ABSTRACT
A reinforced concrete member must behave satisfactorily under normal working loads. The three principal criteria regarding serviceability are that, when a member is subjected to the forces and moments that arise from working loads, deflection, vibration and cracking must not be excessive. This chapter discusses deflection and cracking that are deals with in some detail in Part 2 of BS8110, and the Code requirements. The simplified rules concerning deflection given in the Code consist of selecting a basic span/effective-depth ratio corresponding to the span and the type of fixity of the member. Since BS8110 prescribes limiting basic span/effective-depth ratios corresponding to specific spans, it is a simple matter to express these requirements in the form of minimum effective depths corresponding to specific spans. The relative proportions of dead and imposed loads will differ from those considered when undertaking the ultimate limit-state analysis to determine the reinforcement required.
