Issue 78

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

Qiu et al. [30] Experimental and analytical Ramin et al. [33] Experimental and numerical

Beam-column assembly (Two bays frame)

One-quarter scale

Steel cable

External steel cables installed beneath each beam span with different diameter of cable

Quasi-static loading (0.5 to 5 mm/minute)

Middle column

Beam-column two storey assembly (Two bays frame)

One-half scale Middle column

Corrugated plate

Corrugated plates integrated into RC joints

Quasi-static loading

Table 2: Important parameters related to strengthening studies on reinforced concrete systems.

Author/ Main performance indicator Bao et al. [11] Load-displacement response, failure modes DIC analysis, ductility, energy dissipation

Failure modes

Main Findings

Limitation

• concrete crushing and spalling at junctions for control specimen • rupture of longitudinal rebars and stirrups • fracture and debonding of BFRP sheets along with rebar rupture for strengthened specimen • specimens exhibited flexural action, compressive arch action and catenary action stage • rebar rupture and concrete crushing in control specimen • rebar rupture and CFRP strip rupture in middle column and end column • slight debonding of the continuous CFRP strip near removed column • debonding of L shape strip • failure at beam ends in unstrengthened frame • failure at beam ends as well as regions around CFRP edges in retrofitted frame • severe diagonal crack formed at the center of the slab for control specimen • The failure of the strengthened specimens was mainly due to debonding of the CFRP laminates and severe cracks concentrated in the cut-off point of the CFRP sheets and strips • all three actions are observed for control specimen • concrete crushing and rebar rupture in control specimen

• BFRP strengthening enhanced the ultimate capacity by 39.31% at catenary action stage. • horizontal pull and ductility coefficient increased by 64.22% and 29.20% respectively. • BFRP strengthening delays the failure and effectively improved performance of corroded specimen • proposed strengthening schemes enhanced the load carrying in CAA and CA phases, with maximum increases of 23.80% and 66.70%, respectively. • the enhanced load resistance at the CA stage was mainly due to the continuous CFRP strips attached to the soffits • proposed CFRP retrofitting restored the frame structure to its original capacity. • “strong-column and weak-beam” mechanism considered during design enhanced the progressive collapse resistance higher effectiveness. 82.0% increase in the dynamic ultimate strength compared to control specimen • diagonally laminates oriented exhibiting CFRP

• discontinuity of beams beyond the end columns • absence of transverse beams and slab effect • limited improvement in capacity at compressive arch action

Liang et al. [12] Load-displacement response, response, displacement profiles, failure modes strain

• debonding of CFRP strip • strengthened CA capacity unable to enhance dynamic collapse resistance due to softening of load resistance

Li et al. [13] Load-displacement response,

• the presence of slab is not considered, which affects the retrofitting process in actual structure

crack

development failure modes

and

Qian and Li [14] Load-displacement response, force-displacement, energy response,

• debonding laminates

of

CFRP

restrict

the

laminate capacity • no use of anchors for CFRP laminates

strain

reaction

absorption,

failure modes

Chen et al. [16] Load-displacement response, horizontal displacement, strain

• strengthening scheme improved the load-bearing capacity by 18.5% and ductility by 3.09 times

• strengthening scheme failed to enter the CA stage

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