Question

Distinguish between short-term deflection and long–term deflection.

Answer 1

your answer is :-

• Short term deflection
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(a) Magnitude and distribution of live loads,

(b) Span and type of end supports,

(c) Cross-sectional area of the members,

(d) Amount of steel reinforcement and the stress developed in the reinforcement,

(e) Characteristic strengths of concrete and steel, and

(f) Amount and extent of cracking.

• long-term deflection
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The following are the major factors influencing the long-term deflection of the structures:

(a) Humidity and temperature ranges during curing,

(b) Age of concrete at the time of loading, and

(c) Type and size of aggregates, water-cement ratio, amount of compression reinforcement, size of members etc., which influence the creep and shrinkage of 

Answer 2

As evident from the names, short-term deflection refers to the immediate deflection after casting and application of partial or full service loads, while the long-term deflection occurs over a long period of time largely due to shrinkageand creep of the materials.