Structural walls are widely used as lateral load resisting elements in low- and medium-rise structures located in seismic zones; moreover, they are often considered a primary retrofit remedy for existing structures that do not meet current code requirements. The main focus of the proposed research is to develop a new design for reinforced concrete (RC) structural walls through the use of high-performance fiber reinforced cement composites (HPFRCCs). These materials offer a tensile strain-hardening response, and high compression strain capacity. In this project, an experimental study will be first conducted to understand the shear and flexural behavior of structural walls constructed with HPFRCC materials under displacement reversals. This experimental phase will include the testing of several squat and slender HPFRCC structural walls reinforced with either polyethylene (Spectra) or steel fibers. Emphasis will be placed on studying the effect of variables such as material post-cracking strength and strain capacity, wall aspect ratio, shear stress level and reinforcement detailing on the behavior of HPFRCC structural walls. Analytical studies will be aimed at developing models to predict the shear and flexural behavior of both squat and slender HPFRCC walls under displacement reversals. For this purpose, existing theories developed to predict the response of reinforced concrete members will be modified to account for the superior tension and compression behavior of HPFRCC materials. Simplified models will also be developed to estimate the shear strength vs. displacement relationship and displacement limits corresponding to various performance levels in HPFRCC structural walls. The use of strut-and-tie models, with strength factors developed for struts and ties from material and wall tests, will be explored to predict the shear strength of HPFRCC walls. Finally, provisions for reinforcement detailing requirements will be developed for seismic-resistant HPFRCC walls.
