This video explains the meaning of stress and strain. The stress-strain relation of concrete and steel reinforcement according to the British Standards (BS8110) is explained. The maximum stress in concrete cube and the ultimate strains in concrete. The material safety factors of concrete and steel.
This is very important to understand the design and the analysis of different reinforced concrete sections and elements.
It will help you to understand other topics including:
Design and Analysis of Reinforced Concrete Beams
Design and Analysis of Reinforced Concrete Slabs
Design and Analysis of Reinforced Concrete Columns
Design and Analysis of Reinforced Concrete Footings
Design and Analysis of Reinforced Concrete Stairs

The links of other important videos are given below:
Stress-strain curves for concrete and steel: https://www.youtube.com/watch/akgy9...
Analysis of RC sections according to the BS8110 code: https://www.youtube.com/watch/RzpS9...
Design of singly reinforced rectangular concrete sections: https://www.youtube.com/watch/3AbEl...
Analysis of singly reinforced concrete rectangular sections: https://www.youtube.com/watch/LSTo7...
Design of one-way slabs - Part 1: https://www.youtube.com/watch/J2XB5...
Design of two-way slabs - Part 1: https://www.youtube.com/watch/Nk6qq...
Design of Beams - Part 1: https://www.youtube.com/watch/Nk6qq...
Design of Columns - Part 1: https://www.youtube.com/watch/ZjBTG...
Foundations Part 1: https://www.youtube.com/watch/NI1N1...