6 Construction Joints Can be constructed of multiple types of joints: DoweledTiedKeyedButt JointAre spaced and or located to facilitate constructionConcrete quantity limitationSequencing of construction tasks
12 Joint SpacingFunction of concrete thickness, coarse aggregate size and concrete slumpPCA recommends the joint spacing be 2 to 3 times (in feet) the concrete thickness (inches)Example: a 5 inch slab would have joints spaced 10 to 15 feetIt is good practice to maintain a square shape in so much as practical
14 Joint SpacingStructure geometry and other elements such as interior walls, columns and piers may dictate layout.
15 Recommendations for Hydraulic Structures Contraction joints:Should be doweled or tiedSaw cut floorsFormed with chamfer strips for wallsTry to maintain a square shape between jointsMay need waterstop and or joint sealantConstruction joints:Should be doweled or tied and keyedUse chamfer strips for adequate consolidationMay need special attention regarding drainage because of hydraulic loading.
16 ReferencesBureau of Reclamation, “Concrete Manual,” 8th Edition Revised, 1981Ringo & Anderson, “Designing Floor Slabs on Grade,” 1992Spears & Panarese, Concrete Floors on Ground, EB075.2D, Portland Cement Association, Skokie, IL, second edition 1983; revised 1990.Young & Paxson, Undermining of Spillway Chutes, Safety of Dams Conference, Seattle, WA, Fall 2010.