2039 N Victoria Drive #2 - Plan - Laserfiche WebLink

Home Browse Search

24-8009 Page 9 Conformance to the criteria presented in the above table for seismic design does not constitute any type of guarantee or assurance that significant structural damage or ground failure will not occur during a large earthquake event. The intent of the code is “life safety” and not to completely prevent damage of the structure, since such design may be economically prohibitive. Foundation Design Recommendations The proposed ADU may be supported on continuous and/or spread footings. Bearing capacity recommendations for shallow foundations are presented below. An allowable bearing pressure of 2000 pounds per square foot may be used in the design. These recommendations assume that footings will be supported on a minimum of three (3) feet of engineered fill. However, deeper fill (as much as 10 feet) may be required due to the presence of the demolished pool, as shown in Plate 1. The minimum recommended footing depth is 24-inches below the lowest adjacent grade. The minimum recommended footing width is 18 inches for continuous footing and twenty-four (24) inches for pad footings. A minimum reinforcement of 2-No.4 steel bars top and bottom is required for continuous footings from a geotechnical viewpoint. Foundation design details such as concrete strength, reinforcements, etc should be established by the Structural Engineer. A one-third (1/3) increase on the aforementioned bearing pressure may be used in design for short-term wind or seismic loads. The static total and differential settlements between adjacent footings supported on competent bedrock are not anticipated to exceed one (1) inch and one-half (0.5) inch over 30 feet, respectively. All footings should meet the setback requirements presented in 2022 CBC. Resistance to lateral loads can be assumed to be provided by passive earth pressure and by friction acting on structural components in permanent contact with the subgrade soils. Lateral resistance on the sides of footings may be computed using a passive pressure of 200 pounds per square foot per foot of embedment, subject to a maximum of 2000 pounds per square foot. An allowable friction coefficient of 0.30 may be assumed with dead load forces between concrete and the supporting soils. Passive pressure and frictional resistance could be combined in determining the total lateral pressure resistance, provided one of them is reduce by 50%. Drilled Piers Alternatively, the proposed ADU may be supported on drilled piers embedded a minimum of 10 feet into competent native soils with a structural floor. The recommended minimum pier diameter is 24-inches. The drilled piers may be designed for an allowable frictional resistance of 200 pounds per square foot for competent native. The uplift capacity may be taken as one-half of downward capacity plus the weight of the caisson. The lateral capacity may be taken as 200 pounds per square foot per foot of depth (maximum 2,000 psf). The caisson capacity within the 2039 N Victoria Drive #24/28/2025