From my understanding, sustained loading is essentially dead load as it is a long term load applied to the structure.
When carrying out a design using profis using characteristic forces, would I therefore leave the permanent loading blank and only fill in the variable load and sustained load?
Thanks
Hi, Thanks for your question. You are correct that a sustained load is considered when the bonded anchors are designed to be subjected to a constant tension for a long period of time where creep effects may occur.
Now in relation to Profis you have two loading input options
Firstly, Design loads where you input your factored / ultimate loads there you will see a 2nd line where you can enter a sustained load value in addition to the Design load.
Secondly Characteristic loads where enter your unfactored load as either a dead or live or a combination which the software then applies the relevant load partial safety factor. You will then notice a third input option ‘on screen’ where you can enter the sustained load.
However, in both above cases you will be prompted by the software if your input for the sustained load is incorrect as it must not be greater value. It can be equal or less to your input and must also be acting in the same direction i.e. moment loads.
Thank you for your response.
For added clarity, if we consider an example calculation with 10 kN dead load (self weight) and 5 kN live load, if I was inputting these as characteristic forces, I would add 10 kN perm, 5 kN variable and then also 10 kN sustained?
Hi, In this case certainly the permanent action and if there is also a permanent component of variable action that can also be included . As mentioned the sustained input is left open for you to input a value though it cannot be greater than the combined actions.