1632 46TH ST SE 2020-06-18 - Laserfiche WebLink

July 3,2017 Single-F=11y Residence, L&A Job No. 17-079 Page 15 used. The above soil parameters are ultimate values, and a proper factor of safety should be used in calculating the resisting forces against lateral loads on building. SLAB-ON-GRADE FLOORS Slab-on-grade floors, if used for the proposed residence, should be placed on firm subgrade soil prepared as outlined in the SITE PREPARATION AND GENERAL EARTHWORK and the STRUCTURAL FILL sections of this report Where moisture control is critical,the slab-on-grade floors should be placed on a capillary break which is in turn placed on the compacted subgrade. The capillary break should consist of a minimum four-inch-thick layer of clean, free-draining, 7/8-inch crushed rock, containing no more than 7.5 percent by weight passing the No. 4 sieve. A vapor bather, such as a 6- mil plastic membrane, may be placed over the capillary break, as required, to keep moisture from migrating upwards. CAST-IN-PLACE CONCRETE RETAINING WALLS Building foundation walls restrained at,the top from lateral movement are considered unyielding and should be designed for lateral soil pressure under the at-rest condition. Retaining walls unrestrained at the top from lateral movement may be designed for active soil pressure. We recommend that an at-rest soil pressure of 55 pcf EFD(equivalent fluid density) and an active soil pressure of 35 pcf EFD be used for the design of building foundation walls and retaining walls, respectively, with a level or descending backslope away from the walls. For walls with ascending backslope away from the walls, an additional pressure of 0.75 pcf per degree of the backslope angle above the horizontal should be added to the above design pressures. To counter the above active or at-rest LIU & ASSOCIATES, INC.