Abstract
Steel reinforced concrete (SRC) columns are widely used in super high-rise buildings, since they can provide larger load bearing capacity and better ductility than traditional reinforced concrete (RC) columns. Six concrete – encased composite columns were designed based on a typical mega-column of a super high-rise building constructed in China. The specimens are identical in geometrical configurations having as changing parameter the eccentricity ratio of the applied load: every two of the specimens were loaded statically with the eccentricity ratio of 0, 10%, and 15%, respectively. Such columns are however not covered by EN 1994-1-1 [2] (limited to one single encased profile), while AISC 360-16 [8] allows the design of composite sections built-up with two or more encased steel sections, although the way to perform such a design is not detailed. A finite element analysis was conducted as a supplement to the physical tests to provide a deeper insight into the behavior of SRC columns. The experimental campaign has yielded stable test results, suggesting a desirable performance of SRC columns. It is concluded from these experiments that sufficient composite action exists between the concrete and the steel sections for the tested SRC specimens, and that the current code provisions are applicable for the considered configuration, in predicting the flexural capacity of SRC columns when the eccentricity ratio is less than or equal to 15%. The present paper summarizes the principles and an application method for the design of such columns under combined axial compression and bending. The method is based on simplifications provided in EN 1994–1. The validation of the method is made using experimental and numerical results.
Highlights
Composite columns are frequently used in high rise buildings
The concrete-encased composite column contains a structural steel with or without shear connectors and the surrounding concrete which is further reinforced by longitudinal bars and transverse bars
The test results were in accordance with the expected results and the specimens shown sufficient deformation capacity
Summary
Composite columns are frequently used in high rise buildings. Two commonly used types of composite columns for tall buildings are concrete encased composite columns and concrete filled steel tube columns. A substantial number of experimental tests have been conducted to observe the behavior of concrete encased composite columns subjected to axial and eccentric loads. The current design codes consider composite structural elements but they do not offer specific provisions on the design of composite sections with two or more encased steel sections. The lack of knowledge on the axial, bending and shear behavior of composite mega columns, along with the resulting lack of clarity in the codes, leads to the need for experimental performance tests. These tests provide a base for the simplified design approach and are used to calibrate numerical models to describe the designs and to validate the results. Through three examples of application to selected mega column cross- sections, the given simplified design methods are proven to be an effective and handy design tool
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
