Cooling tower support

[Boiler106]

I need to design the support beams for an 8'w x 12'L x 15'H cooling tower that are supported on vibration isolators which in turn are supported by (4) 30" sq concrete piers in a relatively high wind zone.

I'm picturing the lateral load coming down the cooling tower to the top flange of my, say, W10 beam and causing rollover on the isolators if I use (2) W10 rails like the manufacturer shows in their literature.

I have attached a diagram of what i think needs to happen where i add in perpendicular beams (blue) to form a rectangular frame around the base to prevent the rollover. However, this doesnt match the manuf's layout since they only show two rails.

Do these isolators typically have rollover capacity? Do we typically ignore weak axis bending and torsion from this applied wind force?

Does anyone have experience with supporting these that could give me any insight? Is this just not something that is typically considered in this design?

Obviously, i need to contact the manuf, but i wanted to have a solution in hand first.

 

[EZBuilding]

Look down to the bottom of the download from this product data sheet from Mason Industries and you will see a table which illustrates capacities for both horizontal and vertical reactions. I have not used isolation springs from a different manufacturer. They have several different types of springs available, you can probably call them to get some more information.

https://mason-ind.com/products/product-submittals-2/download-info/slr/

Depending how tall your tower is and your wind pressures you can end up with some rather beefy member sizes and connections.

 

[Agent666]

I've done quite a few of these and always created a welded frame to address the roll over issue you highlight. I usually try and locate these orthogonal members near to the vibration mounts so the forces resolve as near as practical into the return members.

Usually in my case the contractors mount the tower on the frame prior to lifting it up to the roof, we are talking primarily about replacement of existing plant, so the changeover period is usually a weekend to prevent any downtime. So efficiency on site is the key to assisting the contractor to complete the work in the allotted time.

As EZBuilding noted, the vibration isolaters are rated for a certain load, work within these limits. Check the underlying frame for the loads being applied to the top of the isolators. I find that usually the flange width to mount the isolators is the governing thing, so I usually have a significantly larger member than required for strength. You can also put some restraints/buffers (imagine in simplistic terms a vertical post each side/corner of the tower that limits the movement of the frame laterally) to restrain the tower lateral movement and avoid wind or seismic loading on the isolators by designing these restraint members for the lateral wind or seismic forces.