Design of Moment Connections for Composite Framed Structures

Increasingly, engineers are designing composite and mixed building systems of structural steel and reinforced concrete to produce more efficient structures than either guidelines in several areas is in detailing of moment connections in composite framed structures which consist of steel beams and reinforced concrete or composite columns. Such composite frames have been employed for buildings in the 40 to 70 story height range.

Based on experimental research conducted at The University of Texas, the design of moment connections between steel beams and reinforced concrete or composite columns is addressed. An analytic model for calculating joint strength and design recommendations are developed from test data for composite connections and design recommendations for structural steel and reinforced concrete joints. Experimental results are reported for eight 2/3 scale interior composite joint specimens tested under reverse cyclic loading. Also summarized are results from nine composite joint specimens tested in an earlier phase of the research. The aim in the tests is to gain understanding of connection behavior by examining the influence of various joint details in mobilizing shear capacity of concrete in the connection. Attention is focussed on formation of internal mechanisms which transfer load between the steel beam and reinforced concrete.