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Cbnpter 4 <br />LOW- VOLUDIE ROAD DESIGN <br />Pavement structural design for low - volume roads is <br />divided into three categories: <br />(1) awdble pa%vments. <br />0 rigid pa-mments. and <br />(3) shads. <br />nis chaV=covez tbtdesifn of Ions %•oltxme roads for <br />theta dm surface typa Usk procedures based on <br />design ebarts (nomosmprs)arsi de:isa catalogs. These <br />two, proeedoars are emend in Se=iaffi 4.1 sad 4.: <br />�r= Fos stttfasa unme tt ar cwp seal pa-m- <br />=c- .t=xtn 'eL the psoacd�:prfexibia pavomcnts <br />any be usee- . <br />i�ti�^ • _�'�TS�7a -y nZ'S>S 7AS �'1 t.�es }�'dYZL''etiL <br />=mod aPstiI.22i it it ==2324 in La's Guide to <br />•asr ZL-- -1644 egU-:%a_= Sim& azL-- tflad (SSA:.) <br />des*- approach for kw-voh=: =nags regardless of <br />hcw :ow I= =IT= krd is-or what the disaibutior, is <br />basveen a. zcoba3es lac Mucks. <br />Sin= =anY aitg Uncts Mad County roads that f2i <br />nzA she 1ow- vobumr. ea tcgoty tray S carry signi$- <br />cult 3kvels of stock ux -51a, tho stta;dm numb. -r of <br />Wup FSA1,applic shoos eamr;dc:rd for flexible and <br />rigid parent design is 700.000 m I mriWon. The <br />prA=:cvl s®imam tsafe 1cv d thK can be cam idemd <br />for any &MC or ti& patam=t during a given <br />P period is zbout so ow 18-lip ESAL <br />applications. Ford=aMrr Eaced(gm roads'. <br />vsed for many tountyaxtd fa st roads, the maximum <br />nafifSc ::x.00018kip1S Lapplica_ <br />don:, while the Pmt aftitntun k=1 (during a <br />sags= "e=== period) is 10.000. <br />4.1 DESIGN CHART PROCEDLrRES <br />4.1.1 Fkesible and Rigid Pavemeeu <br />T «� 3o:.- calts.-rt rase- des :,n c: ar-t r :et�sr :s for <br />s::.u:; :e z. d rigid pave = - -wts are basi:ally t5: ssr.:c its <br />I : :._ for r:Sh%%ay pate ^.r.: design. Ti.c low- %olun -C <br />relics on t'-.0 ict of design <br />re. ui:ements tda.ciop in Chapter 2) as well as t::e <br />basic step-by-step ,procedures described ill Chapter 3. <br />The primary difference in the design for low - volume <br />roads is the level of reliability that May be used. <br />Because of their relative low usage and the associated <br />IO%X level of risk, the le rYl of reliability recommended <br />for law - volume road design is So percent. The user <br />may, however, design for higher ievcIs of bo to 80 <br />percent. depending on the actual protected Ievel of <br />traffic and the feasibilityof rehabilitation, importance <br />of corridor. ctc. - <br />1f, in estimating sn effective resilient modulus of the <br />roadbed material (M an effective podnlus of <br />subgssde reaction (k). i. is not possible to determine <br />the ien gibs of the seasons or even the seasonal roadbed <br />soil resisieat =o4ulL the following sv should <br />be coraide-sd. i <br />• . Se�.errerlx:.�a1;.zu.. . <br />sax c� w-aas seg~� of t5„i F3ai- s�.Sciwes sir.•! - : • <br />theensireaa:.a lair �. •; <br />_, ':used oa ehaa : sg�a�- ` :ch`=s�'istia. ?a'bied.l3�y <br />.. ..be u=:.+ to d•effine the .season •.L=rtba • baded 'for <br />dete=aingthe cffec iveroadbed soRmisiemtuodubss <br />(Section 33 for ilcxible pzrement desipsr or the <br />of vC%ivc modulus of sublmde reaction (Section 3.2_I) <br />for rigld pavement desigm <br />Sema.-. lRoacrbedSoliRe gZmtAfodu& Table 4.2 <br />provides roadbed soil resilient modulus values that <br />may be used for low - volatile road deli nz if the Nser Can <br />casslfy the general quality of the roadbed material as a <br />foundation for the pavement str eture- If the suggested <br />values in this table are combined with the suggested <br />season lengths identified in the previous section, <br />effective roadbed $oil resilient Modulus values (for <br />flexible pavement design only) can be generated for <br />each of the six U.S. climatic regions. These NI vaiucs <br />are presented in Table 4.3. <br />4.1 .2 Aggrtg2teSurfaced Roads <br />The basis for t:eating the ct cc :sa;seasa- alnoisms_ <br />caarg:s on roadbed sot: resiiitr-t madt -Ws. `.l „. is tl ;- <br />seine for aF =rr ; :�t :•a: riaccd :Mad d:s,;a as it is f. r <br />t : <br />or rlr:v �.S:L't � : ���CL ::!eS� 4Ja: �cr. :tie � : :' C' ^ .• <br />:. <br />L`15C1: <br />..... <br />� :•Sil :�. ^ NtlrC :�trdtylrtrCl <br />a gra+p l :wal solut It is t : a`:t1.:t to n t o tha the <br />11 'd Gfll *ON •out 'uoiirioossw scan: uJaisau _W:/i:I onn7 •nr •,pw <br />REVISED JULY 2006 Attachment 2.05.3(3) -8 -9 <br />