Patent ID: 7716890

Claim:
Apparatus for use in a system for transferring loads between a first concrete on-ground cast-in-place slab and a second concrete on-ground cast-in-place slab, the system comprising the first and second slabs and a joint interposing the first and second slabs, at least the first slab having a substantially planar upper surface, at least a portion of the joint being initially defined by at least one of a crack, cut or a form oriented substantially perpendicular to the substantially planar upper surface of the first slab, wherein a longitudinal axis of the joint is formed by an intersection of the crack, cut or form and the upper surface of the first slab and wherein the joint is subject to opening through a variety of joint opening dimensions; the apparatus comprising: a first tapered load plate and a second tapered load plate that each have a taper, protrude in use into the first and second slabs and have an extent in use across the joint such that the load plates span the joint and transfer between the first and second slabs a load applied to either of the slabs directed substantially perpendicular to the upper surface of the first slab; the tapered load plates each having a width in use measured parallel to the longitudinal axis of the joint; the width of each tapered load plate generally tapering from a relatively wide location in the extent of each plate across the joint to a relatively narrow portion; whereby in use, as the joint opens, a tapered gap opens between the load plate and the slab near the narrow portion such that the slabs are allowed increasingly greater relative movement in the direction substantially parallel to the longitudinal axis of the joint; and whereby in use the first and second tapered load plates are oriented such that as the joint opens, reduced width of one load plate at the narrowest width in the joint of the one load plate due to plate taper is compensated for by increased width of the other load plate in the joint due to opposing plate taper, such that as the joint opens, the combined widths of the first and second tapered load plates in the joint is substantially consistent for substantially consistent load transfer across the joint; and whereby in use the tapered load plates restrict relative movement between the first and second slabs in a direction substantially perpendicular to the upper surface of the first slab, allow the joint to open by allowing the first and second slabs to move away from each other in a direction substantially perpendicular to the joint, allow for increasingly greater relative movement in a direction substantially parallel to the longitudinal axis of the joint as the joint opens, and maintain substantially consistent load transfer across the joint.