Analysis of the Bearing Capacity of Piling Foundation for Bridge Structures in Clay Soils

The Cibitung Cilincing toll road is faced with problems across many rivers and marshlands where the swampland is identified as clay. In building construction, the foundation is very important in bearing the burden of working on the upper construction. This Final Project contains the calculation of the carrying skin capacity and the end resistance of the pile using the Suyono method. S and Nakazawa (1990) based on N-SPT data and dynamic methods using the formula of Hiley (1930) based on the pile driving record data, then proceed to the calculation of the carrying capacity of the pile group, after that calculating the decrease of the pile using the Vesic method (1977). From the results of the analysis conducted by the author in calculating the bearing capacity to using N-SPT data and pile driving record data, the author gets that from the pile diameter of 50 cm, the carrying capacity of a single-pole is 66-ton, obtained using the method of Suyono S and Nakazawa, based on the formula of Hiley, it is obtained 139.34 tons, and settlement that occurred in the pile group foundation was an immediate settlement is 11.2 cm and a consolidation settlement is 6.2 cm. Keyword: Clay soil, pile carrying capacity, settlement

In the initial planning, the Cibitung -Cilincing Toll Road project used a pile of land, but the land that was passed by the Cibitung -Cilincing Toll Road many of which were previously swamp and agricultural soils had sufficiently deep clay content. If using a pile of solid land will take a long time while the BPJT wants the Cibitung -Cilincing Toll project to be completed quickly because it will later become a busy access for the drivers. Besides that, in the section of the Cibitung -Cilincing toll road section 3, there are many underpass bridges to cross rivers and residents' roads that have high clearance.
Formulation problem: a. How is the bearing capacity calculation of the piles group in the Cibitung -Cilincing toll road project section 3? b. How is the settlement calculation of the piles in the Cibitung -Cilincing toll road project section 3? c. Is the bridge structure able to accept the work load?
Research purpose: a. Calculate the bearing capacity of the piles group b. Calculate the settlement of the piles c. Check whether the foundation power accepts the burden of working

Methodology
In compiling this final project report, the writer utilizes data relating to the analyzed project, namely the construction of the Cibitung -Cilincing Toll Road section section 3. Broadly speaking, the data is divided into 2, namely: 1) Primary data is data that is directly related to the state of the project being analyzed. The data is in the form of a SPT investigation report, a test report from the soil mechanics laboratory, design drawings and loading planning data from the planning consultant. 2) Secondary data is data obtained by the author through intermediary media such as books, research that has been done, journals, etc.
Furthermore, the calculation of the carrying capacity of a single pile blanket is presented in Table 1 according to each N-SPT value for each depth Table 1 The intensity of the pole friction resistance

Dynamic Bearing Capacity (Hiley 1930)
Piles with 27 m embedded pole length with 12m + 12m + 12m configurations will be built with diesel hammer. Penetration is taken from the calendering data in the field in the last 10 blows is 1.2 cm  Machine efficiency = 85% (from table)

Settlement
Settlement calculation is divided into 2 components, namely: an immediate settlement and a settlement in consolidation. The thickness of the soil layers (H) in calculating the settlement is presented in the figure below  Table 2

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For the overburden stress can be seen in the figure below :

Conclusion
a. From the results of the analysis, with a diameter of 50 cm piles producing a vertical bearing capacity of 66 tons of single pile (QA), the dynamic bearing capacity derived from the power of the stakes using the Hiley formula is 139.34 tons. b. The settlement that occurs in the pile group foundation in the form of an immediately settlement is 11.2 cm and the consolidation settlement is 6.2 cm.. c. The foundation of the pile group is safe in accepting work loads, both vertical and horizontal because the bearing capacity is more than the working load (Q) of 1006.9 tons.

Recommendation
1. Because the calculation of dynamic bearing capacity using the method of Hiley (1930) has more than double the value of the bearing capacity calculation using the Suyono S and K Nakazawa methods, in my opinion for the piling equipment utilization can reduce the specification of the piling equipment to be more efficient. 2. Need to add the other bearing capacity of static methods for comparison.