5902 EVERGREEN WAY HOUSING HOPE 2018-01-01 MF Import

; � Subsurjace Erplormion, Geofoglc Hazard, and � ' Nousing Nop�Pluur!I Pnfiminary Geatechnical Engineering Rrpor. � Evnrrr. Washingron Design Recommendatlonr � s � � advance of filling activities to perform a Proctor test and determine its field compaction j standard. Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) � is grea[er th:u! approximately 5 percecit (measured on the mi[tus No. 4 sieve size) s6ould be � I considered mouture-sensi[ive. Use of moisture-sensitive soil in structural fills should be 1 limited ro favorable dry weather conditions. Ttte on-site gray, medium dense outwash soils ; generally contain less than 5 percent silt. Below depths of roughly 13 feet on the northwestern I 1 portion of the site, the outwash soils contain a higher percentage of silt and aze currently above I optimum moisture concent for campaction. In ac;dition, construction equipment traversing the 1 [ill soils when wet can cause considerable disturbance. If fill is placed during wet weather abovE the till subgrades or if proper compaction cannot be obtained in these a:eas, a select impon material consis[ing of a clean, free-draining gravel and/or sand should be used. Free- �, � draining fill consis[s of non-organic soil with the amount of fine-grained material limited to 5 ' perccnt by weigl�t when measured on the minus No. 4 sieve fraction with at least 25 percent � recained on the No. 4 sieve. The majority of on-site gray, medium dense recessional outwash � 1 soils should meet these criteria. ; � �� represent�dve from our firm should inspect the stripped subgrade and be present during ! � placemeut of swctural fill to observe the work and perform a representative number of in- � place density [es�s. I❑ this way, the adequacy of the ear[hwork may be evaluated as filling progresses and any problem areas may be corrected at that time. It is important to understand � � tY,at tal:ing random compac[ion [es[s on a part-tirr.e basis will not assure uniformiry or � acceptable performance of a fill. As such, we are available to aid the owner in de��eloping a ' �uitable moniroring and testing frequency. I � !1.0 FOUNDATIONS Spread footings may be used for building support when founded directly on medium dense, � recessional our.wash, dense to very dense till, or on structural fill that extends down to the bearing stratum and u placed as previously discu�sed. We recommend that an allowable bearing pressure of 2,500 pounds per square fcot (ps� be utilized for design purposes, j includir.g both dead and live loads, for footings pfaced on medium dense outwash sand, till, or � structural fill extending down to these sediments. An increase of one-third may be used for short-term wind or seismic loading. Perimerer footings should be buried at least 18 inches into � the surrounding soil for fros[ protection; intecior footings require only 12 inches burial. However, all footings must penetrate to the prescribed bearing stratum, and no footing should be fuunded in or above organic or soft/loose soils. To limit settlements, all footings should ihave a minimum width of 16 inches for single-story and 18 inches for two- and tfuee-story structures. � It should be noted that the area bound by lines extending downward at 1H:1V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at �� February !l, 1002 ASSOCUTED E.ARTH SClENCES, /NC. SG;l4d�Y.f�11719A7-P�o�erni]JJI7M'�KE�WP•kIX Page 11 I� i �