Concrete Foundation. (Tanks supported on concrete slabs)
a. The tank foundation shall be designed by the contractor to safely sustain the structure and its dead and live loads. The weight of the foundation plus the weight of the soil directly above the foundation shall be sufficient to resist the maximum net uplift occurring with the tank empty and the specified wind load blowing in a direction causing the greatest net uplift on the foundation. The size of the foundation shall be such that the allowable soil bearing capacity is not exceeded when the following load combinations of loads are applied: • dead weight of the foundation • dead weight of all permanent construction and fittings including roof • proper proportion of the dead weight of the structure • proper proportion of the water load (weight of all liquid when tankis filled to top capacity level • proper proportion of the wind load • proper proportion of earthquake load
b. Tank foundation design shall be based on a soil bearing capacity of 2000 psf (max.) for the purpose of this contract. Actual soil bearing capacity of the tank site should be verified by the winning bidding utilizing the expertise and recommendation of a certified Geotechnical Engineer.
c. All designs shall be based on the latest edition of the National Structural Code of the Philippines and shall conform to the 1997 Uniform Building Code requirements. The floor slab thickness shall be a minimum of 100mm (4 inches).
Concrete Foundation. The foundation shall be designed and constructed to safely and permanently support the structure. The basis of the foundation construction shall be consistent with the soils investigation data included herein at the end of these specifications. Appropriate changes to construction schedule and price will be negotiated if, during excavation, soil conditions are encountered which differ from those described in geotechnical report. The concrete foundation shall be constructed in accordance with ACI 301. Minimum concrete compressive strength shall be as specified in Section 03300, “Cast-In-Place Concrete”.
Concrete Foundation a. All surface preparation will be conducted in accordance with the Steel Structures Painting Council Specification Surface Preparation Specification Number 13, SSPC-SP13 “Surface Preparation of Concrete”. An acceptable prepared concrete surface should be free of contaminants, laitance, loosely adhering concrete and dust, and should provide a sound, uniform substrate suitable for the application of protective coating or lining systems. All exterior concrete surfaces shall be power washed following a chlorine treatment as set forth in the Steel Structures Painting Council Specification Surface Preparation Specification Number 1, SSPC-SP13 “Concrete Preparation”. Power washing will be a minimum of 2000 PSI (at nozzle tip) to remove contaminants such as dirt, dust, mold, mildew, chalk and other foreign contaminants.
b. Prior to painting all surfaces shall be washed with a salt reducing/removal and corrosion prevention wash such as Chlor Rid or HoldTight. Wash shall be per manufacturer’s recommendations and done within 4 hours of painting.
c. All exterior surfaces shall be coated with two coats of Tnemec Series N140 at a rate of 2.0 to 3.0 mils dry film thickness each.
