Civil engineers can now use concrete-filled steel tubes as beams with more confidence thanks to a simpler and safer design method. This is covered in the latest issue (166 SB1) of the ICE Structures and Buildings journal.
Best method for beam design
The new design method is likely to increase the usage of what is already a highly popular construction technique.
A team of US research engineers at the University of Nebraska-Lincoln have made some interesting findings. They discovered that theoretical sectional analysis was easier and more accurate than finite-element analysis for designing concrete-filled steel tube beams, both non-post-tensioned and post-tensioned circular.
Lead author Yaohua Deng says, ‘both methods are capable of predicting the elastic and ultimate moment capacities of concrete-filled steel tubes.’ However, he concludes that: ‘due to its computational efficiency, theoretical sectional analysis is more suitable for design than finite-element analysis’.
Sectional analysis more accurate
The results from the two methods were compared with published experimental test results. While both sets of predicted strains were in reasonable agreement with experimental data, the researchers found that finite-element analysis tended to over-estimate ultimate strength whereas sectional analysis was more conservative.
Increasing Usage
According to Deng, concrete-filled steel tubes are becoming widely used in construction throughout the world as they make optimum use of both materials. ‘The continuous confinement provided to the concrete core by the steel tube enhances the core strength and ductility. The concrete core restrains inward buckling of the steel tube, while the steel tube serves as tensile reinforcement for the concrete.’
For further information please contact the ICE Proceedings editor Simon Fullalove on +44 20 8744 2028 or email editor@ice.org.uk.