scholarly journals Experimental and Numerical Research on Seismic Performance of Earthquake-Damaged RC Frame Strengthened with CFRP Sheets

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Lai Wang ◽  
Wei Xuan ◽  
Ying Zhang ◽  
Shuping Cong ◽  
Feng Liu ◽  
...  
Keyword(s):  
Seismic Performance ◽  
Fiber Reinforced Polymers ◽  
Experimental Result ◽  
Rc Frame ◽  
Carbon Fiber Reinforced Polymers ◽  
Skeleton Curve ◽  
Cfrp Sheets ◽  
Rc Frames ◽  
Moderate Earthquake ◽  
Curve Skeleton

In order to assess the seismic performance of damaged reinforced concrete (RC) frame strengthened with carbon fiber reinforced polymers (CFRP) sheets, two experimental specimens with identical reinforcement ratio and geometric dimensions were designed following Chinese code for seismic design of buildings. Experimental specimens consist of a reference (undamaged) RC frame, namely, KJ-1, and an earthquake-damaged RC frame strengthened with CFRP sheets, namely, KJ-2. A pseudostatic test was conducted on the two specimens to simulate moderate earthquake damage. The strengthening effects of CFRP sheets on damaged RC frame were discussed in terms of hysteretic curve, skeleton curve, stiffness degradation, and ductility. In addition, numerical method based on fiber model method was utilized to analyze the seismic performance of KJ-1 and KJ-2 and it is compared with the experimental result. Both the results confirm that the method of exterior bonding CFRP sheets on the damaged RC frame has restored the seismic performance such as bearing capacity, stiffness, and ductility to its original undamaged level, and some of the seismic performance of the damaged RC frame strengthened with CFRP sheets is even better than the undamaged one, which proves that the method has significant effect in strengthening postearthquake-damaged RC frames.

Experimental Study on Seismic Performance of CFRP Strengthened RC Frames Damaged by Earthquake

2013 ◽  
Vol 724-725 ◽  
pp. 1749-1753
Author(s):  
Qiu Mei Gao ◽  
Lai Wang ◽  
Ying Zhang
Keyword(s):  
Seismic Performance ◽  
Test Method ◽  
Hysteresis Curve ◽  
Rc Frame ◽  
Loading Test ◽  
Skeleton Curve ◽  
Static Test ◽  
Displacement Ductility ◽  
Rc Frames ◽  
Industry Standards

In this paper, we carried out low cyclic loading test over CFRP strengthened seismic-damaged RC frame named KJ-2 with the quasi-static test method, and compared the seismic performance with the same sections and materials RC frame named KJ-1 which was unstrengthened. We study the seismic performance such as hysteresis curve, skeleton curve, stiffness degradation, bearing capacity degeneration, displacement ductility, and energy dissipation capacity of the reinforced RC frame. On this basis, we analyzed the results of this test in order to obtain some guiding opinions for asymmetric span RC frames that strengthened by CFRP, and provide main preference basis or future national or industry standards.

Experimental Study on Seismic Performance of Reactive Power Concrete Box Piers

2011 ◽  
Vol 94-96 ◽  
pp. 464-468
Author(s):  
Fei Wang ◽  
Zhi Fang ◽  
Xin Feng Yin
Keyword(s):  
Seismic Performance ◽  
Reactive Power ◽  
Axial Direction ◽  
Hysteresis Curve ◽  
Horizontal Load ◽  
Skeleton Curve ◽  
Static Test ◽  
Seismic Force ◽  
Box Piers ◽  
Curve Skeleton

Designing the reasonable cross-section and the structural conformation, three Reactive power concrete box piers samples were designed and studied under the constant axial force and reversed horizontal loads. The effect of the reversed horizontal load on the seismic performance of RPC box pier was studied. Such seismic performance as ductility, hysteresis curve, skeleton curve, etc. of RPC box piers is studied by pseudo-static test on three RPC box piers. The simulation results shows that RPC box piers exists excellent performance of resisting seismic force, the direction of horizontal load significant affect that performance, and the performance of resisting seismic force for the pier loaded by the force from main axial direction are better than that from other direction.

Theoretical and experimental studies on repaired and rehabilitated reinforced concrete frames

2007 ◽  
Vol 34 (8) ◽  
pp. 923-933 ◽  
Author(s):  
Yeou-Fong Li ◽  
Yan-Jie Lin ◽  
Cheng-Wei Chen ◽  
Chih-Tsung Lin
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Earthquake Engineering ◽  
Steel Wire ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Rc Frames ◽  
Carbon Fiber Reinforced

In this paper, an effective repair and rehabilitation working method is proposed for moderately damaged reinforced concrete (RC) building structures after major earthquakes. Three RC frames with nil, half-height, and full-height brick walls are designed and tested at the National Center for Research on Earthquake Engineering (NCREE), Taiwan. After the columns of these nonductile RC frames are damaged, steel wire cables with nonshrinkage mortar are used to repair the damaged columns, and carbon fiber reinforced polymers (CFRP) are used to rehabilitate the damaged columns. A stress–strain relationship of the confined concrete is used in the theoretical sectional analysis. The columns are confined by steel wires and CFRP, and the "equivalent column model" is proposed in this paper and used to analyze the brick walls inside the RC frames. The analytical results can reasonably predict the lateral force–displacement relationships of these RC frames. Key words: nonductile frame, carbon fiber reinforced polymers, steel wire cable, repair, rehabilitation.

scholarly journals Seismic performance of brick masonry infilled frame structures with bed joint reinforcements

2020 ◽  
Vol 156 ◽  
pp. 03004
Author(s):  
Maidiawati ◽  
Jafril Tanjung ◽  
Yulia Hayati ◽  
Agus ◽  
Satria Rangga
Keyword(s):  
Seismic Performance ◽  
Frame Structure ◽  
Frame Structures ◽  
Rc Frame ◽  
Infilled Frame ◽  
Rc Frames ◽  
Lateral Strength ◽  
Plane Direction ◽  
Infilled Rc Frames ◽  
Reversed Cyclic

This paper presents the evaluation of the seismic performance of brick infilled RC frame structures with bed joint reinforcements based on reversed cyclic lateral load tests. Three specimens of the structural model of 1/4 scale-down single-story single-bay brick infilled RC frame was prepared, which were brick infilled RC frames with and without bed joint reinforcements. Two specimens of brick infills with bed joint reinforcements were different in the spacing of bed joint rebars. The specimens were tested by applying a reversed cyclic lateral loading in-plane direction. During the tests, the crack propagation was observed at the peak and residual drifts of each loading cycle to recognize the failure mechanisms of the specimens. As the results, although the use of the bed joint reinforcements ineffective to increase the lateral strength of the overall infilled frame structure. The rebars in mortar bed joints role to sustain the lateral strength in plastic deformation, and provide the whole structure with high ductility. It seemed that the rebars in mortar bed joints confined the brick infills. Therefore, the infilled RC frames can survive in large deformation without failure of the infills in out of the plane direction.

scholarly journals Analysis of the Seismic Performance of Site-Bolted Beam to Column Connections in Modularized Prefabricated Steel Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Xuechun Liu ◽  
Xiaoxiong Cui ◽  
Zhiwei Yang ◽  
Xinxin Zhan
Keyword(s):  
Plastic Deformation ◽  
Failure Mode ◽  
Seismic Performance ◽  
Plastic Hinge ◽  
Ductile Failure ◽  
Steel Structures ◽  
Hysteretic Behavior ◽  
Element Analysis ◽  
Skeleton Curve ◽  
Moderate Earthquake

This paper proposes a site-bolted connection that is suitable for modularized prefabricated steel structures. Excellent ductility is achieved by various structural measures. Six connection specimens with different parameters were subjected to quasi-static loading tests and finite element analysis (FEA) to determine the seismic performance of the proposed connection (e.g., hysteretic behavior, skeleton curve, ductility, and failure mode). The results of the tests and FEA showed that the connection underwent sufficient plastic deformation under cyclic loading and that its ultimate rotation angle could reach 0.09 rad. A clear plastic hinge formed on the beam before the connection failed, which suggests a ductile failure mode. The connection exhibited a wide hysteresis loop, which indicated good seismic performance. The results also showed that the connection does not slip under small earthquakes and could dissipate energy through slippage in the connection region under a moderate earthquake and through slippage in the connection region as well as plastic deformation at the beam end under a severe earthquake. The number of bolts was the main parameter that affected the seismic performance of the connection. The test and FEA results demonstrated that all six specimens had excellent seismic and ductile performance and an exceptional plastic rotation capacity.

Restoring Force Model of Joints of RC Frame Retrofitted by FRP

2012 ◽  
Vol 256-259 ◽  
pp. 693-696
Author(s):  
Peng Li ◽  
Ya Ping Peng ◽  
Er Lei Yao
Keyword(s):  
Seismic Performance ◽  
Seismic Retrofitting ◽  
Frame Structure ◽  
Force Model ◽  
Strengthening Effect ◽  
Rc Frame ◽  
Restoring Force ◽  
Rc Frames ◽  
Restoring Force Model ◽  
Hysteretic Performance

In order to evaluate the seismic performance of reinforced concrete (RC) frames retrofitted by FRP, the experiment of RC frames retrofitted at joints by FRP was carried out. The enhancement in seismic performance of the retrofitted frames is evaluated in hysteretic performance, bearing capacity, stiffness degradation and energy dissipation. And the strengthening effect of the frame retrofitted by CFRP and C/GFRP was compared in the experiment. The restoring force model of RC frame joints retrofitted with FRP was proposed and ranges of the characteristic parameters were determined. The equation of restoring force model for joints strengthened by C/GFRP was suggested. The result show that seismic performance of RC frame retrofitted by FRP based on joints can be improved remarkably. The restoring force model which proposed can be used in seismic elasto-plastic analysis of RC frame structure retrofitted by FRP and practical engineering seismic retrofitting design by FRP.

Seismic Performance of Story Drift–Controlled RC Frames with Hysteretic Dampers

2012 ◽  
Vol 28 (4) ◽  
pp. 1569-1587
Author(s):  
Juan Andres Oviedo-Amezquita ◽  
Mitsumasa Midorikawa ◽  
Tetsuhiro Asari
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Seismic Performance ◽  
Analytical Procedure ◽  
Seismic Damage ◽  
Rc Frame ◽  
Rc Frames ◽  
Wide Range ◽  
Story Drift ◽  
Hysteretic Dampers

This paper investigates the seismic performance of story drift–controlled reinforced concrete (RC) frames with hysteretic dampers. The frame models include a wide range of mechanical properties of dampers, which are defined according to a proportion rule in order to explicitly control the yield story drift of dampers. The story drift response, hysteretic energy dissipation and other parameters are examined to evaluate the effectiveness of dampers. The influence of the global flexural deformation of the frame on the response of dampers is also examined, and an analytical procedure to account for this phenomenon is developed. The obtained results indicate that the seismic performance of the structure is improved by reducing the story drift demand and seismic damage uniformly over the building height. Regarding the global flexural deformation, the proposed analytical procedure can be used for a preliminary estimation of the story number up to which dampers yield before the RC frame.

scholarly journals Experimental assessment of different strengthening techniques for opening in reinforced concrete beams

2021 ◽  
Vol 16 (59) ◽  
pp. 549-565
Author(s):  
Fatma Agag ◽  
Seleem S. E. Ahmad ◽  
Hossam El-Din M. Sallam
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Load Carrying Capacity ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Cfrp Sheets ◽  
Load Carrying

The present experimental study includes testing thirteen reinforced concrete beams with openings at different locations to investigate the efficiency of strengthening such openings. Different strengthening techniques around the opening after and before casting include diagonal bars, upper and lower steel, and carbon fiber reinforced polymers (CFRP), were examined. All beams were made from 30 MPa compressive strength and tested under four-point loading.  The cross section of the beams is 400 mm depth x 160 mm width and beam length 2400 mm. The dimensions of the opening are 200 mm x 200 mm. The stiffness, deflection, failure load, and failure mode of the strengthened beams were discussed. Experimental results showed that the beams strengthened with upper and lower steel around opening at mid-span increase the load-carrying capacity by 16.59%. However, beams strengthened by CFRP sheets around the opening in the shear zone increase the load carrying capacity by 47.7% compared to opened beam.

Seismic Performance of RC Frame with Shape Memory Alloy Bracing Bars

2011 ◽  
Vol 71-78 ◽  
pp. 37-40
Author(s):  
Wen I Liao
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Performance ◽  
Rc Frame ◽  
Test Results ◽  
Base Shear ◽  
Rc Frames ◽  
Story Drift ◽  
Bracing System ◽  
Force Displacement

In this study, high seismic performance RC frames have been proposed to have Shape Memory Alloy (SMA) bars acting as a kind of structural bracing system at both sides of a frame to increase the energy dissipation capacity of the RC frame. The type of SMA bar used in the study is the Superelastic SMA bar. The force-displacement hysteretic loops of the RC frame with SMA bars under seismic loading are presented and compared with the test results of the bare RC frame. Test results show that the SMA bars can effectively reduce the maximum story drift of the tested frame. It was found that the reduction of story drift and base shear was depending on the characteristic of the input ground motions.

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