first, we have to understand what is that two-term
Capping beam
The Capping beam is a steel, and a concrete beam that ties all the piling together creates the foundation for the suspended slab and helps to hold the earth and neighboring houses back.
The steel reinforcement bars are placed over the top of the piling cages with legs designed to the engineer's specs.
Ground Beam
The Ground Beam is the beam, which is provided usually at the foundation level to support building walls, joists, etc. Typically the ground beams are directly rested on the ground, sometimes they can be supported by end piers
now talk about difference
Capping beams for piles aim at transferring loads from closely spaced columns or walls into a row of piles.
On the other hand, ground beams are beams provided between adjacent pile caps, and they perform as compression struts or ties in an attempt to prevent lateral displacement or buckling of piles under the uneven distribution of loads on pile caps.
Both of them have to be specially designed to cater to differential settlement of piles.
Capping beam performs the same functions as pile caps.
However, ground beams are structural elements to connect adjacent pile caps to improve the stability of the foundation.