Design of Doubly Reinforced Beams 2 - Theory of Reinforced Concrete Structures

TL;DR

This video demonstrates an alternative method for designing a W reinforced beam, including determining xu max, mu limit, and area of steel.

Transcript

hello everyone my name is muhammad afuddin in this video we are going to learn design of w reinforced beam with another method okay in exam you can use the previous method or this method whichever you like okay so the given data is same they will give dimensions of the beam span of the beam and external loading or they will directly give bending mo... Read More

Key Insights

• 😁 Designing a W reinforced beam requires determining xu max, mu limit, and area of steel intention one (ast1) based on the grade of steel and concrete.
• 😶 The extra moment to be resisted by compression steel (mu2) is calculated by subtracting mu limit from the total moment (mu).
• 🥳 The fcc and fsc values are determined based on the d/d' ratio, and the area of compression steel is calculated using the formula mu2/(fsc - fcc) times (d - d').
• 😲 The area of tension steel (ast) is calculated by adding ast1 and ast2, which are determined using the formulas pt limit = ast/bd and ast2 = (asc times (fsc - fcc))/(0.7 times fy).

Questions & Answers

Q: What is xu max and how is it determined?

Xu max is the limiting depth of neutral axis in a W reinforced beam. It can be determined using formulas based on the grade of steel. For example, for f250 grade, xu max is 0.53 times d.

Q: How is mu limit calculated?

Mu limit is the limiting moment of resistance in a W reinforced beam. It can be calculated using formulas based on the grade of steel and grade of concrete. For example, for fe415 steel, mu limit is 0.138 times fck times bd square.

Q: How is the area of steel intention one (ast1) determined?

Ast1 can be determined using the percentage of steel (pt) limit and the formula pt limit = ast/bd. The table provided in the video gives the pt limit values based on the grade of concrete and grade of steel.

Q: How is the extra moment to be resisted by compression steel (mu2) calculated?

Mu2 is calculated by subtracting mu limit from the total moment (mu). It represents the additional moment that needs to be resisted by the compression steel in the beam.

Summary & Key Takeaways

• The video explains the procedure for designing a W reinforced beam, including determining the limiting depth of neutral axis (xu max) and mu limit.

• Formulas for xu max and mu limit are provided based on the grade of steel, and a table is given for determining the area of steel intention one (ast1).

• The video also covers calculating the extra moment to be registered by compression steel, determining fcc and fsc values, and finding the area of compression steel.