Investigation and Development of the Design Process for a Pile Group with and without Lateral Resistance from the Soil

Sammanfattning: For bridges in weak ground conditions, piling is an appropriate type of foundation. To manually arrange the piles in a pile group is an iterative, time consuming process where the section forces in the piles must be verified for a large number of load cases. In addition, after installation, piles may have new positions and the capacity must be re-verified. In this thesis, a software was developed to automatize the design process for pile groups, with the aim to increase the efficiency. The pile groups were optimized ac- cording to maximum and minimum normal forces in the piles, by simulating random pile groups using the Monte Carlo method. The randomly simulated pile parameters included the position, inclination and direction of the pile. Interviews with contractors were also carried out to obtain practical requirements, that were implemented in the program. To evaluate the program, four real cases have been studied that resulted in reasonable preliminary pile groups in an hour or less. In some cases, the number of piles could be reduced. The process still requires some manual surveillance, such as calibrating the input data and evaluating the feasibility of the generated pile groups. This is not necessarily negative, as the output always should be verified. A separate investigation of the concept of the distance between pile center and load center was also done, to see if the concept can be used in optimization of pile groups. Correlation tests between this distance and resulting minimum normal forces were performed, where the method partly was unverified and therefore, little can be stated about the relevance of this concept. Thus, it seems more reasonable to evaluate pile groups directly by their section forces.