Figure 7-20-Location of construction joints in beams, columns, and floor
slabs.
Figure 7-22.-Use of a contraction Joint.
incident to shrinkage of the concrete. A typical dummy
contraction
joint (fig. 7-22) is usually formed by cutting a
depth of one third to one fourth the thickness of the section.
Some contracting joints are made with no filler or
with a thin coat of paraffii or asphalt and/or other materials
to break the bond. Depending on the extent of
local temperature, joints in reinforced concrete slabs may
be placed at 15-to 25-ft intervals in each direction.