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Once a design structural nut .ber is se:cczed. it is up to <br />the user to identify an appropriate combination of <br />flexible pavernent layer thicknesses which will provide <br />• th!: ,ccsired .cad - carrying tapaeity. 11sis may be ac- <br />cc- ap.isne3 using the criteria for layer coefficients (a, <br />va:um1 ptes_nted in Section 2a-5 and the general <br />equation for strucctural rtumbx—z. . <br />a., a..., a = layer txTuitnt for surface base, <br />and subbase course =aten -a s. reap= - <br />tiveiy. and <br />Di. D % = tltacb=s (m iris) of su fa,, base. <br />and subinse m use : respe ively <br />4....3'Rilpd Pg ecat -U ilvd= CatxLug <br />i pies 4S a. rd °.9 pr== the A:araing of pertlazd <br />tit <br />a ztk —.- ?:.:t.: 4-9 is <br />i bl 4.9 is <br />bas; oa a_75 -r :'_vci -t= asstaaptioos inh==. <br />ZI) ,7 a - dx=dor'urzctnforced)conc== <br />Sims t6acknt:s d esk recommendations <br />-Cply to all six U.S_ climatic regions. <br />Subbaw is 6 in+che of high quality granular <br />subbase (Farr tvy goad subgzade and. low <br />traf :ic; tbk U3= may be ommitted). <br />(4) Mean PCC raoduhn of rupture (St.) is 600 <br />psi. <br />V) Neze PCC elanic Voodulus ('E.) is 5.000,000 <br />Psi. <br />(W T a are o, tied cp=rctc shoulders (or <br />oasts) rc4uE. -c4. <br />i'� 0!�ai=sagr =rc)conditions are fair (C� <br />- 1 -; . <br />:�+ :.._ l 3 -a:o c'SaL :r»tti� I:�•�:� art <br />b7 'A 4U1 *ON <br />Design of Pavement Structures <br />High 700.0W to 1.000.000 <br />Medium 440,000 to 607,000 <br />Low 50.000 to 300,000 <br />(9) The leercls of roadbed soil quality and cor- <br />responding rams of effective modulus of <br />subgrade reaction (k- value) arc: <br />Very Good `. greater than 550 pei <br />Good 400 to 550 pci <br />Fair 2S0 to' 350 pfd <br />Poor . 150 to 250 pci <br />Very Poor less than 150 pci <br />It should be noted that althott5h the ttfuauz:t slab <br />thickness shown is 5 inches. the user should consider <br />the use of a thicker slab since &a overloaded truck may, <br />is some cases, severe ? d—pge thin slab pavements, <br />T2b>t4_i4pit~xsaczraagozgggtr <br />thit -1 ors rs tba:.asay :lxnscc sx see d if:itst :: ; <br />vai*_srsroods �rsca ib-=rr�� <br />-is not ;possible: Tut_ s.>z <br />- ape:. iz:: anaesa;: S- Iripr'S:�:`agp3i+ca�cai�i�ii'sr - <br />High : 60,Iv04 to, 100,000. <br />hiediurri ; 30,000 to .60,000 <br />Low 10,000 30,000 <br />One other asstrnption Inhercut in these Rase thick- <br />ness recommendations is that the efiecdvt resilient <br />modulus of the aggregate base material is 30,000 psi, <br />regardless of the quality of the roadbed soil. This value <br />should be used as input to the nomograph in Figure 4.5 <br />to convert a portion of the aggregate base thickness to <br />an equivalent thickness of subbase material with an <br />intermediate modulus value between the base and <br />roadbed soil <br />-, u T 'uo1T213ossw si;ni u.12TS2AA <br />IAI.11,I :1 0AA7 'A7 , 121AI <br />Revised March 2010 (PR06) Attachment 2.05.3(3) -8 -24 <br />