T130: Approximate formulas are given in the LRFD Specifications for the stress in the prestressing steel at “nominal flexural resistance,” Mn. The use of these formulas simplifies the calculation of Mn by eliminating consideration of nonlinear material properties of both the concrete and prestressing steel at ultimate conditions (the nominal resistance). Caution should be used when applying the approximate formulas. They are based on a number of simplified assumptions. Other methods such as general strain compatibility will avoid difficulties and inaccuracies in the approximate formulas. These subjects with design examples are presented in this course.

After completing this course, the student will be able to:

• Apply the simplified method to calculate flexural resistance
• Use strain compatibility analysis to calculate flexural resistance
• Determine the section type and ф-factor based on the net strain in the extreme layer of steel
• Check minimum reinforcement requirements for the Strength Limit State