In the plastic method of analysis of steel structures, which of the following conditions is also known as 'plastic moment condition"?

Explanation:

Plastic Moment Condition in Steel Structures

In the plastic method of analysis of steel structures, the term "plastic moment condition" is used to describe the situation where the moment at a section reaches the plastic moment capacity of the section. This means that the entire cross-section has yielded and is capable of sustaining the plastic moment. This condition is critical for the formation of plastic hinges, which are essential for the structure to undergo plastic deformations and redistribute moments. The plastic moment condition is specifically related to:

• Yield Condition

Analyzing the Given Options

1. "Mechanism condition." (NOT the correct answer)

   • The mechanism condition refers to the formation of a collapse mechanism in the structure, which happens after the plastic moment condition is reached but is not the same as the plastic moment condition itself.

2. "Yield condition." (Correct answer)

   • The yield condition is precisely what the plastic moment condition is about. It signifies that the section has yielded completely and can sustain the plastic moment.

3. "Continuity condition." (NOT the correct answer)

   • The continuity condition refers to the requirement that the structure remains continuous and unbroken. It is not directly related to the plastic moment condition.

4. "Equilibrium condition." (NOT the correct answer)

   • The equilibrium condition ensures that the internal forces in the structure are balanced with the external loads. While important, it is not specifically what is meant by the plastic moment condition.