2222 EVERETT AVE 2016-01-01 MF Import

' Subsurjure Ecploration, Geo%gic Hazard, and Everetr Schoo!District Maintenancc Fnci(ity Prclrmirmry Gmtechnica!Engineering Report Evercrt. �t'nshin�rai DesiRn RecommenJatFans � the amount of fine-grained material (smaller than No. 200 sieve) is greater than approximarely 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Use of moisturc-sensitive soil in strucmral fills should be limi[ed ro favorable dry weather conditions. The on-site soils generally contained signiticant .unounts of silt and are considered moismre-sensitive. [n addition, construction equipment traversing the site when the soils are wet can cause considerable disturbance. If fill is placed during wet we:�ther or if proper compaction cannot be obtained, a select import material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with the amount of tinc-grained matcrial limited to 5 percent by wcieht when mcasurcd on the minus No. 4 sicve fraction. A representative from our tirm should inspect die stripped subgradc and be present during placement of structural fill to observe the work and perf'orm a representative number of in- place density tests. In this way, d�c adequacy of the earthwork may be evaluated as filling progresscs and any problem areas may be corrected at that tinre. �1'e are available to aid in developing a suitable monitoring and testing frcquency. [t is pussible that longer than customary times for compaction of thc fill at the site, will be needed due to the use of thin lifts (< 4 inches loose thicknessl and the absence of vibration compacting near the vibration sensitive building. Use of controlled density fill (CDF) or ( backfillin�; with railroad ballest, quarry spalls, or similar cican rock fill will reduce or � eliminate the tinre necded for fill compaction. These materials do not typically rcquire heavy compaction efforts if placed in thin lifts and track walked into placr. 10.0 �OUNDr�'CIONS lo.l snrcad Pootines The existing fill on tlie� site is considered a weak to modcratc toundation bcaring material, primarily suited to parking lot support. The foundation-bearing svatum (glaciolacustrine soil) is behveen 6 to 10 fcet bclow the surface in vicinity of the exploration pits. Active use of the existing m�intenance facility and the existing buildings prevented ezcavation in some areas and the depth to the glaciolacustrine soil may be less or more in those areas. We undcrstand from the structural engineer, that a foundation bcaring pressure of 2,500 (ps� has been utilized for design purposes and that up to 8,000 psf ma�• be used for heavily loaded portions of the structures. A 2,500 psf foundation load may be supported on a minimum of 3 feet of overexcavated and replaced stnicmral fill, while 8,000 psf loads must be supported either direcdy on thc underlying glaciolacustrine soils, or structural fill placed on the glaciolacustrine soils, or by piling embedded in the glaciolacustrine soils. An increase of one- 1 M� �� ASSOClATED Er1RTH SClENCES, lNC. mam-KEaiosr:u.n�„��,:,a.r.o�-w�x P�ge 10 ►a