2002 W Alton Ave - Soils Report - Laserfiche WebLink

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Project No. D-3885-06 Christ Our Savior Catholic Parish Semi-Rigid Mat Foundation After the stabilization of the ground, semi-rigid mat foundation may be designed to support the buildings. The minimum thickness for the semi-rigid mat loundation should be I 8 inches overlying a moisture protective barrier layer of Stego Wrap ( 15 mil or equivalent) over 6 inches of %-inch crushed rock compacted to 95oZ relative compaction and at least 36-inches thick subgrade should be compacted to minimum 93% of the maximum laboratory test standard. The semi-rigid mat footing may be designed for an allowable bearing capacity of 1,200 pounds per square foot. This basic capacity may be increased by one-third for short duration loading, such as wind or seismic forces. Modulus of subgrade reaction, k value may be taken as I 00 pci for the subgrade layer of soil. Other aspects of the design, including rigid mat thickness and reinforcement should be determined by the project structural engineer. Foundation Settlement Assuming the foundation system for these new buildings is a semi-rigid mat foundation over stabilized ground, the static settlement of underlying soils is estimated to be less than 1.5 inch and differential settlement would be less than l/2" within a horizontal distance of 40 feet. Footing Observations All footing trenches for the proposed structure should be observed by a representative of this firm to verifo that they were excavated into competent bearing soils per the recommendations of this report as well as to the minimum depths recornmended above. These observations should be perlormed prior to the placement of forms or reinforcement. The excavations should be trimmed neat, level and square. All loose, sloughed or moisture softened soil should be removed prior to placing concrete. 32 I E r T t l E I f T T E E lt I I n t.l I