By treating the girder grillage supported by piles as a finite beam resting on an elastic foundation

regarding the vertical pile and the surrounding soil as springs with different rigidities

and with consideration of the interaction between the pile and the surrounding soil

a differential control equation for the capping beam is established on the base of the Winkler elastic foundation model. The semi analytical power series solutions for the vertical displacement

rotation

bending moment and shearing force of the capping beam under arbitrary loads such as concentrated load

added moment and distributed load are presented. The validity of the presented solutions is verified by the existing rigid-bar method and Newmark method. On the base of that

the influence factors such as the diversity of pile bearing capacity

the reaction of the surrounding soil

the diameter of pile and the load spreading properties on the behavior of the girder grillage supported by piles are discussed. The results indicate that the above factors significantly affect the behavior of the girder grillage supported by piles. With consideration of these above factors

the vertical deformation

bending moment and support reaction on the top of pile of the beam are different from that without consideration of these factors. So in the real engineering design of the capping pile beam

all those influence factors should be taken into account.