Seismic performance of RC frames strengthened by RC infill walls

2021 ◽  
pp. 136943322199772
Author(s):  
Shao-Ge Cheng ◽  
Yi-Xiu Zhu ◽  
Wei-Ping Zhang
Keyword(s):  
Masonry Walls ◽  
Rc Frame ◽  
Seismic Line ◽  
Shake Table Tests ◽  
Infill Walls ◽  
Displacement Ductility ◽  
Rc Frames ◽  
Story Drift ◽  
Comparison Of The Results ◽  
Bending Failure

This study presents the shake-table tests of a 1/5-scaled RC frame retrofitted with RC infill walls. The intensity of input ground motions increased gradually to comprehensively evaluate the structural seismic behavior. We performed a comparison of the results from the RC frame with masonry walls and that with RC walls. The results showed that the presence of RC infills effectively improved the lateral structural stiffness and loading capacity of the frames and reduced their damage and story drift. RC walls acted as the first seismic line of defense, and their failure was dominated by bending failure and concentrated on the low stories. The displacement ductility of the structure decreased with increasing stiffness of the introducing infills.

Cyclic Performance of Two-Story Ductile RC Frames With Infill Walls

2005 ◽  
Author(s):  
Yung-Hsin Yeh ◽  
Wen-I Liao
Keyword(s):  
Model Building ◽  
General Purpose ◽  
Rc Frame ◽  
Building Structures ◽  
Base Shear ◽  
Concrete Frames ◽  
Infill Wall ◽  
Infill Walls ◽  
Rc Frames ◽  
Short Beam

This paper presents the results of the experimental and analytical investigations conducted on four 0.8 scale 2-story one bay ductile reinforced concrete frames with infill nonstructural walls subjected to cyclically increasing loads. The material properties and the member sizes of beams and columns in the four RC frame specimens are identical, but with different types of infill nonstructural wall. These four frames are the pure frame, frame with short column, frame with short beam and frame with wing walls. The four RC frame specimens were designed and constructed according to the general prototype building structures in Taiwan. Test results indicate that the ductility behavior of the frames with infill wall is similar to those of the pure frame. The ultimate base shear strength of the frames with infill walls is higher than those of the pure frame. Analytical results show that the proposed simplified multi-linear beam-column element implemented in a general purpose structural analysis program can accurately simulate the cyclic responses of the RC frame specimen incorporating the elastic flexural stiffness computations suggested by the model building codes.

A Beam-and-Column Based Macro Model for Masonry Infill Walls in RC Frames under Cyclic Loading

2011 ◽  
Vol 255-260 ◽  
pp. 193-197
Author(s):  
Jia Chao Zhang ◽  
Lei Ming Zhang ◽  
Xi La Liu
Keyword(s):  
Structural Response ◽  
Seismic Action ◽  
Rc Frame ◽  
Wall Panel ◽  
Infill Walls ◽  
Masonry Infill ◽  
Macro Model ◽  
Masonry Infill Walls ◽  
Rc Frames ◽  
Proposed Model

Reinforced concrete (RC) frame with masonry infill walls is a very common structural system in low and medium rise buildings. The infill walls are usually considered as non-structural components in the design or assessment of buildings. However, many damages in earthquakes have shown that the infill walls can significantly change the structural response to seismic action. Consequently the evaluation of the seismic performance of RC frame with masonry infill walls becomes very important, and also turns to be a major challenge for structure engineers. In this paper a beam-and-column (BAC) macro model for walls is proposed to simulate the masonry infill walls in RC frames. In this model, the masonry panel is replaced by an equivalent rigid frame which is made up of some beam-and-column members. The geometric parameters of each member can be determined simply by equivalent stiffness combined with the original dimensions of wall panel. The physical characteristics are described directly by material properties of wall panel under investigation. To validate the rationality of proposed model, a masonry-infilled RC frame under cyclic reversed loading is analyzed by the proposed model. The results, including crack pattern, load versus displacement relation are then compared with the experiment response. Good agreements are found.

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.

scholarly journals Advanced Composite Retrofit of RC Columns and Frames with Prior Damages—Pseudodynamic Finite Element Analyses and Design Approaches

Fibers ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 56
Author(s):  
Theodoros Rousakis ◽  
Evgenia Anagnostou ◽  
Theodora Fanaradelli
Keyword(s):  
Finite Element ◽  
Brick Wall ◽  
Rc Frame ◽  
Base Shear ◽  
Infill Wall ◽  
Rc Columns ◽  
Premature Failure ◽  
Displacement Ductility ◽  
Lap Splices ◽  
Rc Frames

This study develops three-dimensional (3D) finite element (FE) models of composite retrofits in deficient reinforced concrete (RC) columns and frames. The aim is to investigate critical cases of RC columns with inadequate lap splices of bars or corroded steel reinforcements and the beneficial effects of external FRP jacketing to avoid their premature failure and structural collapse. Similarly, the RC-frame FE models explore the effects of an innovative intervention that includes an orthoblock brick infill wall and an advanced seismic joint made of highly deformable polymer at the boundary interface with the RC frame. The experimental validation of the technique in RC frames is presented in earlier published papers by the authors (as well as for a four-column structure), revealing the potential to extend the contribution of the infills at high displacement ductility levels of the frames, while exhibiting limited infill damages. The analytical results of the advanced FE models of RC columns and frames compare well with the available experimental results. Therefore, this study’s research extends to critical cases of FE models of RC frames with inadequate lap splices or corroded steel reinforcements, without or with brick wall infills with seismic joints. The advanced pseudodynamic analyses reveal that for different reinforcement detailing of RC columns, the effects of inadequate lap-spliced bars may be more detrimental in isolated RC columns than in RC frames. It seems that in RC frames, additional critical regions without lap splices are engaged and redistribution of damage is observed. The detrimental effects of corroded steel bars are somewhat greater in bare RC frames than in isolated RC columns, as all reinforcements in the frame are considered corroded. Further, all critical cases of RC frames with prior damages at risk of collapse may receive the innovative composite retrofit and achieve higher base shear load than the original RC frame without corroded or lap-spliced bars, at comparable top displacement ductility. Finally, the FE analyses are utilized to propose modified design equations for the shear strength and chord rotation in cases of failure of columns with deficiencies or prior damages in RC structures.

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.

Cyclic behavior of lightly reinforced concrete moment frames with partial- and full-height masonry walls

2020 ◽  
Vol 36 (2) ◽  
pp. 599-628
Author(s):  
Sang Whan Han ◽  
Chang Seok Lee
Keyword(s):  
Numerical Models ◽  
Masonry Walls ◽  
Moment Frames ◽  
Infill Walls ◽  
Masonry Infill ◽  
Masonry Infill Walls ◽  
Rc Frames ◽  
Numerical Studies ◽  
Lightly Reinforced Concrete ◽  
Full Height

Existing lightly reinforced concrete (RC) moment frames are vulnerable to earthquakes. The seismic behavior of these frames could be affected by the presence of masonry infill walls. The objective of this study was to investigate the seismic behavior of gravity-designed RC frames having partial- and full-height masonry infill walls. For this purpose, experimental and numerical studies were conducted. Three one-story and one-bay gravity-designed RC moment frames with and without partial- and full-height masonry infill walls were made and tested under cyclic lateral loads. Numerical models for RC moment frames and masonry walls were proposed based on test data. Nonlinear static and incremental dynamic analyses (IDAs) were conducted for three-story RC moment frames with and without partial- and full-height masonry infill walls using the numerical models. Both experimental and numerical studies demonstrated that the masonry-infilled RC frames had larger lateral strength and stiffness than bare RC frames, whereas their drift capacity was less than that of bare frames. The partial-height masonry-infilled RC model frame had the least collapse strength among the frames.

scholarly journals Assessment of Seismic Capacity for Reinforced Concrete Frames with Perforated Unreinforced Brick Masonry Infill Wall

2020 ◽  
Vol 6 (12) ◽  
pp. 2397-2415
Author(s):  
Muhammad Umar ◽  
Syed Azmat Ali Shah ◽  
Khan Shahzada ◽  
Muhammad Tayyab Naqash ◽  
Wajid Ali
Keyword(s):  
Reinforced Concrete ◽  
Experimental Testing ◽  
Research Work ◽  
Rc Frame ◽  
Concrete Frames ◽  
Infill Wall ◽  
Reinforced Concrete Frames ◽  
Infill Walls ◽  
Rc Frames ◽  
Infilled Rc Frames

Infill walls increase the strength and stiffness of the reinforced concrete frames, but they usually are not considering in design. However, when the infills are considered in the design, the opening for doors/windows necessitates investigation as well. This research work aims to investigate the effect of perforations (openings) in the infill walls on the performance of infilled RC frames, in other words, this research investigates the number of infill walls in infilled RC frames. Based on the current construction practices in Pakistan, two full scales perforated infilled RC frames were constructed in the laboratory. One infilled RC frame has an eccentric door and window (specimen-1) while the other has only window at its centre (specimen-2). Both the specimens were tested against reverse cyclic loading (quasi-static test). From the experimental testing, it was found that infilled RC frame having less amount of opening in infill wall has more resistance to lateral loads, have more stiffness and dissipated higher energy as compared to infilled RC frame having a significant size of the opening in infill wall. Similarly, displacement ductility (µD) and Response modification factor (R) also depend on the quantity of opening in infill wall in infilled RC frame. Doi: 10.28991/cej-2020-03091625 Full Text: PDF

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.

scholarly journals Seismic Response of RC Frames with a Soft First Story Retrofitted with Hysteretic Dampers under Near-Fault Earthquakes

2021 ◽  
Vol 11 (3) ◽  
pp. 1290
Author(s):  
Santiago Mota-Páez ◽  
David Escolano-Margarit ◽  
Amadeo Benavent-Climent
Keyword(s):  
Cost Effective ◽  
Far Field ◽  
Soft Story ◽  
Near Fault ◽  
Rc Frames ◽  
Story Drift ◽  
Number Of Cycles ◽  
Rc Frame Structures ◽  
Near Fault Earthquakes ◽  
Hysteretic Dampers

Reinforced concrete (RC) frame structures with open first stories and masonry infill walls at the upper stories are very common in seismic areas. Under strong earthquakes, most of the energy dissipation demand imposed by the earthquake concentrates in the first story, and this eventually leads the building to collapse. A very efficient and cost-effective solution for the seismic upgrading of this type of structure consists of installing hysteretic dampers in the first story. This paper investigates the response of RC soft-story frames retrofitted with hysteretic dampers subjected to near-fault ground motions in terms of maximum displacements and lateral seismic forces and compares them with those obtained by far-field earthquakes. It is found that for similar levels of total seismic input energy, the maximum displacements in the first story caused by near-fault earthquakes are about 1.3 times larger than those under far-field earthquakes, while the maximum inter-story drift in the upper stories and the distribution and values of the lateral forces are scarcely affected. It is concluded that the maximum displacements can be easily predicted from the energy balance of the structure by using appropriate values for the parameter that reflects the influence of the impulsivity of the ground motion: the so-called equivalent number of cycles.

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