Interactional Analysis of Steel Plate Shear Wall with Thin Plate using Modified Slope Deflection Method

Majid Gholhaki,Zahra Ebrahimi Sabet 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

Steel Plate Shear Walls have been discussed as a lateral load resisting system in various building and especially high-rise buildings. Application of this system in high-rise buildings requires a detailed analysis of the behavior of Steel Plate Shear Walls. This is due to the fact that in high-rise and mid-rise buildings, great axial deformations of columns and aggregation of their effects in height lead to domination of bending displacement. This study aims at analysis of steel plate shear walls using plate frame interaction and modified slope-deflection method (modified slope-deflection method with consideration of axial deformation effect). The plates in this system are equaled by diagonal springs. Plate - frame interaction method is used for calculating plate stiffness. The process of analysis, which aims at reduction of analysis duration, has been conducted in a programming language, thus the analysis of the system and only by changing the values of steel shear wall parameters, is possible with high accuracy and in a very short time. The results of analysis through this method, which uses plate frame interaction method for calculation of plate stiffness, indicate the incorrect assumption of this method in formation of diagonal tension field in post-buckling phase in comparison with the finite element analysis. After modification, the accuracy of this new method has been investigated by changing the parameters of panel width and thickness in this system. Analytical results, compared with finite element analysis, showed good coincidence. The main cause of difference is in the method of calculating the length of the plate which has not buckled and played any role in the post - buckling phase.

Experimental and numerical evaluation of an innovative diamond-scheme bracing system equipped with a yielding damper

Ghasem Pachideh,Majid Gholhaki,Mohammadali Kafi 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.36 No.2

Application of the steel ring as a type of seismic fuse has been one of the efforts made by researchers in recent years aiming to enhance the ductility of the bracing systems which in turn, possesses various advantages and disadvantages. Accordingly, to alleviate these disadvantages, an innovative bracing system with a diamond scheme equipped with a steel ring is introduced in this paper. In this system, the braces and yielding circular damper act in parallel whose main functionality is to increase ductility, energy absorption and mitigate drawbacks of the existing bracing systems, in which the braces and yielding circular damper act in parallel. To conduct the experimental tests, specimens with three types of rigid, semi-rigid and pinned connections were built and subjected to cyclic loading so that their performance could be analyzed. Promisingly, the results indicate both great applicability and efficiency of the proposed system in energy absorption and ductility. Moreover, it was concluded that as the braces and damper are in parallel, the use of a steel ring with smaller size and thickness would result in higher energy absorption and load-resisting capacity when compared to the other existing systems. Finally, to assess the potential of numerically modeling the proposed system, its finite element model was simulated by ABAQUS software and observed that there is a great agreement between the numerical and experimental results.

Effect of Ni-Ti shape memory alloy on ductility and response modification factor of SPSW systems

Atefeh Khosravikhor,Majid Gholhaki,Omid Rezaifar,Ghasem Pachideh 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.48 No.3

Shape memory alloys (SMAs) have emerged as a novel functional material that is being increasingly applied in diverse fields including medical, aeronautical and structural engineering to be used in the active, passive and semi-active structural control devices. This paper is mainly aimed at evaluating the ductility and response modification factor of the steel plate shear wall (SPSW) frames with and without the Ni-Ti shape memory alloys. To this end, different configurations were utilized, in which the walls were used in the first, third, middle, and all stories. The models were numerically analyzed using OpenSees Software. The obtained results indicate that improving the shape memory properties of alloys can greatly enhance the ductility and response modification factor. Furthermore, the model whose first and third stories are equipped with the SMA shear wall was found to be 290% more ductile, with a greater response modification factor compared to the unequipped frame.

Experimental study of rigid beam-to-box column connections with types of internal/external stiffeners

Omid Rezaifar,Mohammad Nazari,Majid Gholhaki 국제구조공학회 2017 Steel and Composite Structures, An International J Vol.25 No.5

Box sections are symmetrical sections and they have high moment of inertia in both directions, therefore they are good members in tall building structures. For the rigid connection in structures with box column continuity plates are used on level of beam flanges in column. Assembly of the continuity plates is a difficult and unreliable work due to lack of weld or high welding and cutting in the fourth side of column in panel zone, so the use of experimental stiffeners have been considered by researchers. This paper presented an experimental investigation on connection in box columns. The proposed connection has been investigated in four cases which contain connection without internal and external stiffeners(C-0-00), connection with continuity plates(C-I-CP), connection with external vase shape stiffener (C-E-VP) and connection with surrounding plates(C-ESP). The results show that the connections with vase plates and surrounding plates can respectively increase the ultimate strength of the connection up to 366% and 518% than the connection without stiffeners, in case connection with the continuity plates this parameter increases about 39%. In addition, the proposed C-E-VP and C-E-SP connection provide a rigid and safe connection to acquire rigidity of 95% and 98% respectively. But C-I-CP connection is classified as semi-rigid connections.

A study on the seismic behavior of Reinforced Concrete (RC) wall piers strengthened with CFRP sheets: A pushover analysis approach

Fatemeh Zahiri,Ali Kheyroddin,Majid Gholhaki 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.5

The use of reinforced concrete (RC) shear walls (SW) as an efficient lateral load-carrying system has gained recent attention. However, creating openings in RC shear walls is unavoidable due to architectural requirements. This reduces the walls' strength and stiffness, resulting in the development of wall piers. In this study, the cyclic behavior of RC shear walls with openings, reinforced with carbon fiber reinforced polymer (CFRP) sheets in various patterns, was numerically investigated. Finite element analysis (FEA) using ABAQUS software was employed. Additionally, the retrofitting of sub-standard buildings (5, 10, and 15-story structures) designed based on the old and new versions of the Iranian Code of Practice for Seismic-Resistant Structures was evaluated. Nonlinear static analyses, specifically pushover analyses, were conducted on the structures. The best pattern of CFRP wrapping was determined and utilized for retrofitting the sub-standard structures. Various structural parameters, such as load-carrying capacity, ductility, stress contours, and tension damage contours, were compared to assess the efficiency of the retrofit solution. The results indicated that the load-carrying capacity of the sub-standard structures was lower than that of standard ones by 57%, 69%, and 67% for 5, 10, and 15-story buildings, respectively. However, the retrofit solution utilizing CFRP showed promising results, enhancing the capacity by 10-25%. The retrofitted structures demonstrated increased yield strength, ultimate strength, and ductility through CFRP wrapping and effectively prevented wall slipping.

Investigation of performance of steel plate shear walls with partial plate-column connection (SPSW-PC)

Mojtaba Gorji Azandariani,Majid Gholhaki,Mohammad Ali Kafi,Tadeh Zirakian,Afrasyab Khan,Hamid Abdolmaleki,Hamid Shojaeifar 국제구조공학회 2021 Steel and Composite Structures, An International J Vol.39 No.1

This research endeavor intends to use the implicit finite element method to investigate the structural response of steel shear walls with partial plate-column connection. To this end, comprehensive verification studies are initially performed by comparing the numerical predictions with several reported experimental results in order to demonstrate the reliability and accuracy of the implicit analysis method. Comparison is made between the hysteresis curves, failure modes, and base shear capacities predicted numerically using ABAQUS software and obtained/observed experimentally. Following the validation of the finite element analysis approach, the effects of partial plate-column connection on the strength and stiffness performances of steel shear wall systems with different web-plate slenderness and aspect ratios under monotonic loading are investigated through a parametric study. While removal of the connection between the web-plate and columns can be beneficial by decreasing the overall system demand on the vertical boundary members, based on the results and findings of this study such detachment can lower the stiffness and strength capacities of steel shear walls by about 25%, on average.

Active interface debonding detection of a Concrete Filled Tube (CFT) column by modal parameters and Continuous Wavelet Transform (CWT) technique

Younesi, Adel,Rezaifar, Omid,Gholhaki, Majid,Esfandiari, Akbar Techno-Press 2021 Structural monitoring and maintenance Vol.8 No.1

In recent years, damage detection methods have been significantly increased in civil and mechanical structures. One of the most widely used and relatively new methods of signal processing is the method based on wavelet transform; with the help of this powerful tool, the damage in the structures can be detected in the early stages of damage formation, in order to prevent a larger damage event. In this paper, we have investigated the debonding damage of active surfaces in Concrete-Filled Tube (CFT) columns, which greatly reduces the effect of enclosure on concrete and decreases the bearing capacity of these tubes with the help of wavelet transformation (Discrete Wavelet Transform and Continuous Wavelet Transform). The debonding damage of the active surfaces was evaluated using wavelet types, and the occurrence and location of the damage were detected based on variations in frequency and mode shapes. The above studies have been done for the first six modes of the CFT column. The results of the analyzes indicate that the wavelet transform tool is very capable of detecting the occurrence and location of the damage and is able to detect high-level debonding damage in one side of the column that creates curvature and slight jump in the shape of the mode.

Simplified sequential construction analysis of buildings with the new proposed method

Mohammad Jalilzadeh Afshari,Ali Kheyroddin,Majid Gholhaki 국제구조공학회 2017 Structural Engineering and Mechanics, An Int'l Jou Vol.63 No.1

Correction Factor Method (CFM) is one of the earliest methods for simulating the actual behavior of structure according to construction sequences and practical implementation steps of the construction process which corrects the results of the conventional analysis just by the application of correction factors. The most important advantages of CFM are the simplicity and time-efficiency of the computations in estimating the final modified forces of the beams. However, considerable inaccuracy in evaluating the internal forces of the other structural members obtained by the moment equilibrium equation in the connection joints is the biggest disadvantage of the method. This paper proposes a novel method to eliminate the aforementioned defect of CFM by using the column shortening correction factors of the CFM to modify the axial stiffness of columns. In this method, the effects of construction sequences are considered by performing a single step analysis which is more time-efficient when compared to the staged analysis especially in tall buildings with higher number of elements. In order to validate the proposed method, three structures with different properties are chosen and their behaviors are investigated by application of all four methods of: conventional one-step analysis, sequential construction analysis (SCA), CFM, and currently proposed method.

Nonlinear behavior of connections in RCS frames with bracing and steel plate shear wall

Ali Kheyroddin,Saeedeh Ghods,Meissam Nazeryan,Seyed Masoud Mirtaheri,Majid Gholhaki 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.22 No.4

Steel systems composed of Reinforced Concrete column to Steel beam connection (RCS) have been raised as a structural system in the past few years. The optimized combination of steel-concrete structural elements has the advantages of both systems. Through beam and through column connections are two main categories in RCS systems. This study includes finite-element analyses of mentioned connection to investigate the seismic performance of RCS connections. The finite element model using ABAQUS software has been verified with experimental results of a through beam type connection tested in Taiwan in 2005. According to verified finite element model a parametric study has been carried out on five RCS frames with different types of lateral restraint system. The main objective of this study is to investigate the forming of plastic hinges, distribution of stresses, ductility and stiffness of these models. The results of current research showed good performance of composite systems including concrete column-steel beam in combination with steel shear wall and bracing system, are very desirable. The results show that the linear stiffness of models with X bracing and steel shear wall increase remarkably and their ultimate strength increase about three times rather than other RCS frames.