PSI - Issue 78

Alvaro Lopez et al. / Procedia Structural Integrity 78 (2026) 807–814

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5. Test Results 5.1. Visual and measured observations

Before the experimental testing each wall was checked for cracks. In all the tests, except wall W2-SD, the spalling height increased progressively with increasing lateral displacement of the wall. Most of the damage in all the walls occurred at the base of the wall. However, numerous flexural cracks visible under applied loading were observed mostly up to the mid-height of the wall and the formation of flexural cracks continued with increasing levels of displacements for all walls. 5.2. Wall W1-ST Wall W1-ST was tested under the standard three-cycle displacement history Wall W1-ST exhibited moderately ductile behavior. After yielding of the longitudinal reinforcement, the horizontal flexural cracks located near the base of the wall propagated toward the center of the wall specimen. Vertical cracks at the wall base in the position of extreme bars were also visible after yielding, generally at a wall displacement of 19 mm ( ≈4 ), which seems to indicate that vertical reinforcement started to experiment bar buckling due to their large s/db=9 ratio and started to push against the concrete cover. Complete spalling of concrete cover that exposed the reinforcement occurred at the wall boundaries generally at about 30mm wall displacement ( =6 ) for the wall. The primary mode of failure for the wallwas bar buckling followed by bar fracture at both wall’s ends (Fig. 3a). Additionally, the horizontal reinforcement opened due to the poor detailing with the 90 hooks. The lateral load vs. displacement hysteresis curve (shown in Fig. 3b) for this specimen indicates reasonable ductile behavior and energy dissipation. Specimen W1-ST was able to attain maximum displacement ductility of 12. The peak lateral load was 71.4 kN and occurred at a lateral displacement of approximately -30.4 mm. The specimen exhibited a significant decrease in lateral strength at a displacement level of -60 mm and the applied load dropped below 80% of peak at a displacement of 60.5 mm.

(a)

(b)

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Fig. 2. Horizontal actuator displacement history for (a) Standard protocol, (b) short-duration crustal earthquake and (c) long-duration subduction earthquake