• Computers and Concrete
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• v.2 no.2
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• pp.147-164
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• 2005

This paper summarizes an experimental study on the seismic behavior of lower stories of a mid-rise reinforced concrete frame building. Two reinforced concrete frames with two stories and one span were tested and each frame represents lower two stories of an 11-story RC frame building. Both frames were designed in accordance with Japanese design guidelines and were identical except in the variation of axial force. The tests demonstrated that the overall load-displacement relations of the two frames were nearly the same and the first-story column shear was closely related to the column axial load. The columns and beams elongated during both of the tests, with the second-floor beam elongation exceeding 1.5% of the beam clear span length. The frame with higher axial loads developed more cracks that the frame under moderate axial load.

• Advances in concrete construction
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• v.9 no.4
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• pp.423-435
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• 2020

Open ground story (OGS) reinforced concrete (RC) buildings are vulnerable to the complete collapse or severe damages under seismic actions. This study investigates the effectiveness of four different strengthening techniques representing the local and global modifications to improve the seismic performance of a non-ductile RC OGS frame. Steel caging and concrete jacketing methods of column strengthening are considered as the local modification techniques, whereas steel bracing and RC shear wall systems are selected as the global strengthening techniques in this study. Performance-based plastic design (PBPD) approach relying on energy-balance concept has been adopted to determine the required design force demand on the strengthening elements. Nonlinear static and dynamic analyses are carried out on the numerical models of study frames to assess the effectiveness of selected strengthening techniques in improving the seismic performance of OGS frame.. Strengthening techniques based on steel braces and RC shear wall significantly reduced the peak interstory drift response of the OGS frame. However, the peak floor acceleration of these strengthened frames is amplified by more than 2.5 times as compared to that of unstrengthened frame. Steel caging technique of column strengthening resulted in a reasonable reduction in the peak interstory drift response without substantial amplification in peak floor acceleration of the OSG frame.

• Structural Engineering and Mechanics
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• v.73 no.4
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• pp.381-395
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• 2020

Study on the inelastic response of bare and masonry infilled Reinforced Concrete (RC) frames repaired using Carbon Fibre Reinforced Polymers (CFRP) and Glass Fiber Reinforced Polymers (GFRP) subjected to quasi- static loading is presented in the work. The hysteresis behaviour, stiffness retention, energy dissipation and damage index are the parameters employed to analyze the efficacy of FRP strengthening of bare and brick in-filled RC frames. It is observed that there is a significant improvement in load carrying capacity of brick infilled frame over bare RC frame. Also FRP strengthened brick infilled frame performs much better than FRP repaired bare frame under quasi static loading. Repair and retrofitting of brick infilled RC frame shows an improved load carrying and damage tolerance capacity than control frame.

• Steel and Composite Structures
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• v.22 no.5
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• pp.1055-1071
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• 2016

The paper presents an innovative steel moment frame with the replaceable reinforced concrete wall panel (SRW) structural system, in which the replaceable concrete wall can play a role to increase the overall lateral stiffness of the frame system. Two full scale specimens composed of the steel frames and the replaceable reinforced concrete wall panels were tested under the cyclic horizontal load. The failure mode, load-displacement response, deformability, and the energy dissipation capacity of SRW specimens were investigated. Test results show that the two-stage failure mode is characterized by the sequential failure process of the replaceable RC wall panel and the steel moment frame. It can be found that the replaceable RC wall panels damage at the lateral drift ratio greater than 0.5%. After the replacement of a new RC wall panel, the new specimen maintained the similar capacity of resisting lateral load as the previous one. The decrease of the bearing capacity was presented between the two stages because of the connection failure on the top of the replaceable RC wall panel. With the increase of the lateral drift, the percentage of the lateral force and the overturning moment resisted by the wall panel decreased for the reason of the reduction of its lateral stiffness. After the failure of the wall panel, the steel moment frame shared almost all the lateral force and the overturning moment.

• Journal of the Earthquake Engineering Society of Korea
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• v.17 no.3
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• pp.127-132
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• 2013

This study proposed proposes a retrofitting method using an H-beam frame to improve the seismic performance of non-seismic designed reinforced concrete frames. To evaluate the seismic performance with the H-beam frames, a cyclic lateral load test was performed and the experimental result was compared with the bared frame, and a masonry infilled RC frame. The results was were analyzed regarding aspects of the load-displacement hysteresis behavior, effective stiffness, displacement ductility, and cumulative energy dissipation. AlsoIn addition, it was possible to prove both an increase of in the maximum load capacity, effective stiffness, and energy dissipation capacity using the H-beam frame.

• Computers and Concrete
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• v.6 no.4
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• pp.319-341
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• 2009

A new formulation based on lumped plasticity and inelastic hinges is presented in this paper for nonlinear analysis of Reinforced Concrete (RC) frame structures. Inelastic hinge behaviour is described using the principles of Continuum Damage Mechanics (CDM). Member formulation contains provisions to model stiffness degradation due to cracking of concrete and yielding of reinforcing steel. Depending on its nature, cracking is classified as concentrated or distributed. Concentrated cracking is accounted through a damage variable and its growth is defined based on strain energy principles. Presence of distributed flexural cracks in a member is taken care of by modelling it as non-prismatic. Plasticity theory supported by effective stress concept of CDM is applied to describe the post-yield response. Nonlinear quasi-static analysis is carried out on a RC column and a wide two-storey RC frame to verify the formulation. The column is subjected to constant axial load and monotonic lateral load while the frame is subjected to only lateral load. Computed results are compared with those due to experiments or other numerical methods to validate the performance of the formulation and also to highlight the contribution of distributed cracking on global response.

• International Journal of Concrete Structures and Materials
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• v.10 no.1
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• pp.1-13
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• 2016

The progressive collapse analysis of reinforced concrete (RC) moment-frame buildings under extreme loads is discussed from the perspective of modeling issues. A threat-independent approach or the alternate path method forms the basis of the simulations wherein the extreme event is modeled via column removal scenarios. Using a prototype RC frame building, issues and considerations in constitutive modeling of materials, options in modeling the structural elements and specification of gravity loads are discussed with the goal of achieving consistent models that can be used in collapse scenarios involving successive loss of load-bearing columns at the lowest level of the building. The role of the floor slabs in mobilizing catenary action and influencing the progressive collapse response is also highlighted. Finally, an energy-based approach for identifying the proximity to collapse of regular multi-story buildings is proposed.

• Earthquakes and Structures
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• v.5 no.5
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• pp.571-588
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• 2013

Many of the current buildings in Algeria were built in the past without any consideration to the requirements of the seismic code. Among these buildings, there are a large number of individual houses built in the 1980's by their owners. They are Reinforced Concrete (RC) frame structures with unreinforced hollow masonry infill walls. This buildings type experienced major damage in the 2003 (Algeria) earthquake, generated by deficiencies in the structural system. In the present study, special attention is placed upon examining the vulnerability of RC frame houses. Their situation and their general features are investigated. Observing their seismic behavior, structural deficiencies are identified. The seismic vulnerability of this type of buildings depends on several factors, such as; structural system, plan and vertical configuration, materials and workmanship. The results of the vulnerability assessment of a group of RC frame houses are presented. Using a method based on the European Macroseismic Scale EMS-98 definitions, presented in previous studies, distribution of damage is obtained.

• Steel and Composite Structures
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• v.21 no.3
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• pp.661-677
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• 2016

The quasi static test of the steel reinforced concrete (SRC) bridge piers and rigid frame arch bridge structure with SRC piers was conducted in the laboratory, and the seismic performance of SRC piers was compared with that of reinforced concrete (RC) bridge piers. In the test, the failure process, the failure mechanism, hysteretic curves, skeleton curves, ductility coefficient, stiffness degradation curves and the energy dissipation curves were analyzed. According to the $M-{\Phi}$ relationship of fiber section, the three-wire type theoretical skeleton curve of the lateral force and the pier top displacement was proposed, and the theoretical skeleton curves are well consistent with the experimental curves. Based on the theoretical model, the effects of the concrete strength, axial compression ratio, slenderness ratio, reinforcement ratio, and the stiffness ratio of arch to pier on the skeleton curve were analyzed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.121-129
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• 2017

In this paper, the shake table test for the masonry infilled reinforced concrete frame with non-seismic details was carried out in order to evaluate its dynamic behaviour and damage under seismic condition. The tested specimens were the RC frame and the masonry infilled RC frame and the dynamic characteristics, such as a resonant period, acceleration response, displacement response and base shear force response, were compared between them. As a result of the shake table test, RC frame specimen had flexural cracks at the top and bottom of the column and shear cracks at the joints. In the case of masonry infilled RC frame, the damage of the frame was relatively minor but the sliding cracks and diagonal shear cracks on the masonry wall were severe at the final excitation. The resonant period of infilled RC frame specimen was shorter than that of the RC frame specimen because the masonry infill contributed to increase the stiffness. The maximum displacement response of the infilled RC frame specimen was decreased by about 20% than the RC frame specimen. It was analyzed that the masonry infill wall applied in this study contributed to increase the lateral strength of the RC frame with non - seismic detail by about 2.2 times and the stiffness by about 1.6 times.