It is necessary to take into account and evaluate different factors which influence deflections of reinforced concrete beams and slabs before starting design and construction.

These factors are categorized into two group with parameter identified prior to construction and factors unidentified prior to construction. It is established that unidentified factors are more important as compared to identified factors prior to construction.

Besides, the probable deflection variation of reinforced concrete beams and slabs are evaluated by measuring deflections with genuine maximum and minimum values for parameters. This construction sheds light on the most vital and leading reasons.
Reasons for Deflections of RCC Beams and Slabs: Given below, some reasons which influence deflections of flexural members (beams and slabs) in reinforced concrete structures:

a. Mistakes in calculating the deflection of flexural members
b. Loading of flexural members
c. Flexural rigidity
d. Reasons for fixity
e. Construction deviations of flexural members
f. Creep and shrinkage in flexural members