Deener
Mechanical
- Aug 30, 2018
- 48
A column on the exterior wall of a warehouse has been hit by a tractor trailer. We are replacing the column and are currently looking into the the requirements for falsework while the column is removed.I have attached an isometric view of my simple 3D model of the partial structure highlighting the damaged column in red.
As you can see, there is one large roof beam (initial guess is W18x60) at the top of the approximately 18' high HSS column (7" x 7" x 5/16"). Two other smaller beams (let's say a W8) also connect to the top of this HSS column. At approximately 2/3 height, girts connect into the column as well.
The client was under the impression that some simple prop shores would be able to support all of these beams during column replacement. Since the column is located on an exterior wall and that it provides a connection for girts, I don't believe the single prop shores will provide any of the necessary lateral support to resist wind loads. So my questions are as follows.
1) Would it be reasonable to design the falsework for lateral loads which are caused by a 10 year wind? The process of removing the column and replacing it with a new one should take no longer than a week or two at max. Designing temporary falsework for a 50 year wind seems like overkill.
2) I have been given no information on the reaction forces at the column connections. Designing the falsework to support 50% of the beam shear capacity (as notes state in structural drawing) seems unnecessary. I plan to use the dead loads from the beams themselves along with the dead load of the roof slab where necessary. I will also use the live load of 1.9 kPa as stated in the standard for falsework and formwork S269.1-16. Does this seem reasonable?
3) Any recommendations on how to laterally brace those girts once the column is removed?
A few more snapshots of the drawings.
Your insightful comments are appreciated.
As you can see, there is one large roof beam (initial guess is W18x60) at the top of the approximately 18' high HSS column (7" x 7" x 5/16"). Two other smaller beams (let's say a W8) also connect to the top of this HSS column. At approximately 2/3 height, girts connect into the column as well.
The client was under the impression that some simple prop shores would be able to support all of these beams during column replacement. Since the column is located on an exterior wall and that it provides a connection for girts, I don't believe the single prop shores will provide any of the necessary lateral support to resist wind loads. So my questions are as follows.
1) Would it be reasonable to design the falsework for lateral loads which are caused by a 10 year wind? The process of removing the column and replacing it with a new one should take no longer than a week or two at max. Designing temporary falsework for a 50 year wind seems like overkill.
2) I have been given no information on the reaction forces at the column connections. Designing the falsework to support 50% of the beam shear capacity (as notes state in structural drawing) seems unnecessary. I plan to use the dead loads from the beams themselves along with the dead load of the roof slab where necessary. I will also use the live load of 1.9 kPa as stated in the standard for falsework and formwork S269.1-16. Does this seem reasonable?
3) Any recommendations on how to laterally brace those girts once the column is removed?
A few more snapshots of the drawings.
Your insightful comments are appreciated.