Experimental Study on the Flexural and Shear Behaviour of Precast Prestressed Hollow Core Slab
01 Jan 2021-Vol. 94, pp 85-97
TL;DR: In this paper, the flexural behavior of precast prestressed HCS made of Styrofoam, with 10 m span, was examined experimentally, and two specimens were tested, one with screed (topping) concrete and other without screed concrete.
Abstract: In general, the total cost of the building is mainly influenced by the self-weight of structural members. In particular, the self-weight of the floor slab is a key parameter which restricts its span. The hollow core slab (HCS) is being developed as an alternate to the conventional solid slab and results in self-weight reduction up to 50%. However, the reduction in the cross-sectional area increases the flexural deflection, which can be overcome by prestress technology. In this study, the flexural behaviour of precast prestressed HCS made of Styrofoam, with 10 m span, was examined experimentally. Two specimens were tested, one with screed (topping) concrete and other without screed concrete. The influence of screed concrete on the flexural and creep behaviour was investigated. It is found that the screed concrete reduces the flexural and creep deflection significantly. The applicability of HCS system to industrial buildings was investigated by adopting a service load as per Indian standard, IS 875 (Part 2): 1987, and subsequently found that the HCS satisfies the code requirements related to strength and serviceability (deflection and crack). Additionally, it was observed that the voids significantly influences the shear capacity of precast prestressed HCS.
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TL;DR: In this paper, the authors present an experimental study on shear-flexure capacity of composite slabs using precast concrete hollow core unit (HCU) and concrete topping, and the experimental results are also compared with predicted values using the available equation in Eurocode 2 and an equation published by a previous researcher.
55 citations
TL;DR: In this paper, the flexural behavior of precast hollow core slab with different type of reinforcements was discussed, and the results showed that hollow core slabs type 1 and type 2 can reduce the weight by 24% and 25% as compared to the solid slab.
20 citations
TL;DR: A load test of a machine-made hollow-core slab with composite topping verified a number of accepted industry design and fabrication practices, specifically the following: 1. Impact test hammer data taken on the side of the member provided an accurate assessment of concrete strength as determined by uncracked deflection behavior and ultimate moment capacity as mentioned in this paper.
Abstract: This load test of a machine-made hollow-core slab with composite topping verified a number of accepted industry design and fabrication practices, specifically the following: 1. Impact test hammer data taken on the side of the member provided an accurate assessment of concrete strength as determined by uncracked deflection behavior and ultimate moment capacity. 2. The observed ultimate moment was about 10 percent greater than calculations based on Eq.(18-3) in ACI 318-71 but nearly identical to calculations based on strain compatibility by Fig. 5.2.5 in the PCI Design Handbook. 3. The bilinear concept for predicting the deflection of cracked prestressed members was conservative well beyond a nominal bottom fiber tensile stress of 12i,/ f'c. 4. Composite action between the precast and cast-in place portions was evident up to ultimate load. The top surface of the precast slab was a smooth, even, machine cast finish and did not comply with Section 17.7 of ACI 318-71. There was no reinforcing steel projecting from the precast slab into the topping concrete. 5. A shear failure did not occur even though the ultimate shear stress vu was 1.75 times vc as computed in accordance with ACI 318-71.
19 citations
TL;DR: In this paper, the applicability of conventional methods for solid slabs in the design standards, such as ACI 318 (2014), EN 1992-1-1 (2004) and IS 456 (2000), to predict the punching shear capacity of the voided slab is examined.
16 citations
TL;DR: In this paper, the authors investigated the performance of two-way hollow slab under one-way flexure and showed that the ultimate load-carrying capacity of voided slabs was higher or similar to that of solid slab.
Abstract: The Two-way hollow slab system (biaxial voided slab) is an innovative slab system, being adopted all over the world as an alternate for the conventional solid slab. It reduces the self-weight up to 50% in comparison with solid slabs without significant change in its structural performance. The voided slab consists of void formers in shapes like spherical, donut, and cuboid. Experimental and analytical investigations were carried out to study the behaviour of biaxial voided slab under one-way flexure. Voided slab specimens were prepared and tested with two different shapes of voids namely sphere and cuboid, which were manufactured using recycled polypropylene. Comparison of experimental and analytical studies showed that the ultimate load-carrying capacity of voided slabs was higher or similar to that of solid slab. An analytical study was carried out using the yield line analysis in conjunction with Indian Standards. It was found that the capacity of voided slab can be estimated by yield line analysis. The flexural stiffness of voided specimen is approximately 50% lesser in comparison with solid slab of identical dimensions and reinforcement at yield stage. The reduction in flexural stiffness is mainly due to the presence of void former and the maximum void ratio at a section defines the flexural stiffness of the voided slab. Nevertheless, the deflection is under serviceable limit for both the specimens for 75% of ultimate load. Ultimately, it is found that the behaviour of voided slabs under one-way flexure can be predicted by provisions of Indian Standards with necessary correction for loss of cross-section caused by voids.
15 citations