Plastic Design of Steel Beam

Plastic design of a steel beam is a method to determine the design strength of a steel beam by considering plastic behavior of steel. This method is based on the assumption that steel reaches its yield stress in a plastic range without any significant increase in stress.

Modes of Failure in Plastic Design of Steel Beam

There are several modes of failure that are taken care of in plastic design of a steel beam. These are as follows:

1. Hinge Formation: Hinge formation is a phenomenon that occurs due to yielding of steel. In this mode of failure, the beam undergoes inelastic deformation and a plastic hinge is formed at the location of maximum moment. Plastic design of a steel beam takes care of this mode of failure by designing the beam for the formation of hinges at the desired locations.

2. Lateral Buckling: Lateral buckling is a mode of failure that occurs in slender beams when the compression flange of the beam buckles laterally due to the compressive stress. This mode of failure is taken care of in plastic design of a steel beam by designing the beam to prevent the lateral buckling of the compression flange.

3. Elastic Buckling: Elastic buckling is a mode of failure that occurs in slender beams when the beam buckles elastically due to the compressive stress. This mode of failure is not considered in plastic design of a steel beam because plastic design assumes that the steel beam will undergo plastic deformation before it reaches the elastic buckling limit.

4. Plastic Material Deformation: Plastic material deformation is a mode of failure that occurs throughout the beam when the steel material undergoes plastic deformation. This mode of failure is taken care of in plastic design of a steel beam by designing the beam to undergo plastic deformation without significant increase in stress.

Conclusion

In conclusion, plastic design of a steel beam is a method to determine the design strength of a steel beam by considering plastic behavior of steel. Plastic design takes care of several modes of failure including hinge formation, lateral buckling, and plastic material deformation. By designing the beam to prevent these modes of failure, the plastic design method ensures that the beam will have the required strength and stiffness to withstand the applied loads.