ARCH 631 F2007abn
1
ARCH 631. Assignment #11
Date: 11/1/07, due 11/27/07 Worth 25 pts.
Problems:
1. Describe a plastic hinge in a steel beam with respect to the stress and maximum resisting
moment quantities with respect to the stress and maximum moment for linear-elastic design
(non plastic).
2. Sketch, with the appropriate angles, the load distribution on a simply supported lintel over a
masonry wall opening that has sufficient width of wall on both sides of the opening and a solid
story of masonry above (arching action present).
3. Describe how you would identify a moment-resisting (rigid) connection in a steel frame with
respect to geometry and construction.
4. Lateral stability is particularly important for steel shapes such as plate girders and wide flange
sections. Describe the reasoning for the concern and ways to prevent problems.
5. A long span steel joist with a span of 80 feet is required to support a roof. The joists are spaced
at 4 ft apart, the dead load is 12 lb/ft2 (not including the self weight), the live load is 28 lb/ft2
and the live load deflection is limited to L/360 (which is that used to determine the live load
limit based on deflection in the Joist catalogue tables). Using the table provided, select the most
economical joist that can be used.
6. An open web joist has a span of 65 ft and supports a distributed live load of 150 lb/ft and dead
load of 210 lb/ft. In addition, there is a concentrated dead load of 2000 lb at 10 ft from one
support. Neglecting self weight of the joist, determine the equivalent distributed load based on
maximum moment and select a 40LH joist. Use Multiframe4D to determine the maximum
moment from the service loads*. Submit the model file to the Assignments folder in the class
folder, and provide a print of the diagram.
*NOTE: Multiframe4D determines the maximum moment for a limited number of locations on
the beam in order to display a “maximum” in the plot window detail. Because of the large
point load, it is best to put a joint at the application of the load (two beam segments).
Partial Answer: wequivalent = 379.2 lb/ft.
7. Why would you consider reinforcing a masonry shear wall? Give your answer with respect to
stresses developed.
8. A base plate is 18 in. x 16 in. for a W12 x 58 column (d=12.2 in, bf = 10.0 in). The design load,
Pu is 600 kips and the concrete strength is 5000 psi. What is the required thickness of the plate
when it is A36 steel (Fy = 36 ksi)?
Partial Answer:
λ
n’ = 2.76 in, l = 4 in.
