scholarly journals Evaluation of Seismic Demand for Substandard Reinforced Concrete Structures

2018 ◽  
Vol 12 (1) ◽  
pp. 9-33
Author(s):  
Nicholas Kyriakides ◽  
Ahmad Sohaib ◽  
Kypros Pilakoutas ◽  
Kyriakos Neocleous ◽  
Christis Chrysostomou ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Performance Prediction ◽  
Brittle Failure ◽  
Failure Modes ◽  
Shaking Table ◽  
Equivalent Linearization ◽  
Diagram Method ◽  
Capacity Curves ◽  
Non Linear

Background: Reinforced Concrete (RC) buildings with no seismic design exhibit degrading behaviour under severe seismic loading due to non-ductile brittle failure modes. The seismic performance of such substandard structures can be predicted using existing capacity demand diagram methods through the idealization of the non-linear capacity curve of the degrading system, and its comparison with a reduced earthquake demand spectrum. Objective: Modern non-linear static methods for derivation of capacity curves incorporate idealization assumptions that are too simplistic and do not apply for sub-standard buildings. The conventional idealisation procedures cannot maintain the true strength degradation behaviour of such structures in the post-peak part, and thus may lead to significant errors in seismic performance prediction especially in the cases of brittle failure modes dominating the response. Method: In order to increase the accuracy of the prediction, an alternative idealisation procedure using equivalent elastic perfectly plastic systems is proposed herein that can be used in conjunction with any capacity demand diagram method. Results: Moreover, the performance of this improved equivalent linearization procedure in predicting the response of an RC frame is assessed herein. Conclusion: This improved idealization procedure has been proven to reduce the error in the seismic performance prediction as compared to seismic shaking table test results [1] and will be further investigated probabilistically herein.

Experimental Study on Seismic Performance of Steel Reinforced Concrete Column with Recycled Coarse Aggregate

2012 ◽  
Vol 256-259 ◽  
pp. 2063-2066
Author(s):  
Hui Ma ◽  
Jian Yang Xue ◽  
Xi Cheng Zhang ◽  
Zong Ping Chen
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Failure Modes ◽  
Coarse Aggregate ◽  
Reinforced Concrete Column ◽  
Steel Reinforced Concrete ◽  
Recycled Coarse Aggregate ◽  
Proper Design ◽  
Loading Tests ◽  
Cyclic Loading Tests

In order to evaluate whether concrete with recycled coarse aggregate can be applied for steel reinforced concrete (SRC) under the earthquake, low cyclic loading tests of SRC with different recycled coarse aggregate (RCA) replacement percentage were carried out in this paper. Based on the tests of three SRRC column specimens, the failure modes, the hysteresis curves, the skeleton curves, the ductility, and the stiffness degradation of SRRC columns are investigated. The influence of variation in the RCA replacement percentage on the SRRC column is analyzed in detail. Test results show that the seismic performance of SRRC column is reduced to an allowable extent with the increasing magnitude of the RCA replacement percentage. The SRRC column still has a good seismic performance and the recycled coarse aggregate can be applied for steel reinforced concrete through the proper design.

Seismic performance of a controlled rocking reinforced concrete frame

2016 ◽  
Vol 20 (1) ◽  
pp. 4-17 ◽  
Author(s):  
Liang Lu ◽  
Xia Liu ◽  
Junjie Chen ◽  
Xilin Lu
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Loading ◽  
Seismic Performance ◽  
Shaking Table Test ◽  
Joint Stiffness ◽  
Shaking Table ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Metallic Dampers ◽  
Reversed Cyclic

A controlled rocking reinforced concrete frame is a new type of vibration control structure system that uses resilient rocking columns and joints. The effects of earthquakes on this type of structure are reduced by weakening the overall stiffness, whereas the lateral displacement is controlled by the energy-dissipation dampers introduced into the structure. Two tests were performed for research: the reversed cyclic loading test and shaking table test. Two single-span single-story controlled rocking reinforced concrete frames were designed for reversed cyclic loading tests. These tests (i.e. a column-base joint stiffness test, beam-column joint stiffness test, and frame stiffness test) were performed under different conditions. The mechanical analysis model of the rocking joints was derived from the test results. With the parameters obtained from the cyclic tests, a numerical simulation method that established the analytical model of the controlled rocking reinforced concrete frame using the program ABAQUS is proposed, and the dynamic time-history analysis results of the controlled rocking reinforced concrete frame and of the conventional approach are compared to investigate the vibration control effect and seismic performance of the controlled rocking reinforced concrete frame. In addition, the inter-story drift could be effectively controlled by adding metallic dampers, and the shaking table test models of the controlled rocking reinforced concrete frame with metallic dampers were designed and constructed. The comparison of the results of the numerical analysis and the shaking table test demonstrates that the model building of the controlled rocking reinforced concrete frame structure is efficient and that the controlled rocking reinforced concrete frame exhibits an excellent seismic performance.

Shaking table test of reinforced concrete coupled shear walls with single layer of web reinforcement and inclined steel bars

2018 ◽  
Vol 21 (15) ◽  
pp. 2282-2298 ◽  
Author(s):  
Jianwei Zhang ◽  
Wenbin Zheng ◽  
Cheng Yu ◽  
Wanlin Cao
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Shaking Table Test ◽  
Single Layer ◽  
Shear Walls ◽  
Shaking Table ◽  
Large Hole ◽  
Steel Bars ◽  
Web Reinforcement ◽  
Opening Ratio

In this study, five 1/4 scaled shaking table tests were conducted to investigate the seismic performance of reinforced concrete coupled shear walls with single layer of web reinforcement and inclined steel bars. The five tested coupled shear walls included three models with normal opening ratio (19%) and two models with large hole ratio (27%). The three models with normal opening included one model with single layer of web reinforcement, two models with single layer of web reinforcement and 75° inclined steel bars in the limbs’ web or at the bottom. Two reinforced concrete coupled shear walls with large hole and single row of reinforcements also were tested with inclined reinforcements or without them. The dynamic characteristics, dynamic response, and failure mode of each model were compared and analyzed. The test and analysis results demonstrate that the inclined steel bars are identified as an efficient means of limiting overall deformation, increasing energy dissipation, and reducing the possible damage by earthquake for reinforced concrete coupled shear walls with single layer of web reinforcement. Thus, reinforced concrete coupled shear walls with inclined steel bars have better seismic performance than reinforced concrete coupled shear walls without inclined steel bars. With appropriate design, reinforced concrete coupled shear walls with single layer of web reinforcement and inclined steel bars can be applied in multi-story buildings.

Probabilistic Evaluation of Effects of Column Moment Magnification Factor on Seismic Performance of Reinforced Concrete Frames

2011 ◽  
Vol 243-249 ◽  
pp. 251-257 ◽  
Author(s):  
Ming Ji He ◽  
Chun Yang ◽  
Jian Cai ◽  
Yan Sheng Huang ◽  
Yi Wu
Keyword(s):  
Reinforced Concrete ◽  
Failure Mode ◽  
Seismic Performance ◽  
Seismic Vulnerability ◽  
Failure Modes ◽  
Fragility Curves ◽  
Frame Structures ◽  
Rc Frame ◽  
Magnification Factor ◽  
Rc Frame Structures

Enhancing column flexural capacity is the key measure in seismic capacity design to achieve strong column-weak beam failure mode and determinate the probabilistic relation between column moment magnification factor (CMMF). In the paper the effects of column moment magnification factor on seismic performance of reinforced concrete (RC) frames are evaluated to limit the occurrence probability of column-hinging failure modes within an acceptable tolerance. Monte Carlo simulation methodology is used to calculate the probability of drift demand exceeding drift capacity of two typical frame structures with consideration of major uncertainties. And fragility curves are constructed to obtain the relationship between CMMF and probability of structural damages and assess the seismic vulnerability of RC frame structures. Results show that the seismic performance of RC frame structures can be significantly enhanced by improving CMMF. The CMMF is required to be equal to or greater than 2.0 to achieve acceptable probability of exceedance of column-hinging failure mode.

Seismic Performance and Cost Evaluations of Reinforced Concrete Buildings with Various Ductility in Moderate Seismic Zone

2014 ◽  
Vol 08 (02) ◽  
pp. 1450005 ◽  
Author(s):  
Virote Boonyapinyo ◽  
Norathape Choopool
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Seismic Loading ◽  
Building Design ◽  
Seismic Zone ◽  
Cost Estimates ◽  
Diagram Method ◽  
Performance Point ◽  
Failure State ◽  
Design Earthquake

This study is focused on the effects of the new standard of the building design under seismic loading in Thailand (DPT 1302-52) on cost estimates and the seismic performance of nine-story reinforced concrete apartment buildings with various ductility in moderate seismic zone and a gravity load designed (GLD) building. Both the nonlinear static pushover and nonlinear dynamic analyses are applied. Comparisons of performance point (PF) evaluation of studied frames are investigated by three different methods, namely, capacity spectrum method (CSM), inelastic demand diagram method (IDDM), and nonlinear time history analysis (NTHA) method. Five selected ground motion records are investigated in the analyses. In order to examine the influence of design ductility classes, the seismic forces on moment resisting frame buildings are defined according to the new standard of the building design under seismic loading in Thailand with ductility from 8, 5, and 3, corresponding to special ductile frame (SDF), intermediate ductile frame (IDF), and ordinary ductile frames (ODF), respectively. For the cost estimates, ODF is the most expensive among ODF, IDF, and SDF. Costs of SDF and IDF in Chiang Mai are quite similar. The results show that SDF is more ductile than that of ODF, however, the strength of SDF is less than ODF. The results indicate that all frames including GLD are able to withstand a design earthquake. The study also found that the average ductilities at the failure state for SDF, IDF, ODF, and GLD are 1.45, 1.42, 1.28, and 1.17, respectively. The average PGAs at the failure state for SDF, IDF, ODF, and GLD are 0.85 g, 0.83 g, 0.63 g, and 0.35 g, respectively when these buildings have the volumetric ratio of horizontal confinement within joint panel greater than 0.003. Moreover, at the failure state of GLD with volumetric ratio of horizontal confinement within joint panel less than 0.003, the average PGA is only 0.17 g which is lower than the design earthquake of PGA of 0.39 g in the draft DPT. The SDF and IDF are the two best options in consideration of cost and seismic performance.

scholarly journals Time-dependent Seismic Performance Assessment of Corroded Reinforced Concrete Frames

2019 ◽  
Author(s):  
Mohammad Ghanooni-Bagha ◽  
Sajad Zarei ◽  
Hamid Reza Savoj ◽  
Mohsen Ali Shayanfar
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Concrete Compressive Strength ◽  
Concrete Frames ◽  
Reinforced Concrete Frame ◽  
Nonlinear Analyses ◽  
Seismic Performance Assessment ◽  
Concrete Frame ◽  
Capacity Curves ◽  
Severe Intensity

In this study, effects of reinforcement corrosion such as reinforcement cross section reduction, steel yield strength and concrete compressive strength reduction on RC member capacity decrease are studied. Next, a two-dimensional reinforced concrete moment resistant frame is modeled to evaluate the effects of moderate and severe intensity corrosion on moment-curvature behavior of elements and structure seismic response under nonlinear analysis. Structure capacity curves in push-over analysis and failure curves resulted from IDA for both the structure without and with corrosion are obtained and the effects of reinforcement’s corrosion on the reinforced concrete frame seismic performance are determined through comparing the results. The results revealed that in terms of amount, place and type of corrosion in the reinforced concrete frame, value of the reduction resisting moment of elements is different. Furthermore, the outcomes of nonlinear analyses showed that the capacity of structure is reduced and its seismic performance level is changed as a result of corrosion.

scholarly journals Investigation on Seismic Performance of Bidirectional Self-Centering Reinforced Concrete Frame Structures by Shaking Table Tests

2020 ◽  
Vol 2020 ◽  
pp. 1-23
Author(s):  
Zhenying Wang ◽  
Chenxi Mao ◽  
Lili Xie
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
The Self ◽  
Shaking Table ◽  
Structural Deformation ◽  
Shaking Table Tests ◽  
Steel Wires ◽  
Gap Opening ◽  
Hazard Levels ◽  
Column Base

This paper presents an experimental study on the seismic performance of a bidirectional self-centering reinforced concrete (RC) frame structure. In the structure, the column-base joints, which were installed with external mild steel (MS) dampers, could uplift freely and the beam-column joints could open effectively under earthquake excitations. Angle steels and MS dampers were installed at the beam-column joints in the structural X and Y directions, respectively. During the gap opening of the joints, unbonded posttensioned (PT) steel wires, which passed through the plastic ducts inserted in the RC beams and columns, provided the structure with the ability to return to pre-earthquake positions, and the yielding MS dampers and angle steels dissipated the seismic energy. A 1/2-scale two-story model structure was designed and constructed. Shaking table tests were performed on the structure under four different types of earthquake excitations with increasing seismic hazard levels. The test results indicated that the self-centering RC frames installed in both the directions showed satisfactory seismic performance, with only slight damage to the main structure after extreme earthquakes. The natural frequencies of the self-centering frames installed in both the directions degraded progressively, mainly because of the prestress loss of the PT steel wires and the yielding of the MS dampers. The structure showed desirable self-centering ability with very small residual deformation under ground motions of all hazard levels. The structural deformation was mainly concentrated at the column-base and beam-column joints, and hence, damage to the concrete beams and columns was considerably alleviated. In addition, the residual gap opening of the joints was minimal.

Fiber Reinforced Concrete Frame Shaking Table Test

2014 ◽  
Vol 893 ◽  
pp. 597-601
Author(s):  
Guo Wang Meng ◽  
Jia Mei Zhou ◽  
Chuan Yi Sui ◽  
Qi Yan
Keyword(s):  
Reinforced Concrete ◽  
Failure Modes ◽  
Shaking Table Test ◽  
Plain Concrete ◽  
Fiber Reinforced Concrete ◽  
Shaking Table ◽  
Maximum Strain ◽  
Fiber Reinforced ◽  
Reinforced Concrete Frame ◽  
Maximum Acceleration

Two full scale frames were tested on a shaking table to investigate seismic performance and fracture mechanism of fiber reinforced concrete in contrast to the plain concrete. The information about acceleration response, the maximum strain value as well as the time to reach it, the typical strain - time curves and the crack development of two test frames were presented. Test results indicate that reinforced concrete did not crack during the test; the fiber reinforced concrete could better absorb or consume energy in the process of stress redistribution after peak acceleration; maximum strain and maximum acceleration did not occur at the same time; structure came into being deformation even failure when the seismic energy in the structure gone up to certain extent, and the dynamic failure would be their main failure modes.

Seismic Response Analysis of CFRP Retrofitted Reinforced Concrete Structures

2013 ◽  
Vol 671-674 ◽  
pp. 1445-1457
Author(s):  
Bo Jin ◽  
De Feng Zu ◽  
Han Sheng Wu ◽  
Yongwu Gao
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Computational Models ◽  
Concrete Structures ◽  
Time History ◽  
Relative Displacement ◽  
Shaking Table ◽  
Response Analysis ◽  
Reinforced Concrete Structures ◽  
Damage Potential

The use of carbon reinforced polymer (CFRP) to provide lateral confinement for enhanced ductility and strength of reinforced concrete structures has been increasing. The present study, attempts to analytically investigate the effect of the layout of frame columns retrofitted with different layers of CFRP on the seismic performance and damage potential of structures under strong ground motion using realistic and efficient computational models. Based on the shaking table tests of several reinforced concrete (RC) flat slab beamless construction models, the seismic performance of structures strengthened with CFRP composites are investigated. The dynamic response of CFRP retrofitted structures and the components of the model, validation of the model, force-displacement relationship, relative displacement and the time history curves are studied. Then the rational effect of different CFRP layers is found.

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