History of Live Loads

[abusementpark]

Has anyone ever come across an article or publication which documents the history of live loads in prominent building codes throughout the past century?

Seems like this could be valuable information for renovation projects when you are trying to determine for which load the structure should have been designed.

 

[larsacious]

One good resource I found was the early editions of AISC manual. Near the back of the manual they give recommended design live load values. Whether the designer used those values is another question but at least it is a starting point.

 

[ishvaaag]

From

Forensic Structural Engineering Handbook
Robert T. Ratay, Ph.D., P.E., Editor-in-Chief
McGraw Hill

Has a section 2.1 on codes and standards in the US. Even if you may not find there directly the values, you will find guide to the original documents to then trace them. As a example, I quote...

"A report of the Department of Commerce Building Code Committee, entitled “Minimum Live Loads Allowable for Use in Design of Buildings,” was published by the National Bureau of Standards in 1924. The recommendations contained in that document were widely used in revision of local building codes.

These recommendations, based upon the engineering data available at that time, represented the collective experience and judgment of the committee members responsible for drafting this document. The ASA Committee on Building Code Requirements for Minimum Design Loads in Buildings subsequently issued a report in 1945 that represented a continuation of work in this field. This committee took into consideration the work of the previous committee, and expanded on it to reflect current knowledge and experience.

The end result was the American Standard Building Code Requirements for Minimum Design Loads in Buildings and Other Structures, A58.1-1945.8 The A58.1 standard has been revised five times since 1945, the latest revision9 corresponding to ASCE 7-95, Minimum Design Loads for Buildings and Other Structures.* Subsequent to the 1982 edition of ANSI A58.1, the American National Standards Institute (ANSI) and the ASCE Board of Direction approved ASCE rules for the standards committee to govern the writing and maintenance of the ANSI A58.1 standard. The current document prescribes load combinations, dead loads, live loads, soil and hydrostatic pressures, wind loads, snow loads, rain loads, and earthquake loads. Like earlier editions of the ANSI standard, ASCE 7 has significantly influenced the development and revision of other building codes."

More in the book.

 

[Ron]

Good info, Ishvaaag....there's a later edition than the one you referenced.

ABP...Good thread. Something that all of us in the forensic world struggle with almost daily.

Two older government agencies in the US, the Bureau of Mines and the Bureau of Reclamation, had early published documents that were commonly followed by engineers, in the absence of specific code requirements.

Regional and national model codes came much later. Most codes early on were local.

One other consideration you have to make is the applicability of a particular version of the code for the area. Keep in mind that a model code has no validity until adopted by ordinance or statute. Further, many jurisdictions were routinely behind in their adoption of a particular code. For instance, assume the design was done in 1977 in the southeastern US. One would logically assume that the last edition of the Standard Building Code (at that time, called, the Southern Standard Building Code)would prevail. Not so. The local group might have last adopted by ordinance, a code from the 60's.

To further complicate the issue, particularly around code edition change times, is that the date of application for a permit is the selector of the code edition to be followed. So if construction was done in 1998, one might assume the 1997 version of the Standard Building Code might be used. Well, if the date of application pre-dates the adoption of the code or the issuance of the code, the previous edition is the one that would be used.

Ain't life fun in this business??!!

 

[frogit22]

Donald Friedman's book "historical building construction" lists some historical design live loads in appendix G.

 

[abusementpark]

Thanks for the responses, guys. It appears this is yet another one of the uncertainties that we will continue deal with in renovation projects.

Maybe 100 years from now, engineers will have electronic copies of plans and specs to review on their renovations jobs.

 

[WillisV]

More likely 100 years from now nobody will have a clue what the plans looked like because they were done in BIM on a software version that hasn't been around in 95 years and is stored on a type of media that no computer can read anymore...

 

[hokie66]

Agree with Willis. We can often find drawings of buildings from the 1920's, but sometimes not from the 1980's.