The Behaviour of Half-Slabs and Hollow-Core Slab in Four-Edge Supported Conditions

Jakub Zając,Mirosław Wieczorek,Łukasz Drobiec,Radosław Jasiński,Krzysztof Grzyb,Wojciech Mazur,Artur Kisiołek

doi:10.3390/app112110354

Jakub Zając, Mirosław Wieczorek + Show 5 more

Open Access

https://doi.org/10.3390/app112110354

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Abstract

In this study, qualitative tests were carried out to compare the behaviour of selected slabs exposed to short- and long-term loading. Full-scale models of the half-slab and hollow-core slab with dimensions of 6.30 m × 6.30 m, built of four different precast panels, were tested. The first two were semi-precast lattice girder slabs, the third semi-precast prestressed ribbed panels, and the last was composed of hollow-core panels. A common feature was the lack of joint reinforcement and the same modular width of 600 mm. The short-term load was applied sequentially in the first stage, and displacement was measured using an electronic method. In the second stage of long-term testing, the load was mainly applied to one part of the slab. Testing under short-term and long-term load allows determining the change in the performance of panel slabs over time. The panels maintained the ability of load redistribution based on their interaction despite the work of the longitudinal joints being only through the concrete cross-section. The behaviour of slabs with concrete topping shows more significant lateral interactions than elements connected only by shear key. Comparative calculations were made based on four computational models. Comparative analysis showed that the current design procedures lead to a safe but conservative estimation of the slab behaviour.

Highlights

The amount of primary cracking was small in the lattice girder panels withThe secondary rebars (LGR) (Figure 13a), and there were no cracks in ribbed panels (RP) and HC models
A significant difference was found in the lattice girder panels with fibre reinforcement (LGF) model with the precast units with fibre reinforcement (LGF)
Differences in displacements between the sequences J-10 and L-12 show that the shape of a shear key used in the HC model had less impact on the load transfer than the concrete topping laid on the whole surface of the slab

Summary

Introduction

Composite slabs with precast panels are being increasingly used in the construction sector as an alternative to monolithic slabs or beam and block systems [1]. Many tests have been performed in recent years, and new types of composite slabs have been designed. They include but are not limited to a slab bonded to vertical tongues serving as shear keys that join two layers of the slab [8], multi-span slabs of slimfloor type with prestressed steel beams bonded to hollow-core (HC) slabs [9], and one- or two-way slabs on thin prestressed boards (narrow slabs) [10]. Basalt rebars are pretensioned using various methods [11], and steel reinforcements have been used as

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