The reinforcement and construction details for machine foundations
The reinforcement of the concrete block in no case lower than 25 kg/m3. For the machines demanding special design consideration of foundations like for the machine pumping explosive gases the lowest limit of reinforcement is 40 kg/m3.
The steel reinforcement around the pits and opening at minimum has to be 0.5-0.75% of cross-sectional area of the pits and openings.
The reinforcement needs to run at all 3 directions. The minimum limit of reinforcement should have 12 mm bars at 200-250 mm spacing extending on both directions vertically and horizontally near all the faces of the foundation block. Remember the ends of each bars shall always be hooked.
In case the height of foundation block exceeds 1 meter, shrinkage reinforcement is required to be used at suitable spacing at all three directions.
Clear cover minimum ranges; 75 mm at bottom portion and 50 mm on sides and top portion of foundations.
The characteristic strength of concrete need to be at minimum 15 N/mm2 i.e. M-15.
The castings of foundation block have to be performed preferably in a single and continuous operation. For very big/thick blocks (>5m) construction joint shall be used.