I can't answer your question in its entirety, partially because I do not
what's happening and what you want to achieve.
However, keep in mind that strain at failure, epsilon u, is not
something commonly tabulated.
(Strain at max stress, epsilon m, is much better known.)
Epsilon u can be reasonably estimated for most concrete grades.
I have done that in one of my recent papers.
If this bit of info could be of help, I can email you the text.
Gregory from Oz
Subject: Allowable flexural crack width
This is a multi-part message
have a concrete wall of a subgrade parking structure that is on
soils. The foundation wall also acts as the grade beam
piers. The voids have been compromised and we are in
the process of
restoring the proper void depth. One side of the garage is
like a walkout
basement with large ventilation openings in the wall. At this
grade beam goes from a 10' tall grade beam to a 42" tall grade
Instead of placing piers at each side of the opening, one pier was
the center of the opening. I had previously observed vertical
the bottom corners of the openings. Now that the concrete
slab has been
removed to restore the void spaces, the cracks are clearly
that start at hairline widths at the top and taper to up to
1/8" at the
bottom. Looking at the bottom of the grade beam and the
exterior face of
the grade beam, the crack extends completely through the
grade beam and it
looks to be the same on each side of the wall. So I
checked the grade beam
right at the point where it tapers down to 42" tall
and it doesn't work
according to the details on the existing plans. So
we are going to install
additional piers on each side of the openings.
Now I finally get to my
question, say that the grade beam did work
calculation wise. Obviously the
steel inside has yielded, there is no
concrete crushing damage at the top.
How much crack width is
acceptable? In the event the calculations work,
would it be reasonable
to calculate the strain in the steel and determine
the elongation from
that. Does anyone know of any documents, text books,
etc. that provide
guidance on this? I have done a lot of searching on the
can't seem to find anything