Final Exam for Structural Technology I | CM 3505, Exams of Introduction to Business Management

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CM 3505 Final Exam Sample Test Do not consider this sample test as limiting what may be on your final exam. Consider possible variations and alternative questions and problems. Part 1 may include some old material and some questions on topics not addressed in this sample test. Part 2 may also include old material not addressed here, as discussed in class. INSTRUCTIONS Part 1 is to be completed without notes, calculator or any other reference materials. A calculator, 3 sheets of HANDWRITTEN notes (front and back) and beam tables are allowed while taking Part 2 of the exam along with the reference materials provided with this test. Read the questions carefully. Do all that is asked for. Show your answers clearly. Include units wherever appropriate in your final answers for full credit. Part 1 Short answer: For a beam with a symmetrical cross section, horizontal shear stress will be greatest at the _____________________________________. Cables are always considered to be in _____________________________. (type of stress) Give an example of a dead load. ____________________________________________ Wood is generally stronger when stressed in a direction ________________ to the grain. Following the sign convention used in the text, a simple beam with only gravity loads acting between the supports would have a __________________ bending moment. (positive or negative) A simple beam as described in the previous question would be in _______________ on the top surface and in _________________ on the bottom surface. (type of stress)

SAMPLE

A cantilever, having only either concentrated point or uniformly distributed gravity loads placed on it will: have the maximum shear force at or near _______________________. (location) have the maximum bending moment at or near ________________________. (location) be in _______________ on the top surface and in _________________ on the bottom surface. (type of stress) have maximum deflection at or near _________________________. (location) If two columns vary only in the end conditions, then: a column with fixed ends will have a ____________________ critical load of buckling than one with pinned ends. (relative magnitude) A larger KL/r indicates a ______________________ critical load of buckling. (relative magnitude) Give a reason for limiting the deflection of a beam, even though that beam is well within other limits regarding failure. ________________________________________________ In the blanks near each member indicate T, C or 0 for Tension, Compression or zero force. Also be prepared for a qualitative Framing problem.

Part 2

1. PINNED FRAME Determine all the force components and reactions acting on members AC, BE and DE of the pin-jointed structure shown below and label FBD’s with the results.

2. SHEAR and MOMENT DIAGRAM Determine the reactions and draw the shear and moment diagram and the deflected shape for the beam shown below. Label the drawings with values for reactions, shear and moment. V ____________________________________ M ____________________________________ D ____________________________________

3. TRUSS Find the forces in the members AC, AI, CD, CI, DI, EF, EJ, EK, GH, and JK for the truss shown below. Indicate magnitude and sense of the forces in each member. AC = _______________ AI =

---

CD =

---

CI =

---

DI =

---

EF =

---

EJ =

---

EK =

________________

GH =

________________

JK =

________________

4) HORIZONTAL SHEAR STRESS Find f v max for the two beam cross sections if each

were loaded as shown below. For the built-up section Ix = 533 in^4

f v max = ________________ f v max =

________________

5) DEFLECTION

a) Find maximum deflection for a 36’ W10x30 beam with a uniformly distributed load of 200 lb./ft. Allowable deflection is limited to L/360, is deflection O.K.

Δ allow = ________________

Δ max = ________________

Deflection O.K. ______________ b) Write the equation for maximum deflection of the beam shown below.

6. FRAMING Complete the beam loading diagrams for the indicated beams from the framing plan shown. Include loading patterns with values and reactions for all loads for beams AB, CD and GH. LL = 60 lb/ft^2 DL = 20 lb/ft^2 A ______________________ B C ______________________________________________ D

G ______________________________________________ H

7. Select the lightest adequate W-section with a nominal depth of 14 in or less, for a 32ft. beam with a total uniformly distributed load of 1200 lb/ft. Select the beam based on bending stress then check to see if deflection is O.K. LL Allowable deflection = L/ Fb = 2/3 Yield strength for mild, low carbon steel (as listed in appendix) LL is 70% of total load M (^) max = ________________ Sr = ______________

Selection = ________________

Δ LL allow = ________________

Δ LL max = ________________

Deflection O.K. ______________

8. WOOD BEAM SELECTION Select the joist to be used to frame a floor spanning 14 ft. Use Southern Pine No. 2 2 x’s with a 16” spacing on center. Consider the joist to be repetitive members. Check Bending Stress, Shear Stress and LL deflection. LL Allowable deflection = L/ LL = 30 lb/ft^2 DL = 10 lb/ft^2 M (^) max = ________________

Sr or f b = ______________

f b O.K. ________________

Selection ________________ V = ________________

f v max = ________________

Shear stress O.K. ______________

Δ LL allow = ________________

Δ LL max = ________________

Deflection O.K. ______________

9. COLUMNS A W8x48 is used as a column. The weak axis is braced 25’ from the bottom and the bottom end condition is fixed in all directions. The top is pinned in all directions and the weak axis bracing is pinned. Draw the buckled shape for each axis. Find the critical load of buckling and the critical stress of buckling. Length = 40ft.