Question

SECTION A : ANSWER ALL QUESTIONS A1. Explain the term “moment redistribution”. Then, discuss the implications in the design of reinforced concrete structures. (8 marks) A2. Prove (with the aid of diagram) that the depth of the neutral axis of a balanced reinforced concrete section is equal to 0.617d for steel strength, fyk = 500 N/mm² and concrete strength, fck = 30 N/mm². (10 marks)

Reinforced concrete. Needed answer

Answer 1

Moment rec redistribution : determinate. to make moment redistabulion refers to the behavious of Statistically inderterminale Structures that are not completely elastic, but have some researe plactic Capacity, when one location first fields, further application of load to the structure causes Bendig moment to redictabute differently from what a purely Elastic analysis would suggest. When the load is applied to a beam, the beam has the property to resist it when the beam is indeterminate, it forms Sufficient number of hinges itself Hence in this process few hinges formed callier f formed afterwalds. Further increment in load does not increase the moment at the points where the plastic hinges The increated load increases the moment in the less further Streffed sections of the beam, hence due to this, plastic hinges are formed. This process of shift of application of moment in the bearm is termed as moment rediche РОСО, the rest are are farmed. beam SHOT ON POCO F1

A2) Prove - Depth of Neutral Axle of Balanced Reinferced Section N.A= Concrete 0.617d Steel strength byk SOON/mm² concrele Strengtes fex = 30 mil m2 Td² 500 T 4 de = 25mm Depth of Neutral Axis: - o ustek 0.45X 30 0.0035 13.5 Ast ООО Beam 0.87 0-97fy = 435 •87 fy: >o.002 t 0.87x500 0.002+ position NA = 4.175x10² 2x ios by Ast Compression Tension. On 87 0.36 fex deb 87 fy 0.87 fy 0.36 fex ab 0.617 d ru SHOT ON POCO F1 POCO Xx25 0.87 x 500 x y = 0-36x30

de lim d-de, in 0-0035 4.175x10 3 xulim 0.0035 d-delim 4.1758103 0.838. dulin ruskin Muli d 0.838 dy = 1.1935. 2193 o.ussd. du POCO SHOT ON POCO F1