Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : CFRP strips

Strengthening of Ferrocement Beams in Torsion by CFRP Strips

Aseel Sami Al-Obaidy; Kaiss F.Sarsam; Alaa K. Abdul Karim

Engineering and Technology Journal, 2014, Volume 32, Issue 3, Pages 702-719

Torsion is resisted well by closed form reinforcement, due to the circulatory nature of the torsion inducing shear flow stresses in a beam. Therefore, it will be more efficient to have strengthening schemes, which are wrapped in closed form around the cross section. An experimental work was carried out and used superplasticizer with mix 1:1.5 to improve the mechanical properties of mortar. 12 rectangular beams (50x120)mm and 1m length are cast, strengthened and tested under pure torsion. The Variables considered in the test program include: effect number of wire mesh layers ( unit ), this unit consists of two layers of wire mesh with skeletal steel, (2, 3, 4) units and effect spacing of CFRP strips, (100,160,200) mm c/c. Test results are discussed based on torque – rotation behavior and influence of parameters on ultimate torque and failure modes. Generally, using optimum dosage of super plasticizer (1.4 % of weight of cement) gave compressive strength 65.65 MPa. Increasing the number of units from 2 to 4(reinforcement near the surface of beam section) led to increased ultimate torque by (13.44 %) and from 2 to 3(uniformly distributed reinforcement) led to increases the ultimate torque by only (3.24 %). When the beams are strengthened with CFRP strips, the lowest and highest increase in torque is at 112 % (4-units,@200 spacing) and 312 % (4-units,@100 spacing), respectively. The ultimate torque of beams with CFRP strips @ 100 mm and 160 mm spacing is greater than beams with CFRP strips @ 200 mm spacing by ( 94.34,45.28) %, respectively for the group having 4-units.

Nonlinear Behavior of Steel-Concrete Composite Beams Curved in Plane with CFRP Strips Bonding

Ahmed F. Kadhum

Engineering and Technology Journal, 2010, Volume 28, Issue 12, Pages 2308-2324

This paper deals with the behavior of structural steel-concrete composite beams
curved in plane. The analytical investigation included the use of three dimensional
nonlinear finite elements to model the performance of the composite beams
strengthened with CFRP strips by using (ANSYS 11.0) computer program. The
numerical results showed very good agreement with the experimental results reach
to 100% before the strengthening, while the increase in strength after the curved
strengthened with CFRP strips 32% for the curve beam with L/R equal to 0.05 and
48% for the curve beam with L/R equal to 0.10 and 53% for the curve beam with
L/R equal to 0.25.