2312 W CASINO RD COMMUNITY TRANSIT 2018-01-02 MF Import

i IGec-draining backfill ageinsl the back of the wall or (2) a prefabricatcd gcocomposite wall drain. 7'he frce-draining backfill should consist of(I) pca gravel or(2) sand or sand and gravel contnining no more � than 3 percent passing the U.S. No. 200 sievc bascd on thc 3/4-inch fraction. The prefabricated geocomposite wsll droin should consist of Mirodrain 6000, Delta Drain 6000, or epprovcd equivalcnt. In addition, a perforated drainpipc having a minimum diameter of 4 inchcs should be pleced in the granular fill ur in thc bouom of the prcfabricatcd drain at the base of walls for the entire length. l'hc drainpipe should consist nf rigid PVC or ADS N-12, not the (lexible ADS vancty. The drainpipe should bc slopcd ;o drain by gravity and rnutcd to a suitablc dischargc point so �hat watcr dischargcd Gom lhe pipc docs nut cause crosion. PAVEMENT CONSIDERATIJNS I l'hc pavcment s��bgrade arca should bc prcpared according to our rccommend .ions for sitc prcparation nnd carthworl.. It is critical that all conswction traffic bc kept off the silry subgradc soils during wct I wcather to prevent disturbancc (rutting and wcaving) Gom ocr,urring. Wc rec�mmend the minimum G-incFrthick gravel base conlain Icss than 5 percent pussing the U.S. No. 200 sieve to perform as a drainagc laycr bctwcen thc silty soils and the pavemenl section, The minimum thickncss is not intendcd ta scrve as a working surfacc for conslruction traffic dunng wet weather. Additional subbase will likely Ibc rcquircd if carthwork and site grnding is not completed during the dry season. Wc complctcd pavcmcnt design nnalyscs using the design mcthodology outlined in thc AASHTO Guidc Ifor Dcsign of Pavcmem Structures and the cstimated trnftic loading as summarized bclow: • Tbtal avcragc daily traffic(ADT)of 400 in Dcsign Lanc • Thrce troflic distributions including: • Aulamobilc and light duty vchicics I • I lcavy duty�raflic and limiled bus traf7ic(50 percent cars, 50 percent busscs) ■ I3us traf(ic with slow moving tums(100 perccnt husses) • M avcrogc tnick factor for thc busscs of 3.0 I • 20-ycardesignlifc • Pcrccnt growth of LS perccn� • Rcliabiliry of 95 percent • Iniiialscrviccabilityof4.2 �� • '1'cnninal scrviccability of 2.0 • Ovcrall standard dcviation of 0.45 � • Compressivc strcngth of PCC pavcment of 4,000 psi, modulus af rupturc of 650 psi • Califomia 13caring Rntio(C13R) for subgradc soils of al Icast I S Using thc inliirniation prescntcd abovq wc rca�mmcnd ihc follnwing altcrnativc pavcmenl scctions: I I � FiL•Nn.:�Wynl4�ui PageR GFOENGINEEII� l/nr 7'. ?lN14