## 5 Conclusions  
In the study, the existing quay wall was evaluated, and geotechnical and structural alternatives of the new structure to be built for an increase in capacity were evaluated. Among the different foundation alternative methods, a combined system was designed in the form of a pile foundation reinforced with plastic piles so as not to damage the existing dock structure. The obtained results from the study are presented below.  
* The existing conditions of the port area were insufficient to support the new crane loads due to insufficient bearing capacity and inadequate stability. For that reason, a piled foundation platform was planned for the new crane loads within the scope of the project. The three rows of reinforced piles have been planned in the project site  
Figure 11: Pile load test plan.  
Figure 12: Pile load test set-up.  
as bored piles with 65 cm in diameter, 13 m, 14 m, and 18 m in lengths with varying spacing. Soil improvement is also planned together with these reinforced piles.
* To this end, in addition to the support provided by three rows of a piled foundation system, four rows (3.00, 5.50, 8.50, and 8.50 m in length) of 65 cm in diameter of unreinforced bored piles are planned under the cantilever slab part. Selected engineering fill material (USCS classification; well-graded gravel, GW) was placed with a 30 cm thickness above the unreinforced piles. The thickness of the foundation has been designed as 80 cm.
* The pile foundation system was evaluated using PLAXIS 2D 2021 finite element software. Stability analyses of the pile foundation were conducted using the SLOPE/W 2021 program. The 3D geometry of the system was modeled using CSI's SAP2000 V21 software and reinforced concrete calculations were conducted.
* According to the results of PLAXIS analysis, the displacement values obtained from the analyses carried out by taking the initial groundwater level as +3.00 m and +2.50 m are well below the permissible limit values.
* The stability analysis was conducted with SLOPE/W and the obtained factors of safety values are above 1.50 in all cases. So, there is no stability problem in the system.
* The axial forces obtained as a result of the analysis are less than the pile-bearing capacities, so the piles can safely carry the loads imposed on them. The bearing capacity of the cantilever slab was found to be sufficient under the foundation loads.
* The pile with a diameter of 65 cm is loaded up to 283.5 tons, which is 250% of the service load and thereafter unloaded four steps. The settlement at maximum load is measured as 7.56 mm. The average settlement after unloading is measured as 4.81 mm.
* From a scientific perspective, the most important difference that distinguishes this study from the literature is that the ground conditions are analyzed nonlinearly with Plaxis 2D 2021 software based on the finite element method and then the pile behavior is harmonized linearly with the structural analysis from the Sap2000 program.
* As seen from this case study, the capacities of existing port structures can be safely increased provided that necessary geotechnical precautions are taken.  
This research received no external funding.  
Not applicable.  
The author declares no conflict of interest.