How far apart should construction joints be in concrete?

The following recommended tips should be observed: Maximum Joint Spacing should be 24 to 36 times the thickness of the slab. Joints should be spaced about 10 feet and a maximum of 15 feet. When using joint groove for contraction joints, the joint should be a minimum depth of ¼ thickness of the slab.

Where are construction joints in concrete?

Construction joints – are surfaces where two successive placements of concrete meet. They are typically placed at the end of a day’s work but may be required when concrete placement is stopped for longer than the initial setting time of concrete. In slabs they may be designed to permit movement and/or to transfer load.

Where should rebar be placed in concrete slab?

Therefore, for a typical 100 mm residential concrete slab, the rebar should be placed at a depth of approximately two thirds the slab thickness from its surface. Placing the rebar at the bottom of the slab will provide no benefit to the concrete.

How does rebar work in a concrete wall?

The concrete structure is designed to act as a single unit, though parts of it are poured separately, resulting in a construction joint. The rebar has to carry through the joint for continuous resistance to stresses. It splices with the rebar on the other side, overlapping for a specified distance.

Is it necessary to splice rebar at construction joints?

No. It is not necessary. However, in vertical elements like columns and shear walls, reinforcing is spliced above floor levels / construction joints. RE: Rebar Splices at Construction Joints JAE(Structural)4 Feb 12 16:08

How are concrete construction joints supposed to work?

After the concrete dried, each slab shrinking away from each other opened the construction joint enough so the keywayed edge proved not to be very effective and more prone to fail. For dowels to be effective they must be aligned properly. Dowels must be perpendicular to the joint both horizontally and vertically or joint deterioration can occur.

How big of a spacing do you need for rebar?

Horizontal spacing for #4 rebar is a minimum 2 feet, within 12 inches of the top and bottom of the wall. The concrete structure is designed to act as a single unit, though parts of it are poured separately, resulting in a construction joint. The rebar has to carry through the joint for continuous resistance to stresses.