What's Happening @ BELCO ENGINEERS;: Reinforcing Primary Members In Semitrailers

The topic I have taken today is very important and relevant. The manufacturers have to understand that all approved designs take into consideration the rated load to be carried and also a factor of safety is added along with the corrosion allowance depending on the climatic conditions of a place where the fleet is to be operated.

This results in a structure which is optimal in weight and the transporter also ends up getting more payload for a prime mover of a particular capacity. But this market of manufacture of trailers is highly competitive and is also customer driven. Sometimes the design of a vehicle is altered to suit the customer's whims and fancies flouting all engineering norms.

A case in point is if we consider the transporters operating over dimensional cargo with over load. They insist that the primary member be reinforced with an additional flat which is welded on the bottom flange of the main beam. The point I am trying to make is here is that the flat is welded in such a location that it does not affect the moment of inertia in any way, moreover the thickness of the flat welded for reinforcing is three times the thickness of the bottom flange or the primary members. After welding such a flat to the beam it only results in increase in stresses due to heavy welding. Failure due to heat affected zone is evident and the purpose is defeated!! A classic example of failure is shown in the pictures above.

This factor must be considered by the transporters because it affects the rated payloads and the fabricator ends up using more steel without acheiving the objective of strengthening.

REINFORCEMENT OF PRIMARY MEMBERS AT OUR WORKS