PSI - Issue 70

Blessy Grant C J et al. / Procedia Structural Integrity 70 (2025) 247–254

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the free end of the cantilever beam portion and unloaded till it reached zero. In order to measure the displacement during the forward loading cycle and vice versa for reverse loading cycle, the dial gauge is fixed at the bottom of the beam exactly under the loading point. The test has been repeated till the beam reached ultimate load. The load was gradually increased from 0 to 25 kN in the initial cycle. The load cell was kept above the beam at about 0.16m from the free end of the cantilever beam. The dial gauge was placed below the beam so as to capture the displacement. It was then unloaded to zero kN during the forward cycle. The swapping of the position of the dial gauge and the load cell is done in each cycle. And for the reverse loading, the load is applied from the bottom surface from 0 kN to 25 kN. However, in this experimental setup, due to experimental constraints and to ensure precise alignment and load application from each direction independently, separate configurations are used for upward and downward loading. 3. Theoretical analysis of beam A G+4 frame was modelled in STAAD.Pro software, considering the dead load, including the self-weight of the structure, and a floor finish load of 1 kN/m². A live load of 4 kN/m² was applied, in accordance with relevant building standards. The seismic load was defined based on the provisions of IS 1893:2016, ensuring compliance with the seismic design requirements. After performing the analysis, the shear force distribution and bending moment distribution across the structural elements were obtained. Bending Moment Diagram (BMD) of the beam is shown in Fig. 3 and Shear Force Diagram (SFD) is shown in Fig. 4. The STAAD.Pro model provides a global structural response of the G+4 frame, the cantilever beam tests offer localized insights into material and detailing performance under reverse cyclic loading conditions.

Fig. 3. BMD of the beam

Fig. 4. SFD of the beam

Table 1. Geometric details of test specimen Beam

LRC – 45

LRC – 30

RC – 90

Total Length (m) Width (mm) Depth (mm)

1.50 (0.68+0.82)

1.50 (0.68+0.82)

1.50 (0.68+0.82)

300 300

300 300

300 300

Longitudinal reinforcement

5 numbers of 12 mm dia in tension and compression zone each (T and C)

5 numbers of 12 mm dia in tension and compression zone each (T and C)

5 numbers of 12 mm dia in tension and compression zone each (T and C)

Stirrups (mm) Lacing angle

12

12

12

45 degree 16 mm

30 degree 16 mm

Closed stirrups 90 degree

Diameter of cross rod Span of beam (m)

16 mm

0.66

0.66

0.66

Schematic figure of shear reinforcement