Behavior of Defective Cast in Place Piles

This paper deals with testing defected model piles in the soil in order to study their behavior. In this respect, the results of model pile tests are discussed either geotechnically or structurally according to the type of failure. Two parameters were studied in order to evaluate the general behavior of defective piles. These parameters include the defect location and the defect type for floating and end bearing pile. The results of the experimental work indicated that the critical case for floating pile is seen to be when the defect of (5%) at the first third of the pile length at which the decrease in the bearing capacity is about (21%), while the decrease in the bearing capacity is found to be (14%) and (10%), when the defect is at the middle and the lower third of the pile length, respectively. The decrease in the bearing capacity for floating pile is found to be (31%) and (21%) for void and neck defect, respectively, while the decrease in the bearing capacity for end bearing pile is found to be (43%) and (52%) for void and neck defect, respectively.

Analisis Fondasi Raft Pile Bangunan Tinggi Terhadap Struktur Bangunan Di Sekitar

Raft pile is an option for high rise building that has more than 30 stories on soft to moderate soil conditions. Either spun pile or bored pile can be used as the pile foundation. This study focuses on 34-story building that is constructed near electric rail train station, where the soil type is dominantly clay with average N-SPT 20 – 30, there is also thin layer of soil with N-SPT 60. The study compares two types of piles, 30 m depth floating pile and 32 m depth end bearing pile, where the raft thickness is 2 m. The study was conducted by calculating the bearing capacity and settlement with formulas based from correlations of N-SPT and the N-SPT data. Midas 3D also used to simulate the settlement of the building and settlement around the building. The results show that for bored pile with depth of 30 and 32 m respectively has settlement of 20,757 cm and 3,0475 cm while the settlement around the building consecutively is around 10 – 11 cm and 1,5 – 2 cm. Bearing capacity of bored pile with 30 m depth is around 1593,6779 – 5382,5954 kN while bored pile with 32 m depth is around 1978,9153 – 6021,3859 kN.Fondasi rakit merupakan salah satu pilihan yang dapat digunakan untuk bangunan tinggi lebih dari 30 lantai pada tanah kondisi lunak sampai sedang. Untuk jenis fondasi tiang dapat digunakan tiang bor atau tiang pancang. Dalam penelitian ini dilakukan studi fondasi bangunan 34 lantai yang didirikan dekat dengan stasiun kereta rel listrik di mana lapisan tanah dominan lempung dengan N-SPT rata-rata 20 – 30 dan juga ada nilai N-SPT 60 namun berupa lapisan tipis. Studi dilakukan dengan membandingkan dua jenis tiang yaitu tiang dengan daya dukung friksi kedalaman 30 m dan tiang dengan daya dukung ujung kedalaman 32 m dengan ketebalan fondasi rakit 2 m. Studi dilakukan dengan menghitung daya dukung serta penurunan menggunakan pendekatan rumus-rumus berdasarkan data N-SPT dan korelasi dari data N-SPT, juga dilakukan simulasi Midas 3D untuk mengetahui besar penurunan yang terjadi di sekitar bangunan. Dari hasil studi banding diperoleh penurunan fondasi tiang 30 m dan tiang 32 m berturut-turut sebesar 20,757 cm dan 3,0475 cm sedangkan penurunan sekitarnya diperoleh berturut-turut 10 – 11 cm dan 1,5 – 2 cm. Daya dukung yang diperoleh tiang 30 m berkisar 1593,6779 – 5382,5954 kN dan tiang 32 m berkisar 1978,9153 – 6021,3859 kN.

Influence of Pile Geometry on Responses of End-Bearing Pile Groups Subjected to Vertical Dynamic Loads

An analytical solution is presented for evaluating the dynamic responses of pile groups subjected to vertical harmonic loads. The solution allows us to consider the effects of pile geometry on the pile head impedance of the vertically loaded pile groups by the use of a new dynamic interaction factor. To this end, the stress distributions of the soil surrounding the vertically vibrating pile is first determined for calculating the pile–pile interaction factor, instead of the classical interaction factor based on two-pile displacements in past studies. Accordingly, the impedances of the pile group are derived using the proposed pile–pile interaction factor and the superposition principle. Some selected examples are presented to demonstrate the proposed refined technique for evaluating the dynamic characteristics of the pile group.

Reliability analysis of an end-bearing pile with account for friction forces on the pile surface

Introduction. The behavior of end-bearing piles in the foundation soil and the methodology for their reliability analysis, treated as operational safety measures applicable to a separate bearing element of a pile foundation, need clarification and further development. The weakness of the established reliability analysis methodology, focused on the bearing capacity of the foundation soil, is its failure to take account of each case of the soil behavior above rock or low compressibility soils pursuant to Construction rules and regulations 24.13330.2011. Taking account of the bearing capacity of this soil layer in respect of the load accommodation by an end-bearing pile (taking account of the pile weight) may improve its reliability by the criterion of the bearing capacity in combination with the soil behavior below the bottom tip of a pile. Nizhne-Suyanskiy Waterworks Facility had the mission to solve water household, energy and socio-economic problems. Materials and methods. The author analyzed piles made of any applicable materials; their reliability analysis methods are based on the possibility theory due to the limited amount of statistical information on controllable parameters to be entered into the limit state design model to verify the bearing capacity of the foundation soil. Results. The author presents the design formula to identify the parameters ensuring reliable failure-free behavior of an end-bearing pile in the foundation soil and in respect of the soil bearing capacity. The pile reliability analysis performed in respect of its bearing capacity (and focused on the strength of the pile material) is provided in the references section. The author uses two performance criteria to analyze the reliability of an end-bearing pile, given that an end-bearing pile is analyzed as a consistent mechanical system in terms of the reliability theory. Conclusions. The author has developed a methodology used to analyze the reliability of end-bearing piles. It is focused on the bearing capacity of the foundation soil below the bottom tip of a pile and along its length with a view to the quantitative assessment of its safe performance at the stage of design of a facility that has a piled footing; the groundwork has been laid for further research into the behavior of end-bearing piles and for the development of design regulations applicable to various types of piles that may differ in material, behavior, sinking techniques, etc.