Module 5 : Force Method - Introduction and applications
Lecture 3 : Analysis of Statically Indeterminate Structures by Energy Method

Example 5.20 Analyze the portal frame shown in Figure 5.23 by strain energy method.

 

 

Solution: Static indeterminacy of the frame = 2. Horizontal and vertical reactions at A are taken as redundant.

For the span AB ( x measured from A ),

 

                           

 

                           

                             
                     
                              
                            
                             
 

Since                          

 

or                     6 V + 4 H = 3 wL

 (i)
 

and                             

 

or                     32 V + 12 H = 15 wL

 (ii)
 

Solving Eqs (i) and (ii) for H and V ,  
   
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