Decrease in failure load of inclined driven piles by using Allpile program

One of the problems in construction piles in field is driven inclined which maybe become by error during putting pile or driven. This type of problem in construction is difficult to determine bearing capacity. In this research, studying the determination of bearing capacity of inclined pile in deferent angles and different types of soil as well as deferent types of piles shapes by using AllPile program. The results demonstrate that the reduction in bearing capacity of 30 inclined pile less than 20% from the non inclined pile.


Introduction
The load at the pile head gradually increases from a very small value to the limit load (Q L ) required for pile to penetrate into the ground at a constant rate (Salgado, 2006) [1] . Sometimes piles are driven or constructed inclined in civil structures by mistake or for some reason. Many codes and standards do not prefer to use inclined pile in structures especially in seismic regions. (Li and Luo, 2011) [2] studied the development of pile foundation by using group of piles constructed inclined with a center pile constructed in the different angles of inclination. The result showed that the optimum inclination angle for the center pile is located between 8-12 o .
A significant amount of work (Mylonakis et al. 1997) [3] has been carried out in reliable prediction of the response of structures with vertical piles exposed to seismic excitations as vertical piles are undoubtedly a popular choice for a wide range of structures. Inclined piles (sometimes named 'batter piles' or 'raked piles'), on the other hand, are particularly desired for structures demanding substantial lateral stiffness and these piles were used in hydraulic structures, towers, and bridges. The major problem of inclined piles are the mechanism of transfer the vertical load from the structure through the piles cap to piles then the bed of the soil, so the bearing capacity is reduced. In recent years, evidence has been accumulating that inclined piles may, in certain case, be beneficial rather than detrimental both for the structure they support and the piles themselves, (Gazetas and Mylonakis, 1998) [4] . Studies by (Sadek and Shahrour, 2004) [5] showed that supporting by using inclination piles improved some sided of the seismic reaction of the structures.

AllPile program
The program AllPile for Windows analyzes pile load capacity efficiently and accurately. AllPile can handle all types of piles: drilled shaft, driven pile, auger-cast pile, steel pipe pile, H-pile, timber pile, tapered pile, bell pile, shallow foundation, etc. You can define new pile types and input customized parameters based on local practices and experience. The program is capable of performing the following calculations:  Lateral … capacity … and … deflection.  Vertical … capacity … and … settlement.  Group … vertical … and … lateral … analysis.  FHWA … SHAFT … program.  Static … and … cyclic … conditions.  Negative … and zero … friction.  Shallow … footing.  Tower … foundation.
The main AllPile window is shown in Figure (1). And the AllPile operations can be divided into three main steps as shown in Figure (2) (Allpile manual, 2014) [6] .

Soil
In this research two types of soil were used (Sand and Clay). In sand soil two states dry and fully saturated and fully saturated clayey soil were used. The properties of soil used is shown in Table (1).

Pile
In this research four types of piles were used (square driven concrete, circle driven concrete, steel driven, and hollow steel driven pile) each of them had length (h) 12 m and diameter (or width) (d) 30 cm. The properties of piles is shown in Table (2). The sketch of pile in the soil with different angles of inclination are shown in Figure  (3).

Presentation of test results
Failure of model tests is defined as the stress required to cause settlement corresponding to 10% of the footing diameter (width) depending on the proposal given by (Terzaghi, 1947). The analysis of results of all model tests regarding the compression load and the corresponding settlement is illustrated in terms of corresponding load (Q) versus settlement (X).   Table (3).   (10) and (11) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (12) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table ( (13) and (14) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (15) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table (3).  Figures (16) and (17) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (18) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table ( Figures (19) and (20) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (21) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table (3).        Figures (25) and (26) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (27) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table (3).     Figures (28) and (29) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (30) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table (3).   Figures (31) and (32) show the relation between load and settlement for bearing effect and friction effect only for pile, respectively. Figure (33) shows the relation between load and settlement. The loads corresponding 10% settlement ratio are shown in Table (3).

Conclusions
 The reduction ratio in failure load for the piles driven in soft clay soil are between 15-16% when the inclination increases from 0 o to 30 o .  The reduction ratio in failure load for the piles driven in fully saturated sandy soil are between 13-19% when the inclination increases from 0 o to 30 o .  The reduction ratio in failure load for the piles driven in dry sandy soil are between 13-15% when the inclination increases from 0 o to 30 o .  Type of soil is the main effect on bearing capacity of piles and the degree of saturation of sand is plays an important role on bearing capacity but did not effect on clayey soil according to Tomlison's equation for piles in clayey soils.  Shaft resistance is more effective than bearing resistance for clayey and sandy soils and all types of pile because of dimensions and depth of piles.