Question

- A contractor wants to design a flexible pavement which has a 4-inch sand-mix asphalt wearing surface, 11-inch soil cement base, and a 11-inch crushed stone subbase. It is designed to withstand 400 22-kip single-axle loads and 800 34-kip tandem axle loads per day. The subgrade CBR is 8, the overall standard deviation is 0.45, the initial PSI is 4.2, and the final PSI is 2.5. What is the probability that this pavement will have a PSI above 2.5 after 25 years? (Drainage coefficients are 1.0.) **Round up the SN value to nearest integer**

urgent solution needed

Answer 1

be Ang According to the given in formation of the given problem, firstly we find the design Esala on the facity during the design life. ule lcnow the truck loada. Assume no gorowth in traffic Casince are not given any information about growth rate). But design life is 25 years. So, the ESAL loading for est Total design ESAL load. Assume Lane distribution factor and directionality factoo are Calculate truck factors for different loadingen Truck factor (per truck) for 22 lip single axle loads year 495 22 x 1000 18000 1. Jde

→ Truck factor (per truck) for 34 kip single axle loade; 34 X 1000 :1.889 (8000 Dellepp trucke Bo, Esal's due to Indled x 400 x 365 X25 4461117 So, ESAL's due to 34 kip trucks 1889 x 800 x 365 x 25 on Total ESALS the design during 13788889 the roadulay life = 4461111 +13788889 18250000 Assume that layeon coefficientes foor asphalt wearing surface is 0.35, for soil cement bagge it is 0.00 for crushed stone sub-base is ooll. Based on an empinical cruation MR 10, 33 Y CBR CBR = 8

MR = S2. 64 be IS, MpA = 11983psi 28., have Onlar three layers as follows Structural number? SN=5 Now use the flexible porement design thickness- formula to this formula is ię known to be calculate the where SN = 5 18 predicted number of 18 løp Coads ie; Esals s ( 8 250000 ToR = Standard normal deviate So combined standard error of traffic prediction and peor formance predictiona given to be SN = structural numbers can index that ia indicative of the total pavement thickness required) 0,45

o is in inches, a 9, Dimt aqoamat 930₂ m 3 where We are given that mema-mg / This is calculated to be 6 (Grounded off) Layer coffficients assume that layer coffficients foot asphalt cleaning Surface ię 0. 35, poor soil cement base it is o.20 and for crushed stone sub-bagse it is ooll. o is the thickness in inches. All drainage coffficients are difference design Serviceability inder Po and terminal design Serviceability index Pk 4. Q.5 and ',' Delta psi betroeen initial Mr = subgrade resilient modulus Cinpsi) 11983 psi

So, calculate and find oud zor value 207: -3.72 a&o, Based on 24 tableas, this meana the reliability is close to 100% there probability of terminal Service index falling below 2.5 is Alternatively Service index being above please "uprote", Shank you. 23090. probability of terminal 2.5.2 }