Document Type : Research Paper
Authors
Civil Engineering Department, University of Technology - Iraq
Abstract
This paper investigates experimentally the torsional behaviour of hybrid reinforced concrete beams composed of reactive powder concrete (RPC) at the outer edges of the cross-section and conventional concrete (CC) at the inner parts of the cross-section. Hybrid reinforced concrete members are used extensively to deal with the members strength requirements related to flexural, shear and torsion in structural systems. The torsion failure is undesirable because of its brittle nature, it is obligatory to avoid this kind of failure in the earthquake areas. Seven reinforced concrete beams, with dimensions (100X200X1500 mm), the interior dimensions of hybrid beams of the cross-sectional area (20mm width and 120mm height) with 1500 mm length were cast and tested to failure using two opposite cantilevers steel arms that contribute to transferring the torque to the centre of the beam. The first beam was RPC, the second beam was CC and the other five beams were all poured as hybrid ones. Experimental data of the ultimate capacity, cracking torsional loads, the failure pattern and twisting angle for each beam were gained. Experimental results showed higher value of ultimate torsional strength of hybrid beams than CC ones by about (50) % and lower than reactive powder concrete specimen by about (16.67) % for both varying steel fibre and spacing of stirrups.
Keywords
Main Subjects
reinforced Concrete Box Girders Composed of
Conventional Concrete and Modified Reactive Powder
Concrete,” MSc. Thesis, Civil Eng. Dept., Univ. of ALMustansiryah, Iraq, 2017.
[2] J.R. Hillman, “Hybrid - Composite Beam (HCB)
Design and Maintenance Manual,” The Missouri
Department of transportation. 27 Aug. 2012.
[3] S. M. AL-Zuabidi, “Strengthening of RPC Beams
with External CFR in Torsion,” MSc. Thesis, Civil Eng.
Dept., Univ. of Technology, Iraq, 2016.
[4] ACI Committee 318, “Building code requirements for
structural concrete (ACI318M) and commentary
(ACI318RM),” American Concrete Institute, Michigan,
USA, 2014.
[5] ASTM C 39/C39M-14, „„Standard Test Method for
Compressive Strength of Cylindrical Concrete
Specimens,‟‟ ASTM International, 100Barr Harbor Drive,
west Conshohocken, United States, 2014.
[6] ASTM C496/C496M-11, „„Standard Test Method for
Splitting Tensile Strength of Cylindrical Concrete
Specimens,‟‟ ASTM International, 100Barr Harbor Drive,
west Conshohocken, United States, 2011.
[7] ASTM C 469/C469M-14, „„Standard Test Method for
Static Modulus of Elasticity and Poisson's Ratio of
Concrete in Compression,‟‟ ASTM International, 100Barr
Harbor Drive, west Conshohocken, United States, 2014.
[8] Hebei Yusen Metal Wire Mesh Co., LTd., (2018),
Steel fibre quality certificate, available: http://www.chinasteelfiber.com.cn.
[9] R.S. Attea, “Torsional behaviour of reinforced
concrete T-beams strengthened with CFRP strips,” Case
Studies in Construction Material, Vol. 7, pp 110-127, 2017.
[10] BS 8110 Code, “Structural Use of Concrete-Part 2,”
British standards, Institution, London, 1997.
)
