Strengthening an existing concrete structure through the use of shear dowels is a primary application of post-installed rebar. Though this is commonly done to improve the performance of concrete slabs and structures experiencing earthquake and seismic loads, the application is not limited to geographic areas experiencing these conditions.
Shear dowels are typically used to resist interface shear across a shear plane – the roughened joint between existing and new concrete. The primary shear mechanism – friction across the irregular surface – is enabled by the shear dowels that hold the surfaces together. Therefore, the standard design assumption is that the shear dowels are placed in direct tension as the irregular shear plane is translated laterally.