Abstract
In design, the sectional depth of reinforced concrete spread footings is usually governed by design code provisions for punching shear, which are derived primarily from experiments on slab-column connections. Previous experiments have shown that the punching behavior of concentrically loaded spread footings differs from that of slab-column connections. This paper describes punching of a concentrically loaded spread footing by combining conventional strut and tie modeling with the concept of an arch strip, part of the Strip Model. By itself, the Strip Model describes the behavior of slab-column connections under a variety of loading conditions. For spread footings, Strip Model concepts need to be combined with conventional strut and tie modeling to adequately describe load transfer in a concentrically loaded spread footing. Two methods are explored, each producing closed-form expressions for the footing capacity that agree well with experimental results (112 tests from the literature). The analyses make it possible to estimate the fraction of footing load that is carried by conventional strut and tie behavior. The experimental results are also compared to punching shear capacities in accordance with ACI 318-19. The Strip Model produces results with roughly the same average test-to-predicted ratio (in the order of 1.3) as ACI 318-19 but with a lower coefficient of variation (10.3% compared to 15.8%). This work shows how a lower-bound plasticity-based model can be used for the practical case of determining the capacity of reinforced concrete spread footings failing in punching shear.
Original language | English |
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Title of host publication | Punching Shear of Concrete Slabs |
Subtitle of host publication | Insights from New Materials, Tests, and Analysis Methods |
Editors | Aikaterini Genikomsou, Trevor Hrynyk, Eva Lantsoght |
Publisher | American Concrete Institute |
Pages | 19-40 |
Number of pages | 22 |
ISBN (Electronic) | 9781641952125 |
DOIs | |
Publication status | Published - 2023 |
Event | Punching Shear of Concrete Slabs: Insights from New Materials, Tests, and Analysis Methods at the ACI Spring Convention 2023 - San Francisco, United States Duration: 2 Apr 2023 → 6 Apr 2023 |
Publication series
Name | American Concrete Institute, ACI Special Publication |
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Volume | SP-357 |
ISSN (Print) | 0193-2527 |
Conference
Conference | Punching Shear of Concrete Slabs: Insights from New Materials, Tests, and Analysis Methods at the ACI Spring Convention 2023 |
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Country/Territory | United States |
City | San Francisco |
Period | 2/04/23 → 6/04/23 |
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-careOtherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Keywords
- arched strut
- punching shear
- reinforced concrete
- spread footings
- Strip Model