A Study on the Behavior of Composite Concrete and Open Web Steel Joists

In this research, the results of three composite open web steel joist static tests are presented along with the results of companion pushout tests. The effect of shear connection degree and span-to-depth ratio on the behavior of composite open web joists under distributed static loading is reviewed and discussed, followed by a comparison of results of the shear stud strength from push-out tests, back-calculated from the ultimate capacity of the composite joist tests, and to the provisions in the AISC, EC4, NZS, SJI, and BS5950. Specimen test results of the studied span-to-depth ratios showed that the load-deflection behavior was similar to ultimate capacity difference less than 10%, but they experienced different failure modes and deflection. And when the test results were compared based on the shear connection degree, they revealed that the composite open web joist designed with partial shear connection suffered from severe deformation and deflection accompanied with higher ultimate capacity

FRC-Steel Joist Composite Frames for Seismic Resistance

The research reported in this paper is concerned with development of fiber-reinforced concrete-encased open web steel joist composite frames for seismic resistance. This new and innovative system completely eliminates the need for any shear connectors between steel joists and surrounding concrete as well as that for conventional longitudinal and transverse reinforcement, all of which are quite labor intensive. In the initial phase of the study tests were carried out on half-scale beam specimens subjected to monotonic and reversed cyclic loading. The results showed that the presence of steel fibers as well as the open web steel significantly enhances the shear capacity of the system thus making it very suitable for seismic resistance. In the final phase, a half-scale, one-story, one-bay frame was designed by strong column-weak beam concept. The results showed ductile and stable hysteretic behavior. The study indicates that this type of composite framing system has excellent potential in seismic regions.

Dynamic testing of an open web steel joist floor

A non-composite open web steel joist warehouse floor was tested to determine its dynamic characteristics and maximum strain levels under actual operational conditions. Altogether 28 tests were carried out. The strain and acceleration information for each test was recorded on strip chart and magnetic tape recorders. The recorded data were examined and analyzed through a dual channel spectrum analyzer and the results were compared with calculated values. Good agreements are noted.