Impact of different concrete classes on the lateral resistance and failure mode of columns made with concrete-encased steel profiles
Building use
Office building
Country/Region
Romania
Overview
The purpose of the research is to understand how different concrete classes impact on the lateral resistance and failure mode of columns made with concrete-encased steel profiles. It stems from three independent testing campaigns conducted in Romania and Taiwan that adopted similarly-designed composite columns with different types of concrete and steel profiles. Samples are loads with axial forces and subject to monotonic and cyclic lateral loads to measure their strength and failure mode. The results of the tests confirm the expectations of the researchers.
Issue and/or innovation
The test adopts the “Recommended Testing Procedure for Assessing the Behavior of Structural Steel Elements under Cyclic Loads” and Eurocode 4 but it exceeds the concrete class strength considered in Eurocode.
Technical details
The study describes experimental aspects for composite steel-concrete columns, with steel encased profile. In composite columns with HSC case, even if elastic displacement decreases, the value of the lateral force corresponding to the displacement and the maximum lateral loading Hmax indicates a significant increase. Failure modes were different, characterized by sudden and violent concessions due to cracking developments through aggregate in columns with HSC, while columns with NSC shows a “slow” failure mode characterized by gradual decline of bearing capacity with the growth of the displacements. It is well known that the high strength concrete is more susceptible to fragile failure than the normal concrete, so it is, in a way, the presumed result. On the other hand, from the graphics and parameters analysis we can conclude that the columns with HSC have a higher energy absorption capacity, which can recommend this solution to the construction in seismic areas, even the failure mode was brittle. In structural terms, composite columns with concrete class C70/85 provide obvious better performances to structures, having significant increases to almost all analyzed parameters. The solution of fully encased composite column is a competitive solution for seismic and non-seismic zones, due to the excellent seismic performances (resulted from the presented experimental tests) and also because of improved fire protection. The results obtained on the columns made with high strength concrete showed improved performances, especially resistance. Due to the brittle fracture of the high strength concrete more experimental and numerical research must still be made.
References / Technical Papers Content
Campian C., Nagy Z., Pop M., “Behavior of Fully Encased Steel-Concrete Composite Columns Subjected to Monotonic and Cyclic Loading”, Procedia Engineering 117 (2015) 439 – 451 doi:10.1016/j.proeng.2015.08.193
Categories
Building, Floor (slab)