Papers by Keyword: Concrete Frame

Abstract: In this paper, using the Sap2000 analysis software, established the analysis model of high-rise reinforced concrete filled steel tube frame structure, in allusion to the damping effect in different number, different layout and different spectral characteristics, and carried out the optimization of damping wall configuration scheme. According the calculations, comparing the influence of seismic performance between the original structure and after optimization of concrete filled steel tube structure in the condition of earthquake, the results showed that the viscous damping walls in the structure damping control effect is obvious.

Abstract: In order to analyze the residual mechanical properties of concrete frame structures after fire, a novel numerical model considering the distribution of non-uniform temperature in the cross-sections of structural members and the changing of mechanical properties of materials damaged by fire is developed in this paper by dividing the cross-sections of structural members into a lot of concrete fibers and steel fibers based on the concept of fiber model. Besides, the Analytical System of Fire-damaged Concrete Frame (ASFCF) is established through the secondary development of ABAQUS Software that is completed by the programming language of Python. This system is used to analyze the temperature fields and the nonlinear mechanical performances of a multi-story, multi-span, three-dimensional concrete frame after fire. The results indicate that ASFCF can properly analyze the mechanical properties of concrete frames after fire, and it provides valuable references for assessing the residual mechanical properties of concrete frames after fire.

Abstract: Through predict activities trend of ground fissures, given to the ground surface subsidence curve on the topper side in the next 50 years. Established a tall concrete frame construction model, using SAP2000 finite element programs, take a distance of the building depart from the fissure as analytical variables, in considering the dead load, live load, horizontal seismic action and combine with foundation differential settlement working conditions, analyze the elastic displacement and internal forces of the structure. The results showed that，in the topper side area near to the fissure, affected by the avoidance distance, the displacements and internal forces of the frame structure change remarkably. The growth and redistribution of internal forces performance are the most serious in the building base floor of framework， the internal forces change in ends of both beam and column will cause a change in the direction of bending moment， but also an inflection point of the column will change with the internal forces growth and regression.

Abstract: This paper gets the column-end moment amplification factors of the concrete frame in the seismic zones of intensity seven and eight, by using the software CANNY and the method of pushover. The results show that when considering the casting slab, the reinforced concrete frame can develop a strong column and weak beam yielding mechanism when the column moment amplification factor adopts 1.4 for seven intensity area and 1.2 for eight intensity zone, preventing the development of collapse.

Abstract: In this paper, the influence of temperature on the cracking of reinforced concrete frame is studied. Finite element analysis software is used to simulate the concrete cracking. In the modeling process, separate model element of SOLID65+LINK8 is used. Also, the Hongestad model is applied to the stress-strain relation of concrete and the rule of BISO is applied to the stress-strain relation of steel. By comparing the stress and strain of three different structure frames before and after temperature increasing, the extending rules of concrete cracking and the stress character of beam and column are analyzed. It is found that the maximum stress of beam is located in the end of the beam-column joints and the middle of beam under the temperature action. It is suggested that they are caused by moment and axis-force respectively. However, the greatest stress of column is situated at the end of beam-column joints. The reason is that the end of beam-column joints should deform to coordinate the influence of temperature. Thus, greater peak stress is caused. So, the concrete cracking is always distributed in the middle of beam span or beam-column joints, where the position of stress concentrates. In addition, the stress of steel in beams increases greatly under the temperature load, suggesting that the temperature leads to the internal force redistribution in the concrete component and the cracking of component.