Tips: DETAILING OF RCC BEAMS

The detailing of beams is normally associated with:
i) Size and number (or spacing) of bars,
ii) Lap and curtailment (or bending) of bars,
iii) Development length of bars,
iv) Clear cover to the reinforcement and
v) Spacer and chair bars.
Anchorage in steel bars is normally provided in the form of bends and hooks. Twisted steel bars or deformed steel bars are not provided with hooks. The anchorage value of bend of bar is taken as 4 times the diameter of bar for every 45⁰ bend subjected to maximum of 16 times the diameter of bar. Fig.1 shows the standard hooks and bends. Bars are lapped over each other for increasing the length of bars. Minimum lap length should be equal to development length. Development length for bars in different concrete mix is given tables 4.2 to 4.4 of SP34.

Fig.1: Standard Hooks and Bends in Reinforcement

The value of K in above figure depends on type of steel used which is given below:

Sl. No.	Type of steel	Min. value of K
1	Mild steel	2
2	Cold worked steel	4

Fig.2: Reinforcement details in Beams

Different types of stirrups used are shown in Fig.3.

Fig.3: Details of Beam Reinforcement