SCE5422 Bridge Engineering Assignment 2
Due date: 14 May 2021 Notes: Please submit your solution in a single PDF file. Submission in any other format will not
be accepted. Question 1
A simply supported bridge deck is subjected to various vertical actions with arrangement as shown in Figure 1. The vertical actions are comprised of distributed loads of 20 kN/m2 and 10 kN/m2, as well as axle loads of 250 kN, 300 kN, and 400 kN, where each axle has two wheels. (a) Determine the maximum and minimum vertical forces in Bearing B1 and B2 due to the
vertical actions. (b) Determine the torsional moment diagram along the deck and identify the location and
magnitude of maximum torsion.
Figure 1 Vertical load arrangement for the bridge in Question 1 (dimensions in mm)
B1
B2
B3
B4
Elevation
Plan Deck C.L.
Each axle has two wheels Deck C.L.
1400 1400
Section at support
Bearing C.L. Bearing C.L.
20 kN/m2
10 kN/m2
Prepared by: Dr. Cliff Leung Revision: Rev. 00 Page 2 of 2
Question 2
A two-span continuous concrete beam-and-slab bridge deck is shown in Figure 2a. Deck surfacing of 100 mm is provided. (a) Determine the temperature difference profile for the case of heating and the equivalent
moment corresponding to the temperature difference profile. (b) Determine the bending moment diagram for the bridge deck when the deck is subjected to
the temperature action by the temperature difference determined in Part (a). Reaction forces at each support of a two equal span continuous beam subject to concentrated moment at both ends are given in Figure 2b.
The coefficient of thermal expansion for concrete is to be taken as 10×10-6. The elastic modulus of concrete is to be taken as 32 GPa.
Figure 2a Two-span concrete bridge deck of Question 2
Figure 2b Reaction forces for a 2-span continuous beam subject to moment at both ends.
40 m 40 m
Span arrangement
Typical deck section
5 m
0.15 m
0.85 m Neutral axis
b
3 m 1 m 1 m
w For all girders: w = 0.2 m b = 0.5 m t = 0.15 m
t
0.28 m t
L L
R1 R2 R3
R1 = R3 = 1.5Me/L
R2 = -3Me/L
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