Machine foundation reinforcement

[sdz]

I am designing a concrete block foundation for a reciprocating compressor and motor. I would normally provide reinforcing to the face of the block only but someone has suggested that reinforcement should be provided throughout the concrete volume.
Can anyone tell me which is the preferred practice and if reinforcement is to be provided throughout the concrete can you provide a reference to show my boss.

 

[concretemasonry]

Normally, I hate to see block cores filled unless there is rebar in the core. If you have vibrations and reciprocating equipment there usually are better of with more mass, so full grouting should be better and is not costly. Use a grout (8"-11" slump) and NOT concrete. You never know about the harmonics and the ultimate effects.

Extra reinforcement beyond what is required structurally is usually not needed or productive.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[sdz]

Sorry Dick, I wasn't clear. When I say a concrete block foundation I mean a large monolithic lump of concrete, not a foundation made of concrete blocks.

 

[concretemasonry]

sdz -

Thanx for the clarification.

The mass principle is still valid in most cases and usually the reinforcement must be adequate to hold the massive block solid and tight so it acts as a single unit.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[chicopee]

Check this site

http://civildesignhelp.info/;

foundation details about several types of equipment however look at the PDF drawing details on pumps.
Two grillages of rebar on thick concrete pads is a good idea as you could encounter negative and positive moments on the concrete pads. Also with reciprocating equipment you will be faced with vibratory forces on the concrete pads.