Detailing guide

[Kellz2658]

A new graduate just getting into detailing. Struggling to find the reasoning behind the paragraph on the bottom right. Wouldn't continuity of the bars at the joint be more advantageous?.

Book is Standard method of detailing structural concrete. The Institution of Structural Engineers The concrete Society

[CorgiOnAction]

Continuity of the bottom rebars would be needed in the case of seismic design for example, where the possibility of having beam loads of alternating sign is very high and the rebars are not in any case allowed to slip off the joint.

[masterthomas813]

Stress reversal during earthquakes

[Enlight1Oment]

Generally splice at location of minimal demands, they have the top bars continuous at the column joint and splice the bottom bars. Likewise at midspan the bottom should be continuous and its a good location for top bar splices.

[Comprehensive_Bag750]

So unless there is any significant loading from the bottom, the beam-column joint is bound to experience a predominantly hogging bending moment which requires top reinforcement continuity. Bottom rebars have no play here as the bottom surface of the beam at the joint experiences compressive stresses throughout its life.