Experimental Response and Analysis Model of an Innovative Pile-To-Pile Mechanical Connector

• Author / Creator

  Rosales Espinoza, Ramon Omar

• Pile-to-pile mechanical connections are used when the depth of the soil layers with sufficient bearing strength exceeds the standard pile length and extensions are needed to reach the deep stable soil. Mechanical connectors permit a safe transmission of forces while meeting strength and serviceability requirements. Common types of connectors consist of an assembly of sleeve-type external couplers, bolts, pins, and other mechanical interlock devices that ensure the transmission of compressive, tensile, torsional and bending stresses between leading and extension pile segments. While welded connections allow for a relatively simple structural design, mechanical connections are advantageous over welded connections because they lead to shorter installation times and significant cost reductions since specialized workmanship and inspection activities are not required. The current designs of mechanical connections seem to be effective to sustain installation torque and service loads, but systematic studies or in-depth research data has not been made available. It is not known how piling companies test or design their proprietary connectors. This indicates a need for developing a pile-to-pile mechanical connector designed following rational guidelines from limit states design and provide experimental evidence for its mechanical performance. In this way, pile-to-pile connections can be designed in a safe and economic manner. In this study, the experimental response under compressive forces of a type of mechanical connector is presented in terms of strength, deformations, and failure mode. The tests revealed that the type of connector used can safely transmit forces from pile to pile. Using the results from the compressive tests, an analysis model was developed using the Finite Element Analysis (FEA) method. The model was used to study the interaction of the components in the connection under an axial compressive load and present a tool that helps developing a more efficient design of iii mechanical connections. The results from the FE model show its capability of effectively reproducing the response of an actual mechanical connection under axial compressive loading conditions. A parametric study was conducted to address the influence of the thickness of the external coupler, and the diameter of the pins in the overall behaviour of the connection under axial compressive load. The location of the connector in full-length piles was also changed to determine its influence on the system under compressive and lateral loads. The results were able to demonstrate how the stiffness of the connection can be compromised if the thickness of the coupler or the diameter of the pins are reduced. The reduction of the stiffness of the full-length piles was found to occur when the connection is located where the highest moments are caused in the assembly. Further analyses can be developed from the FE model presented in this study and implementations to the design can be applied to achieve the safest and most economic design of mechanical connections.

• Subjects / Keywords

  • Mechanical
  • Pile
  • Models
  • Experiment
  • Connector

• Graduation date

  Fall 2017

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3959CN6R

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.