Study On Design Theory Of RC Flat Plate Structure With Special Columns

In the 21st century, the human oriented designing method has become an important design principle in either exterior environment design or interior function design of residential building, and it has attracted more and more attention to it. Therefore it is absolutely necessary to explore the comfortable and practical residential building with characteristics of sustainable development, which is large-space residential building with constant main structures and changeable interior wall. By introducing the special-shaped columns into conventional flat-plate structures, so the author presents a new structural system, namely R.C. Large-bays Residential System of Flat Plate Structure with Nonrectangular Columns. The research of this doctoral thesis is aiming to the punching shear behavior and design method of slab-column connections with nonrectangular columns on this new structural system. The main research work covers the following aspects:(1) One of the critical points in the design of reinforced concrete flat plat structures is proportioning of slab-column connections for adequate punching strength and ductility. However, the provisions for the design of slab-column connections with nonrectangular columns have not been provided clearly in current code of China, and few of the experimental investigation on slab-column connections with nonrectangular columns has been found. Therefore, one experimental program is conducted, in which eleven reinforced concrete slabs with typical special-shaped columns (cross-shaped section, T-shaped section and L-shaped section) and square columns were tested. The purpose of this experimental program is to investigate the behavior of slab-column connection with nonrectangular columns and the differences between it and conventional connection. It is shown that the punching shear strength and ductility of the connections with nonrectangular columns are higher than that of the corresponding connections with square columns. Based on the test results, one method for calculating punching shear strength of connections with nonrectangular columns is proposed, which consists with provisions of China Code. Also, the test results are compared with the predictions of four Codes of Practice: ACI 318-95, BS 8110, CEB-FIP Model Code, GB50010-2002.(2) With cross-shaped column as the representative of nonrectangular columns, one experimental program is conducted to study behavior of slab-column connection with nonrectangular column provided with shear reinforcement, the shear reinforcement include traditional stirrup and stud shear reinforcement (SSR). The results of the experiment showed that higher strength and more ductile behavior are achieved when the SSR is used. Based on present and reported test results for study on SSR, the rules to design and detail stud shear reinforcement in accordance with China Code (GB 50010) is proposed.(3) Based on the test results and ACI code, a convenient and practical method forcalculating critical section perimeter of nonrectangular column is presented. And a method for predicting the punching strength of slab-column connection with different column shape is proposed. The proposed method of prediction is relatively simple to use and is shown to give significantly better correlation with large number of test results reported by different researcher than methods advocated by the present codes of practice: ACI 318-95 and GB50010.(4) Based on the experimental behavior and results of nonrectangular column-slab connections in present thesis, the calculating formulas for flexural strengths of reinforced concrete slab-column connection with cross-shaped column, T-shaped column and L-shaped column are derived by yield-line theory. And the calculating result is agree with the test results.(5) Another experimental program is conducted, which purpose is to study the behavior of slab-column connections with nonrectangular columns subjected to earthquake forces. The specimens include interior slab-column connections with cross-shaped column and edge slab-column c...