4620 SEAHURST AVE 2020-05-20 - Laserfiche WebLink

March 7, 2011 Mr. Paul Thompson/Kolbear, Inc. L&A Job No. 11.-001 Page 12 parameters are unfactored values; and a proper factor of safety should be used in calculating the resisting forces against lateral loads on the proposed residence. SLAB-ON-GRADE FLOORS Slab-on-grade floors, if used for the residences, should be placed on firm subgrade soils 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, 3/4-inch crushed rock, containing no more than 3 percent by weight passing the No. 4 sieve. A vapor barrier, such as a 6-mil plastic membrane,may be placed over the capillary break, as required,to keep moisture from migrating upwards. DRIVEWAY PAVEMENT Performance of driveway pavement is critically related to the conditions of the underlying subgrade soils. We recommend that the subgrade soils under the driveway be treated and prepared as described in the SITE PREPARATION AND GENERAL EARTHWORK section of this report. Prior to placing base material, the subgrade soils should be compacted to a non- yielding state with a mechanical compactor and proof-rolled with a piece of heavy construction equipment, such as a fully-loaded dump truck. Any areas with excessive flexing or pumping should be over-excavated and re-compacted or replaced with a structural fill or crushed rock placed and compacted in accordance with the recommendations provided in the S 1'RUCTURAL FILL section of this report. LIU & ASSOCIATES, INC.