Siamak Epackachi

Siamak Epackachi
University at Buffalo, The State University of New York | SUNY Buffalo · Department of Civil, Structural and Environmental Engineering

PhD, University at Buffalo
Assistant Professor Head of Structural Engineering Laboratory Amirkabir University of Technology – Tehran Polytechnic

About

68
Publications
35,012
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
495
Citations
Additional affiliations
May 2015 - present
University at Buffalo, The State University of New York
Position
  • Teaching Assistant Professor

Publications

Publications (68)
Conference Paper
This paper presents a database of Buckling-Restrained Brace (BRB) cyclic tests and predicts the Cumulative Plastic Ductility (CPD) capacity of BRBs by using a regression-based Machine Learning (ML) model trained using the collected data. A summary of the past cyclic tests performed on BRBs is first presented. The hysteretic responses obtained from...
Article
Steel-plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear deman...
Article
Steel‐plate composite (SC) walls can be connected to a concrete basemat using a base plate and a set of anchors eccentric to the wall. The base plate can be separated into two parts so that the concrete of the wall and basemat is cohesive, and thus, the wall can be manufactured more easily and economically. Additionally, compression and shear deman...
Article
Full-text available
The progressive collapse of the 16-story Plasco steel building induced by fire in Tehran on 19 January 2017 led to the death of dozens of firefighters. This paper presents the results of a comprehensive 3D nonlinear finite element analysis of a floor of the Plasco building under fire condition. The LS-DYNA program is used to investigate the cause o...
Article
This paper evaluates the applicability of several concrete models to simulate the behavior of concrete elements under monotonic and cyclic loadings. Several robust constitutive models based on the combination of plasticity and continuum damage or plasticity and smeared crack approach are selected. The behavior of one concrete element is evaluated u...
Article
Post-installed connections are widely used in the rehabilitation, strengthening, and expansion of existing concrete structures. These connections accommodate the connecting of new elements to old concrete using post-installed anchoring techniques. Attachment of new segments to concrete beams and columns requires the installation of anchors in slim...
Article
Steel-concrete composite shear wall offers a favourable lateral strength and deformation ductility for seismic applications while significantly shortening the project schedule through eliminating the use of formworks and taking advantage of modular construction methodology. This paper presents a fibre-based modelling technique for simulation of the...
Article
Full-text available
This paper focuses on the application of a new shear link in moment-resisting frames by perforating the web at the mid-span of the beam. Typically, in moment-resisting frames the plastic hinges are formed at the end of the beams adjacent to the beam-column connections. Seismic codes specify a minimum length for the beams that are part of the moment...
Article
A through plate connection consisting of a vertical plate passing through the column is proposed as a moment connection between steel and composite beams to encased columns. A numerical model is developed to simulate the cyclic behavior of the proposed steel beam to the SRC column connection via a through plate using a general-purpose finite elemen...
Article
Full-text available
The seismic performance of steel-plate concrete (SC) shear walls is numerically investigated for various SC wall geometrical shapes. Steel faceplates and infill concrete are two main components of SC walls; a full connection between steel and concrete is required for composite action. A comprehensive set of SC wall specimens with different cross-se...
Article
This paper focuses on the performance evaluation of several concrete models in reinforced concrete (RC) structures subjected to seismic loading. Despite many studies conducted on implementing different characteristics of concrete in constitutive models, there is an essential need for investigating the ability of these models in predicting the behav...
Article
Full-text available
In the past three decades, several experiments were conducted to investigate the seismic behavior of composite plate shear walls (C-PSW) because of their advantages to conventional reinforced concrete (RC) and steel plate shear walls (SPSW). Numerical studies, however, are limited due to the complexities for the finite element modeling of the steel...
Conference Paper
Full-text available
Reinforced Concrete (RC) shear walls are one of the widely used lateral force resisting systems in building structures. The behaviour of this structural element during an earthquake depends on different parameters such as the loading condition, aspect ratio (height to length ratio), reinforcement ratio, and cross-section shape. Accurate performance...
Conference Paper
Post-installed anchors are generally defined as any type of anchorage in which the anchor is installed after complete curing and hardening of concrete sections. This type of anchoring systems are typically used for retrofitting, repairing, and strengthening of structures. Based on load transfer mechanism, post-installed anchors are generally divide...
Conference Paper
Full-text available
Although adhesive bonded anchors are currently widely used, there is a lack of robust and economical method of design. The Iranian structural code does not provide any guidelines regarding design of post installed anchors. The equations available in ACI 318 are in most cases accurate for single anchors but provide conservative results for group anc...
Article
Full-text available
To date, many researchers have developed various types of macro models to simulate the general response of conventional steel plate and reinforced concrete shear walls. Although extensive numerical and experimental studies have been conducted to assess the seismic response of steel-plate concrete composite shear walls, a robust macro-model for simu...
Article
Steel-plate concrete (SC) composite shear walls, comprising of steel faceplates at two sides, infill concrete , steel studs, and tie rods, have become popular recently due to the convenience in their construction and reliable seismic performance compared to conventional steel and reinforced concrete shear walls. The new generation of seismic perfor...
Article
Full-text available
On January 19, 2017 an accidental fire, which started by an electric shorting, resulted in the complete collapse of the 16-storey Plasco Building in Tehran. Twenty-two people including sixteen firefighters were killed in that incident. This paper reports the study carried out to investigate the most likely causes of the events and collapse of the s...
Technical Report
Full-text available
Low aspect ratio reinforced concrete (RC) walls are widely used for low- and medium-rise buildings and safety-related nuclear structures. Studies have demonstrated that the seismic performance of conventional low aspect ratio walls cannot be estimated accurately using existing predictive equations or hysteretic models. To improve the profession’s u...
Article
Backbone curves are used in seismic design standards as the basis for developing component models for nonlinear static and dynamic analysis. Herein, data from 240 tests of rectangular, barbell, and flanged shear-critical walls are assembled and analyzed to develop an improved cyclic backbone curve for use in nonlinear response-history analysis. Val...
Article
A finite element model is developed in LS-DYNA to simulate the in-plane cyclic behavior of lightly reinforced, low-aspect ratio reinforced concrete (RC) shear walls. Data from tests of 22 low-aspect ratio RC shear walls in three laboratories are used to validate the numerical model. The design variables in the testing programs included aspect ratio...
Conference Paper
Shear-resisting mechanisms generally dictate the seismic behavior of squat (low aspect ratio) reinforced concrete (RC) shear walls. Such walls are widely used in low-rise commercial buildings and energy-related facilities. A significant number of experimental studies have been performed over many decades to characterize the behavior of shear-critic...
Conference Paper
Full-text available
Building codes and standards of practice recommend reductions in the flexural and shear rigidities of uncracked reinforced concrete shear walls for estimation of effective stiffness for the purpose of static and dynamic analysis. There are no comparable recommendations for composite shear wall piers consisting of steel faceplates, infill concrete,...
Technical Report
Full-text available
This report investigates the seismic response of components of nuclear power plants constructed using steel-plate-concrete composite walls, subjected to combined in-plane and out-of-plane loadings. Steel-plate concrete (SC) composite shear walls are composed of steel faceplates, infill concrete, shear studs bonding the faceplate to the infill, and...
Article
This paper presents results of numerical studies on the in-plane monotonic response of steel-plate concrete (SC) composite shear wall piers. Results of finite element analysis of 98 SC wall piers are used to investigate the effects of wall aspect ratio, reinforcement ratio, slenderness ratio, axial load, yield strength of the steel faceplates, and...
Conference Paper
Full-text available
Steel-plate concrete (SC) composite shear walls are typically composed of steel faceplates, infill concrete, shear studs bonding the faceplate to the infill, and tie rods linking the faceplates. To date, most studies of these shear walls have focused on in-plane (IP) response and the effects of co-existing out-of-plane (OOP) loading have not been c...
Conference Paper
Full-text available
The lack of analysis, design and detailing guidance in standards and manuals has contributed to the limited use of steel-plate concrete (SC) composite shear walls. In this paper, a process to design SC wall piers is proposed, which accounts for wall aspect ratio, faceplate reinforcement ratio, axial force, and concrete and faceplate strengths. The...
Technical Report
Full-text available
The seismic performance of rectangular steel-plate concrete (SC) composite shear walls is assessed for application to buildings and mission-critical infrastructure. The SC walls considered in this study were composed of two steel faceplates and infill concrete. The steel faceplates were connected together and to the infill concrete using tie rods a...
Conference Paper
There are a number of methods to connect SC walls to RC foundations. An experimental study of the cyclic nonlinear behavior of SC walls at the University at Buffalo used a connection detail involving the post-tensioning of an SC wall with a steel baseplate to a RC foundation. This connection introduced flexibility that influenced substantially the...
Article
This paper presents an approach based on an acoustic emission technique for the health monitoring of steel–concrete (SC) composite shear walls. SC composite walls consist of plain (unreinforced) concrete sandwiched between steel faceplates. Although the use of SC system construction has been studied extensively for nearly 20 years, little-to-no att...
Article
A finite element model is developed in LS-DYNA to simulate the nonlinear cyclic response of flexure-critical steel-plate concrete (SC) composite shear walls. The developed finite element model is validated using data from tests of four large-scale SC wall piers with an aspect ratio (height-to-length) of 1.0. Each SC wall was constructed with steel...
Conference Paper
Full-text available
An experimental program on steel-plate concrete (SC) composite shear walls was executed in the NEES laboratory at the University at Buffalo. Four large-size specimens were tested under displacement-controlled cyclic loading. The design variables considered in the testing program included wall thickness, reinforcement ratio, and faceplate slendernes...
Conference Paper
Full-text available
An experimental study investigated the cyclic behavior of low aspect ratio reinforced concrete shear walls in the SEESL laboratory at the University at Buffalo. The testing program involved 12 shear walls with aspect ratio ranging from 0.33 to 0.94, and horizontal and vertical web reinforcement ratios ranging from 0.33% to 1.5%. A finite element mo...
Conference Paper
Full-text available
A steel-concrete (SC) composite wall is composed of steel faceplates at both sides of the wall and infill concrete. The faceplates and concrete are typically connected using cross-wall tie rods and shear studs welded to the faceplates. This paper summarizes the results of in-plane cyclic-loading tests of four steel-concrete composite (SC) walls. Th...
Article
An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. The testing program involved four rectangular SC wall specimens with an aspect ratio (height-to-length) of 1.0. The specimens were anchored to a concrete basemat with a pre-tensioned bolted connection that was designe...
Conference Paper
Full-text available
Steel plate composite (SC) wall piers are composed of two steel plates on both sides of a concrete infill. Composite action between the steel plates and concrete infill is achieved using shear connectors and tie bars. The tie bars also provide structural integrity by connecting the two steel plates together. SC wall piers do not have any flange wal...
Thesis
Full-text available
The seismic performance of rectangular steel-plate concrete (SC) composite shear walls is assessed for application to buildings and mission-critical infrastructure. The SC walls considered in this study were composed of two steel faceplates and infill concrete. The steel faceplates were connected together and to the infill concrete using tie rods a...
Conference Paper
Full-text available
In recent decades, shear walls and tube structures are the most appropriate structural forms, which have caused the height of concrete buildings to be soared. So, recent RC tall buildings would have more complicated structural behavior than before. Therefore, studying the structural systems and associated behavior of these types of structures would...
Conference Paper
Full-text available
Steel-plate composite (SC) walls are composed of steel faceplates, infill concrete, shear studs bonding the faceplate to the infill, and tie rods linking the faceplates. In new build nuclear power plants, elastic response is sought of SC walls in design basis earthquake shaking and numerical and experimental studies on SC walls have focused primari...
Data
Full-text available
An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. Four large-size specimens (SC1 through SC4) were constructed and tested under displacement-controlled cyclic loading in the NEES laboratory at the University at Buffalo, with support from Bowen Laboratory at Purdue Un...
Data
Full-text available
An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. Four large-size specimens (SC1 through SC4) were constructed and tested under displacement-controlled cyclic loading in the NEES laboratory at the University at Buffalo, with support from Bowen Laboratory at Purdue Un...
Data
Full-text available
An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. Four large-size specimens (SC1 through SC4) were constructed and tested under displacement-controlled cyclic loading in the NEES laboratory at the University at Buffalo, with support from Bowen Laboratory at Purdue Un...
Data
Full-text available
An experimental study investigated the behavior of large-scale steel-plate composite (SC) walls subjected to cyclic lateral loading. Four large-size specimens (SC1 through SC4) were constructed and tested under displacement-controlled cyclic loading in the NEES laboratory at the University at Buffalo, with support from Bowen Laboratory at Purdue Un...
Conference Paper
Full-text available
Steel-concrete (SC) composite walls are being used for the construction of containment internal structures and shielding structures in nuclear power plants. SC walls are composed of steel faceplates, connectors and infill concrete, where the connectors are typically constructed from cross-wall tie rods and shear studs welded to the faceplates. The...
Conference Paper
Full-text available
Steel-concrete (SC) composite walls are being used for the construction of containment internal structures and shielding structures in nuclear power plants. SC walls are composed of steel faceplates, connectors and infill concrete, where the connectors are typically constructed from cross-wall tie rods and shear studs welded to the faceplates. The...
Article
Full-text available
In recent decades, shear walls and tube structures have been the most appropriate structural forms for the construction of high-rise concrete buildings. Thus, recent Reinforced Concrete (RC) tall buildings have more complicated structural behaviour than before. Therefore, studying the structural systems and associated behaviour of these types of st...
Article
Full-text available
Tehran Tower is a 56-storey reinforced concrete tall building consisting of three wings with identical plan dimensions each approximately 48 m by 22 m. The three wings are at 120° from each other and have no expansions/seismic joints. This paper contains the consideration of the rehabilitation of the Tehran Tower based on the findings of an exhaust...
Conference Paper
Full-text available
In design practice of many countries, seismic analysis and proportioning of structures are usually based upon linear elastic analysis due to reduced seismic forces by response coefficient; R. Setback structures are one of the most popular shapes of the constructed buildings. In setback structures, the shape and proportions of the building have a ma...
Conference Paper
Full-text available
Reliable prediction of forces, stresses, and deflections in reinforced concrete structures has long been the goal of structural engineers. In fact analytical determination of the displacements, internal forces, stresses and deformations of reinforced concrete structures throughout their load histories has been complicated by a number of factors. N...
Conference Paper
Full-text available
Tehran tower is a 56 story reinforced concrete tall building consisting of three wings with identical plan dimensions each approximately 48 meters by 22 meters. The three wings are at 120 degree from each other and have no expansions/seismic Joints. This paper contains the consideration of the retrofitting of the Tehran tower based on the findings...
Conference Paper
Full-text available
In recent years, new combinations of shape, height and configuration of buildings have induced intense near ground wind flows, which can cause unacceptable human discomfort. Therefore, the wind environment in public access ways and leisure areas has become a major design consideration in new and existing building complexes. Recently, Computational...
Conference Paper
Full-text available
Using of steel elements which are connected to concrete members by anchors is one of the current methods to modify the local behavior of concrete components. Definitely it is a matter of fact that proper performance of anchors can be considered as a certain guarantee in order to have a coordinated behavior of connected elements be true and that's w...
Conference Paper
Full-text available
Chemical steel fastenings are one of the most common parts in several retrofitting designs and generally have a lot of unknown structural problems when are used in group. Consequently it would be very interesting to investigate the group structural behaviour of embedded chemical steel fastenings and their failure modes in some experimental simulati...
Conference Paper
Full-text available
A high-rise reinforced concrete tower with 56 stories in Tehran is evaluated for its performance against seismic demands according to FEMA 356. The tower consists of three transverse shear walls which are the main walls and several side walls perpendicular to each main wall. Concerning FEMA 356, a nonlinear dynamic model is developed which is analy...
Conference Paper
Full-text available
To have a reasonable and economic design, having some information about the initial condition of the structure is very important because different primitive states can change the seismic analysis results and may cause some problems to satisfy prescribed limits of deformations and strengths. So, having a real seismic design should be accompanied by...
Conference Paper
Full-text available
Tehran tower is a 56 story reinforced concrete tall building consisting of three wings with identical plan dimensions each approximately 48 meters by 22 meters. The three wings are at 120 degree from each other and have no expansions/seismic Joints. This paper contains the consideration of the retrofitting of the Tehran tower based on the findings...
Conference Paper
Full-text available
A Tuned Mass Damper (TMD) is a passive energy dissipation device connected to the structure in order to reduce the dynamic vibrations. Evaluation of site effect is also one of the most important problems considered in geotechnical earthquake engineering field which plays an important role in earthquake resistant design. In most of the cases, the ef...
Conference Paper
Full-text available
Practical experiences has shown that structures can be subjected to very large deformations due to creep and shrinkage; the consequences are excessive deflections of the structural members, wide cracks in the tension zone of the concrete and redistribution of stresses in statistically indeterminate structures. To have a reasonable and economic desi...

Network