Reference no: EM133141029
EG7032 Highway & Railway Engineering Assignment - University of East London
Assignment title - Highway & Railway Engineering Individual Project
Project Brief - You are an engineer working for an engineering consultancy who has been commissioned by a transport authority to provide technical assistance related to the following highway and railway problems:
1. Highway maintenance, assessment and methods
1a) A site investigation was conducted on an existing highway pavement located in a subtropical temperature environment. Sections of the highway have experienced premature distresses such as that shown in Figure Q1.1. Overloading is a known problem in the area. Results of gradation tests conducted on samples taken within selected sections of the road revealed the particle size distribution shown Table Q1.1 and average air voids of 2.5%. Falling Weight Deflectometer (FWD) deflection data indicated that the base can be considered as marginal. Based on the given information, write a short report indicating what you think are the likely causes of the premature failure. Clearly describe your approach assuming the pavements were designed using UK pavement mix design standards. Clearly state all your assumptions.
1b) A section of the pavement was overlaid with 50 mm of asphalt concrete (AC) binder course and 40 mm of AC wearing course. The pavement developed rutting (average rut depth of 20 mm) during the first summer after construction. Which AC course has likely contributed to the development of rutting? What is the most suitable way to determine the layer causing the problem?
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Table Q1.1 Gradation results for asphalt layer along highway route
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Sieve size (mm)
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25.0
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19.0
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12.5
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4.75
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2.36
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0.600
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0.300
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0.150
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0.075
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% passing
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100
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100
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100
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65
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49
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33
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21
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16
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9
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2. Highway Pavement Analysis and Design
A highway pavement is to be designed for the 2-lane access road servicing a large distribution warehouse. The pavement is to consist of hydraulically bound material (HBM) base layer (C3/4) surfaced with high quality asphalt layers. The exit lane (considered the design lane) pavement is to be trafficked by heavily loaded trucks only. The following trafficking conditions apply:
The exit lane pavement will be trafficked by 150 OGV2s trucks per day.
Each loaded truck has four axles of load 110kN and one (steering) axle of load 65kN as illustrated in Figure Q2.1.
Assume a load equivalency factor of 4.
Sharp turns, braking and accidental loading are expected to contribute to about 50% increase in the applied axle loads.
Number of operating days per year = 365.
Design life is estimated at 25 years.
The subgrade quality based on the falling Weight Deflection (FWD) deflection / back- calculated modulus inferred CBR of ranged from about 5-7% (40-98 MPa stiffness) which indicates low quality, clayey soil with lot of plastic fines (Table Q2.1). Assume 15 percentile subgrade stiffness for design.
Tire pressure = 566 kPa.
Assume Figure Q2.2 represents the cross-section of the pavement to be designed.
a) Determine the thicknesses of the HBM sub-base and the asphalt layers using CD 225.
b) Check the designs provided in a) using the WESLEA pavement analysis software focusing on the critical pavement responses in the asphalt layer, the HBM subbase and the clayey subgrade. Assume tensile strength of the HBM to be a minimum of 250 kPa. The stress ratio is to be limited to 50% and the tensile strain limited to 120 microtrains. Maximum tensile strain in the asphalt should not exceed 150 microstrains. Maximum compressive strain in the subgrade should be limited to between 200-400 microstrains.
c) Discuss the impact of overloading in HBM and in asphalt layers indicating which material type is more sensitive to overloading.
3. Track structure analysis & design
a. Describe, with illustrations, four types of trackbed structures in common use indicating some of their advantages and disadvantages.
b. For the track structure shown in Figure Q3.1, it is desired to replace the concrete ties with wooden ties. Determine the reduction in service life as a result of the change from wooden ties to concrete ties. Clearly state all assumptions made. You can use any layer elastic analysis software of your choice, but it is recommended to us Kentrack software as discussed in class.
4. Environmental impacts
a. Discuss the different hardness tests for ballast and state their advantages and disadvantages.
b. Discuss the factors that are critical to aggregates used for construction track ballast high speed rail applications.
c. Discuss the different types of rail defects and their causes.
Note - It should be 6000 words and all related figures are in attached file. Weslea and kentrack these are software's that we used to do the assignment.
Attachment:- Highway & Railway Engineering Assignment File.rar