Browsing Engineering and Informatics by Subject "Buildings"
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Experiments on composite steel beams with precast concrete hollow core floor slabs.Precast concrete hollow core floor units are frequently used in multistorey steel- framed buildings where they bear on to the top flanges of universal beams. The steel beam is normally designed in bending in isolation from the concrete slab and no account is taken of the composite beam action available with the precast units. Although some commercial data are avail- able, there is no general design guidance to cover the wide range of material and geometric variables found in this form of construction. This paper summarizes research carried out at the University of Nottingham on this form of construction and presents the results of three full-scale bending tests of steel beams acting com- positely with proprietary precast hollow core slabs. The 150 mm deep units were attached to the universal beams through 19 mm diameter headed shear studs, and tested in four-point bending over a span of 6 m. For typical geometry and serial sizes the composite beams were found to be twice as strong and nearly three times as sti as the equivalent isolated steel beams. The failure mode was ductile, and may be controlled by the correct use of small quantities of tie steel and in situ infill concrete placed between the precast units. To generalize the findings, isolated push- off tests and eccentric compression tests were used to study the horizontal interface shear resistance of the headed studs and the strength of the slab, respectively.
Inclined reinforcement around web opening in concrete beamsTwelve reinforced-concrete continuous deep beams having web openings within interior shear spans were tested to failure. The main variables investigated were the opening size and the amount of inclined reinforcement around openings. An effective inclined reinforcement factor combining the influence of the amount of inclined web reinforcement and opening size is proposed and used to analyse the structural behaviour of continuous deep beams tested. It was observed that the end support reaction, diagonal crack width and load capacity of beams tested were significantly dependent on the proposed effective inclined reinforcement factor. As this factor increased, the end support reaction and increasing rate of diagonal crack width were closer to those of companion solid deep beams. In addition, a higher load capacity was exhibited by beams having an effective inclined reinforcement factor above 0.077 than the companion solid deep beam. A numerical procedure based on the upper-bound analysis of the plasticity theory was proposed to estimate the load capacity of beams tested. Comparisons between the measured and predicted load capacities showed good agreement.
Recovery and reuse of structural products from end-of-life buildingsBuildings and construction have been identified as having the greatest potential for circular economy value creation. One source of value creation is to recover and reuse building products from end-of-service-life buildings, rather than destructive demolition and downcycling. While there is a trade in non-structural and heritage product recovery and reuse, the largest volume, mass and value of most buildings comprise structural elements – concrete, brick and masonry, and steel – which present many challenges. A comprehensive literature review confirms limited attention to innovation and advanced techniques to address these challenges and therefore the potential reuse of the stocks of accumulated building products globally and associated environmental benefits. Potential techniques being tested in an Engineering and Physical Sciences Research Council circular economy research programme are referenced as a key building block towards circular economy building system redesign.