Building Construction: Concrete Mixes and Placing Notes

Study Notes

Maximum size aggregate is 20mm with a maximum concrete slump of 100mm
Minimum concrete cover for reinforcing steel:
- Directly against earth: 75mm
- Suspended slab: 20mm
- Slab on grade: 40mm
Minimum days for stripping of forms and shores:
- Foundation: 1 day
- Suspended slab: 8 days
- Beams: 14 days
- Walls and columns: 21 days
Contractor must submit pouring schedule and construction joint locations to the structural engineer at least 4 days prior to pouring for approval

Footings are designed for an allowance soil bearing pressure of 96 kPa (2000psf)
Footings shall rest at least 1.50m below natural grade line
Minimum concrete protection for reinforcement: 75mm clear for concrete deposited in the ground and 50mm for concrete deposited against a formwork

Yield strength of reinforcing steel bars: 414 MPa or 60,000 psi
Re-bars sizes 10mm or larger shall be deformed, and smaller than 10mm may be plain

All slab reinforcements shall be 20mm clear minimum from the bottom and top of the slab
Spacing of bars at column strips shall not be more than 1% slab thickness
Bedded slabs shall be reinforced with 10mm @ 250mm O.C each way to the center of the slab, and construction joints shall be at least 3.65m apart

Provide extra sets of ties at 100 O.C for tied column reinforcement above and below beam-column connections
Column ties shall be protected everywhere by a covering of concrete cast slope monolithically with the core with a minimum thickness of 40mm and not less than 40 times MSA
Alternate bars shall be welded or mechanically spliced at any level, with vertical distances between welds or splices of adjacent bars not less than 600mm

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