A series of experiments is being conducted on five 12.8 m long composite floor beams at the newly-commissioned National Fire Research Laboratory at the National Institute of Standards and Technology. The test beams were designed according to current U.S. building codes with input and design-review provided by panel of expert practitioners. Each specimen consists of a W 18x35 beam and a 1.83 m wide lightweight concrete slab cast over profiled steel deck units. Composite action between the steel beam and concrete slab is achieved using 19 mm diameter steel shear connectors spaced at 305 mm on center. One of the five specimens was tested at ambient temperature to measure its behavior and flexural strength, and to verify the purpose-built mechanical loading system. The remaining four specimens will be tested under simultaneously applied mechanical loading and an enclosure fire using a natural gas fuel delivery system. The beam-to-column connections and rotational restraint of the slab ends over the support girders were varied among those four specimens.
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