Evaluation for Punching Shear Strength of Slab-Column Connections with Ultra High Performance Fiber-Reinforced Concrete Overlay

Authors: H. S. Youm, S. G. Hong

Abstract:

This paper presents the test results on 5 slab-column connection specimens with Ultra High Performance Fiber-Reinforced Concrete (UHPFRC) overlay including 1 control specimen to investigate retrofitting effect of UHPFRC overlay on the punching shear capacity. The test parameters were the thickness of the UHPFRC overlay and the amount of steel re-bars in it. All specimens failed in punching shear mode with abrupt failure aspect. The test results showed that by adding a thin layer of UHPFRC over the Reinforced Concrete (RC) substrates, considerable increases in global punching shear resistance up to 82% and structural rigidity were achieved. Furthermore, based on the cracking patterns the composite systems appeared to be governed by two failure modes: 1) diagonal shear failure in RC section and 2) debonding failure at the interface.

Keywords: Punching shear strength, retrofit, slab-column connection, UHPFRC, UHPFRC overlay.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1315725

References:

[1] ACI Committee 318. (2011). Building Code Requirements for Structural Concrete (ACI 318-11) and Commentary (pp. 503). Farmington Hill, MI: American Concrete Institute.
[2] Bastien-Masse, M., and Brühwiler, E. (2016). Experimental investigation on punching resistance of R-UHPFRC-RC composite slabs. Materials and Structures, 49(5), 1573-1590.
[3] British Standards Institution. (2004). Eurocode 2: Design of Concrete Structures – Part 1-1: General Rules and Rules for Building (pp. 225). Bruxelles, Belgium: European Standard EN-1992-1-1: 2004:E, European Committee for Standardization.
[4] Japan Society of Civil Engineers. (2010). Standard Specifications for Concrete Structures-2007 ‘Design’ (pp. 469). Tokyo, Japan: Japan Society of Civil Engineers.
[5] Kinnunen, S., and Nylander, H. (1960). Punching of concrete slabs without shear reinforcement (p.112). Elander
[6] Korea Concrete Institute. (2012). Korean Structural Design Code (KCI 2012) (pp. 342). Seoul, Korea. (in Korean).
[7] Muttoni, A. (2008). Punching shear strength of reinforced concrete slabs without transverse reinforcement. ACI structural Journal, 105(EPFL- ARTICLE-116123), 440-450.
[8] Muttoni, A., and Schwartz, J. (1991). Behavior of beams and punching in slabs without shear reinforcement. In IABSE colloquium (Vol. 62, No. EPFL-CONF-111612, pp. 703-708). IABSE Colloquium.
[9] Noshiravani, T., and Brühwiler, E. (2013). Experimental investigation on reinforced ultra-high performance fiber-reinforced concrete composite beams subjected to combined bending and shear. ACI Structural Journal, 110(2), 251.
[10] Wuest, J (2007) Comportement structural des bétons de fibres ultra performants en traction dans des éléments composes (Doctoral dissertation, Ecole Polytechnique Fédérale de Lausanne). (in French)