CE 3014 DESIGN OF TIMBER STRUCTURE Sample Questions

YANGON TECHNOLOGICAL UNIVERSITY
DEPARTMENT OF CIVIL ENGINEERING
CE 3014
DESIGN OF TIMBER STRUCTURE
Sample Questions
(For Semester II)
August 2008
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CE 3014 – Design of Timber Structure
Sample Questions and Solutions for Semester II
Chapter 1: Design of Wood Bridges
1. Write an introductory short note about timber bridges.
Solution: See page-1 of the text book.
The simplest type of wood bridge used consists of ………………. The advantages of
this product over the nail-laminated deck are numerous.
2. Discuss the provisions of AASHTO Specifications affecting the design of wood bridges
for the maximum bending moment.
Solution: See from page-1 to page-3 of the text book.
Two systems of highway live loading are provided, the H loading and the HS
loadings. ………………. No longitudinal distribution of the wheel loads is assumed;
lateral distribution is considered by applying to the stringer the fraction of a wheel load
(both front and rear) given by Table1.1. (Including Figure 1.2 and Table 1.1)
3. Discuss the provisions of AASHTO Specifications affecting the design of wood bridges
for the end shear and the additional effects of impact.
Solution: See from page-1 to page-2, and from page-3 to page- 4 of the text book.
Two systems of highway live loading are provided, the H loading and the HS
loadings. ………………. The concentrated load and uniform load shall be considered as
uniformly distributed over a 10-foot width on a line normal to the center line of the lane.
For the determination of end shears and end reactions in transverse floor beams and
longitudinal beams and stringers, …………….. L is the length in feet of the portion of
the span which is loaded to produce the maximum stress in the member. (Including
Equation 1.1)
4. Design a two-lane highway trestle suitable for H-20-44 traffic with bents at 17 ft. spacing
and a minimum 24 ft. width of roadway. For the laminated decking, use rough sawn wood
and any unevenness to be covered by the asphaltic wearing surface. The stringers are to
be designed using surfaced-four-sides, S4S, timbers. Use wood for which Fb = 2.3 ksi,
Fv = 0.125 ksi and unit weight, γ = 50 pcf for decking and for stringer, select a grade and
species of wood with the following design stresses; Fb = 1.7 ksi, Fv = 0.105 ksi, E = 1600
ksi, and unit weight, γ = 50 pcf. Assume unit weight of asphaltic concrete = 150 pcf.
Solution: See the illustrative example from page-51 to page-11 of the text book.
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5. Design the timber bridge with doweled decks using the following design criteria for
stringer design, deck design and dowel design.
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6. Design the timber bridge with non-doweled decks on longitudinal stringers using
the following design criteria for stringer design, deck design, and post and rail design.
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7. Design the simple-span longitudinal deck bridge with transverse stiffeners using
glued laminated timber panels for the following design criteria.
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