# A Novel Approach Proposal for Estimation of Ultimate Being Capacity Based on Pile Loading Test Data
## 1 Introduction  
The safe transfer of loads from structures to the ground is very important in terms of geotechnical engineering. If the foundation cannot bear these loads, serious damage may occur to the structures and may even result in the loss of life. Pile foundations, which are the deep foundation type, are a solution that can be applied in cases where the shallow foundations are insufficient in terms of bearing capacity due to heavy structural loads and insufficient ground conditions. There are many methods developed for the efficiency of piles. The load transfer mechanisms of pile foundations need to be well known because the load transfer mechanisms of piles are extremely complex [1]. In general terms, the vertical bearing capacity of a single pile can be calculated by testing the soil that the pile is in with soil tests or by determining its mechanical properties by experimental methods [2]. The Standard Penetration Test (SPT), which is one of the oldest soil tests and is still widely used today, is a test that determines soil density and consistency as well as helps in the calculation of pile bearing capacity. There are commonly used methods based on SPT data, such as Meyerhof, Bazaraa and Kurkur, Decourt [3; 4; 5]. Meyerhof is a method based on empirical coefficients and SPT data for determining the pile bearing capacity in coarse-grained soils, developed taking into account the presence of driven or drilled piles [3]. There are empirical coefficients based on SPT data using the Bazaraa and Kurkur method, which was developed by studies on Egyptian soils [4]. In the Decourt method, there are empirical coefficients that can be used in driven and bored piles developed forboth fine- and coarse-grained soils depending on SPT values [5]. Studies on 81 cases in Vietnam were conducted by [PERSON] et al. [6]. As a result of the study, it was found that the ultimate bearing capacity of the bored piles was estimated by a new SPT direct method. This method gives the highest correlation of all available SPT methods and is validated with soil data. Additionally, there are some methods in which the shear strength parameters of the soil are added to the calculation of the pile's ultimate bearing capacity by passing from the SPT values to the empirical relations [7; 8; 9; 10; 11; 12; 13]. Another method used in pile ultimate bearing capacity calculations is the finite element analysis method. This method has been widely used in recent years due to its reliable results [14; 15]. In addition, in recent years, studies have been carried out to determine the ultimate bearing capacity of piles using artificial intelligence applications [16; 17]. As can be seen from the years of experience in geotechnical engineering, the pile bearing capacity can be determined using the results obtained from the loading tests performed on the piles manufactured at full scale in situ. Of these loading tests, the static loading test is undoubtedly the most reliable method. In determining the ultimate bearing capacity of bored piles, axial compression tests, and axial tensile tests are used to resist buoyancy in piles under groundwater [18]. The axial compression test ASTM D 1143-81 and the tensile test ASTM D 3689-07 are the most widely used standards [19; 20]. There are many methods for pile load test evaluation, such as Chin-Kondner, Mazurkiewicz, Decourt, and Ozkan-Alku [21; 22; 23; 24]. Loading test studies on 10 piles were carried out by [PERSON] and evaluated with the methods in the literature [24]. Accordingly, the lowest failure load values were obtained by [PERSON] and [PERSON] methods, and the highest failure load values were obtained by [PERSON] and Decourt methods [21; 23; 25; 26]. As a result of statistical analysis, it was concluded that [PERSON] and [PERSON]'s methods gave more uncertain results than other methods [25; 26]. In the second part of the study, the Ozkan-Alku method was developed [24].