CEASAR II - Wind Calc - Load Factors

Question

CEASAR II - Wind Calc - Load Factors

smithrj_40 (Structural)

(OP)

10 Jan 18 14:13

I am a structural engineer and not a CEASAR user, therefore I don't know a whole lot about the programs inner workings, but I was talking to a mechanical engineer that is using the program and we were discussing wind loads. When specifying ASCE7-10 as your wind loading criteria in the program I wanted to make sure that the wind load is being factored correctly on the back end for analysis. I didn't see anywhere to specify, check, or modify load combinations. If you are familiar with the changes made to wind load calcs back when ASCE7-10 was released, you will know that the wind speeds were increased, but load adjustment factors modified as well. So when doing an ASD analysis before the wind would have a load adjustment factor of 1.0 it now has a load adjustment factor of 0.6.

I wanted to verify that CEASAR is doing this properly. How would I navigate to that in the program, or where could I find that out?

Load combination differences between ASCE7-05 and 7-10 are attached for reference.

http://files.engineering.com/getfile.aspx?folder=6c25beef-aa0c-4be0-ad39-07

DSB123 (Mechanical) · Answer 1 · 2018-01-10 14:22:01

I presume the Load factors are for the loads on the structure which is not what the wind load in Caesar wants. How you apply factors for the structural design for combined loads is different to what the pipe stress engineer applies. He wants the actual wind load calculated to the Code and applied to the Pipe to check the pipe meets the Code limits.

smithrj_40 (Structural) · Answer 2 · 2018-01-10 14:49:50

Load factors are specified in ASCE7 and are not specific to structures, they are part of that code and are used to get a final wind force. I have attached a document that may help explaining what I am talking about. Specifically see the section on page 2 "Design Velocity Pressure Example" and also the pressure comparisons in Table 1 (page 4) that show with the factors applied, even though the design wind speed increased significantly, the actual design pressure applied to objects has decreased.

http://files.engineering.com/getfile.aspx?folder=1bea44ed-16d4-413d-a40f-10

Come Join Us!

Posting Guidelines

CEASAR II - Wind Calc - Load Factors