Study On Influence Of Plastic Hinge Length On Hysteretic Energy Of The Plan Frame

The displacement-based seismic design highly regards maximum displacement response of structures under strong ground motion, it requires that the structure has enough ductility.For guaranteeing the elastic-plastic deformation capacity of structure, Chinese Code for Seismic Design of Buildings orders that the beam and column must be reinforced according to different seismic grade (such as stirrup densification at the ends of members of structure). Although the research shows that the establishment of the allowed storye-drift-angle which is 2% is used to judge structure failure, it can't reflect the structural cumulative damage failure caused by the duration of strong earthquake. The analysis and design methods based on energy not only is clear in concept and simple in form, but also better reflects the the duration,intensity of ground motion and spectral characteristics, particularly structural cumulative damage failure caused by the duration of strong earthquake. Therefore, seismic response analysis based on energy has been increasingly paid concern by domestic and international earthquake engineering research community. To reduce the possibility of failure of column and the probability of collapse of overall structure,strong column-weak beam seismic design of structures is adopted so that the plastic hinge of the beam-end appers before column-end. Hysteretic energy dissipates the total energy of structure input by seismic waves. However, plastic hinge is often seen as a section and neglected the impact of the plastic hinge length. For the difference of the hysterectic energy between considering the plastic hinge length or not, the analysis on the same structure using different plastic hinge lenth model may be very different in conclusion. Therefore understanding the influence of the hysterectic energy of the plastic hinge length is very necessary.In this paper, Mainly compared with the displacement and hysteretic energy between the two conditings, this article has done the following work:①In accordance with Chinese Code for Seismic Design of Building, seven three-bay reinforced concrete plane frame of 4 layers, 5 layers, 7 layers, 9 layers, 11 layers, 13 layers and 15 layers are designed. And then these frames are modeled and analyzed using large commercial finite element software ABAQUS. The energy dissipation and relative displacement response is calculated. Different from the previous energy-based analysis in which the beam and column are regarded as an element and the mass of a beam and a column is set at the two ends of the beam and column, this paper apply material restoring force model based material constitutive model, divide elements and use consistent mass matrix and consistent stiffness matrix, avoiding increasing errors due to too many hypothesis.②Considering changes of ground motion factors and structural dynamic properties, changing law of total input energy and its distribution of plane frame structure for using different plastic hinge length model is analyzed, and then it is obtained that the difference of the total input energy and its distribution as a result of different plastic hinge length model selection, reaching a preliminary understanding of these quantitative and qualitative differences in the law.③Considering changes of ground motion factors and structural dynamic properties, changing law of distribution of hysteretic energy and damping energy of beams and columns for adopting different plastic hinge length model or not is analyzed, and then it is obtained that the difference between beam and column distributions of hysteretic energy as a result of considering plastic hinge length model or not, getting a preliminary understanding of these quantitative and qualitative differences in the law.④The previous researchs of plastic hinge are based on structural members by test. They can't reflect the impact of the structure to plastic hinge length. Different from the previous researchs of plastic hinge on structural members, this paper analyzes the plastic hinge length through the plan frame. It analyzes the different impact of hysteretic energy of single beam considering plastic hinge, plastic hinge length model selected and the actual plastic hinge length .⑤This paper gives a suggestion on the selection of plastic hinge length model for the energy-based analysis by the above analysis.