Experimental Evaluation of Repairing Techniques for Holes Made in Reinforced Concrete Columns for Core Tests

Main Article Content



This paper presents the experimental and theoretical studies of reinforced concrete short columns drilled laterally with a hollow of a 50 mm in diameter. As known, the purpose of the core test is to evaluate the strength of the existing concrete. Seven square reinforced concrete columns of 150 mm x 150 mm cross-sectional area with 520 mm height were cast and tested. The specimens were reinforced with 8-Ø10 mm having yield strength of 570MPa and concrete compressive strength of 31.0MPa. Five different strengthening techniques were adopted to drilled columns. The results indicated that the combination method of strengthening like filling the drilled hole with cement base grout and wrapping it with CFRP sheets lead to an increase in load carrying capacity up to 19.5% and 50.5% relative to solid and drilled columns, respectively. While strengthening with steel pipe and wrapping by CFRP sheets enhanced the load capacity by 13.6% and 43.0%, respectively when compared to solid and drilled column specimens. Briefly, the strengthening process of the drilled column can lead to load carrying capacity even more than that of the solid column. The modified ACI Code equations gave conservative results (PExp./PTheor  ≥ 1.0) for tested strengthened specimens of this study, and they showed good agreement when applied to the available drilled columns from literature.
Abstract 143 | PDF Downloads 28


Lei, Z. ; Qingfeng, X.; Xiangmin, L. and Chunming, Z.
(2010)`` Experimental Studies of reinforced Concrete
Columns Capacity Affected by Core Drilling``
Scientific.Net Materials Science and Engineering
Vol.133-134, pp.1195-1200. Neville, A.M. and
Brooks, J.J.(2008) ` Concrete Technology`` Pearson
Prentice Hall. 438p.
Al-Saloum, Y.A. (2007)`` Influence of Edge Sharpness
on the Strength of Square Concrete Columns
Confined with FRP Composite materials`` Composite
Part: B Engineering Vol.38, pp.640-650.
Chastie,C. and Silva, M.A.G. (2010) ``Monotonic Axial
Behavior and Modelling of Reinforced Concrete
circular Columns Confined with CFRP`` Engineering
Structures, Vol.32, pp.2268-2277.
Pham, T.M.; Lei, X. and Hadi, M.N. (2013) ``Effect of
Eccentric Load on Retrofitted Reinforced Concrete
Columns Confined with FRP`` 22nd Australian

Conference in the Mechanics of Structures and
Materials, (ACMSM22) pp.139-144.
Son, K.S.; Pillakoutas, K., and Neocleous,K. (2006) ``
Behavior of Concrete Columns with drilled Holes ``
The magazine of Concrete Research, Vol.58, No.7,
Masi, A., Nigro, D. and Vona, M. (2012) `` Effect of
Core Drilling And Subsequent Restoration on RC
Column Strength``15 WCEE Conference LISBOA
ACI 440.2R-08 (2008) `` Guide for the Design and
Construction of Externally Bonded FRP Systems for
Strengthening Concrete Structures ``ACI Committee
440 report, American Concrete Institute, USA.
Compione, G. Cucchiara, C. and Minafo, G. (2015) ”
Effects of Circular Openings on the Compressive
Behavior of R.C. Columns” Materials and
Structures Cross Marks, Vol.48, pp.1995-2008.