Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Load Testing

[Subject Prev][Subject Next][Thread Prev][Thread Next]
I have done several full scale load tests on existing structures.  

I've found that people (technical and non-technical) often make
different assumptions re what the test will mean, so it is EXTREMELY
important to define the consequences of every possible test result. 
It's a lot easier to do that in advance for 20 different scenarios than
it is to do afterwards for one.

Load magnitudes depend on why the test is being performed.  My
speciality is steel, so I'm used to a design factor of safety of 1.67 to
1.93.  However, when evaluating an existing structure I like to use
actual dead loads plus 1.7 times live, which usually comes out to around
1.5.  If I can define the anticipated live loads better then I'll reduce
the 1.7 factor.  Again, it depends why you're doing the test.

The only industry standard I'm aware of is The Steel Joist Institute,
which uses 1.5 times total design load.

When doing your test be very careful to ensure the safety of your test
personel.  Assume the unexpected will happen, such as sudden and total
collapse.  Watch the effects of large deformations on the structure,
adjacent structures, and the test itself.  I always like to design the
test such that the loads relieve themselves instantly and automatically
when deformations exceed some given value.

Good luck.

Philip T. Hodge, PE  (no relation that I'm aware of!)

W. Gray Hodge wrote:
> I am working on the renovation of an existing structure and the Owner
> has expressed an interest in performing a load test to verify the load
> carrying capacity for a portion of the structure.  My question is this:
> Is there an ASTM or other industry standard which defines how such a
> test should be performed?  Does anyone else have experience in load
> testing - are there any "do's" or "don'ts"?
> Thanks for your help.