Spacing Of Construction Joints In Concrete Walls

An information series from the national authority on concrete masonry technology ncma tek 10 2c 1 control joints for concrete masonry walls empirical method introduction concrete masonry is a popular construction material because its inherent attributes satisfy the diverse needs of both exterior and interior walls.

Spacing of construction joints in concrete walls.

Construction joints must be designed in order to allow displacements between both sides of the slab but at the same time they have to transfer flexural stresses produced in the slab by. Thus for a 10 foot high wall control joints should be. Concrete joints are used to compensate when concrete expands or shrinks with changes in temperature. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness.

Chapter 9 liquid retaining structures p. Residential basement walls usually are placed without con s t r uction joints. For example in the construction of a concrete wall we cannot avoid construction joint just above the base. Joint spacing in feet contraction joints may be tooled into the concrete surface at the time of placement.

Unplanned joints also occur on many jobs when equipment bre a k s down or concrete supply is interru p t ed. 8 2 types of joints in concrete walls 8 3 contraction joints 8 4 isolation or expansion joints 8 5 construction joints. 9 1 introduction 9 2 contraction joints 9 3 isolation or expansion joints 9 4 construction joints. While these attributes are the primary basis for concrete masonry s.

Construction joints use construction joints when the c o n c r ete placement cannot be done at one time. 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. Concrete joints are normally used to prevent cracks when the concrete shrinks by creating forming tooling sawing and placing joint formers. Joint spacing that is greater than 15 feet require the use of load transfer devices dowels or diamond plates.

Providing construction joint in concrete limits the area to be concreted in a one pour. 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. Construction joints are placed in a concrete slab to define the extent of the individual placements generally in conformity with a predetermined joint layout. Joint spacing in meters.

Control joints are not intended to stop cracking but rather control cracking. A complete or monolithic con s t r uction joint. Plan out your control joint spacing 24 36 times the depth of your concrete slab.