## 1 Introduction
The BFRP and GFRP wraps improved the resistance to uplift of the piles by approximately 35% and 15%, respectively, more than the unrestrained coverage in dry conditions. The study presented in [13] focused on investigating the seismic performance of hollow FRP piles in liquefiable sand deposits using shaking table tests. Four GFRP and four CFRP piles were manufactured and embedded as end-bearing piles within the soil and tested under different seismic input motions. A group of four aluminium piles was also employed and tested under similar conditions to compare their response with FRP piles. The resultsof strong excitation indicated lower deviation of the foundation to free-field motions in the frequency range of 10-20 Hz and, hence, lower amplification of input motions for FRP piles (i.e., response spectra ratio of 1.45 to 2.20 times) due to higher flexibility of the hollow FRP piles compared to conventional piles. Among the FRP piles, glass FRP showed better performance than carbon FRP piles in terms of soil-pile interaction and foundation input motions. In summary, the results indicated that a hollow FRP pile can be a suitable alternative in liquefiable soils because of their favourable material characteristics in seismic-prone area. The justification for the use of GFRP piles presented in [14] was assessed based on experimental studies involving the evaluation of potential factors influencing the behaviour of FRP piles under axial and lateral loads in sandy soil. Nowadays, artificial neural networks (ANNs) are used in various engineering applications, especially for the prediction of load-bearing capacities [15], due to their ability to learn complex patterns and relationships from data. An approach for the structural optimization of a GFRP-concrete-steel composite column using genetic algorithms (GAs) and artificial neural networks was presented in [16]. The trained ANN efficiently and rapidly predicted the load-bearing capacity of such columns under various parameters, with most of the errors staying within 10%. This article proposes a novel tube foundation intended for use under transmission line poles. The analysed foundations were designed as a monopile to be implemented in the construction of low- and medium-voltage overhead transmission lines. Experimental field tests of innovative piles made of the composite material were carried out on a 1:1 scale. The GFRP foundations were driven into a sand-filling special steel tank separated from the rest of the ground. A steel tube pole, approximately 6 m high, was mounted onto the foundation. Laboratory tests were carried out on the GFRP, from which the piles were made, in order to determine the characteristics of the material and build a material numerical model. Equivalent characteristics of GFRP composites were determined using FEM analyses of the model of piles with poles. The results of the field tests and FEM models of the monopile embedded in sand were compared. The developed FE model allowed for the load-bearing capacity of the GFRP monopile to be reliably determined by taking into account the EN 61773:1996 [17] and EN 50341-2-22:2016 [18] standards' criterions using a graphical method [19; 20].