Issue 78

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

Figure 14: Degradation of lateral secant stiffness.

D ISCUSSION OF TEST RESULTS

Influence of anchorage length on global lateral capacity he results showed that the embedment length of the implanted reinforcement bars, affected the capacity of the shear walls while all shear wall specimens had the same geometry, material properties, reinforcement layout, and loading protocol, substantial differences in strength and deformation capacity were observed as the anchorage depths varied. The Control shear wall (C.S.W) constructed with fully developed cast in place reinforcement achieved the highest peak lateral load of 236.38 kN, which gave an upper benchmark for performance. In contrast, the shear wall with the shortest embedment length (S.W.I with 10 Ø) developed only 26% of the control wall’s peak strength. This reveals that insufficient anchorage badly affects force transfer between the shear wall and the foundation. Increasing the embedded length of the reinforcement bars led to noticeable improvements, as can be seen in S.W.I 2 (with 15Ø embedded length) and S.W.I 3 (with 20Ø embedded length). Since their peak resistance reached about 44% and 63%, respectively, of the control shear wall. The observed increase in strength with embedment length agrees with previous findings on post installed reinforcement systems, where longer anchorage lengths improve bond stress distribution and force-transfer efficiency. Although the 20Ø specimen exhibited the best performance among the implanted walls, its peak capacity remained approximately 63% of that of the control specimen, indicating that complete development of the reinforcement was not achieved within the investigated embedment range. Therefore, embedment lengths greater than 20Ø would likely be required to approach the full capacity of the control wall; however, identifying the development length necessary for full capacity requires further experimental investigation. The results demonstrated that the global response of shear walls anchored with implanted reinforcement depends not only on the flexural or shear capacity of the wall section, but also on the effectiveness of force transfer at the wall– foundation interface. For insufficient embedment lengths, early bond-related slip and partial separation at the wall– foundation interface limited the development of tensile stresses in the vertical reinforcement, preventing the wall from reaching its full sectional capacity. Cracking patterns and other damage noted during testing illustrate the various structural responses and help them understand the underlying mechanisms, as noted in Fig. 15. The control shear wall showed a flexural dominated failure mode with bends and cracks developing at the base of the wall, vertical reinforcements yielding, and concrete crushing happening at higher drift levels. This response indicates a good concrete wall/foundation interface and active participation of all reinforcements, whereby the wall achieved the full intended sectional capacity collapse. Failure modes and force transfer mechanisms Cracking patterns and post-test damage illustrate the various structural responses as can be seen in Fig. 15, The control shear wall showed a flexural failure mode characterized by the formation of flexural cracks with bends and cracks developing at the base of the wall, in addition to concrete crushing at higher drift levels. This response indicates a good concrete wall-foundation interface and active participation of all reinforcements, whereby the wall achieved the full intended sectional capacity collapse. In contrast, specimen (S.W.I 1) (with a 10Ø embedment length) showed early horizontal cracking at the wall-foundation joint, accompanied by noticeable opening, and sliding at the interface. This T

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