Papers by Keyword: Seismic Behavior

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Authors: Pu Yang, Jing Tang
Abstract: Using flexibility-based finite element method based on fiber model, several experiments of reinforced concrete specially shaped columns under cyclic loading which cross section is ‘L’, ‘T’ and ‘+’ shape with different longitudinal reinforcement and hoop reinforcement have been simulated, and the seismic behavior of columns such as strength, ductility and energy dissipation are analyzed. Results from the analytical study indicate that: 1) ductility of the column increases as quantity of hoop reinforcement increases. 2) strength capacity of the column increase linearly as ratio of longitudinal reinforcement increase, but is not seriously affected by hoop reinforcement; 3) energy dissipation capacity of the column is not significantly affected by hoop and longitudinal reinforcement, particularly in slightly nonlinear range.
Authors: Fatih Suleyman Balik, Hasan Husnu Korkmaz, Mehmet Kamanli, Fatih Bahadir, Serra Zerrin Korkmaz, Alptug Unal
Abstract: In the last decade, seven major earthquakes caused significant casualties and extensive structural failures. Thousands of RC buildings were severely damaged or collapsed in Turkey due to various deficiencies. This has initiated experimental studies on strengthening methods and intensive researches regarding the rehabilitation of reinforced concrete structures by introducing reinforced concrete infill walls were carried out. Strengthening of reinforced concrete frames by cast-in-place reinforced concrete infills is commonly used in practice. Many structures were also repaired using this technique after the recent earthquakes. In this experimental research, six, one-bay/two-story, 1/3-scaled non-ductile, undamaged reinforced concrete (RC) frames were constructed and tested to investigate the behavior of frames strengthened by introducing infills with or without openings. The test specimens were subjected to reversed cyclic quasi-static lateral loading. The specimens were constructed with the most commonly observed deficiencies in residential RC buildings in Turkey. The first specimen was the reference bare specimen and contained no strengthening. The other specimens were infilled with RC panels with openings having different ratios and configurations. Strength, stiffness and storey drifts of the test specimens were measured and compared. Test results indicated that infilled RC frames displayed significantly higher lateral strength and stiffness than the non-ductile bare frame considerably.
Authors: Wan Lin Cao, Hong Ying Dong, Jian Wei Zhang
Abstract: A comparative study is conducted on the seismic behaviors of five 1/2 scale recycled concrete short columns with 1.75 shear span ratios. The stirrup ratio in the specimens was changed from 0.4%, 0.9%, to 1.29% while the ratio of their longitudinal reinforcement was the same. Crossed reinforcing bars were set in two of the specimens. Cyclic loading test was carried out for the specimens under axial compression ratio 0.4. The stiffness and its degradation, load-carrying capacity, ductility, hysteretic behavior, energy dissipation and failure phenomena of each short column were analyzed. Results show that, with the increase of the stirrup ratio in the specimens, the shear failure of the specimens is getting lighter and lighter. And the load-carrying capacity, ductility, energy dissipation capacity are improved greatly, but the rate of the increase is tending to slow. Moreover, crossed reinforcing bars in the short columns are able to improve the seismic behavior. Recycled concrete can be used for structural columns with low axial compression ratio in earthquake area.
Authors: Ying Hu, Jin Song Lei, Wen Xia Luo
Abstract: In order to research the seismic behaviors of the eccentrically braced steel frames, used finite element software SAP2000 to build 20-storey single frame models with type D, K, and Y eccentrically braces, and did the seismic time history analyses to them. Comparisons were set between different kinds of braces in the distributions of moments, displacements, and accelerations for different layers produced by the EICENTRO seismic wave, TianJin seismic wave and NanJing seismic wave. Also, the analyses were set in the time history curves of displacements and accelerations. The results reveal that: type K is able to control the moments and displacements of the layers; while type Y is good at restricting the acceleration amplified effect, and the seismic behavior of type D is between the former two types.
Authors: Li Ping Wang, He Ping Zhong, Lin Qing Huang
Abstract: In order to know more about the seismic behavior of structures supported by foundations with different locations, using the elastic and static elastic-plastic analysis method, the research is respectively from the aspects of the distribution characteristic of elastic inter-story displacement angle, the distribution law of story shear, and the distribution characteristic of elastic-plastic displacement angle and the sequence of plastic hinges. In the end, it is got that the characteristics of force and deformation of structures supported by foundations with different locations. It is found that the position of weak story would change along with the change of story stiffness. In order to guarantee the structures supported by foundations with different locations to have good seismic behavior, it needs to take the necessary internal force adjust measures and details of seismic design.
Authors: Yun Zou, Hui Lin, Wei Qiang Ma
Abstract: In order to research the self-centering capacity of prefabricated frame joints, this paper designed analysis models of prefabricated frame joint with the finite element software ABAQUS, contrastively analyzed seismic behavior of joint applied pretention and joint without pretention. Joint applied pretention is found to have better self-centering capacity. Then the paper calculated and analyzed the factors of stretching control stress, number of post-tensioned steel. The results show that number of post-tensioned steel has a greater influence on the seismic behavior of the structure, and the stretching control stress has influence in a certain range. The results have some degree of guiding significance for the popularization of prefabricated frame.
Authors: Wen Hui He, Chun Qiang Yang, Yuan Ye Yi, Zhi Han Tang, Peng Chen He, Hai Bing Weng
Abstract: Simulation studies of seismic behaviour of bolt-endplate connected composite structural systems consisting of CFDST columns and steel beams frame with reinforced concrete slabs are presented in this paper. Based on fiber-section model, analytical models were developed to predict the elastic-to-plastic behaviour of the prototype frame. Analysis results indicated that the structural behaviour under the simulated seismic loadings was consistent with the expected performance objects for different earthquake hazard levels corresponding to current seismic design codes, implying that effective seismic performance of composite CFDST frame with bolted connections can be achieved. The primary analytical simulation shows the suggested bolted endplate CFDST system has the potential to offer appropriate strength and adequate stiffness for buildings located in areas of high earthquake intensity, and provides basic information for further experimental researches to validate the seismic performances of the bolted end-plate CFDST structures.
Authors: Hong Ying Dong, Wan Lin Cao, Jian Wei Zhang
Abstract: According to the structural design in a project in Dalian, experimental study on seismic behavior of composite core walls with steel tube-reinforced concrete (STRC) columns were carried out. Five 1/6 scale composite core wall specimens with different steel reinforced details in the walls and different openings on the walls were designed and tested under cyclic loading. Based on the experiment, hysteretic property, load-carrying capacity, ductility, energy dissipation capacity and damage characteristics of the five specimens were compared and analyzed. The results show that the core walls with STRC columns have good seismic behavior. And the seismic behavior can be greatly improved by setting concealed steel trusses in the walls.
Authors: Jun Yan Lu, Wei Wang Pang, Shuai Chang
Abstract: Through earthquake simulation experiment of nine regional confined concrete columns with different axial compression ratio, the bearing capacity and seismic behavior of regional confined concrete columns were studied in this paper. Considering the ductility, stiffness, energy-dissipation performance and related factors of regional confined concrete columns under different axial compression ratio, by comparative analysis of the hysteretic behavior of the specimens, the limit of axial compression ratio of regional confined concrete columns is proposed for seismic design.
Authors: Ming Gao
Abstract: The 5•12 Wenchuan earthquake was in M8.0, Mianyang felt strongly. Majority of the buildings have varied at different degrees of damage, especially in masonry-frame structures, Which reinforcement cost much higher for repairing; The 1200 buildings in Mianyang city or it’s Suburbs were surveyed. The results showed: masonry suffered much heavier damage and masonry-frame of the mixed structure by designing, which damage were significantly lower than without seismic design. Realization of the earthquake will not be collapsed, and after a simple repair it can be used. Buildings that suffered heavy damage which combined with the relevant code requirements and research in the past, adopt specific measures for strengthening the houses.
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