PSI - Issue 70

Saravanakumar P. et al. / Procedia Structural Integrity 70 (2025) 533–539

535

150mm were also cast to ensure the compressive strength of the concrete mix. All the beams and cube specimens were kept for 28 days curing before testing. After curing, the beams were placed in the universal testing machine with an edge clearance of 100mm on both sides and an effective length of 1 m. The simply supported conditions were applied for testing. First type of the beams was the conventional one with vertical stirrups of 8mm ∅ at 112mm c/c and the second type was with single link stirrups of 8mm ∅ at 125mm c/c on either side of the beam where the top and bottom cord was eliminated. The third series of beam was with inclined single link stirrups with alternate inclination on either side at 45° with 8mm ∅ bars at 210mm c/c. And the fourth series was alternate X with vertical stirrups of 8mm ∅ bars at 112.5mm c/c. Table 2. Reinforcement details of beams

Specimen

Tension Reinforcement

Compression Reinforcement ShearReinforcement

10mm ∅ 10mm ∅ 10mm ∅ 10mm ∅

10mm ∅ 10mm ∅ 10mm ∅ 10mm ∅

8mm ∅ 8mm ∅ 8mm ∅ 8mm ∅

Control beam

Single-Legged stirrup Inclined stirrup beam Alternate X stirrup beam

5. Test Procedure

All the reinforced concrete beams were tested with a universal testing machine under two-point loading condition using a 1000 kN capacity loading frame, controlled by a hydraulic motor as shown in Fig.1. Two-point transverse loading was applied at one third of the span and the beam was placed over the universal testing machine in a simply supported condition. This was achieved by placing two rollers below the I-sectioned beam, which distributed the total load symmetrically to two points on the beam. Before placing the beam over universal testing machine, the beam was coated with white cement and was let to dry. Then the grid lines were marked at a spacing of 5cm interval for the purpose of crack study. To measure deflection (flexural response) during loading, Linear Variable Differential Transformers (LVDTs) were positioned at the mid-span and at the quarter-span of the beam. The ultimate load-carrying capacity was recorded as the maximum load the beam sustained before failure or significant deformation.

Fig. 1. Two-point Loading Frame