Concrete Wall Expansion Joint Spacing

Joints are most effective when the aspect ratio of the slab is kept to 1 1 for example 5m x 5m if the slab is a narrower than it is long it is possible to increase this to a maximum aspect ratio of 1 5 for example 2m x 3m don t leave the placing of concrete expansion joints to chance and enlist the services of a structural engineer if.

Concrete wall expansion joint spacing.

Adjacent to corners of walls or intersections within a distance equal to half the control joint spacing. Plan out your control joint spacing 24 36 times the depth of your concrete slab. Table 1 2 expansion joint spacings. There is a special check to be done at the construction joints when larger retaining walls or structures having very high lateral loads are designed.

Expansion joints should be located at intervals up to 90 feet. Greased steel dowels are often cast horizontally into the wall to tie adjacent sections together. Consideration must also be given to the effect of control joint placement on load distribution within the wall. The pre planned cracks will provide a better finish concrete product and will be formed in specific locations where those cracks could be monitored.

Concrete joints are normally used to prevent cracks when the concrete shrinks by creating forming tooling sawing and placing joint formers. Joint spacing varies with amount and grade of shrink age and temperature reinforcement. For example locating control joints at the ends of lintels may compromise arching action. 2 wall height spacing 8 feet or less 3 times wall height.

Concrete joints are used to compensate when concrete expands or shrinks with changes in temperature. Author spacing lewerenz 1907 75 ft 23 m for walls. 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. These joints may be filled with flexible joint fillers.

Control joints are not intended to stop cracking but rather control cracking. Joint spacing in feet contraction joints may be tooled into the concrete surface at the time of placement. Hunter 1953 80 ft 25 m for walls and insulated roofs 30 to 40 ft 9 to 12 m for. Recommended spacing of vertical contraction joints modified from ref.

Joint spacing that is greater than 15 feet require the use of load transfer devices dowels or diamond plates. Use projecting strips to reduce wall thickness by at least one fourth ref. The hight shear force is applied at the horizontal construction joints located at the lower level. Vertical expansion joints are incorporated into the wall to account for expansion due to temperature changes.

Aci 224r 92 one to three times the height of the wall in solid walls. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness.