Physical Tests and Analyses of Composite Steel-Concrete Beam-Columns

Abstract

The composite steel-concrete beam-columns in which steel shapes are encased in concrete and second-order effects are significant were studied from 16 specimens loaded to failure. Loading included combinations of axial and transverse forces producing a wide range of different external eccentricities. Observations from the physical tests indicate that, for static loads, the bonding condition at the interface of steel rib connectors and the surrounding concrete has a small effect on ultimate strength. The tests also show that the ACI 318 assumption of maximum usable strain of 0.003 at concrete extreme compression fibers near ultimate load is valid for such beam-columns. Analyses based on ACI 318, Eurocode 4, and finite-element modeling procedures were compared to test results that provided further insight into understanding the structural behavior of such beam-columns.