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For this assignment, you will be responsible for some calculations related to the steel arch members on the
new Sellwood Bridge.
Figure Sellwood Bridge During Construction (Looking East from West Abutment/Shore)
Assume that you are an intern working for the principal designer of the bridge, and that your supervisor asks
you to run "quick normal stress calculation" at specific location on the arch member because the
contractor is proposing a revised construction sequence that will increase the demands at that point. In
deciding whether the revised construction sequence is even feasible your supervisor wants to know "how
hard the arch is working."
The supervisor specifically asks you for themaximum normal stress and maximum shear stress at the cross-
section/location of interest. The supervisor tells you to "ignore torsion and weak axis' shear (i.e V2)-those
are too smallto make any real difference).
Finally, the supervisor asks you to provide Demand to-Capacity Ratio" (D/C) for normal stress and shear
stress, thatis equal to the maximum actual stress, divided by the yield stress. Assume Tyield = 0.58 Tyield
Attached, find the relevant excerpts from the Sellwood plan set and structural analysis calcs
1. General Plan and Elevation: Shows the section of interest relative to the entire structure
2. General Notes: Shows the material properties for the steel (50 ksi yield strength)
3. Arch Rib Details: Shows the cross-sectional dimensions for the section of interest (Note: use the
"Typical Arch Rib Section" diagramin concert with the highlighted row from the table)
4. Structural Analysis Output: This provides the cross-sectional resultants (N, Vv. V2, Mz, My) for the
section of interest (Note: read the column headers to determine which resultants (and units) are
provided)
Deliverable
You are tasked with producing a calculation package for the stress checks.
1. Cover Page provide cover page with the following:
a. Centered on the page, provide descriptive title for the calo package Make sure to clearly
indicate the project location, descriptive title, and description of the types of calculation
2.
Calculations: Provide the following calculations, each must have its own descriptive heading (bold,
underlined), and clearly indicate the final answer (boxed, at right margin):
a. Given: Provide the relevant given information
i. Engineering diagram of cross section (showing relevant geometry, axes, etc.)
ii. Relevant loads/resultants
b. Normal Stress: Calculate the maximum normal stress at the cross -section/location of interest.
Make sure to use subheadings and clearly identify/provide:
i. Fundamental Equations
ii. Moment of Inertia calculations
iii. Maximum normal stress (including sign, magnitude, and location)
iv. Demand Capacity Ratic (P/ =
c. Shear Stress: Calculate the following for a in diameter shaft comprised solely of the steel core
material
i. Fundamental Equations
ii. Moment of Inertia, and first moment of area (Q) calculations (may refer to normal stress
calculations where duplicative)
iii. Maximum shear stress (including magnitude and Nocation)
iv. Demand Capacity Ratic (P/c Tactual
/Tyield'
d. Summary
i. Provide [again] the Demand Capacity ratios for normal stress and shear stress

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