Portal Method Of Analysis  For Lateral Loads

Portal Frame Method Forces

Portal Frame Method Forces


portal frame

Horizontal loads

Shear force calculation

BM Calculation


Compare with Actual Results


This method Presented by Albert Smith in the journals of “ Western society of  engineers” in 1915.

Approximate method,Horizontal force


Portal frame can be defined as two-dimensional rigid frames that have the basic characteristics of a rigid joint between column and beam. Portal frame construction is a method of building and designing structures. Because of these very strong and rigid joints, some of the bending moment in the rafters is transferred to the columns.   Portal frame construction is therefore typically seen in Warehouses and other places where large, open spaces are required at low cost and a pitched roof is acceptable.

The main objective of this form of design is to reduce bending moment in the beam, which allows the frame to act as one structural unit.

Portal frames are designed for the following loads

  • Roof load
  • Wind load

While designing, care should be taken for proper

  • Joints
  • Foundation


  • Point of contra-flexure occurs at the middle of all members of the frame.
  • Horizontal shear taken by each interior column is double of that taken by external Column,




  • 3