New Slenderness Limitations for Shear Strength Estimation of Reinforced Concrete Walls

This article suggests a new practical method to estimate the nominal shear strength of reinforced concrete (RC) walls. This method identifies whether a specific RC wall is short, slender, or intermediate in height. The aspect ratio (height/length) is a dominant parameter in defining the slenderness of RC walls by many provisions such as the Federal Emergency Management Agency, FEMA 356, in which the aspect ratio of short walls $\le 1.5$, slender walls $\ge 3$, and intermediate walls valued between 1.5 and 3. In this paper, different aspect ratio limits are proposed to determine the slenderness of RC walls, with short walls being $\le 0.5$, slender walls $>1.5$, while intermediate walls are valued in between 0.5 and 1.5. Based on this categorization, the nominal shear strength of short walls is estimated at 75% of the shear capacity calculated based on the American Concrete Institute, ACI 318-14M, for ordinary walls. The shear at nominal flexural strength is considered the nominal shear strength of slender walls. For intermediate walls, a new method is suggested to determine whether shear capacity or shear at nominal flexural strength affects and influences nominal shear strength estimation. To validate this method, the nominal shear strength is estimated as proposed herein for 147 wall specimens experimentally tested by other researchers. The nominal shear strength of these tested walls is calculated based on FEMA 356 provisions and then compared to the results of the proposed method. It is concluded that the proposed method is optimal in estimating the experimental shear strength as compared to FEMA 356.