A layered beam model to analyse composite truss girders

Abstract

In non-steel manufacturing countries like Sri Lanka, where the cost of heavy rolled steel sections are very high, composite floor trusses tend to provide an economical solution in achieving moderate spans in the range of 8m-12m. A high degree of service integration can be provided in these floor systems by allowing rectangular openings, as often preferred in constructing high-rise buildings. However, allowance of rectangular openings in the web creates additional local moments in the comers of the openings, which are generally known as "vierendeel" moments and render the composite truss statically indeterminate. Failure to account for these vierendeel moments in composite floor structures often leads to undesirable cracking in the concrete floor slab.