11419 19TH AVE SE Geotech Report 2018-01-02 MF Import

� �. � 9.1 l�ootin� 'Trenchcs, continucd To detemiine�vhen suitable bearing has bcen achieved and to verify proper backfill placement, the � geotechnical engineer/engineering geolo�ist must be present on a full-time basis during footing trench escavation and backflL A pump may be required to control seepage so that the bearing Ievel cari be visually determined. Seepage entering the excavation on an ovemight basis must be removed � prior to commencing trench excavation the following day. After the be.zring stratum has been reached, the trenches should be immediately backfilled. We recommend the use of Stone�vay 1351 controlled density fill (CDF) or equivalent for trench backfill. The trenches should be filled to the � fooung subgrade elevation. The building footings should be designed in accordance with the Foundations section of tl�is repoR. The footings must be centered over the trenches. � IU.J FloorSupport � Slab on grade floors may be used over approved structural fiil or approved dense native soils. � We recommend the floor slab be cast over a six inch layer of pea gravel, coarse sand or clean crushed rock to provide a capillary break beriveen the structural fill and the new ftoor. A vapor � barrier should also be provided over the capillary break layer. The vapor barrier should consist of an impermeable membrane of reinforced plastic (at least t0-mil thickness). The contracror should exercise care during the installation of the vapor barrier to provide at least 12 inches of overlap � beRveen individual sheets and to prevent punctures. A three inch layer of damp sand or clean cn�shed rock should be placed behveen the concrete siab and vapor barrier to protect membrane and � to aid in unifonn curing of concrete. The potential for concrete shrinkage cracks can be reduced by utilizing a low shrink concrete mix, proper corcrete placement and curing procedures, and by the placement of crack control joints at periodic intervals, particularly�vhere re-enhy slab corners occur. � 11.0 Drainage Considerations � The perimeter of the buildings should be provided with a drain at the footing elevation. Drains should consist of rigid, perforated, PVC pipe surrounded by washed pea gravel. The level of the perforations in the pipe should be set approximately two inches below tt,e bottom of the Cootings and � the drains should be constructed �.vith sufficient gradient to allow gravity discharge away from the building. The perforations should be located on the lower one-half of the pipe. Roof and surface runoff should not dischazge into the perimeter drain system but should be handled by a sepazate, � rigid, tightline drain. In planning, exterior o ades adjacent to walls should be sloped dowmvazd a�vay &om the s[ructure ro achieve surface drainage. � 12.0 Pavement Recommendations We understand that asphaltic concrete pavement (ACP) will be used as a pavement s,ufacing course � on this projecL 1'he parking and access areas planned for this project appeaz to be u.�dedain by firm soils, which, �vith proper preparation, will be capable of providing suitable subgrade support for the pavement. ! 1 �� i6 � MAYES TESTING ENG/NEERS