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1.
Inelastic Seismic Response of Reinforced Concrete Frame Structures Reinforced with HRB500 Steel Bars
To achieve sustainable development of construction industry, the application of HRB500 reinforcement with high strength and high ductility in RC structures is being promoted in civil and structural engineering in China. But few studies focus on seismic behaviors of RC structures reinforced with HRB500 bars. In this analysis, three RC frame structures on the Zone of Fortification Intensity 8 (0.3g) in China reinforced with HRB500, HRB400 and HRB335 bars respectively, are designed confirming to the latest draft of the revising Code for the Design of Concrete Structures. Then inelastic seismic response analyses of the three frames with multiple inputs of ground motions are conducted. The seismic response rules and seismic performances of the RC frame reinforced with HRB500 bars are compared with those frames reinforced with HRB400 and HRB335 bars. The analytical results indicate that under ground motions in rare earthquake level, the maximum displacements of the frame reinforced with HRB500 bars are roughly the same as those of the frames reinforced with HRB400 and HRB335 bars, while the rotation ductility demand of elements in the former structure is smaller than those of elements in the latter structures. It is also found that the frame reinforced with HRB500 bars develops a plastic energy dissipation mechanism that is dominated by beam hinges under major earthquake, and the maximum inter storey drift of the frame can satisfy the requirement in the Code for the RC Frame Structures. 相似文献
2.
With an inelastic dynamic analysis program developed by the authors, seismic response analysis of regular RC frames designed to Chinese codes in different earthquake fortification zones are carried out. The results indicate that the displacement responses of structures are improved due to the more rigorous limitation on the inter-story drift under frequent earthquakes in the revised codes. The frames in seismic-intensity-9 zone designed to the former codes and the revised codes form plastic energy-dissipated mechanisms mostly With beam hinges, which can satisfy the requirement of seismic performance expectably. The frame in seismic-intensity-8 zone designed to the former code forms a plastic energy- dissipated mechanisms mostly with column hinges and shows a risk of occurrence of story-sway mechanism, while the frame in seismic-intensity-8 zone designed to the revised codes exhibits a relatively improved seismic performance but still with excessive column hinges, which suggests a need to further increase the column moment amplification measures for this kind of frames. The frame in seismic-intensity-7 zone shows a somewhat improved seismic performance than the frames in seismic-intensity-8 zone, but the protection to columns by the seismic measures is sill insufficient, which indicates that the column moment amplification measures for this kind of frames should be enhanced further. 相似文献
3.
Two 16-storey frame-wall structures with slender coupling beams in regions of Intensity 8(0.2 g),with and without considering the stiffness reduction of the coupling beams,were designed.Nonlinear dynamic response analyses of two typical frame-wall structures subjected to several ground motions were carried out.The analyses were based on the quasi-tridimensional program for nonlinear dynamic response analysis TS-EPA.The analyses led to the following conclusions: Under rare earthquake actions,the coupling beams in framewall structures yield first.This shows that the coupling beam in frame-wall structures is the member at the forefront of earthquake resistance.Comparison of the analytic results of two couples with and without considering the stiffness reduction of the coupling beam found that,in view of the dynamic response to and the requirement for ductility under rare earthquake motions,reducing stiffness causes a minor unfavorable influence on the dynamic response of frame-wall structures. 相似文献
4.
Summarizing building damage in all previous large earthquakes is an important approach to promote the development of structural seismic design. We conducted a statistical analysis of the earthquake damage to various buildings in Mianyang city, Sichuan province, P. R. China. This analysis was based on the emergency assessment and investigation of building damage in Mianyang city caused by the large earthquake that occurred on May 12, 2008 in Wenchuan. We also summarize the damage characteristics of different buildings and the lessons learned. We present the following findings and suggestions for structural seismic design:(1)Buildings in Mianyang designed according to current seismic code withstood the rare earthquake.(2)Different structural systems have obviously varied seismic behaviors. (3)Old buildings always have been the weak links in earthquakes, and should be evaluated and strengthened selectively after an earthquake.(4)Studies of anti cracking measures for masonry walls should be conducted. (5)Effective measures should be taken to reduce earthquake damage to non structural components, for example, infill walls in frames.(6)Seismic design methods and construction measures for stairs should be studied. 相似文献
5.
Based on evaluation of the basic principle and error of the modal pushover analysis method, an improved method is suggested by selecting rational values of stiffness reduction parameters of beams and columns in a reinforced concrete frame corresponding to the global target displacement ductility ratio. A 10 story and a 16 story reinforced concrete plane frame are designed as examples to investigate the influence of higher modes. Nonlinear seismic responses of the two frames under excitations of seven earthquake waves of varying earthquake intensities are selected to be the reference points for a comparison study. The changing rules of the results of modal pushover analysis and modified modal pushover analysis with respect to various natural fundamental periods and different earthquake intensities are studied. Research results show that the error of modal pushover analysis and modified modal pushover analysis will not increase with a larger fundamental period, which implies that modal pushover analysis can cover the effect of higher modes reasonably. When the degree of nonlinearity of the structure is more severe, the modified modal pushover analysis we suggest could decrease the error of normal modal pushover analysis to a certain extent. 相似文献
6.
A shear vibrational model applied assemblage of multiple particles is proposed for the seismic response analysis of masonry building with R/C frame wall in the two bottom floors.On the basis of analyses,some problems are discussed,these mainly are:dynamic properties,main factors that have influence on seismic behavior,earthquake resistant reliability of this building under strong earthquake and the rational ratios of lateral rigidity.[WT5HZ] 相似文献
7.
Using the software, ABAQUS, accurate simulations of seismic behavior of 2 coupled wall specimens and 2 cantilever structure wall specimens using high performance fiber reinforced concrete (FRC) in plastic hinge under quasi static cyclic loading were carried out. The analysis model proves to be effective with the accordance between results of computation and experiment, then it can be used to analyze the seismic behavior of coupled wall system with FRC coupling beams. By using the verified numerical model, the ability of FRC coupling beams instead of RC coupling beams to provide acceptable performance was discussed. In addition, the impact of coupling ratio on seismic behavior of coupled walls was studied. The results show that coupled walls in which FRC coupling beams are used instead of traditional RC beams have good energy dissipation and ductility, and its initial stiffness is increased and stiffness degradation is slow. And as the coupling ratio of coupled wall structures increases, the stiffness and strength increase. But if the coupling ratio is too large, the ductility and energy dissipation capacity will be significantly reduced. 相似文献
8.
The Quasi static tests of one steel frame and two the composite deep beams infilled steel frames were carried out. The effects of the deep beams on the load capacity, ductility, hysteretic property and energy dissipation of pure steel structure were analyzed. It is found that the hysteresis curve is a straight line with the constant of the stiffness at the beginning and without residual deformation. And the hysteresis curve of specimen was full after yielding, and the skeleton curves had a clear plastic flow phase with triple linear. The lateral drifts of the beam specimens at failure were 1/25 and 1/22. The composite deep beams enhance the initial stiffness, yield load and maximum load bearing capacity of steel frame. Therefore, seismic performance of the composite deep beams is better. 相似文献
9.
The Effect of horizontal strengthened story to the seismic response of super high - rise steel braced frame is analyzed in this paper through the finite element software ANSYS. By comparison of six different schemes of a 32 - story building, further research is presented on the influence of the quantity of strengthened story to the lateral stiffness, the inner force of components under earthquake and the distribution of shear force among inner tube and outer frame. According to the study, the Wuhan International Securities Mansion, which is a super high -rise steel structure, is described as verification. The response of the building is analyzed in small earthquake. The study can serve as the references of super high - rise structure with horizontal strengthened story design. 相似文献
10.
In order to improve seismic performance of steel frame with prefabricated reinforce-concrete infill shear walls (SFCW), the ear bar device was used in the connection between the steel frame and the infill wall. Two one-bay, two story and one-third scaled models of SFCW were tested with low cyclic load. The working performance of ear bar connection, the cracks development in infill walls and deformation performance of SFCW were investigated. And the failure mode, hysteretic behavior,stiffness degradation,deformation and ductility and energy dissipation of composite structure were analyzed. The comparison study of steel frame with prefabricated, cast-in-place and silt reinforce-concrete infill shear walls was carried out. The results show that no failure occurs in the connection between the steel frame and the infill wall because ear plates below and up the beam-to-column connections are added in the specimens, and the connection device of ear plate presents good working performance. The properly designed SFCW has good ductility. 相似文献
11.
With the flexibility-based fiber model,the seismic behaviors of RC structures with specially shaped columns,designed according to the current code,are analyzed under unidirectional rare earthquakes using nonlinear dynamic analysis method.The beam strength is calculated with or without consideration of the diaphragm and its reinforcement.The results are compared and the conclusion has been drawn that the bending capacity of beams would be increased due to the effect of diaphragm and its reinforcement,and which would change the failure mechanism of RC frames under rare earthquake,especially in high intensity areas.Therefore the influence of the diaphragm should be considered during the seismic design of the type of structure. 相似文献
12.
According to the code and technical regulation,an irregular RC frame with specially shaped columns has been designed,which situated at the area of fortification intensity 8. Subsequently,the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results,this paper has examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it could achieve the predetermined anti-seismic aims. It indicates that the structure designed according to the codes can achieve the predetermined anti-seismic aim under the rare earthquake. 相似文献
13.
A finite element model based on the flexibility method and a fiber section model of nonlinear beam column elements was adopted within the OpenSees framework. A typical multistory reinforced concrete 3D frame designed in accordance with the Chinese building code and a representative plane frame parallel to the X axis were used as examples. The relationships of the responses obtained from the plane and 3D models were studied by comparing global and local seismic responses of the frame, and by taking the responses of the 3D model under unidirectional earthquake action as a medium for comparison. Because the results show the global responses of the plane model are similar to those of the 3D model, it is reasonable to replace the 3D model with the plane model when examining global seismic responses. The local responses are evidently different. For the plane model under unidirectional action, numerous plastic hinges develop at the beam ends. Many more plastic hinges at column ends exist than in beams for the 3D model under bi directional action. Column ductility demands obviously exceed those of beams. The frame tends to develop a column sway mechanism, implying that simplified plane analysis model significantly underestimates the seismic responses of the 3D frame column. 相似文献
14.
Pushover analysis is a tool to study the inelastic behavior of structures under strong seismic action. The 3D-pushover analysis was performed to analyze the inelastic lateral-torsional coupled response of multistory asymmetric structures. The symmetric frame and frame-wall systems were studied in this paper, and the capability curve of the top displacement and base shear,the story drift and the position of rotation center were compared with reference to corresponding symmetric structures. The characters of inelastic response of multistory asymmetric structures were found. The conclusion provides reference for performance-based seismic design of asymmetric structures. 相似文献
15.
Response Spectrum Method for Seismic Response Calculation of Pipeline System Multiply Supported on Structures 总被引：1，自引：0，他引：1
In order to ensure the function of building in the earthquake, reduce economic losses and facilitate post-disaster relief, it is necessary to accurately evaluate the seismic performance of pipeline system on the structure under seismic excitation. Considering this practical need, seismic response calculation methods of piping systems on structures were systematically studied. Firstly, theoretical derivation was performed based on the pseudo-excitation method for seismic response of pipeline system. It is found that the formula in previous studies has obvious defect: the accurate relative displacement values of degree of freedom near the supports can not be obtained in the formula. Thereby, the theoretical basis for derivation was mended to correct the defect, and the uniform combination expressions available for pipeline's seismic response calculation which is in the form of ground response spectrum or floor response spectrum were presented. Moreover, the simplified formulas and calculation method of correlation coefficients in the obtained expressions were put forward according to the assumption of white noise earthquake excitation. Finally, case studies were adopted to verify the proposed method's effectiveness and applicability in the seismic response calculation of pipeline system. 相似文献
16.
RC加气混凝土砌块组合墙加固框架抗震性能试验研究 总被引：1，自引：0，他引：1
RC加气混凝土砌块组合墙（简称组合墙）是由混凝土梁柱网格与加气混凝土砌块组合形成的一种轻型网格式抗震墙,可用于框架结构的抗震加固。笔者进行了1/2比例空框架试件、组合墙试件和组合墙加固框架试件的低周反复荷载试验,分析了各试件的主要破坏过程,对比了组合墙加固框架前后试件承载能力、刚度等抗震性能变化。试验结果及分析表明：组合墙加固框架后承载力、抗侧刚度有较大幅度提高,中大震及大震阶段其承载力、等效刚度约为空框架和组合墙单独受力之和的0.9倍,两者具有良好的协同工作性能;加固试件的破坏过程基本上遵循填充砌块混凝土框格外框架的破坏顺序,能够发挥组合墙多重抗震防线的特点,采用RC加气混凝土砌块组合墙加固框架是一种较为经济实用的加固方法。 相似文献
17.
Three reinforced concrete plane frames with total heights of 6, 10, and 16 stories, respectively were taken as examples. Nonlinear dynamic responses of three frames under excitations of seven earthquake waves with varying earthquake intensities were selected as the datum mark of a comparison study. The changing rules of the responses analyzed by four kinds of ordinary Pushover Analysis and Modal Pushover Analysis were studied by reviewing the inter story drift ratio and rotation at beam and column ends. Results show that the error of inter story drift ratio analyzed by Modal Pushover Analysis essentially is invariable when the total frame height increases, while the error of ordinary Pushover Analysis is added corresponding to a larger fundamental period. This indicates that Modal Pushover Analysis can cover the influence of higher modes more reasonably. When nonlinear responses of frames were more severe, the inter story drift ratio errors of Modal Pushover Analysis and ordinary Pushover Analysis also increase correspondingly. The errors of rotation at upper story beam ends and the majority of column ends analyzed by Modal Pushover Analysis are smaller than those of ordinary Pushover Analysis. 相似文献
18.
Many experimental results indicates, beam bar slippage within joints is a frequent local nonlinear response of reinforced concrete structures under the rare earthquakes. For the sake of modeling and evaluating seismic behaviors of reinforced concrete structures entirely and rational, the model way of the quantity and hysteresis order of beam bar slippage within joints, which was found in the elasto plastic earthquake response of structures, is discussed thoroughly. And the personal characteristics of several structure analysis ways to model the beam bar slippage within joints are evaluated respectively. Based on the results already gotten, a hysteresis model of beam bar slippage within frame joints is advanced, and the relative issues are also discussed. The beam bar slippage model suggested is convenience to the elasto plastic dynamic response analysis of whole reinforced concrete structures. 相似文献
19.
Earthquakes for the loss of life and property to people is immeasurable. Want to reduce such losses, on the one hand we hope that Government departments can forecast and notify you in a timely manner, on the other hand we need to develop anti-seismic structure of the building, reducing losses when the earthquake happened. Interlayer seismic isolation frame structure is the latest development of a seismic isolation structure.It compared with the ordinary seismic structural damping performance is better, had a large advantage. 相似文献
20.
Microstructures, Reaction Kinetics and Properties of Reaction Between Magnesium and Silica Glass 
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下载免费PDF全文 In earlier calculation models,the stiffness centers in frame-shear wall structures have been located by the structural torsion stiffness.However,the results are illogical owing to the difference between the distortion character and the shears distribute mechanism of the frames and shear walls.In this paper,a new formula for calculating story stiffness is introduced,which can consider the stiffness of the frames and shear walls at the same time.The structural stiffness centers,the torsion eccentric distances and torsion effect are calculated,and the stiffness of elements is considered also.It is shown that the concept of the presented stiffness model is clear and the results are reasonable,which can be used to calculate the appreciative torsion effect. 相似文献