Issue 78

S. A. Mustafa et alii, Fracture and Structural Integrity, 78 (2026) 298-314; DOI: 10.3221/IGF-ESIS.78.18

behavior is indicative of bond-slip controlled response, in which the implanted bars were unable to develop sufficient anchorage to sustain tensile forces, resulting in reduced strength and unstable hysteretic behavior. Specimens (S.W.I 2) and (S.W.I 3) (with a 15Ø and 20Ø embedment length, respectively) demonstrated a transitional response; while interface cracking was still observed, flexural cracking propagated higher along the wall height and concrete crushing occurred at later stages, indicating a progressive shift toward section-controlled behavior as anchorage length increased.

(a)

(b)

(c)

(d)

(e)

(f)

Figure 15: Shear wall specimens after testing: (a) & (b) C.S.W, (c) S.W.I 1, (d) S.W.I 2, (e) & (f) S.W.I 3

Hysteretic behavior and energy dissipation The hysteretic loops show that the performance of the shear walls depends on the anchorage length. The control wall (C.S.W.) had wide and stable hysteretic loops, which had little pinching, and indicative of a good dissipation of energy and stable cyclic stiffness. On the contrary, rapid stiffness loss was observed in the case of (S.W.I 1), which is the result of successive bond slippage and openings at the wall and foundation interface. Large, stable, and increasingly fuller loops were seen in hysteretic loops of (S.W.I 2 and S.W.I 3), and were associated with less pinching and a greater load retention at large displacements. (S.W.I 3) in particular had an improved cyclic response, that almost replicated the control wall behavior, even with its use of implanted reinforcement. This shows that the undesirable effects of cyclic loading have been minimized with adequate embedment length. To further evaluate the cyclic performance of the tested specimens, cumulative energy dissipation was calculated from the area enclosed by the load-displacement hysteresis loops throughout the loading history. Fig. 16 presents cumulative energy dissipation versus drift ratio relationships for all specimens. The Figure shows that cumulative energy dissipation increased consistently with embedment length. Among the implanted specimens, S.W.I3 exhibited the highest cumulative energy dissipation, reaching approximately 52.6% of the energy dissipation capacity of the control wall, while S.W.I2 and S.W.I1 reached approximately 27.4% and 16.5%, respectively. These results confirm that increasing embedment length enhances cyclic energy absorption and supports the conclusion that S.W.I3 most closely replicated the behavior of the control specimen.

311