Issue 78

D. D. Joshi et alii, Fracture and Structural Integrity, 78 (2026) 315-345; DOI: 10.3221/IGF-ESIS.78-19

Experimental and analytical

slab sub structure (two bays × one way) Beam column assembly (Two bays frame) Beam column assembly (Two bays frame) Beam column assembly (Two bays frame) Beam column assembly (Two bays frame)

Middle column from perimeter One-half scale Middle column One-half scale Middle column Full scale Middle column One-half scale Middle column

locally around the beam column-slab interface. At the bottom surface, strips were applied continuously across the entire slab length CFRP sheets applied on the side faces of beam, anchored with carbon and steel hybrid reinforced polymer anchors

Pan et al. [49] Experimental and analytical

Wet connection - cast-in-place concrete at beam top and columns

CFRP sheets and hybrid fibre reinforced

Displacement controlled vertical load (0.25 to 2 mm/minute) Displacement controlled vertical load (0.25 to 2 mm/minute) Monotonic vertical displacement

polymer anchors

Pan et al. [51] Experimental analytical

Wet connection - cast-in-place concrete at beam top and columns

Carbon fiber ropes (CFR)

Implanting CFR into concrete with polymer and binding CFR with special knots

Zhang et al. [52] Numerical

Wet connection - embedding beam top rebar within column gap at joints Mechanical connections at beam column joints - Beam seated on column corbel through neoprene pad and connected using dowel bar

Hybrid - Bolted steel plates with CFRP strips

Bolted steel plates with CFRP strips at top and bottom for entire two-bay beam, Bolted steel plates with fully wrapped transverse CFRP strips 4 nos. of U-shaped NSM steel rebars covered with one horizontal and one vertical layer of CFRP sheet around beam-column joint Parametric study through numerical analysis - effect of end anchorage, no. of CFRP layers, diameter of NSM rebars

Elsanadedy et al. [53] Experimental and numerical

Hybrid - near surface mounted steel rebars along with CFRP sheets

Vertical dynamic / cyclic load 100 mm/s Half cyclic

Table 4: Important parameters of strengthening studies on precast specimens.

Author / Main performance indicators Al-Salloum et al. [45] Load-displacement behaviour, hysteresis response, failure modes, strain measurement, energy dissipation, displacement ductility

Failure modes

Main Findings

Limitations

• brittle shear failure of strengthened specimen developed outside the strengthened region.

• precast connection considered for the study was vulnerable to progressive collapse due to lack of continuity at beam-column joints and absence of redundancy in the load path. • use of bolted steel plates improved the collapse resistance, with the ultimate load capacity increasing by up to 29 times compared to the control specimen under column removal condition • development of catenary action was inhibited due to discontinuity of beams beyond the exterior columns and the insufficient restraint provided by outer columns.

• absence of axial loads on the exterior columns • discontinuity of beams beyond the exterior columns • exclusion of RC floor slabs from the test specimen • simple linear elastic analysis adopted in the study may not be appropriate for the simulation of the failure involving complex nonlinearity and large displacement.

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