If pavement and sub grade are considered as two layer system a stiff factor is to be introduced to take into account the different values of modulus of elasticity of the two layers. if the modulus of elasticity of the subgrade is 100 kg/cm2 and the modulus of elasticity of the pavement is 1000kg/cm2, what is the stiffness factor ?

If pavement and sub grade are considered as two layer system a stiff factor is to be introduced to take into account the different values of modulus of elasticity of the two layers. if the modulus of elasticity of the subgrade is 100 kg/cm2 and the modulus of elasticity of the pavement is 1000kg/cm2, what is the stiffness factor ?

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter20: Design Of Rigid Pavements

Section: Chapter Questions

Problem 7P

See similar textbooks

Similar questions

The thickness of a concrete pavement slab is 20 cm and has modulus of elasticity and Poisson's ratio of 3x105 kg/cm2 and 0.15, respectively. Determine the radius of relative stiffness of the slab if it is resting on a subgrade of 5 kg/cm3 modulus.
A concrete pavement slab is 20 cm thick, with a modulus of elasticisty of 3x105 kg/cm2 and a poisson's ratio of 0.15, respectively. Determine the slab's relative stiffness radius if it is sitting on a 5 kg/cm3 modulus subgrade.
A rigid pavement has a wheel load capacity of 53.96 kN. The allowable tensile stress of concrete is 1.37 MPa. Determine the thickness (cm) of the pavement if dowels are negligible. Express your answer in 1 decimal place.
Design a pavement for a rural interstate highway. The expected design ESAL is 13x106. The pavement structure is to consist of asphalt concrete with an elastic modulus of 400000psi, a granular base with an elastic modulus of 26000psi, and a granular subbase with an elastic modulus of 12000psi. The elastic modulus of the subgrade is 8000psi. It is estimated that it will take a week for water to drain from the pavement and that the pavement will be saturated about 15% of the time. Assume that a reliability level o about 90% is required and that the initial serviceability index is 4.2 and the final serviceability index is 2.5.
Problem 32: What is the stiffness factor of a pavement if the modulus of elasticity is 180 MPa and whose subgrade modulus is 40 MPa?
A rigid pavement is to be used to carry a wheel load of 58.77 kN. Enough dowels will be used across the joint. The allowable tensile strength of concrete is 1.45 MPa. Thus, what will be the difference in thickness (in mm) between the edge and the center of the pavement?
What are the critical pavement responses in flexible pavements that can be analyzed using structural models? What are the typical resilient (elastic) modulus values for fine-grained subgrade soil, coarse grained subgrade soil, granular base, cement stabilized base, PCC, AC (at different temperatures), etc.? How sensitive are the critical pavement responses to (a) increased tire pressure, (b) increased subgrade strength, (c) Poisson's ratio changes, (d) lime stabilization of top 6 in. of subgrade, (e) asphalt or cement stabilization of base layer, etc.?
Question 18 A rigid pavement has a wheel load capacity of 53.96 kN. The allowable tensile stress of concrete is 1.37 MPa. Determine the thickness (cm) of the pavement if dowels are negligible. Express your answer in 1 decimal place.
The following figure shows concrete pavement with the layer thickness and elastic modulus as indicated. Assume modulus of rupture of 650 psi, load transfer coefficient of 3.2, serviceability loss from 4.5 to 2.5, and drainage coefficient of 0.9. The bedrock depth and loss of support is not considered for the subgrade. Use the design equation or monograph with 50% reliability to solve the following: 1) Determine the number of ESAL that the pavement can carry before failure. 2) If the daily traffic has 1080 single axles (20-kip), 400 single axles (24-kip), and 680 tandem axles (40-kip), and the annul traffic is the same over the design period, how many years would the concrete pavement last before failure? 8-inch Portland Cement Concrete Ec=4×106 psi 8-inch Granular Subbase Ec=30,000 psi Subgrade Mr = 5000 psi
Discuss various tests used for the quality of aggregate used in flexible pavements.
3. a) What is meant by dowel bar? Why it is used in the rigid pavement? b) Design the Dowel Bars for the following parameters: i) Design wheel load = 5100 kg ii) Design load transfer 40% iii) Slab thickness 30 cm iv) Joint width = 2.0 cm v) Modulus of dowel support = 42000 kg/em3 vi) Modulus of elasticity of dowel bar = 2x106 kg/cm2 vii) Modulus of subgrade reaction = 8 %3D viii) Grade of concrete = M 50
A 16 cm thick reinforced concrete pavement slab has an elastic modulus equal to 3x105 kg/cm? and Poisson's ratio equal to 0.12. Calculate the radius of relative stiffness for the slab if it is placed on a sub grade of modulus equal to 7 kg/cm³.