Creep in Concrete (Staged Construction)

[Hark88]

Hello Everyone,

I am using SAP2000 to model a concrete box structure with horizontal loads on the top of it.

In order to include creep in my analysis I added the "Time Dependant Properties" in my concrete material and I used a "Nonlinear Static Staged Construction" as a load case.

In this load case I added 2 stages: one with duration 0, where I added the whole structure and loads; and the second with a duration of 273 days (7months) but with no loads added (just to allow for the creep to act).

The problem is that the displacements I get when included creep increase from 0.1mm to 156 mm. I do not think creep can have such a big impact in 7 months.

Can anyone help me with what the problem might be?

I really appreciate your help.

Regards,

Skerdi

 

[stressed]

Typically when concrete is first poured you often have temporary shoring supports and formwork and you wouldn't add additional loads until AFTER the concrete has cured for a time if you are considering creep. Putting all your loads in at age 0 will give high deflections because the concrete doesn't have strength.