CVE80020 Bridge Design – Assignment 3: Bridge analysis Due: 5 PM Wednesday 25 April
Assignment submissions must be neatly written or typed, scanned and uploaded on Blackboard. All pages including the cover sheet must be submitted as a single pdf (i.e. all pages in one document) – no other format will be accepted. Mark deductions (or no marks) will be given where pages are unreadable, upside down or rotated.
This assignment is worth 15% of the marks for this subject.
The presentation of engineering concepts is an important part of your work – as an engineer, other engineers will need to read and understand what you have done. For this assignment either hand written or typed is acceptable: • use A4 portrait pages (use lined paper if hand written)
• all writing is to be neat and is to be written on the lines of the paper
• all diagrams are to be drawn to scale (where “Spacegass diagrams” are required these are to be taken from Spacegass, but all other diagrams are to be drawn by you)
• all lines are to be drawn with a ruler (includes diagrams, graphs, underlining, formulae, arrows, crossing out etc. – no freehand lines)
• You will automatically lose half your assignment mark if you fail to comply with just one of these requirements
A new wharf is to be built to handle shipping containers. The containers will be moved along the wharf using a straddle carrier.
The wharf will be built as a series of single span bridges. Each bridge has a width of 6.3 m and a span of 21 m.
The critical design load is the load from a fully loaded straddle carrier driving along the bridge.
Each bridge is not required to have any edge barriers or any asphalt surfacing – only the beams and the slab, both of which will use 40 MPa concrete (26.5 kN/m3).
Each bridge will be constructed using 3 identical beams (equally spaced laterally) and a 200mm thick slab.
The straddle carrier is a Kone model N SC 644 E.
Consider just one span of the wharf (one bridge). The only loads you need to consider are the static axle loads and the self weight of the bridge. Do not apply any load factors (either for ultimate limit state or for dynamic load allowance). You do not need to report any results for the transverse slab.
Using the data provided in Lecture 2, select an appropriate size of open top Super T beam for the bridge, and a slab thickness.
Calculate the appropriate section properties for the composite beams (Super T + slab). Model the structure in Spacegass as a grillage, with 7 transverse members.
Submit your design report with the following information:
1. Hand calculations for the section properties of the composite section A, Ix, Iy, J (the properties of the Super T beam should be taken from the relevant table in AS 5100, provided in the lectures).
2. Hand calculations to determine both the longitudinal and the transverse location of the straddle carrier on the bridge that gives the maximum bending moment in any longitudinal beam, and the equivalent loads to be applied in the Spacegass model. Assume that the wheel centreline will never be closer than 600mm from the edge of the slab.
3. A loading diagram (drawn by you on a scale plan of the bridge showing all grillage members). This loading diagram should show the actual dimensioned location of every wheel so as to produce the maximum bending moment in a longitudinal beam. It should also show the values and locations of the loads applied to the grillage members to represent these actual wheel loads and locations.
4. Separate Spacegass diagrams of (a) wheel loading only (b) self weight loading only (c) total deflection in all members, and (d) total bending moment in the longitudinal beams only. All of these are for the straddle carrier position that produces the maximum bending moment in a longitudinal beam. All diagrams are to have the values displayed.
5. The checking that you have undertaken to verify your results.