ST 20AB : Design of slender concrete columns using compatibility and equilibrium approach
Ngoc, Nguyen Pham Tuan
Date of Issue2016
School of Civil and Environmental Engineering
For a short column, when it reaches maximum capacity under applied load, it fails. However for slender column, it is also subjected to failure due to lateral deflection. There are various methods designed to predict the failure load of slender reinforced columns. The purpose of this report is to study the proposed design method which is used to calculate the structural capacity of pin-ended slender columns subjected to uniaxial bending and axial loading using compatibility and equilibrium approach. The calculated failure loads from the proposed method would be compared with experimental values and predicted values obtained from code of practices which are BS 8110 and EC 2. Chapter 1 would be an introduction to slender columns and proposed design method. After that, chapter 2 would include the overview of the past study of slender columns. Chapter 3 describes the proposed method and chapter 4 reviews two code of practices which are BS 8110 and EC 2. Finally chapter 5 and 6 concludes with results, discussions and recommendations. 146 columns tested by past researchers which are mentioned in result and discussion section are analyzed in this study. Slenderness ratio of columns is from 15 to 58, eccentricity ratio from 0.033 to 0.83, reinforcement percentage ratio from 0.78% to 4.23%, compressive strength of concrete fcu from 19.74 MPa to 106.7 MPa and yield strength of steel from 272MPa to 531MPa. Generally, for columns of high strength concrete which are analyzed in this report, proposed method and EC2’s failure load predictions are more conservative than those obtained from BS8110. However, for columns of normal strength concrete, proposed method gives predictions of failure load closer to experiment results than those from BS8110 and EC2. It is generally observed with columns that have eccentricity to load ratio (e/h) which is below 0.2, proposed method can be unsafe when its prediction of column failure load tend to be higher than experiment results.
Final Year Project (FYP)
Nanyang Technological University