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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Indirectly-Supported One-Way R/C Slabs: Durability And Safety Issues
Author(s): Pietro G. Gambarova and Francesco Lo Monte
Publication: Special Publication
Appears on pages(s): 15.1-15.10
Keywords: cracking (in R/C), crack control, dapped ends, one-way slabs, R/C slabs, service loads, strut-and-tie systems, ultimate loads
Abstract:Simply-supported one-way R/C slabs are commonly used in the covers of small and medium underground facilities, where durability is the main issue face with rather limited service loads and short spans (2-4 m [6.5-13.0 ft]). The structural performance, however, should not be underrated, as being the slab in a roundabout does not prevent a heavy truck from straying off the right lane!
To have fresh information on durability and cracking (working loads), and on the bearing capacity and failure mode (ultimate loads), displacement-controlled tests have been recently performed in Milan on four typical rectangular R/C slabs suspended along their short sides via corbels (dapped ends; size: 1.3x2.2x0.15 m [51x87x6 in.]). A transversely-distributed or concentrated load was applied either at mid-span (in the bending tests), or at 1/10 of the span (in the shear tests).
The two slabs Type A are provided with longitudinal bent-up bars in the main body and hooks in the corbels. On the contrary, the slabs type B are reinforced via two continuous layers of longitudinal straight bars.
Under the working loads, cracking never occurred, neither in bending nor in shear – to the advantage of durability – while above the working loads rather complex crack patterns formed in the D zones close to the corbels, particularly under the concentrated load, which brought in 3-D effects, with a limited reduction in the bearing capacity.
Refining the reinforcement layout is shown – once more - to markedly improve slab performance, with little or no extra cost.
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