1318 W MUKILTEO BLVD 2016-01-01 MF Import

Wrought Corporation August 11, 2006 JN 06287 Page 6 to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfiil in order to provide the appropriate design eaRh pressures. The surcharge due to tra�c loads behind a wall can typically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The wall design criteria assume that the backfill will be well-compacted in lifts no ?hicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. Retainina Wall Bac�ll and Waterproofinc Backfill placed behind retaining or foundation wa structural fill containing no organics. This backfill sho or clay particles and have no gravel greater than 4 ii particles passing the No. 4 sieve should be between that does not contain organics or debris can be use section entitled Drainage Considerations should al related to subsurface drainage behind foundation and ils should be coarse, free-draining ild contain no more than 5 percent siit ches in diameter. The percentage of 25 and 70 percent. The onsite sand d as free-draining backfill. The later �o be reviewed for recommendations retaining walls. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because or a build-up of hydrostatic pressure behind the wall. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. The section entitled General Earthwork and Sbuctural Fill contains recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. The above recommendations are not intended to waterproof below-grade walls, or to prevent the formation of mold, mildew or fungi in interior spaces. Over time, the performance of subsurface drainage systems can degrade, subsurface groundwater flow patterns can change, and utilities can break or develop leaks. Therefore, waterproofing should be provided where future seepage through the walls is not acceptable. This typically includes limiting cold-joints and wall penetrations, and using bentonite panals or membranes on the outside of the wails. There are a variety of different waterproofing materials and systems, which should be installed by an experienced contractor familiar with the anticipated construction and subsurface conditions. Applying a thin coat of asphalt emulsion to the outside face of a wall is not considered waterproofing, and will only help to reduce moisture generated from water vapor or capillary action from seeping through the concrete. As with any project, adequate ventilation of basement and crawl space areas is important to prevent a build up of water vapor that is commonly transmitted through concrete walls from the surrounding soii, even when seepage is not present. This is appropriate even when waterproofing is applied to the outside of foundation and retaining walls. We recommend that you contact a specialty consultant if detailed recommendations or specifications related to waterproofing design. or minimizing the potential for infestations of mold and mildew are desired. GEOTECN CONSULTANTS. INC.