Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

RE: Concrete Wall Shrinkage & Construction Joints

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I detail 3 general types of concrete joints:
 
1. Construction joints:  These are intended to act like monolithic concrete once complete, so the joint is bonded and reinforcing steel completely extends thru them.  They only dissipate shrinkage insofar as time is allowed between adjacent concrete placements.  
 
2. Contraction or Control Joints:  These are intended to allow shrinkage to occur and a crack to open at the joint.  The reinforcing steel is either fully interrupted or at least 50% of the steel is interrupted.  A bond breaker is applied to the formed joint surface, and smooth dowels may be provided where reinforcement is fully interrupted and if differential out of plane movement is desired to be controlled.  On one side of the joint, the dowel must be coated to prevent bond. 
 
3. Expansion and Isolation Joints:  These are intended to allow expansion or differential movement as well as shrinkage/contraction.  All reinforcing steel is interrupted but smooth dowels may be provided as noted above.  A gap is formed between adjacent concrete joint surfaces and is filled with a premolded joint filler. 
 
For liquid-containing structures, waterstops and joint sealants are also provided - see ACI 350.4R for examples of joints for such structures.
 
William C. Sherman, PE
(Bill Sherman)
CDM, Denver, CO
Phone: 303-298-1311
Fax: 303-293-8236
email: shermanwc(--nospam--at)cdm.com

From: Rich Lewis [mailto:seaint03(--nospam--at)lewisengineering.com]
Sent: Sunday, August 21, 2005 2:02 PM
To: seaint(--nospam--at)seaint.org
Subject: Concrete Wall Shrinkage & Construction Joints

Does ACI have recommended details for shrinkage and construction joints in walls?  I have a 15” thick basement foundation wall that I want to include some details for.  I have seen some details where the main reinforcing stops and dowels are placed at the joint, both with shrinkage and construction joints.  Is this what most engineers typically detail?

 

Thanks.

 

Rich