A Beginner's Guide to ASCE 7-05 Chapter 2 - Load Combinations © 2007, 2009, T. Bartlett Quimby
 Overview The Load Combination Equations Comparing LRFD & ASD Results Example Problems Homework Problems References Report Errors or Make Suggestions

Section 2.5

Homework Problems

Last Revised: 08/02/2008

For all these problems, submit your work in a single Microsoft EXCEL file unless otherwise approved by your instructor.

Problem 2.1:  Create a general spreadsheet (using Microsoft EXCEL unless otherwise approved) to compute all load combinations (ASD and LRFD) that are listed in ASCE 7-05.  Test the spreadsheet using the data in Table 2.5.1.  You might want to test other load sources as well, but submit your spreadsheet with only the load sources shown.  The instructor will test it with other data sets.

Problem 2.2:  Sketch an isometric diagram of the beam in problem 2.1 with the annotated loads for cases LRFD-LC2b, LRFD-LC4b, ASD-LC2, and ASD-LC6a.  You will end up with four sketches, each showing the fully loaded beam for one load case (i.e. combine all the appropriate load sources from Figure 2.5.1 for each load case).  See Figure 2.5.2 for an example load combination drawing.  Digitally include the sketches in your EXCEL file on a page separate from the calculation.  Assume that the unit live load is less than 100 psf and that the beams supports neither a garage or place of public assembly.

Figure 2.5.1

Table 2.5.1
Sample Data and Results

 Loads Identifier uni1 uni2 lateral point Units klf klf klf k Dead D 0.85 8 0 12 Fluid Pressure F 0 0 0 0 Lateral Earth Pressure H 0 0 0 0 Live L 0.55 0 0 10 Roof Live Lr 0 0.25 0 13 Snow S 0 0.85 0 0 Rain R 0 0 0 0 Self Restraining T 0 0 0 0 Wind W 0 0 0.25 0 Earthquake E 0 0 0.35 0 LRFD max value 1.9 11.2 0.4 40.2 min value 0.765 7.2 -0.4 10.8 LRFD-LC1 1.19 11.2 0 16.8 LRFD-LC2a 1.9 9.725 0 36.9 LRFD-LC2b 1.9 10.025 0 30.4 LRFD-LC2c 1.9 9.6 0 30.4 LRFD-LC3a 1.295 10 0 40.2 LRFD-LC3b 1.02 10 0.2 35.2 LRFD-LC3c 1.295 10.96 0 19.4 LRFD-LC3d 1.02 10.96 0.2 14.4 LRFD-LC3e 1.295 9.6 0 19.4 LRFD-LC3f 1.02 9.6 0.2 14.4 LRFD-LC4a 1.295 9.725 0.4 25.9 LRFD-LC4b 1.295 10.025 0.4 19.4 LRFD-LC4c 1.295 9.6 0.4 19.4 LRFD-LC5a 1.295 9.77 0.35 19.4 LRFD-LC5b 1.295 9.77 -0.35 19.4 LRFD-LC6a 0.765 7.2 0.4 10.8 LRFD-LC6b 0.765 7.2 -0.4 10.8 LRFD-LC6c 0.765 7.2 0.35 10.8 LRFD-LC6d 0.765 7.2 -0.35 10.8 ASD max value 1.4 8.85 0.25 29.25 min value 0.51 4.8 -0.25 7.2 ASD-LC1 0.85 8 0 12 ASD-LC2 1.4 8 0 22 ASD-LC3a 0.85 8.25 0 25 ASD-LC3b 0.85 8.85 0 12 ASD-LC3c 0.85 8 0 12 ASD-LC4a 1.2625 8.1875 0 29.25 ASD-LC4b 1.2625 8.6375 0 19.5 ASD-LC4c 1.2625 8 0 19.5 ASD-LC5a 0.85 8 0.25 12 ASD-LC5b 0.85 8 -0.25 12 ASD-LC5c 0.85 8 0.245 12 ASD-LC5d 0.85 8 -0.245 12 ASD-LC6a 1.2625 8.1875 0.1875 29.25 ASD-LC6b 1.2625 8.6375 0.1875 19.5 ASD-LC6c 1.2625 8 0.1875 19.5 ASD-LC6d 1.2625 8.1875 -0.1875 29.25 ASD-LC6e 1.2625 8.6375 -0.1875 19.5 ASD-LC6f 1.2625 8 -0.1875 19.5 ASD-LC6g 1.2625 8.1875 0.18375 29.25 ASD-LC6h 1.2625 8.6375 0.18375 19.5 ASD-LC6i 1.2625 8 0.18375 19.5 ASD-LC6j 1.2625 8.1875 -0.18375 29.25 ASD-LC6k 1.2625 8.6375 -0.18375 19.5 ASD-LC6l 1.2625 8 -0.18375 19.5 ASD-LC7a 0.51 4.8 0.25 7.2 ASD-LC7b 0.51 4.8 -0.25 7.2 ASD-LC8a 0.51 4.8 0.245 7.2 ASD-LC8b 0.51 4.8 -0.245 7.2

Figure 5.2.2