Friday, November 11, 2011

Re: Transfo outrigger platform

        I have two points for you to consider.
        First, if you have tie-off points for workers to anchor their fall protection harness to you will have very high anchor point loads.  I can not tell you what these loads are because your codes are different than ours.
        Secondly, review your insurance policy.  Some policies do not cover the design of temporary structures.  If you are not covered you can probably have this coverage added for very little cost. This is not something you want to do if you are not insured.
        Good luck with the project.
H. Daryl Richardson
----- Original Message -----
Sent: Friday, November 11, 2011 12:06 PM
Subject: Transfo outrigger platform

Hello everyone,
I was asked to design temporary structure to allow the installation of new transformers into existing building.
These transformers will be lifted by crane and placed on the "dolly" to move at their inside locations.
The weight of one transformer is about 8000 lbs + dolly + workers = 10000 lbs.
Because of crane lifting I am taking dynamic coefficient at trafo landing of 1.5.
The other issue is that all steel members need to be transported inside the building by elevators with ceiling at about 10 ft, no ceiling opening.
The platform should have minimum 12 feet length (cantilever).
Because of max. member length of about 10 ft, splices will be at the cantilever part of the structure. I have possibility to add hangers - braces to give additional strength to this platform, being just a little bit scary with all splices outside. Am I over-designing?
This structure will be used at the 5th level and after at 53rd level.
Is there anything else I should take into consideration?
Your help will be greatly appreciated.
John W. Sieszycki, P.E.
ph.: 514-332-9165