Space joints in feet no more than 2 3 times the slab thickness in inches.
Control joint spacing in concrete walls.
How frequently should control joints be spaced in unreinforced concrete masonry walls.
An engineered method is presented in tek 10 3 control joints for concrete masonry walls alternative engineered method which is based on limiting crack width to 0 02 in.
Control joint spacings are based on the use of horizontal reinforcement having an equivalent area of no less than 0 025 in2 ft of height.
0 51 mm since water repellent coatings can effectively resist water penetration for cracks of this size.
8 ft 5 bars at 144 in.
Control joints are not intended to stop cracking but rather control cracking.
4 recommends a contraction joint spacing of 30 times the wall thickness or 20 feet for an 8 inch thick wall 30 8 240 inches 20 feet.
Saw cutting cuts joints as soon as the concrete is hard enough that the edges abutting the cut don t chip from the saw blade.
The american concrete institute.
Fintel 1974 15 to 20 ft 4 5 to 6 m for walls and slabs on grade.
Cut joints deep enough cut joints 25 of the depth of the slab.
A 4 slab should have joints 8 12 feet apart.
A 4 thick slab should have joints 1 deep.
4 ft 4 bars at 96 in.
Tial basement walls and the national ready mixed concrete association ref.
Gener a l l y closer joint spacings decrease the width of cracks that form at the joint.
By the use of bond beams and.
When no joint reinforcing is used national concrete masonry association ncma tek 53 design of concrete masonry for crack control recommends spacing control joints in straight wall sections without openings no farther apart than twice the height of the wall 40 feet maximum.
Plan out your control joint spacing 24 36 times the depth of your concrete slab.
Recommends joint placement at abrupt changes in plan and at changes in building height to account for poten tial stress concentrations.
3 bars at 48 in.
Founded in 1904 and headquartered in farmington hills michigan usa the american concrete institute is a leading authority and resource worldwide for the development dissemination and adoption of its consensus based standards technical resources educational programs and proven expertise for individuals and organizations involved in concrete design.
It is best to cut joints as early as possible either while finishing with a concrete groover or within 6 18 hours after finishing with a concrete saw.
For example locating control joints at the ends of.
Control joints for concrete masonry walls alternative engineered method which is based on limiting crack width to 0 02 in.
Some designers recommend re ducing joint spacings by about 20 in walls with frequent openings such as doors and windows.
Table 1 1 contraction joint spacings.
How to cut joints groover tools cut joints in fresh concrete.
Distance equal to half the control joint spacing.
Author spacing merrill 1943 20 ft 6 m for walls with frequent openings 25 ft 7 5 m in solid walls.