scholarly journals Experimental Study on Seismic Behavior of Steel Frames with Infilled Recycled Aggregate Concrete Shear Walls

2019 ◽  
Vol 9 (21) ◽  
pp. 4723 ◽  
Author(s):  
Sun ◽  
Guo ◽  
Liu
Keyword(s):  
Bearing Capacity ◽  
Seismic Behavior ◽  
Steel Frames ◽  
Shear Walls ◽  
Steel Frame ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Initial Stiffness ◽  
Aggregate Concrete ◽  
Displacement Ductility

Experiments were performed on four specimens of steel frames with infilled recycled aggregate concrete shear walls (SFIRACSWs), one specimen of infilled ordinary concrete wall, and one pure-steel frame were conducted under horizontal low cyclic loading. The influence of the composite forms of steel frames and RACSWs (namely, infilled cast-in-place and infilled prefabricated) on the failure modes, transfer mechanisms of lateral force, bearing capacity, and ductility of SFIRACSWs is discussed, and the concrete type and connecting stiffness of beam–column joints (BCJs) are also considered. Test results showed that infilled RACSWs can increase the bearing capacity and lateral stiffness of SFIRACSWs. The connecting stiffness of BCJs slightly influences the seismic behavior of SFIRACSWs. In the infilled cast-in-place RACSWs, the wall cracks mainly extended along the diagonal direction. The bearing capacity was 2.4 times higher than in the pure steel frame, the initial stiffness was 4.3 times higher, and the displacement ductility factors were 2.44–2.69 times higher. In the infilled prefabricated RACSWs, the wall cracks mainly extended along the connection between the embedded T-shape connectors and walls before finally connecting along the horizontal direction. Moreover, shear failure occurred in the specimens. The bearing capacity was 1.44 times higher than that of the pure steel frame, the initial stiffness was 2.8 times higher, and the displacement ductility factors were 3.32–3.40 times higher. The degradation coefficients of the bearing capacity were more than 0.85, indicating that the specimens demonstrated a high safety reserve.

scholarly journals Analysis on Mechanical Properties of Recycled Aggregate Concrete Members after Exposure to High Temperatures

2019 ◽  
Vol 9 (10) ◽  
pp. 2057 ◽  
Author(s):  
Zongping Chen ◽  
Ji Zhou ◽  
Peihuan Ye ◽  
Ying Liang
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Bearing Capacity ◽  
High Temperatures ◽  
Elevated Temperatures ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Displacement Ductility ◽  
Energy Dissipation Capacity

In order to study the mechanical properties of recycled aggregate concrete (RAC) specimens after exposure to high temperatures, 120 RAC prism specimens, 57 reinforced recycled aggregate concrete (RRAC) specimens, and 56 steel reinforced recycled aggregate concrete (SRRAC) specimens were designed, involving two varying parameters such as recycled coarse aggregate (RCA) replacement percentage and temperature. The performance degradation of RCA materials, RRAC members, and SRRAC members after exposure to high temperatures was analyzed in depth. The research results show that after exposure to high temperatures the surface color of members may change from cinereous to gray-white. Some cracks may appear on surface of members and the mass of members may be lighter. With the increase of the experiencing temperatures, the bearing capacity (compressive, bending, and shearing) of RAC and its members are reduced, but their ductility and energy dissipation capacity have little effect on the change of high temperature. With the increase of the RCA replacement percentage, the mass loss ratio, ultimate bearing capacity, and peak deformation of each RAC and its members increase slightly, and the displacement ductility and energy dissipation capacity of the RRAC members decrease slightly. With the increase in replacement percentage of RCA, mechanical properties of RAC and their members have little effect after exposure to elevated temperatures, and the fluctuation range is within 20%.

scholarly journals Seismic Behavior of Concrete-Filled Circular Steel Tubular Column–Reinforced Concrete Beam Frames with Recycled Aggregate Concrete

2020 ◽  
Vol 10 (7) ◽  
pp. 2609 ◽  
Author(s):  
Zongping Chen ◽  
Ji Zhou ◽  
Zhibin Li ◽  
Xinyue Wang ◽  
Xingyu Zhou
Keyword(s):  
Reinforced Concrete ◽  
Energy Dissipation ◽  
Seismic Behavior ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Scale Model ◽  
Hysteresis Curve ◽  
Small Scale ◽  
Skeleton Curve ◽  
Aggregate Concrete

The application of recycled aggregate concrete (RAC) in concrete filled steel tubular (CFST) structures can eliminate the deterioration of concrete performance caused by the original defects of the recycled aggregate, which also provides an effective way for the recycling of waste concrete. In this paper, a test of a small scale model of a circular CFST column-reinforced concrete (RC) beam frame with RACs under low cyclic loading was presented in order to investigate its seismic behavior. The failure modes, plastic hinges sequence, hysteresis curve, skeleton curve, energy dissipation capacity, ductility and stiffness degeneration of the frame were presented and analyzed in detail. The test results show that the design method of the recycled aggregate concrete filled circular steel tube (RACFCST) frame complies with the seismic design requirements of a stronger joint followed by the stronger column and the weaker beam. The hysteresis curve of the frame is symmetrical, showing a relatively full shuttle shape; at the same time, the ductility coefficient of the frame is greater than 2.5, showing good deformation performance. In addition, when the frame is damaged, the displacement angle is greater than 1/38, and the equivalent damping ratios coefficient is 0.243, which indicates that the frame has excellent anti-collapse and energy dissipation abilities. In summary, the RACFCST frame has good seismic behavior, which can be applied to high-rise buildings in high-intensity seismic fortification areas.

scholarly journals Residual Properties Analysis of Steel Reinforced Recycled Aggregate Concrete Components after Exposure to Elevated Temperature

2018 ◽  
Vol 8 (12) ◽  
pp. 2377 ◽  
Author(s):  
Zongping Chen ◽  
Rusheng Yao ◽  
Chenggui Jing ◽  
Fan Ning
Keyword(s):  
Elevated Temperature ◽  
Energy Dissipation ◽  
Mass Loss ◽  
Bearing Capacity ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Residual Properties ◽  
Significant Fluctuation ◽  
Capacity Degradation

The application of recycled aggregate concrete (RAC) has developed rapidly in recent years. But how to evaluate the residual properties of RAC after the fires is more beneficial to the further popularization and application of RAC. This paper presents the residual properties of RAC and steel reinforced recycled aggregate concrete (SRRAC) components after exposure to elevated temperature. A total of 176 specimens (120 rectangular prisms specimens, 24 SRRAC short columns and 32 SRRAC beams) were designed and tested after exposure to elevated temperature. The parameters were considered in the test, including replacement percentage of recycled coarse aggregate (0%, 30%, 50%, 70% and 100%) and exposure to different temperatures (20, 200, 400, 600 and 800 degrees centigrade). According to the test results, heat damage and residual properties of specimens were analyzed in detail, such as surface change, mass loss, bearing capacity degradation, stiffness degradation, ductility and energy dissipation of specimens under the elevated temperature. The results showed that a series of significant physical phenomena occurred on the surface of RAC and SRRAC components after exposure to elevated temperature, such as the color changed from green-grey to gray-white, chapped on the concrete surface after 400 degrees centigrade and the mass loss of concrete is less than 10%. The degradation of mechanical properties degenerated significantly with the increase of temperature, such as the strength of RAC, and compressive capacity, bending capacity, shear capacity and stiffness of SRRAC components, among that, the degradation of the strength of RAC was most obvious, up to 26%. The ductility and energy dissipation of SRRAC components were insignificant affected by the elevated temperature. Mass loss ratio, peak deformation and bearing capacity showed a slight increase trend with the increase of replacement percentage. But the stiffness showed significant fluctuation when replacement percentage was 70% to 100%. And the ductility and energy dissipation showed significant fluctuation when replacement percentage was 30% to 70%.

Investigation on Seismic Behavior of Recycled Aggregate Concrete Structures under Dynamic Loadings

2013 ◽  
Vol 772 ◽  
pp. 149-155
Author(s):  
Chang Qing Wang
Keyword(s):  
Seismic Behavior ◽  
Fatigue Behavior ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Recycled Aggregate Concrete ◽  
Shaking Table ◽  
Frame Structure ◽  
Recycled Aggregate ◽  
Scale Model ◽  
Aggregate Concrete

Based on the ever finished investigations of physical and mechanical properties of recycled aggregate concrete (RAC), and a series of experimental studies on the durability, the fatigue behavior, mechanical behavior and the seismic behavior of RAC components. A full scale model of a one-storey block masonry structure with tie column + ring beam + cast-in-place slab system and a one fourth scaled model of a 6-storey frame structure, which are made of reinforced recycled aggregate concrete, are tested on a shaking table by subjecting it to a series of simulated seismic ground motions, and the seismic behaviors of the RAC structures were experimentally investigated. The dynamic characteristics and the seismic response were analyzed and discussed. The overall seismic performance of RCA structures are evaluated, the analysis results show that the recycled aggregate concrete structures with proper design exhibits good seismic behavior and can resist the earthquake attacks under different earthquake levels in this study. It is feasible to apply and popularize the RAC block masonry buildings less than 2 stories and the RAC frame buildings less than 6 stories in the region where the seismic fortification intensity is 8.

Experimental Study on Seismic Behavior of Double-Wall Precast Concrete Shear Wall

2014 ◽  
Vol 919-921 ◽  
pp. 1812-1816 ◽  
Author(s):  
Quan Dong Xiao ◽  
Zheng Xing Guo
Keyword(s):  
Energy Dissipation ◽  
Seismic Behavior ◽  
Failure Modes ◽  
Precast Concrete ◽  
Shear Walls ◽  
Shear Wall ◽  
Initial Stiffness ◽  
Displacement Ductility ◽  
Energy Dissipation Capacity ◽  
Double Wall

To study the seismic behavior of Double-Wall Precast Concrete (DWPC) shear wall, three full scale specimens are tested and compared under low-cyclic reversed loading, including two DWPC shear walls and one normal Cast-In-Situ (CIS) shear wall. By observing their experimental phenomena and failure modes, contrasting their displacement ductility coefficients, hysteretic curves, skeleton curves and energy dissipation capacity, the seismic behavior were synthetically evaluated on aspects of strength, stiffness, ductility and energy dissipation. Compared with CIS specimen, DWPC specimens have higher initial stiffness, increased cracking loads by 43% to 47%, and the ultimate loads increased by 22% to 23%. The displacement ductility ratios also meet the ductility requirements with value of 5. The hysteretic curves of three specimens are plump, and the trend of skeleton curves is basically the same. The DWPC specimens demonstrated a good energy dissipation capacity. All the specimens had shown favorable seismic performance.

Study on Recycled Aggregate Concrete Frame Joints with Method of Nonlinear Finite Element

2009 ◽  
Vol 417-418 ◽  
pp. 745-748
Author(s):  
Jian Zhuang Xiao ◽  
M.M. Tawana ◽  
Xiao Hui Zhu
Keyword(s):  
Finite Element ◽  
Seismic Behavior ◽  
Low Frequency ◽  
Nonlinear Finite Element ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Displacement Curve ◽  
Element Analysis ◽  
Aggregate Concrete ◽  
Concrete Frame

With the achievements made in the research of mechanical properties for recycled aggregate concrete, this paper adopts the method of nonlinear finite element to analyze the seismic behavior of frame joints. The frame joints are made of recycled aggregate concrete. It also takes into account the bond behavior between steel bars and recycled aggregate concrete in the core area of the joints, and the force-displacement curve of the joints is calculated. Nonlinear finite element analysis shows that the results of the calculations are in accordance with the test results. It is concluded in this paper that, built models with nonlinear finite element method can be applied in simulating exactly the same seismic behavior of frame joints under low frequency reversed lateral loading.

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