assessment of existing stuctures - code variance
assessment of existing stuctures - code variance
(OP)
if your assesing an old structure for a given loading (which may or not be higher than original, you don't know) do you assess to the current code, or the code at time of design or a hydbrid method. Particuraly when the code approach is different i.e. designed to permissible stress but current code is limit state (factored loads).






RE: assessment of existing stuctures - code variance
Living in Australia, seismic codes were non-existant pre-Newcastle Earthquake in 1989. Since then there are more stringent requirements for the lateral design of structures and I have found some designs of older-type structures that I have dealt with to be 'undercooked' if there were to be designed to todays standards.
How do I insert hyperlinks into the main body of my reply??
RE: assessment of existing stuctures - code variance
If your assessment results in remediation, the level of remediation might bring current code into play.
Some areas have codes for existing buildings and those typically interject levels of remediation and to which code those must be done.
RE: assessment of existing stuctures - code variance
1) If I use current code to what material strength do I use as the old codes is permissible stress (i.e. factored to some degree). I don;t know the actual material strengths.
2)If I use old code is there something inherently 'weak' or missing that has been picked up in new codes that the old code wouldn't take into account.
RE: assessment of existing stuctures - code variance
Whether you use ASD or factored design doesn't matter that much as both provide similar safties against probability of failure. If you don't have the original strengths, then it is on you to find them out by sampling, testing, etc.
RE: assessment of existing stuctures - code variance
Mike McCann
MMC Engineering
RE: assessment of existing stuctures - code variance
I don't think anyone has answered your hyperlink question. You simply copy and paste the link as follows:
http://en.wikipedia.org/wiki/Newcastle_earthquake
It appears as ordinary text in your message, but when you Preview Post, it appears in bold, hyperlink text.
BA
RE: assessment of existing stuctures - code variance
If the structure is very old, use 33ksi steel, but you should be able to tell from the shapes, the time frame for it's original design. I assume you do have drawings.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: assessment of existing stuctures - code variance
If you don't know the allowable stress levels or the age of the material, then you'll have to do a little detective work. Assuming you can't get other information, do some testing on the steel. You can remove enough of a specimen to get a tensile strength of the steel without compromising the structure. If you can't or are not allowed to do so, check the hardness of the steel and use correlations. That's not the better of the two approaches, but it will get you in the ballpark. Make sure that whomever does the portable hardness testing knows how to prepare the surface and understands the localized surface conditions of hot rolled steel materials.