1.6 Stress-strain relationship of concrete

Understanding the Stress-Strain Relationship in Concrete

Overview of the Stress-Strength Curve

• The stress-strength curve for concrete under compression illustrates how stress is defined as force per unit area, while strength refers to deformations relative to the original size of the concrete member.

• The relationship between stress and strength initially follows a parabolic response, with ultimate strength reaching approximately 0.0035 (or 0.35% of the original size).

Elastic and Plastic Responses

• In the early stages, there is a linear relationship where stress development is nearly proportional to strength development; this phase is referred to as the elastic state.

• Beyond a certain point, the gradient of the curve decreases, indicating a transition to non-linear behavior known as plastic response; releasing stress in this region results in permanent deformations.

Simplified Analysis of Stress Strength Relationships

• While actual situations show a parabolic response in stress-strain relationships, for analytical simplicity, it can be approximated as a straight line.