PSI - Issue 28

Jamal A. Abdalla et al. / Procedia Structural Integrity 28 (2020) 2342–2349 Author name / Structural Integrity Procedia 00 (2019) 000–000

2344

3

2. Experimental Program 2.1. Test specimen and test matrix

The test specimens are reinforced concrete beams with a total depth of 250 mm, width of 150 mm and a total length of 1840 mm. The beam is simply supported with an effective clear span of 1550 mm, a shear span of 650 mm and an effective depth of the beam is 209 mm as shown in Fig. 1. The shear span to depth ratio (a/d) is around 3.1. The beams were reinforced in flexure with 3Φ16 mm bars in the tension zone located at 209 mm from the top of the beam. In the compression zone, the beams are reinforced with 2Φ10 mm bars. All beams are internally reinforced against shear using Φ8 mm stirrups at 50 mm on center in one half of the beam only while the remaining half has no shear reinforcement as shown in Fig. 1. Two beams are used as control beams - one with no EBR (CO) and the other with two sided externally bonded CFRP sheets used as shear reinforcement on plain surface (S-EBR). Three beams were strengthened with CFRP sheets on two sides using bore-epoxy method. Three types of bores are used in anchoring the sheets – narrow bores (SBN) with 15 mm diameter, medium bores (SBM) with 25 mm diameters and large bores (SBL) with 35 mm diameter. The CFRP sheets width is 50 mm and they were spaced at 104.2 mm in the shear deficient side only. Table 1 shows the test matrix of one unstrengthened beam and four strengthened beams one with EBR (S EBR) only and three with EBR on bore-epoxy (SBN, SBM, SBL).

2#10

2#10

650.0

250

650.0

NO.8@50

NO.8@50

3#16

3#16

1550.0 1840.0

Fig. 1: Specimen and loading detailing

Table 1. Test matrix. Specimen

Method

bore diameter (mm)

FRP Width (mm)

FRP Spacing

Wrapping Method

CO

--

--

--

--

--

S-EBR

EBR

--- 15 25 35

50 50 50 50

125.0 125.0 125.0 125.0

Two-sided Two-sided Two-sided Two-sided

SBN SBM SBL

Boring Boring Boring

2.2. Materials Concrete : Three concrete cubes were tested after 28 days and the average compressive strength of them is 37.2 MPa. Steel bars: Three specimens of the steel bars have been tested and their average yield strength and modulus of elasticity are 590.4 MPa and 199.9 MPa, respectively. CFRP materials: CFRP plates have thickness of 1.4 mm, modulus of elasticity of 170 GPa and Ultimate tensile strength of 3100 MPa based on the manufacturer technical worksheet sheet (MAPEI 2017). Epoxy adhesive: Adesilex PG2 with modulus of elasticity of 6.0 MPa is the epoxy adhesive used in this study based on the manufacturer technical worksheet sheet (MAPEI 2017).