• Steel and Composite Structures
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• 제20권1호
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• pp.107-125
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• 2016

Steel shear wall system has been used in recent years in tall buildings due to its appropriate behavior advantages such as stiffness, high strength, economic feasibility and high energy absorption capability. Coupled steel plate shear walls consist of two steel shear walls that are connected to each other by steel link beam at each floor level. In this article the frames of 3, 10, and 15 of (C-SPSW) floor with rigid connection were considered in three different lengths of 1.25, 2.5 and 3.75 meters and link beams with plastic section modulus of 100% to the panel beam at each floor level and analyzed using three pairs of accelerograms based on nonlinear dynamic analysis through ABAQUS software and then the performance of walls and link beams at base shear, drift, the period of structure, degree of coupling (DC) and dissipated energy evaluated. The results show that the (C-SPSW) system base shear increases with a decrease in the link beam length, and the drift, main period and dissipated energy of structure decreases. Also the link beam length has different effects on parameters of coupling degrees.

• Steel and Composite Structures
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• 제46권5호
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• pp.591-609
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• 2023

In some buildings, the lateral structural response of steel framed buildings depends on the shear walls and it is very important to study the behavior of these elements under near-field seismic loads. The link beam in the opening of the shear wall between two wall plates is investigated numerically in terms of behavior and effects on frames. Based on the length of the beam and its bending and shear behavior, three types of models are constructed and analyzed, and the behavior of the frames is also compared. The results show that by reducing the length of the link beam, the base shear forces reduce about 20%. The changes in the length of the link beam have different effects on the degree of coupling. Increasing the length of the link beam increases the base shear about 15%. Also, it has both, a positive and a negative effect on the degree of coupling. The increasing strength of the coupling steel shear wall is linearly related to the yield stress of the beam materials, length, and flexural stiffness of the beam. The use of a shorter link beam will increase the additional strength and consequently improving the behavior of the coupling steel shear wall by reducing the stresses in this element. The link beam with large moment of inertia will also increase about 25% the additional strength and as a result the coefficient of behavior of the shear wall.

• Earthquakes and Structures
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• 제5권2호
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• pp.143-160
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• 2013

This paper presents the results of an experimental program concerning the efficiency of a specific strengthening technique which utilizes a small steel link element connected to the R/C frame through bracing elements. Brittle types of failure, especially at the connections between steel and concrete elements, can be avoided by appropriate design of the local details. Five single storey one bay R/C frames scaled 1:3 were constructed according to older codes with substandard details. The first one was a typical bare reference frame. The other four were identical to the first one, strengthened by steel bracing elements. The behavior of the strengthened frames is described with respect to the reference bare frame. The concrete frames were constructed according to older code provisions by the use of smooth steel bars, low strength concrete, sparsely spaced stirrups and substandard details. The strengthening scheme aimed to the increase of both strength and deformation capacity of the original R/C frame. The inelastic deformations are purposely concentrated to a short steel link element connecting the steel bracing to the R/C frame. The results show that the steel link element can increase considerably the strength and the energy dissipation capacity of the frame.

• Steel and Composite Structures
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• 제42권6호
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• pp.827-841
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• 2022

The rotation capacities of the plastic hinges located at beam-ends are significantly reduced in traditional steel framed-tube structures (SFTSs) because of the small span-to-depth ratios of the deep beams, leading to the low ductility and energy dissipation capacities of the SFTSs. High-strength steel framed-tube structures with replaceable shear links (HSSFTS-RSLs) are proposed to address this issue. A replaceable shear link is located at the mid-span of a deep spandrel beam to act as a ductile fuse to dissipate the seismic energy in HSSFTS-RSLs. A 2/3-scaled HSSFTS-RSL specimen with a shear link fabricated of high-strength low-alloy Q355 structural steel was created, and a cyclic loading test was performed to study the hysteresis behaviors of this specimen. The test results were compared to the specimens with soft steel shear links in previous studies to investigate the feasibility of using high-strength low-alloy steel for shear links in HSSFTS-RSLs. The effects of link web stiffener spaces on the cyclic performance of the HSSFTS-RSLs with Q355 steel shear links were investigated based on the nonlinear numerical analysis. The test results indicate that the specimen with a Q355 steel shear link exhibited a reliable and stable seismic performance. If the maximum interstory drift of HSSFTS-RSL is designed lower than 2% under earthquakes, the HSSFTS-RSLs with Q355 steel shear links can have similar seismic performance to the structures with soft steel shear links, even though these shear links have similar shear and flexural strength. For the Q355 steel shear links with web height-to-thickness ratios higher than 30.7 in HSSFTS-RSLs, it is suggested that the maximum intermediate web stiffener space is decreased by 15% from the allowable space for the shear link in AISC341-16 due to the analytical results.

• Steel and Composite Structures
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• 제43권5호
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• pp.553-564
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• 2022

Many existing reinforced concrete (RC) structures need to be strengthening for reason such as poor construction quality, low ductility or designing without considering seismic effects. One of the strengthening methods is strengthening technique with eccentrically braced frames (EBFs). The characteristic element of these systems is the link element and its length is very important in terms of seismic behavior. The link element of Y shaped EBF systems (YEBFs) is designed as a short shear element. Different limits are suggested in the literature for the link length. This study to aim experimentally investigate the effect of the link length for the suggested limits on the behavior of the RC frame system and efficiency of strengthening technique. For this purpose, a total of 5 single story, single span RC frame specimens were produced. The design of the RC frames was made considering seismic design deficiencies. Four of the produced specimens were strengthened and one of them remained as bare specimen. The steel YEBFs were used in strengthening the RC frame and the link was designed as a shear element that have different length with respect to suggested limits in literature. The length of links was determined as 50mm, 100mm, 150mm and 200mm. All of the specimens were tested under cyclic loads. The obtained results show that the strengthening technique improved the energy consumption and lateral load bearing capacities of the bare RC specimen. Moreover, it is concluded that the specimens YB-2 and YB-3 showed better performance than the other specimens, especially in energy consumption and ductility.

• Steel and Composite Structures
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• 제24권4호
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• pp.441-453
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• 2017

In Y-shaped eccentrically braced frame fabricated with high strength steel (Y-HSS-EBF), link uses conventional steel while other structural members use high strength steel. Cyclic test for a 1:2 length scaled one-bay and one-story Y-HSS-EBF specimen and shake table test for a 1:2 length scaled three-story Y-HSS-EBF specimen were carried out to research the seismic performance of Y-HSS-EBF. These include the failure mode, load-bearing capacity, ductility, energy dissipation capacity, dynamic properties, acceleration responses, displacement responses, and dynamic strain responses. The test results indicated that the one-bay and one-story Y-HSS-EBF specimen had good load-bearing capacity and ductility capacity. The three-story specimen cumulative structural damage and deformation increased, while its stiffness decreased. There was no plastic deformation observed in the braces, beams, or columns in the three-story Y-HSS-EBF specimen, and there was no danger of collapse during the seismic loads. The designed shear link dissipated the energy via shear deformation during the seismic loads. When the specimen was fractured, the maximum link plastic rotation angle was higher than 0.08 rad for the shear link in AISC341-10. The Y-HSS-EBF is a safe dual system with reliable hysteretic behaviors and seismic performance.

• Structural Engineering and Mechanics
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• 제41권5호
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• pp.645-662
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• 2012

Deteriorative effects of steel corrosion on the structural response of reinforced concrete are simulated for varying degrees of corrosion. The simulation approach is based on a three-dimensional irregular lattice model of the bulk concrete, in which fracture is modeled using a crack band approach that conserves fracture energy. Frame elements and bond link elements represent the reinforcing steel and its interface with the concrete, respectively. Polylinear stress-slip properties of the link elements are determined, for several degrees of corrosion, through comparisons with direct pullout tests reported in the literature. The link properties are then used for the lattice modeling of reinforced concrete beams with similar degrees of corrosion of the main reinforcing steel. The model is successful in simulating several important effects of steel corrosion, including increased deflections, changes in flexural cracking behavior, and reduced yield load of the beam specimens.

• Advances in concrete construction
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• 제1권3호
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• pp.253-272
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• 2013

The use of steel bracing systems is a popular method for the strengthening of existing reinforced concrete (RC) frames and may lead to a substantial increase of both strength and stiffness. However, in most retrofitting cases, the main target is the increase of the energy dissipation capacity. This paper studies numerically the efficiency of a specific strengthening methodology which utilizes a steel link element having a cross-section of various shapes, connected to the RC frame through bracing elements. The energy is dissipated through the yielding of the steel link element. The case studied is a typical one bay, single-storey RC frame, constructed according to older code provisions, which is strengthened through two different types of link elements. The presented numerical models are based on tests which are simulated in order to gain a better insight of the behaviour of the strengthened structures, but also in order to study the effects of different configurations for the link element. The behaviour of the strengthened frames is studied with respect to the one of the original bare frame. Moreover, the numerically obtained results are compared to the experimentally obtained ones, in order to verify the effectiveness of the applied simulation methodology.

• 국제초고층학회논문집
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• 제5권3호
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• pp.195-203
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• 2016

Shear wall structures have been widely used in high-rise buildings during the past decades, mainly due to their good overall performance, large lateral stiffness, and high load-carrying capacity. However, traditional reinforced concrete wall structures are prone to brittle failure under seismic actions. In order to improve the seismic behavior of traditional shear walls, this paper presents three different metal energy-dissipation shear wall systems, including coupled shear wall with energy-dissipating steel link beams, frame with buckling-restrained steel plate shear wall structure, and coupled shear wall with buckling-restrained steel plate shear wall. Constructional details, experimental studies, and calculation analyses are also introduced in this paper.

• 한국강구조학회 논문집
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• 제30권1호
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• pp.37-48
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• 2018

이 연구에서는 원형 개구부가 있는 전단지배 하이브리드 강재 연결보의 내진성능을 평가하기 위해 탑-시트 앵글이 있는 실험체 3개(SCB1, SCB2, SCB3)와 앵글이 없는 실험체 1개 (SCB4) 등 총 4개의 강재 연결보 시스템에 대한 반복가력 실험이 수행되었다. 실험변수는 웨브 개구부의 크기, 즉 전단강도비이다. SCB1, SCB2, SCB3, 그리고 SCB4 실험체의 전단강도비(웨브 개구부 크기)는 0.34(300mm), 0.49(268mm), 0.78(200mm), 그리고 0.34(300mm)이다. 실험결과, 제안된 연결보 시스템은 우수한 변형능력과 강성을 보여주었다. 실험연구를 통해 하이브리드 강재 연결보 시스템에 적용가능한 설계전단강도를 제안하였다. 연결보의 전단강도가 소성전단강도의 50% 이하일 때 핀칭이 완화되는 것으로 나타났으며, 이로 인해 내진 성능이 향상되는 것으로 나타났다. 핀칭을 최소화하고, 내진성능을 향상시키기 위해서는 연결보 구조설계 시 연결보의 전단강도를 50% 이상 저감시키는 방안도 고려될 수 있을 것으로 판단된다.