Effect of Cement Matrix’s Type on the Shear Performance of Lightly Reinforced Squat Shear Walls Subjected to Cyclic Loading

This study was conducted to experimentally investigate the shear behavior of non-ductile squat shear walls with different cement matrixes such as normal concrete, fiber-reinforced concrete(FRC), and strain-hardening cement composite(SHCC). The cement matrix type’s effect in the lightly reinforced squat shear wall was evaluated through the testing of three one-third scale walls with a height-to-length ratio (hw/lw) of 0.55 under top displacement reversals. Experimental results show that the cement matrix type in the non-seismically detailed squat shear walls has a significant effect on the shear behavior and failure mode. Compared to reinforced FRC and SHCC shear walls, reinforced concrete wall exhibited brittle behavior. Reinforcing fibers in the FRC and SHCC mitigated the crack damage of wall and increase the shear strength.

High-Performance Steel Bars and Fibers as Concrete Reinforcement for Seismic-Resistant Frames

Experimental data are presented for six concrete specimens subjected to displacement reversals. Two specimens were reinforced longitudinally with steel bars Grade 410 (60 ksi), two with Grade 670 (97 ksi), and two with Grade 830 (120 ksi). Other experimental variables included axial load (0 or 0.2fc′ Ag) and volume fraction of hooked steel fibers (0 or 1.5%). All transverse reinforcement was Grade 410, and the nominal concrete compressive strength was 41 MPa (6 ksi). The loading protocol consisted of repeated cycles of increasing lateral displacement reversals (up to 5% drift) followed by a monotonic lateral push to failure. The test data indicate that replacing conventional Grade-410 longitudinal reinforcement with reduced amounts of Grade-670 or Grade-830 steel bars did not cause a decrease in usable deformation capacity nor a decrease in flexural strength. The evidence presented shows that the use of advanced high-strength steel as longitudinal reinforcement in frame members is a viable option for earthquake-resistant construction.