The Simplified Calculation Of The Extremity Strengthening Reinforcemen Of The T-shaped Column In Two-way Eccentric Compression Flexural And Axial Capacity.

For their unique qualities, specially shaped column structure were widely developed and applied by the majority of users in recent years in our residential construction.There was national industry standard "Technical Specification for Concrete Structures with Specially Shaped Columns" to guide the design and construction of specially shaped columns. However, to the ordinary reinforced T-shaped cross-section column, when the web of section was in two-way eccentric compression, the ultimate axial compression ratio of large and small eccentric compression was small, which might prone to brittle failure of small eccentric compression. If not change the form of reinforcement, it would be bound to increase the longitudinal reinforcement in order to avoid the damage. This paper summarized the variation of the extremity strengthening reinforcement of the T-shaped column in two-way eccentric compression flexural and axial capacity. On this basis, put forward its simplified calculation formula. The N-M_x-M_y three-dimensional surface described by the formula was not only related to high precision, but also smooth, continuous, with a convex, simple and practical, and had overcome the shortcomings of the specially shaped column flexural and axial capacity accurate calculation of consuming too much time, and laid the foundation for the specially shaped column of engineering applications.Based on the existing research achievements, the theoretical and experimental researches, the primary work are included as follows:1,The computer program of yield bending moment of reinforced concrete was Analyzed in order to calculate the flexural and axial ultimate bearing capacity of the extremity strengthening reinforcement of the T-shaped column according to different concrete strength, steel strength, bar diameter, ratio of height to thickness of column leg, the cover of steel, and to draw all M_x-M_y curves at different axial compression ratio in one picture.2,The flexural and axial ultimate bearing capacity of the extremity strengthening reinforcement of the T-shaped column was calculated by Numerical Integration (Fiber method)in different concrete strength, steel strength, bar diameter, ratio of height to thickness of column leg which can all meet the requirements of " Technical Specification for concrete Structures with Specially Shaped Columns". The changing states of M_x-M_y related curves were compared according to various factors (such as concrete strength, steel strength, bar diameter, ratio of height to thickness of column leg) and the causes of changes had been analyzed.3,The results calculated by the computer program(the following called"the precise value") were imported into Origin. In order to fit M_x-M_y related curves with minimized error to the precise value, different curve features has been analyzed. Then the simplified calculation formula was put forward. The changes of the coefficients in these formulas with the different concrete strength, steel strength, bar diameter and ratio of height to thickness of column leg were analyzed to sum up the variation of the coefficients and to give a more accurate simplified formula.