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Highyway Mini Project

The document discusses six questions related to determining properties of multi-layer pavement systems under various loading conditions. Question 1 asks to determine the elastic modulus of layer 1 in a two-layer system given the total load, plate diameter, layer thicknesses, and measured deflection. Question 2 asks to determine the vertical deflection at the interface beneath a dual tire loading. Question 3 asks to determine the critical tensile strain in the asphalt layer for a dual tire loading. Questions 4-5 ask to determine deflections or strains at various times and configurations. Question 6 provides traffic data and asks to determine the traffic class and design pavement thickness.

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kinde meko
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22 views5 pages

Highyway Mini Project

The document discusses six questions related to determining properties of multi-layer pavement systems under various loading conditions. Question 1 asks to determine the elastic modulus of layer 1 in a two-layer system given the total load, plate diameter, layer thicknesses, and measured deflection. Question 2 asks to determine the vertical deflection at the interface beneath a dual tire loading. Question 3 asks to determine the critical tensile strain in the asphalt layer for a dual tire loading. Questions 4-5 ask to determine deflections or strains at various times and configurations. Question 6 provides traffic data and asks to determine the traffic class and design pavement thickness.

Uploaded by

kinde meko
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© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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1.

A total load of (89kN) was applied on the surface of a two-layer

system through a rigid plate (305 mm) in diameter, as shown in


Figure 1. Layer 1 has a thickness of (203 mm) and layer 2 has an
elastic modulus of (44 .2 MPa). Both layers are incompressible with a
Poisson ratio of 0 .5. If the deflection of the plate is (2 .54 mm),
determine the elastic c modulus of layer 1.

2. Figure 2 shows a set of dual tires, each having contact radius (115

mm) and contact pressure (483 kPa). The center-to-center spacing of


the dual is (343 mm). Layer 1 has thickness (152 mm) and elastic
modulus (690 MPa); layer 2 has elastic modulus (69 MPa).
Determine the vertical deflection at point A, which is on the interface
beneath the center of one loaded area.
3. For the same pavement as in question 1, if the (40-kN) load is applied

over a set of dua l tires with a center-to-center spacing of (292 mm)


and a contact pressure of (467 kPa), as shown in Figure 2 .24,
determine the critical tensile strain in the asphalt layer.

4. Figure 4 shows a viscoelastic two-layer system under a circular

loaded area having radius (254 mm) and uniform pressure (690 kPa).
The thickness of layer 1 is (254 mm), and both layers are
incompressible, with Poisson ratio
0.5. The creep compliances of the two materials at five different
times are tabulated in Table 2.5. Determine the surface deflection

under the center of the loaded area at the given times.

5. Same as above question #3 above, except that an identical set of duals

is added to form dual-tandem wheels having the tandem spacing St


(1.25 m), as shown in Figure 5. Determine the strain at the bottom of

layer 1.

6. Based up on the given the initial AADT in table below, determine the traffic
class and design the pavement thickness
The anticipated traffic growth is a constant 5%, and the opening of the road is scheduled for

2027E.C. To make more accurate we use 2020 traffic data as seven days count and we estimate

AADT0 for the counting time. The projected AADTs 2027 for both directions can be calculated

as;

Traffic Forecasting
Vehicle Cars 4WD Small Large Large Medium Heavy Truck &
classification bus bus bus
truck truck trailer

AADTo (2000) 20 100 80 70 102 208 130 120

➢ Opening of the road = 2027, Surveying year = 2020

➢ The anticipated traffic growth is constant 5% and

➢ The directional flow is assumed 50/50.


➢ Paved road with design period of 20 years

For this project opening of the road is at starting of 2027. So, X= (2027-2020) -1= 6

AADT1 = AADTo(1 + i)x

Where: i=growth rate = 5% x=the anticipated number of years between


traffic survey & the opening of the road ✓ Axle load survey for the
project
S/Bus L/Bus L/Truck M/Truck T/Trailer

Axle Axle Axle Axle Axle Axle Axle Axle Axle Axle Axle Axle

1 2 1 2 1 2 1 2 1 2 3 4

2178 2870 3038 5184 5634 6829 5612 8963 5465 12036 7323 7623

2405 2876 2925 5617 5782 6436 6289 7189 5645 10405 7305 7418

2315 2832 2977 5665 4694 7374 5308 9894 5148 10372 6964 8699

2251 2855 3099 5376 4351 7075 6531 7615 5635 11955 8206 7550

1917 3096 2998 5620 4928 6464 6601 9407 5046 9397 7208 6660

2291 3212 2698 5665 4784 7895 5394 8634 5787 8154 8892 9704

1950 2829 2844 5267 5249 6350 6917 8954 5669 12279 7889 9138

2234 3184 2753 5191 4154 7822 5592 7451 5941 9940 7368 9435

2293 3056 3064 5271 4733 7680 5312 9991 5137 12523 6005 9481

2427 2652 3119 5036 4900 6641 5888 7764 5835 11497 6385 6718

2013 2766 3046 5286 4358 6717 6021 9298 5348 8825 8197 7776

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