2130 E 4th St - REV 1 - Plan - Laserfiche WebLink

Home Browse Search

EARTH STRATA GEOTECHNICAL SERVICES 13 March 30, 2023 Project Number 234812-10A recommended compacted fill reinforced with geogrid will further mitigate the estimated settlement, however increased structural slab design will be required to mitigate the effects of the remaining settlement. TENTATIVE FOUNDATION DESIGN RECOMMENDATIONS General Provided grading is performed in accordance with the recommendations of this report, shallow foundations are considered feasible for support of the proposed structures. Tentative foundation recommendations are provided herein and graphic presentations of relevant recommendations may also be included on the enclosed map. Allowable Bearing Values An allowable bearing value of 2,000 pounds per square foot (psf) is recommended for design of 24-inch square pad footings and 12-inch-wide continuous footings founded at a minimum depth of 12 inches below the lowest adjacent final grade. This value may be increased by 20 percent for each additional 1-foot of width and/or depth to a maximum value of 2,500 psf. Recommended allowable bearing values include both dead and frequently applied live loads and may be increased by one third when designing for short duration wind or seismic forces. Settlement Based on the settlement characteristics of the earth materials that underlie the building sites and the anticipated loading, we estimate that the static maximum total settlement of the foundation will be on the order of approximately 2 inches. Differential settlement is expected to be about ½ inch over a horizontal distance of approximately 20 feet. It is anticipated that the majority of the settlement will occur during construction or shortly after the initial application of loading. The above settlement estimates are based on the assumption that the grading and construction are performed in accordance with the recommendations presented in this report and that the project geotechnical consultant will observe or test the earth material conditions in the footing excavations. Lateral Resistance Passive earth pressure of 250 psf per foot of depth to a maximum value of 2,500 psf may be used to establish lateral bearing resistance for footings. For areas covered with hardscape, passive earth pressure may be taken from the surface. For areas without hardscape, the upper 12 inches of the soil profile must be neglected when calculating passive earth pressure. A coefficient of friction of 0.36 times the dead load forces may be used between concrete and the supporting earth materials to determine lateral sliding resistance. The above values may be increased by one-third when designing for short duration wind or seismic forces. When combining passive and friction for lateral resistance, the passive component should be reduced by one third. In no case shall the lateral sliding resistance exceed one-half the dead load for clay, sandy clay, sandy silty clay, silty clay, and clayey silt. 2130 E 4th St 2/11/2025