Universal Plastic Hinge Length for Reinforced Concrete Walls

When using a plastic hinge analysis, an estimate of the ultimate displacement capacity of reinforced concrete (RC) structural wall buildings is highly dependent on the assumed plastic hinge length. A plastic hinge length equal to 0.5 times the wall length has typically been regarded to provide a safe and lower-bound estimate and has subsequently been used in building codes internationally. Recent numerical and experimental research has shown that the typical design plastic hinge length of 0.5 times the wall length can give an overestimate of the actual length, which would provide false indication of the ultimate displacement capacity of the wall. This research uses a large database of planar and nonplanar experimental and numerical research results with a wide range of design parameters to investigate the plastic hinge length and efficacy of some of the empirical expressions that exist in the literature. A simple expression is derived that can be used by design engineers to calculate a conservative estimate of the plastic hinge length of planar and nonplanar RC walls.