Burke Lockable Dowel
The use of Burke Lockable Dowels can save a significant amount of time and materials over other construction methods. Concrete shrinkage has traditionally been accommodated by leaving gaps in the slab called “pour strips” or “closure strips.” These strips are filled once movement has stabilized, however until they are filled the slabs must be shored, restricting site access and delaying site progress. Gaps in the slab also create a hazard for site workers, use additional formwork and leave the soffit face marked.
Lockable Dowels improve site access, minimize formwork requirements and accelerate the rate of construction. With a Lockable Dowel, there is less requirement for the slabs to be shored or a support corbel to be constructed, as shear load is transferred by the dowel. The time saved by early removal of slab props can be significant.
A Lockable Dowel also provides many advantages over the site-assembled arrangement of carbon steel reinforcing bar, galvanized or plastic ducting, vent tubes and a non-specific grout, which is sometimes used by contractors.
In addition, engineers have found the Burke Lockable Dowel to be the preferred design solution for pin-ended joints. Although it is customary for practical reasons to use U-bars or other rebar continuity systems at these connections, these options do not truly act as hinges and so rotation of the slab under load can induce cracking at the wall-to-slab interface with potential integrity issues.
The Lockable Dowel is closer to a true pin-ended joint and, being manufactured from stainless steel, provides additional corrosion protection over systems using carbon steel reinforcement.