Oct 12, 2007 Question: What should the concrete contractor have done differently to avoid the reentrant corner cracks? Answer: There are a number of ways to reduce the chance that a random crack will develop off a re-entrant corner. Along foundation walls, the most reliable method is to isolate pilasters with a diamond-shaped box-out, such that the point on the diamond is aligned with the proposed. Re-entrant corners. Re-entrant corners are corners that point into a slab. For example, if one were to pour concrete around a square column, he would create four re-entrant corners. Because the concrete cannot shrink around a corner, the stress will cause the concrete to crack from the point of that corner. Jul 01, 2006 The aim of this paper is the evaluation of the strength of structures composed by FGMs incorporating re-entrant corners – tending to the more common crack for vanishing corner angle. The end result is useful in engineering applications predicting the strength of the element corresponding to the unstable brittle crack propagation in such.
Reentrant Corner Definition
![Re Entrant Corner Crack Re Entrant Corner Crack](/uploads/1/1/8/9/118994359/441695825.png)
Re Entrant Corners
Re-entrant corners of cut material…..
Beam copes and weld access holes at 5.17 doesn’t mention a minimum radius. 5.16 states that reentrant corners of cut material must be formed to a radius not less than 1”, but doesn’t mention what this applies to. It’s my understanding that the 1” radius applies to everything that is cut.... (with 'cut' meaning cope cuts), including beams, connection plates, bent plates, angles, channels, tubes… i.e., everything that is coped. But…
Under “copes, blocks, and cuts”, AISC states that all reentrant corners must be shaped notch free to a radius. An appropriate minimum radius to which this corner must be shaped is ½”.
The two codes seem to contradict each other in the way they’re worded. It has always been my practice to cope main members with a ½” radius and to cope secondary members with a 1” radius whenever possible. However when this is not possible/practical in secondary members, they’re coped with a ½” radius.
Regardless, the cope has to be smooth and free of notches. We recently did a job in Wyoming and a third party inspector was in our shop checking cope radius with the back of a key. He would run the back of the key back and forth on the radius, and if it wasn't perfectly smooth, he would reject them. California typically has to follow D1.8, and I thought that was an interesting way to verify that the radius is smooth. I just check them with my uncalibrated finger.
Beam copes and weld access holes at 5.17 doesn’t mention a minimum radius. 5.16 states that reentrant corners of cut material must be formed to a radius not less than 1”, but doesn’t mention what this applies to. It’s my understanding that the 1” radius applies to everything that is cut.... (with 'cut' meaning cope cuts), including beams, connection plates, bent plates, angles, channels, tubes… i.e., everything that is coped. But…
Under “copes, blocks, and cuts”, AISC states that all reentrant corners must be shaped notch free to a radius. An appropriate minimum radius to which this corner must be shaped is ½”.
The two codes seem to contradict each other in the way they’re worded. It has always been my practice to cope main members with a ½” radius and to cope secondary members with a 1” radius whenever possible. However when this is not possible/practical in secondary members, they’re coped with a ½” radius.
Regardless, the cope has to be smooth and free of notches. We recently did a job in Wyoming and a third party inspector was in our shop checking cope radius with the back of a key. He would run the back of the key back and forth on the radius, and if it wasn't perfectly smooth, he would reject them. California typically has to follow D1.8, and I thought that was an interesting way to verify that the radius is smooth. I just check them with my uncalibrated finger.