top and bottom reinforcement of footing

[hiluxxx03]

i have a problem for my cutting list of the footing reinforcement... the footing is 2500mm x 3200mm x 600mm... the bottom reinforcement is 16mm @ 200mm o.c. bothways while the top reinforcement is 10mm @ 200m o.c. bothways... if i bend 90degrees and use e=12db, the top and bottom bars wont meet... there is a space of 65mm... i'm worried about the installation... should i overlap the top and bottom reinforcement? how much would be my required lap length? and may i know the theory behind? i'm new to the field and did not study well during college but i'm trying to make-up now for my loss... please help me and thank you... by the way, i used 75mm concrete covering for all sides of the footing... i have doubt for my top bars concrete cover... hope you would mentor me guys...

 

[TXStructural]

For gravity downward loads, top bars are not usually required under US codes. However, it may be valuable to provide top bars for footings in expansive soils and soils subject to subsidence. Anywhere loading or bearing conditions may result in tension at the top, it is good practice to provide top bars.

Bottom bars may need to be hooked or headed, depending upon the loads, bearing, and geometry. As with any beam, the bar must be FULLY developed where there is tension demand on the bars.