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Re: Acceptable Level of Overstress

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I do not know if codes say anything about the acceptable level of overstressing; and would be surprised if they do.

To tell you my experience working with my previous bosses, they were very much comfortable with 10% overstressing on existing sawn lumber.   I was even told to assume Doug Fir #1 citing better quality wood during the good ol' days. But I am not sure this reasoning applies to the GLUE-laminated lumber.

Good luck with the plan check.

Suresh Acharya, S.E.

Gerard Madden, SE wrote:

I guess what I am saying is I am not concerned about a 6% overstress, but the plan checker is. I didn’t realize it was written in stone somewhere about the level of overstress. I know the 5% rule is there for DSA projects.


Thanks again,



-----Original Message-----
From: Suresh Acharya [mailto:struct(--nospam--at)]
Sent: Thursday, December 04, 2003 1:48 PM
To: seaint(--nospam--at)
Subject: Re: Acceptable Level of Overstress


 I  would not worry about slight overstressing if:
    -it is a roof  beam and the tributrary area is substantial.
    -it is continuous beam and the controlling mode is flexure because there a chance of redistribution of moments. /*The beam would not know whether you used ASD or LRFD method!! */

Suresh Acharya, SE

Gerard Madden, SE wrote:

What is the general practice on acceptable level of overstress when checking an existing member for capacity?


I have an existing wood beam that is 6% overstressed with new loads. I am prepared to deem that “Acceptable”. I was always taught that 10% or less overstressed is okay. I have a plan checker wanting to cut the limit at 5%. Is this somewhere in the code???





Gerard Madden, SE, PE

California Licensed Structural and Civil Engineer


Madden Engineering

2183 Eaton Drive

Lodi, CA 95242

T: 209.368.9955

F: 209.368.9966

E: gmadden(--nospam--at)