Seismic analyses of concrete structures under maximum-considered earthquakes require the use of reduced
stiffness accounting for cracks and degraded materials. Structural walls, different to other flexural dominated components,
are sensitive to both shear and flexural stiffness degradations. Adoption of the gross shear stiffness for walls in seismic
analysis prevails particularly for the design codes in the US. Yet available experimental results indicate that this could
overstate the shear stiffness by more than double, which would hamper the actual predictions of building periods and
shear load distributions among columns and walls. In addition, the deformation capacity could be drastically understated
if the stipulated constant ductility capacity is adopted. This paper reviews the available simplified shear and flexural models,
which stem from classical mechanics, empirical formulations and/or parametric studies, suitable for structural walls at
the state-of-the-art. Reviews on the recommended flexural and shear stiffnesses by prominent design codes such as
ACI318-11, Eurocode 8 and CSA are included. A database comprised of walls subjected to reverse-cyclic loads is formed
to evaluate the performance of each model. It is found that there exist classical models that could outweigh overconservative
codified values with comparable simplicity for practical uses.
Shear and Flexural Stiffnesses of Reinforced Concrete Shear Walls Subjected to Cyclic Loading
