancing the buckling resistance of cold-formed steel (CFS) built-up beams through intermittent stiffening, external stiffening and adoption of concrete as composite sections were successful , they may compromise the lightweight constructional feature of these elements. This paper presents a test program aimed at dev...
Article
Full-text available
A comprehensive experimental programme was designed and executed with the aim of investigating the out-of-plane bending behaviour and capacity of cold-formed steel (CFS) stud walls sheathed with wood-based boards. The influence of key design variables, including the screw spacing, the board material and thickness, the stud and track thicknesses, th...
Article
Designing thin‐walled structural members is a complex process due to the possibility of multiple instabilities. This study aimed to develop machine learning algorithms to predict the buckling behavior of thin‐walled channel elements under axial compression or bending. The algorithms were trained using feed‐forward multi‐layer Artificial Neural Netw...
Article
Oriented Strand Boards (OSB) are currently one the most widely used cladding options in cold‐formed steel (CFS) stud wall panels. The sheathing generates significant resistance to lateral loads owing to its diaphragm stiffness, which is however typically not fully exploited in design. This paper aims to investigate the lateral inplane behaviour of...
Article
Full-text available
Friction tuned mass dampers (FTMDs) are widely used to control the displacement of structures located in seismically active areas. Typically, the frequency and friction ratios of FTMDs are tuned up during design, but this task is complex if real ground motion records are considered. This article proposes a novel and accurate approach to calculate o...
Article
Full-text available
This article investigates analytically the seismic performance of a new RBS beam-column connection system with Double Nut Bolts (RBS-DNB) and double shear tabs. The bolts in the proposed RBS-DNB connection are used to: i) increase the strength of the beam's reduced section, ii) increase the energy dissipating capacity of the connection, and iii) de...
Chapter
Rapid urbanisation and population growth have increased the exposure of existing buildings to seismic risk in earthquake prone regions. The need to address the growing demand for a low-cost building stock has also led a large proportion of residential buildings in developing countries to be constructed with substandard materials, insufficient desig...
Preprint
Full-text available
This paper presents an experimental study on demountable steel-concrete composite reduced web section (RWS) connections for use in seismic areas. Four composite connection specimens were subjected to sagging and hogging moments to investigate the performance of RWS connections under reversible actions. For such purpose, a single opening was made ne...
Article
Cold-formed steel (CFS) members generally have slender cross-sections making them more prone to geometric imperfections. The presence of different geometric imperfections with varying magnitudes can significantly influence the structural behaviour of CFS members, which is well-reported in the literature. However, limited data is available on the st...
Article
Full-text available
Steel structures with dual systems, including special moment-resisting frames (SMRFs) and special concentrically braced frames (SCBFs), have found extensive applications in seismically active regions due to their considerable lateral stiffness and ductility. However, the seismic performance of such system has not been investigated subjected to near...
Article
Assessing large structures on the basis of multivariate static data sets is a challenging task for a number of reasons. One is that a low-frequency sample does not consistently capture longitudinal discrepancies in the data and thus cannot translate multivariate information into structural conditions and performance metrics. Another is the fluctuat...
Article
Full-text available
Incremental dynamic analysis (IDA) is one of the widely used methods for structural assessment analysis and fragility curve development, given its unique capabilities in taking into account the aleatory uncertainties of earthquake records and its ability to provide a desirable statistical population of the system response. However, the strong depen...
Conference Paper
Full-text available
The adoption of cold-formed steel (CFS) in structural systems has risen significantly in recent years due to various favourable features such as cost-effectiveness, speed of construction, and lightweight structures. As a result, CFS members are suitable for modular construction. Beams are primary structural members responsible for transferring load...
Article
Full-text available
The nonlinear force-velocity behavior of fluid viscous dampers (FVDs) complicates the design of structures fitted with such elements. Soil-structure interaction (SSI) changes the response of the structure and thus the FVD force, making the design even more complex. This study proposes a novel stochastic linearization technique (SLT) to analyze stru...
Article
Full-text available
While earthquakes can have a devastating impact on the economic growth and social welfare of earthquake prone regions, probabilistic seismic risk assessment can be employed to assess and mitigate such risks from future destructive events. In a previous study (Sianko et al. in Bull Earthq Eng 18:2523–2555, 2020), a probabilistic seismic hazard analy...
Article
Full-text available
Cold-formed steel (CFS) load-bearing members in multi-storey frame systems are subjected to combined actions sourced from gravity and lateral loads. However, limited information is available on the complex interaction behaviour of such elements affected by different buckling modes. This study aims to provide a better understanding of the behaviour...
Article
Full-text available
The design process of thin-walled structural members is highly complex due to the possible occurrence of multiple instabilities. This research therefore aimed to develop machine learning algorithms to predict the buckling behaviour of thin-walled channel elements subjected to axial compression or bending. Feed-forward multi-layer Artificial Neural...
Preprint
Full-text available
Unlike influence lines, the concept of influence zones is remarkably absent within the field of structural engineering, despite its existence in the closely related domain of geotechnics. This paper proposes the novel concept of a structural influence zone in relation to continuous beam systems and explores its size numerically with various design...
Article
Previous attempts to develop lightweight cold-formed steel (CFS) composite sections have successfully improved their buckling strengths but have been limited to unstiffened profiles only. This paper reports the results of an experimental program on the flexural behaviour of newly developed CFSGFRP (Glass Fiber Reinforced Plastic) composite built-up...
Article
Full-text available
This paper investigates the in-plane lateral behaviour and capacity of cold-formed steel (CFS) stud wall panels which are sheathed with Oriented Strand Board (OSB). Detailed nonlinear FE models of the panels were developed, accounting for nonlinear material properties, geometric nonlinearity, realistic fastener behaviour and geometric imperfections...
Article
The code-based response modification factors are mainly developed based on engineering judgments and experiences from past earthquakes, and hence, they may not lead to reliable solutions considering different performance targets and hazard levels. On the other hand, the uncertainties associated with these proposed values are more significant for ne...
Chapter
The design of seismic isolators as specified by building code requirements is well defined and well established. However, there is still some refinement required for these design practices, especially in terms of estimating the yield strength and confinement of lead cores. The Lead Core is a key component in a Lead Rubber Bearing (LRB) that provide...
Article
Recent studies showed that while code-compliant structures can generally protect the safety of the occupants, they may exhibit extensive damages during strong earthquake events. On the other hand, structures are generally designed to satisfy the seismic code requirements with the least initial cost regardless of their life cycle cost. In recent yea...
Article
Under a specific ground motion excitation, even if structural components all satisfy a target performance level, the serviceability of the structure might get affected by the performance of non-structural components. Although the overall performance of a structure is affected by the performance of both structural and non-structural components, seis...
Article
In high-intensity seismic zones tunnel lining is generally utilized to provide efficient protection against tunnel collapse by withstanding pressure under strong earthquake events. However, this can be a challenging task in the case of fault-crossing tunnels, since tunnel lining follows the deformation of surrounding rock. To address this issue, th...
Article
The design of seismic isolators as specified by building code requirements is well defined and well established. However, there is still some refinement required for these design practices, especially in terms of estimating the yield strength and confinement of lead cores. The current codes have specified Upper Bound (UB) and Lower Bound (LB) crite...
Article
Full-text available
Cold-formed steel (CFS) systems have seen an increased application in the past few decades, especially in the construction of low- to mid-rise buildings. CFS members offer considerable structural and environmental advantages, such as low weight, ease and speed of construction, greater manufacturing flexibility, recyclability and low embodied carbon...
Preprint
Full-text available
The Newmark design spectra are commonly adopted in seismic codes to calculate design spectra, while these spectra generally differ from the statistically driven ones. This study aims to re-construct the Iranian design spectra by implementing a modified Newmark method on an extensive database of previous earthquakes in Iran. To this end, three sets...
Conference Paper
Full-text available
In the presented research small-scale specimens consisting of cold-formed steel (CFS) stud segments attached to wood-based boards were tested to identify the response of fasteners under push-out (shear), pull-out (tension) and rotational actions. The experimental programme was designed to investigate the effects of key design parameters, namely the...
Article
Full-text available
Assessing large structures on the basis of multivariate static data sets is a challenging task for a number of reasons, one is the low-frequency sample hardly consistently captures longitudinal discrepancies in data and translates multivariate information into structural conditions and performance metrics. Other is the fluctuation of data due to t...
Preprint
Full-text available
While earthquakes can have a devastating impact on the economic growth and social welfare of earthquake prone regions, probabilistic seismic risk assessment can be employed to assess and mitigate such risks from future destructive events. In a previous study (Sianko, 2020), a probabilistic seismic hazard analysis (PSHA) tool based on the Monte-Carl...
Article
Numerical modeling of tunnel-form buildings entails the utilization of 3D finite element models consisting of large numbers of shell and fiber elements. Accordingly, the non-linear analysis of such models under seismic excitations is both time consuming and computationally expensive, especially in the case of large scale structures. To address this...
Article
Cold-formed steel (CFS) structures typically rely on diagonally braced stud walls to withstand lateral forces. While the response of CFS single-wall panels has been extensively investigated, limited studies focused on the seismic performance of multi-storey CFS strap-braced frames. Previous research highlighted that the presence of vertical loading...
Article
To determine the load-bearing capacity of cold-formed steel (CFS) beam-column members, closed formed interaction formulas are generally used in most current design guidelines by linearly combining axial load and biaxial bending moment effects. However, this approach ignores the nonlinear interactions between these actions. To evaluate this issue, i...
Article
Incremental dynamic analysis is one of the most widely used methods to develop fragility curves due to its ability to deal with various inherent uncertainties in the prediction of earthquake recurrence and characteristics. The dependence of the results to the selected ground motion records, uncertainties associated with the selection of appropriate...
Article
Cold-formed steel (CFS) portal frames are gaining increased popularity around the world. The structural performance of these frames is to a large extent controlled by the CFS beam-to-column connections, which in most practical applications transfer the loads through the beam web using a gusset plate, while the flanges are left unconnected. This can...
Article
This study aims to develop a low computational cost framework to optimize the seismic performance of the steel moment-resisting frames (SMRFs) equipped with friction dampers at different performance levels. To achieve the optimal design of dampers in a structure, a novel approach called adaptive optimisation technique (AOT) is adopted. The basis of...
Article
In current design standards, cold-formed steel (CFS) beam-column elements are generally designed by considering fully warping free behaviour in their supports, which means the benefit of warping-restrained boundary conditions is neglected. In addition, while a non-linear relationship governs the interaction of axial compression and bending, simplif...
Article
Distribution of hysteretic energy along the stories of the building structures is a challenging topic in the energy-based design methods as the key design parameter. This paper aims to determine the vertical distribution of seismic hysteretic energy in the buildings equipped with hysteretic dampers required for the development of reliable energy-ba...
Article
Full-text available
The field of structural engineering is vast, spanning areas from the design of new infrastructure to the assessment of existing infrastructure. From the onset, traditional entry-level university courses teach students to analyse structural responses given data including external forces, geometry, member sizes, restraint, etc.—characterizing a forwa...