ENGN150 – Fundamentals of Engineering Studies
Design Project 2
Preliminary Design of a Truss Bridge
Description: The local council in your city is required to connect two riverbanks by a truss bridge like the one in Figure 1. The designs, and their development, should comply with relevant requirements including:
• Manufacturer's guidelines and specifications such as the bridge must be capable of safely carrying the weight of the deck, the weight of the main trusses, and the weight of one standard H25 truck loading per lane.
• Sustainable design principles
• Australian standards
• Code of practice
• Health, safety, and environmental requirements
Figure 1: Sample proposed Truss Bridge [1]
The requirements of the bridge areas follows:
1. The Problem: You are a civil designer working for the State Department of Transportation. You have been assigned responsibility for the design of a truss bridge to carry a two-lane highway across the river valley shown below.
2. Design Objective: Satisfy all the specifications listed below, while keeping the total cost of the project as low as possible. The estimated cost of the project is between $5M – $7M.
3. Bridge Configuration
1. The bridge may cross the valley at any elevation from the high-water level to 24 meters above the high-water level.
2. If the elevation of the bridge is below 24 meters, excavation of the riverbanks will be required to achieve the correct highway elevation.
3. To provide clearance for overhead power lines (shown above), the highest point on the bridge may not exceed an elevation of 32.5 meters above the high-water level (8.5 meters above the top of the riverbanks) and 10 meters wide. The deck of the bridge will be made from a Medium-strength concrete thickness of 23 centimetres (0.23 metres).
4. Member Properties
• Materials. Each member of the truss will be made of carbon steel.
• The members of the truss can be either solid bars or hollow tubes. Both types of cross- loads
5. Cost
The cost of the design will be calculated using the following cost factors:
• Material Cost:
• Carbon steel bars - $4.50 per kilogram
• Carbon steel tubes - $6.30 per kilogram
• Reinforced concrete deck (medium strength) - $5,150 per 4-meter panel
• Each joint connector costs $500.00
Required:
1. Make a detailed list of all constraints and requirements for the bridge design.
2. Prepare functional specifications.
3. Present your design to meet the design specifications. The designs are to include, as relevant: Load calculations, which may include: free body diagram, loads, sheer forces, bending moments, and shear stresses.
4. Construction materials and services quantities
5. Construction cost estimates.
6. Standard engineering drawings of scale (1 : 200)
Report Format
The report must include the following:
Grade distribution Points
1) Frontpage (Name, school, project name, year, Session, etc.). 5%
2) Description of the requested design and related theories. 5%
(a) Clear specifications and related theories.
(b) The design should include 3D diagrams of the proposed design with dimensions.
3) Definitions, Equations used in the design and assumptions. 5%
4) Calculation of the design outlines shown above. 65%
(a) Volume calculation
(b) Mass Calculation
(c) Weight calculation and Force Analysis
(d) Cost Analysis
5) Discussion 10%
(a) Discuss your design considerations and decisions,
(b) Health, safety, and environmental requirements,
(c) Discuss what are the sustainable design requirements,
(d) Project total cost and feasibility of the design.
6) Conclusion
7) References 5%
8) Presentation 3-5 minutes (in week 13) 5%