The architect wants an open layout for a new medical facility. Therefore, the best lateral load-resisting system is a rigid frame. In order to make the preliminary selection of members, the team leader would like an idea of the internal forces in the beams. At the same time, the geotechnical engineer would like preliminary results for the requirements on the foundations. A team member has calculated the unfactored lateral wind load on each rigid frame. Consider wind acting on the short face of the building. It is resisted by the longer rigid frame.
a. Guess the direction of each of the reactions at the base of columns B1 and B2.
b. What is the most appropriate method for approximate analysis of this frame? Why is that method most appropriate?
c. List the assumptions you make in order to perform an approximate analysis of the frame.
d. Use approximate analysis to determine the peak positive and negative moments for each of the beams in bay B 1-B2.
e. Use approximate analysis to find the reactions at the base of columns B1 and B2.
f. To demonstrate the effectiveness of approximate analysis, use structural analysis software to find the peak positive and negative moments for each of the beams in bay B 1-B2. Also, find the reactions at the base of columns B1 and B2. An experienced member of the team recommends we preliminarily estimate that all of the beams will be steel (E = 200 GPa = 200 kN/mm2 ) W530 x 82s (A = 1.045x104 mm2, I = 4.75x108 mm4) and all of the columns will be steel W310 x 86s bending about their weak axes (A = 1.097 x 104 mm2, I = 4.45x10 mm4 ). Submit a printout of the displaced shape.
G. Identify at least four features that suggest the displaced shape is reasonable.
h. Verify equilibrium of the computer aided analysis results.
i. Are the results of your computer aided analysis reasonable? Make a comprehensive argument to justify your answer. Comment on why your guess in part (a) was or was not close to the solution in part (e).
