Fire water storage tank roof structure bolting

[Satyenrp]

Kindly guide me for the requeremet of tank roof structure bolt tightening.

As drawing not showing any torquing requeremet not ITP. Even API 650 also not giving such cleraity for torquing requeremet for the roof structure members.

So, Please advise me os there any torquing requeremet for the roof structure bolts or tightening with impact wrench machine is ok

 

[Geoff13]

First, you should be asking the roof designer/manufacturer this, not the Internet.

Second, the usual rule is that if the bolts need to be pretensioned (turn-of-nut, torqued, etc.) then the drawing should say so, along with the acceptance criteria. When the drawings say nothing then AISC would default to snug tight bolts which are defined as:
[ul]
[li]The snug tightened condition is the tightness that is attained with a few impacts of an impact wrench or the full effort of an ironworker using an ordinary spud wrench to bring the plies into firm contact.[/li]
[/ul]

 

[mk3223]

May add DTI washer to the bolting to facilitate the structure installation and inspection.

 

[Satyenrp]

I have asked my engineering team and they told torquing not required as It is low load static structure.

But one client inspector raising the concen

 

[HTURKAK]

The bolts apparently snug tight as Geoff13 (Structural) stated. However there is another problem...the snip picture of the roof structure shows the main supporting members are trusses and these trusses supporting the rolled section rafters.
The vertical bracings are visible ..however , i could not see horizontal bracings...

The roof structure erected on scaffolding and shall be checked for horizontal bracing before dismantling the scaffolding.
The picture below depicts the typical roof bracing...

 

[Geoff13]

I've seen your problem myself. Inspectors want a torque, or a DTI, or a turn-of-nut, so they have something to inspect. With the standard snug-tight installation there's nothing to inspect, other than "Are the plies in firm contact?".

However if snug tight bolts are all that's needed for a design (and that's probably 99% of structural bolts) then all these other methods are just wasted manhours and dollars.