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353 Main Street Apartments <br />Redwood City, California <br />May L, 2018 <br />(Original Report Dated November 78,20L6) <br />5 Flatwork constructed adjacent the unstable creek bank may need to be protected by <br />sheet piles or retaining walls. <br />Asphalt Pavement Design <br />L. For design considerations, an R-Value of 5 was selected to account for variations in <br />subgrade soil conditions. The asphalt concrete (AC) sections were designed in accordance <br />with the Caltrans Highway Design Method for Traffic lndices {Tls) of 4 through 6.5. <br />Determination of the appropriate Tl for each area to be paved is the province of the <br />architect/engineer. The calculated base and AC thicknesses are for compacted material. <br />Traffic lndex (Tl)4 4.5 5 5.5 6.0 6.5 <br />AC Thickness (inches)2.5 2.5 3 3 3.5 4 <br />AB Thickness (inches)8 9.5 10 T2 13 13.5 <br />The thicknesses are nominal values for compacted material: normal construction <br />tolerances should apply. The aggregate base should conform to Caltrans Class 2. The <br />subgrade soil and aggregate base should be firm and unyielding when proofrolled by <br />heavy rubber tired equipment prior to continuing construction. <br />Soil subgrade in the proposed asphalt pavement areas should be prepared as described <br />in previous sections of this report. Soil subgrade should be compacted to at least 90 <br />percent relative compaction. lmport aggregate base should be compacted to at least 95 <br />percent relative compaction based on the laboratory test procedure ASTM ÐL557-L2. <br />Concrete Pavement <br />L. No traffic data has been provided. We have assumed that the majority of the traffic would <br />be multi-axle truck traffic. The concrete pavement was designed using the methodology <br />outlined in the Army Corp of Engineers engineering and design manual, "Rigid Pavements <br />and Roads, Streets, Walks and Open Storage Areas." For design purposes the subgrade <br />soil was assumed to have a modulus of subgrade reaction of 100 psi, a Traffic Category of <br />lV, and a Design lndex of 4. <br />The minimum thickness of concrete pavement is 7.5 inches and should be underlain by 6 <br />inches of Aggregate Base, compacted to 95 percent relative compaction. The concrete <br />should have a minimum modulus of rupture of 650 psi. Construction joints should be <br />doweled. <br />2. <br />3 <br />2 <br />301842-00L 19 16L0-038.SER.REV2 <br />7.B. - Page 77