Issue 63

L. A. Aboul-Nour et alii, Frattura ed Integrità Strutturale, 63 (2023) 134-152; DOI: 10.3221/IGF-ESIS.63.13

Structural behavior of Lightweight and High strength Layered Hollow Core Slabs

Louay A. Aboul-Nour, Ahmed S. Eisa, Asmaa El-Ghamry University of Zagazig, Egypt louayabdelrazek @yahoo.com ahmedeisa@zu.edu.eg, http://orcid.org/0000-0002-6606-3253 f_ghamry@yahoo.com

A BSTRACT . A new technique of Layered Hollow Core Slab (LHCS) has been used to obtain a slab with an optimum weight-to-strength ratio. Specimens with a 90 mm top layer of High Strength Concrete (HSC) and a 90 mm bottom layer of Lightweight Aggregate Concrete (LWAC) were examined. Nine full scale slabs with dimensions of 1600* 450* 180 mm were tested under a 4 point loading test. The %core, a/d, RFT ratio, and connection method were the different studied parameters. A push-out test was conducted on triplet specimens to study the bond strength at the interface between HSC jacket and LWAC cubes using bond agent material or shear dowels, or without treatment, to determine which method of them is suitable for connecting the two layers of the tested slabs. Load, deflection, ductility, strain, crack pattern, and mode of failure were studied. The results indicate that ultimate strength is enhanced with decreasing a/d and %core and with an increasing RFT ratio of the LHCS specimens. Using shear dowels ensures an efficient bond between the two layers of the tested slabs. ANSYS program used for modelling the slab. The numerical study accepted the experimental data with a variation of less than 10% for all slabs. K EYWORDS . Hollow core slab, Layered slab, Lightweight aggregate concrete, High strength concrete.

Citation: Aboul-Nour, L. A., Eisa, A. S., El Ghamry, A., Structural behavior of Lightweight and High strength Layered Hollow Core Slabs, Frattura ed Integrità Strutturale, 63 (2023) 134-152.

Received: 07.09.2022 Accepted: 27.10.2022 Online first: 15.11.2022 Published: 01.01.2023

Copyright: © 2023 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

I NTRODUCTION

hollow core slab (HCS) is defined as a simply supported concrete slab with about (40%–50%) voids in the center of the slab cross section through its length in one direction with a typical diameter of (.667-.75) of the slab thickness, a typical width of 120 cm, a typical thickness of about (15–50) cm, and the clear span reaches up to 18m [1–4]. There are many advantages of using HCS, like reducing overall weight, saving cost and time of construction, providing long spans, and increasing fire resistance [5–8]. The shear span to effective depth (a/d) ratio affects the mode of failure of the HCS and changes it from a flexural to a shear mode [9]. The ultimate load decreases with increasing the deflection when increasing the A

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