A comparison of two dimensional and three dimensional finite element analysis for settlement behavior of piled raft foundations

Download
2009
Kaltakcı, Volkan
In this study, the settlement behavior of the piled raft foundations resting on overconsolidated clays under uniform loading, is investigated for different pile configurations and load levels. A total of 100 plane strain and three dimensional finite element analyses are carried out and the results of these analyses are compared both with each other and with the results presented by Reul & Randolph (2004). The material parameters used in the analysis are selected mainly referring to the previous studies cited above on the same subject and slight modifications are made for convenience in the analysis. The analysis method and the applied pile configurations and load levels are directly taken from the reference study, excluding the soil model employed. A drained Mohr Coulomb failure criteria is employed in the analysis of this study in modeling the soil instead of an elastoplastic model which was used in the analysis of the reference study. The results are evaluated for the average and differential settlements of the foundations and it is seen that; although the average and differential settlements calculated in this study are not always very close to the values calculated in the reference study, the calculated settlement reduction factors due to piles (especially for the average settlements) compared well with the findings of the reference study for all pile configurations and load levels considered. Based on this, a new approach is suggested to estimate the average settlements of the piled raft foundations. Moreover, correction factors are recommended in order to estimate the average settlements of the piled rafts by directly using the programs employed throughout the thesis.

Suggestions

An experimental study into bearing of rigid piled rafts under vertical loads
Türkmen, Haydar Kürşat; Ergun, Mehmet Ufuk; Department of Civil Engineering (2008)
In this study, the load bearing behavior of piled raft foundations is investigated performing laboratory and field tests. Piled raft foundation of a multi storey building was also instrumented and monitored in order to study the load sharing mechanism of piled raft foundations. A small reinforced concrete piled raft of 2.3 m square supported by four mini piles at the corners was loaded and contribution of the raft support up to 41 % of the total load was observed. The soil was stiff fissured Ankara clay wit...
Behaviour of pile groups under lateral loads
Ercan, Anıl; Erol, Orhan; Department of Civil Engineering (2010)
To investigate the lateral load distribution of each pile in a pile group, the bending moment distribution along the pile and the lateral group displacements with respect to pile location in the group, pile spacing, pile diameter and soil stiffness three dimensional finite element analysis were performed on 4x4 pile groups in clay. Different Elatic Modulus values, pile spacings, pile diameters and lateral load levels used in this study. In the analysis PLAXIS 3D Foundation geotechnical finite element packag...
A simple assessment of lateral pier response of standard highway bridges on pile foundations
Yüksekol, Ümit Taner; Bakır, Bahadır Sadık; Department of Civil Engineering (2007)
Group of piles are widely used deep foundation systems to resist lateral and vertical loads. Seismic and static performance of pile groups mostly depend on soil type, pile spacing and pier rigidity. Not many pile lateral load tests have been performed due to high costs. Advanced and complex analytical methods were developed over the years to assess nonlinear lateral pile response. This research is conducted aiming at developing a practical analysis method to verify the lateral performance of pile groups and...
Investigation of strenghthening techniques using pseudo-dynamic testing
Kurt, Efe Gökçe; Özcebe, Güney; Department of Civil Engineering (2010)
Pseudo-dynamic testing was employed to observe the seismic performance of three different retrofit methods on two story three bay reinforced concrete frame structures. The three test frames have hollow clay tile (HCT) infills in the central bay. All of the test frames represent the seismic deficiencies of the Turkish construction practice such as use of plain reinforcing bars, low strength concrete and insufficient confining steel. Two non-invasive and occupant friendly retrofit schemes suggested in the Tur...
Analysis of mechanical behavior of high performance cement based composite slabs under impact loading
Satıoğlu, Azize Ceren; Gülkan, Polat; Department of Civil Engineering (2009)
Studies on the behavior of steel fiber reinforced concrete (SFRC) and slurry infiltrated fibrous concrete (SIFCON) to impact loading have started in recent years. Using these relatively new materials, higher values of tensile and compressive strength can be obtained with greater fracture toughness and energy absorption capacity, and therefore they carry a considerable importance in the design of protective structures. In this thesis, computational analyses concerning impact loading effect on concrete, steel...
Citation Formats
V. Kaltakcı, “A comparison of two dimensional and three dimensional finite element analysis for settlement behavior of piled raft foundations,” M.S. - Master of Science, Middle East Technical University, 2009.