scholarly journals Shear Behavior of a Reinforced Concrete Frame Retrofitted with a Hinged Steel Damping System

2020 ◽  
Vol 12 (24) ◽  
pp. 10360
Author(s):  
Hyun-Do Yun ◽  
Sun-Woong Kim ◽  
Wan-Shin Park ◽  
Sun-Woo Kim

The purpose of this study was to experimentally evaluate the effect of a hinged steel damping system on the shear behavior of a nonductile reinforced concrete frame with an opening. For the experimental test, a total of three full-scale reinforced concrete frame specimens were planned, based on the “no retrofitting” (NR) specimens with non-seismic details. The main research questions were whether the hinged steel damping system is reinforced and whether torsion springs are installed in the hinged steel damping system. From the results of the experiment, the hinged steel damping system (DR specimen) was found to be effective in seismic retrofitting, while isolating the opening of the reinforced concrete (RC) frame, and the torsion spring installed at the hinged connection (DSR specimen) was evaluated to be effective in controlling the amount of deformation of the upper and lower dampers. The strength, stiffness, and energy dissipation capacity of the DSR specimen were slightly improved compared to the DR specimen, and it was confirmed that stress redistribution was induced by the rotational stiffness of the torsion spring installed in the hinge connection between the upper and lower frames.

2020 ◽  
Vol 10 (20) ◽  
pp. 7061 ◽  
Author(s):  
Kyong Min Ro ◽  
Min Sook Kim ◽  
Young Hak Lee

Buildings constructed with non-seismic details are at risk of damage and collapse when an earthquake occurs due to a lack of strength, stiffness, and ductility. For reinforced concrete (RC) moment-resisting frames, seismic retrofitting methods that can enhance strength or ductility should be applied. However, such strategies have many disadvantages related to constructability, serviceability, securing integrity, and cost. In this paper, a welded concrete-filled steel tube (WCFST) system was examined in order to resolve the problems of the existing seismic retrofitting methods for RC moment-resisting frames. To evaluate the seismic performance of the proposed system, two specimens, one with non-seismic details and another reinforced with a WCFST seismic system, were manufactured for the cyclic loading tests. As a result of the experiments, the specimen retrofitted with the WCFST system showed maximum load, effective stiffness, and energy dissipation capacity values approximately 3, 2, and 2.5 times greater, respectively, than those obtained from the existing reinforced concrete frame specimen. The experimental results indicate that the proposed WCFST system is expected to be effective at improving the seismic performance by enhancing both the strength of the existing reinforced concrete frame structures and the dissipation of the seismic energy.


Author(s):  
Made Sukrawa ◽  
Ida Bagus Dharma Giri ◽  
I Putu Deskarta ◽  
Made Hendra Prayoga

Abstract: Analysis of reinforced concrete frame with steel braces has been done to compare the behavior of the open frame structure with reinforced concrete structure with steel braces. Three models of 2D open frame structure with 3, 4 and 5 floors were made and analyzed in SAP2000 v17 with intermediate detailing according to Indonesian Codes for Seismic Load (SNI 1726: 2002). 3-span frame structure with a span length of 6 m and level height of 3,5 m were designed according to SNI 1726: 2002, and then re-analyzed with special detailing according to New Indonesian Codes for Seismic Load (SNI 1726: 2012). After that, it was added with braces as seismic retrofitting. Two types of braces (X and concentric inverted V) were used in this study and analyzed with conventional analysis and stage construction analysis according to their stages of implementation. From the analysis results, several structure components that analyzed according to SNI 1726:2012 provitions were experience over-stressed. After retrofitted with steel braces, those components fulfill strength provition according to SNI 2847:2013 about structural concrete regulations for buildings. In addition to that, displacements that occurs on braced frame are smaller than displacements of the open frame structure with ratio of 0.08, 0.12, and 0.18 for X-brace frames with 3,4, and 5 storey and 0.07, 0.11, and 0.16 for inverted-V brace. With staged construction analysis, displacements of  X-braced frame structure increased by 14.38%, 13.62%, and 9.98% from the conventional analysis results for structure with 3, 4,and 5 storey. For structure with inverted-V brace, displacements increased by 15.83%, 14.29%, and 10.09%.


Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 310
Author(s):  
Fei Wang ◽  
Kaozhong Zhao ◽  
Jianwei Zhang ◽  
Kai Yan

To study the influence of masonry infill walls on the hysteretic performance of reinforced concrete frames, a cyclic experiment was conducted for three two-story and two-span reinforced concrete frame structures, including one reinforced concrete frame without infill walls and two frames with infill walls. Whether the infill walls were constructed in the frames and the type of infilled material were the main parameters of the test. The major results reveal that: the infill walls clearly changed the mechanical mechanism of the frame structure at the early stage of loading, magnified the stiffness and horizontal bearing capacity of the frame structure, and enhanced the energy dissipation capacity of the frame structure, but reduced the deformation performance of the frame structure. In the later stage of loading, the infill walls would no longer work as one with the frame gradually with the failure of the infill walls, and the above performance of the structure would approach the empty frame structure. Moreover, the initial stiffness, energy dissipation capacity, and horizontal bearing capacity of the frame with infill walls of clay hollow bricks were the highest among the three specimens. But due to the strong diagonal bracing effect, the damage to the top of the columns and beam-column joints was serious, the yield displacement was reduced significantly, and the shear failure of the top of the columns and the joints occurred prematurely, which showed poor performance of deformation and ductility. However, the frame with infill walls of relatively soft aerated lightweight concrete blocks showed better performance of deformation and ductility.


2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Made Sukrawa ◽  
Ida Bagus Dharma Giri ◽  
I Putu Deskarta ◽  
Made Hendra Prayoga

Abstract: Analysis of reinforced concrete frame with steel braces has been done to compare the behavior of the open frame structure with reinforced concrete structure with steel braces. Three models of 2D open frame structure with 3, 4 and 5 floors were made and analyzed in SAP2000 v17 with intermediate detailing according to Indonesian Codes for Seismic Load (SNI 1726: 2002). 3-span frame structure with a span length of 6 m and level height of 3,5 m were designed according to SNI 1726: 2002, and then re-analyzed with special detailing according to New Indonesian Codes for Seismic Load (SNI 1726: 2012). After that, it was added with braces as seismic retrofitting. Two types of braces (X and concentric inverted V) were used in this study and analyzed with conventional analysis and stage construction analysis according to their stages of implementation. From the analysis results, several structure components that analyzed according to SNI 1726:2012 provitions were experience over-stressed. After retrofitted with steel braces, those components fulfill strength provition according to SNI 2847:2013 about structural concrete regulations for buildings. In addition to that, displacements that occurs on braced frame are smaller than displacements of the open frame structure with ratio of 0.08, 0.12, and 0.18 for X-brace frames with 3,4, and 5 storey and 0.07, 0.11, and 0.16 for inverted-V brace. With staged construction analysis, displacements of  X-braced frame structure increased by 14.38%, 13.62%, and 9.98% from the conventional analysis results for structure with 3, 4,and 5 storey. For structure with inverted-V brace, displacements increased by 15.83%, 14.29%, and 10.09%.


2003 ◽  
Vol 6 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Sayed A. Attaalla ◽  
Mehran Agbabian

The characteristics of the shear deformation inside the beam-column joint core of reinforced concrete frame structures subjected to seismic loading are discussed in this paper. The paper presents the formulation of an analytical model based on experimental observations. The model is intended to predict the expansions of beam-column joint core in the horizontal and vertical directions. The model describes the strain compatibility inside the joint in an average sense. Its predictions are verified utilizing experimental measurements obtained from tests conducted on beam-column connections. The model is found to adequately predict the components of shear deformation in the joint core and satisfactorily estimates the average strains in the joint hoops up to bond failure. The model may be considered as a simple, yet, important step towards analytical understanding of the sophisticated shear mechanism inside the joint and may be implemented in a controlled-deformation design technique of the joint.


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