Search
 
 

MECHANICS - CASE STUDY

    Introduction


Basic Steel Frame Structure


Center Column Joint at Top

 

A simple, four bay office building is being considered for additional equipment storage facility at the construction company where you work. The company would like to use the steel I-beams currently in storage at the company for the center columns. The list of available I-beams are given in the table at the left.

What is known:

  • Young's modulus, E, is 200 GPa.
  • Dead load on the roof is 300 kg/m2.
  • Live load on the roof is 250 kg/m2.
  • A factor of safety of 2.5 is required for all loads.
  • Columns are rigidly fixed to the ground.
  • Columns are assumed to be fixed at the top due to the rigid beams.
  • Yield stress in compression is 250 MPa.
   
  Question

 

What I-beam should be specified for the center column to minimize the total weight of the building? Chose only from the list at the left.

   
    Approach

Section Number
W310 x 67 W250 x 58
  x 39   x 45
  x 33   x 28
  x 24   x 22
  x 21   x 18
W200 x 59 W150 x 37
  x 46   x 30
  x 36   x 22
  x 22   x 24

Wide-Flange Beams Available
in the Storage Yard
 
  • Roof loads, dead and live, need to be combined for total design load.
  • Roof load needs to be distributed to each of the columns.
  • Assume failure will be buckling.
  • Use Euler's formula for fixed-fixed columns.

          
     
   
 
Practice Homework and Test problems now available in the 'Eng Mechanics' mobile app
Includes over 400 problems with complete detailed solutions.
Available now at the Google Play Store and Apple App Store.