Study On Seismic Design Of Reinforced Concrete Structure With Spicial Shaped Columns

Reinforced concrete special-shaped columns used in residential construction in recent years, for their unique qualities, are widely welcomed by the users and have been gained a wide development. Local technical specifications were set by Tianjin and other places one after another. National Ministry of Construction has issued the order of compiling national technical standard. The so-called special-shaped column structure is that the cross section of the frame structure column adopted is special-shaped (T-shaped, L-shaped, cross-shaped, etc.) other than generally used rectangular cross sections. But there is a need to deepening the research systematically on the differences of load-bearing capacity, ductility performance, aseismic behavior due to the shape changed of the cross sections of columns. Continuous progresses are made on the research on special-shaped column structure, and understanding to aseismic behavior of the special-shaped column structure are getting deepening. These have laid a good foundation of both experiment and theory for the development of the special-shaped column structure. In the light of the feature of the special-shaped columns, combine with the existing experiment research achievements, this paper has made calculation analysis and research on some basic aspect in special-shaped column structure design, and thus put forward the design suggestion for the designer's reference and can provide some basic material for technical specification compilation. The main research contents are as follows:1. Through massive calculation, analysis and comparison, sum up the similarities and differences between the special-shaped cross sections and rectangular cross sections in mechanical features, between reinforced concrete special-shaped columns and rectangular columns in load-bearing capacity, ductility performance and provide necessary basic concepts and data for further understanding the characteristics of the special-shaped columns;2. Through massive elastic calculations and elasto-plastic analysis, under the preconditions of satisfying the code's requirements for axial compression ratio, limit value of lateral displacement and load-bearing capacity of normal section,oblique section and beam-column joint, under circumstances of different intensity of earthquake, structure dead weight, sort of site and column grid bay dimension, the variation regularity of maximum suitable height of structure, and thus sum up the maximum suitable height of structure for code for the purpose of macro-control while deciding the design scheme;3. Make a preliminary study on the stress feature of reinforced concrete special-shaped column and Z-shaped column of which the ratio of limb length to limb thickness is between 4~5 ,and the preliminary design method is suggested;4. Through elato-plastic time history dynamic analysis of typical projects, check up the weak storey of the special-shaped column structure and yielding, breaking and collapse mechanism to satisfy the earthquake resistant requirement to buildings of remaining stand under strong earthquake;5. Derive for project use simplified calculation formula of vibration period, suitable vibration period, suitable rigidity of special-shaped column structure through theoretical analysis, and provide an easy and practical method for deciding the structure scheme economically, safely and reasonably;6. Based on the study achievements in theory and massive analysis and calculations of this paper, sum up the regularities of inner force, deformation of special-shaped column structure and seismic conceptual design, and thus the suggection of seismic design of special-shaped column structures is presented.