Alternative Materials and Configurations for Prestressed-precast Concrete Pile Splice Connection

Link to the Latest: September 2020 Progress Report

Background:
Driving prestressed-precast concrete piles (PPCP) is one of the options among various types of piles and installation methods that conforms to the principals of Accelerated Bridge Construction since it employs pile segments prefabricated in precast plants and delivered to the site for installation. This option provides in many cases an economic and rapid alternative to other types, therefore reducing the construction time overall in line with the benefits promised by ABC methods.  However, traditional prestressed piles that use carbon steel strands and bars are prone to corrosion, especially when they are in marine environment. There have been attempts and investigations into the use of alternative prestressing strand and reinforcing material that are corrosion resistant.  The use of Carbon Fiber Reinforced Polymers (CRFP) and High Strength Stainless Steel (HSSS) for strands and other reinforcement in concrete piles have shown great improvements in the resistance against corrosion.

It often happens that shipping and transportation constraints or other reasons limit the length of PPCP segments that can be delivered to the bridge site. Variable and unforeseen soil conditions may also require longer piles than anticipated. Hence, splicing of pile segments has to be performed at the site to achieve longer lengths using various types of joints.  FDOT has used splicing methods and has undertaken efforts to develop more effective and corrosion resistant joints for their marine environment. Because of lack of understanding of the structural behavior and sometime associate complexity and cost, their use has been very limited and scarce.  On the other hand, much has been done in relation with ABC connections and details for sub- and super-structure joints and connections, and a variety of new and effective joints have been developed and are in use.  The aim of the proposed study is to build upon the experiences gathered in general for ABC connections and develop an effective yet simple splice connection for PPCP using alternative configuration and new materials.  The focus will be on connection types that are easy to implement, provide adequate strength, and reduce interruption to operation.

Objective:
The objective of this project is to explore alternative pile splice connection configurations and materials, and to investigate the feasibility of these connections in comparison with the existing epoxy dowel splice for prestressed-precast concrete piles.

This research project focuses on the use of analytical modeling and computational means for investigation on the structural behavior for newly developed conceptual designs.  Future activities, within a separate project, will include performing experimental verification of the newly developed details.

Scope:
An overview of the study tasks is given below.

  • Task 1 –   Literature Review
    • The project will include a comprehensive review of the current practice in pile splicing and a compilation of available ABC methods for connection and joints for substructures and superstructures.
  • Task 2 –Development of New Splice Details and Configurations
    • The aim of this task is to build upon the experiences gathered in general for ABC connections and develop an effective yet simple splice connection for prestressed-precast concrete piles.
  • Task 3 – Modeling and Analysis
    • The candidate details and configurations identified in the previous task will analyze using FE modeling and section analysis, and will compare their structural performances to that of the existing splice details. This should result in selection of few configurations as most promising splice connections.
  • Task 4 – Constructability Analysis
    • The most promising configurations will be scrutinized for their constructability according to the ease of implementation, time to use, and cost.
  • Task 5 – Design Considerations
    • Means and methods for designing the selected splice connections will be investigated.
  • Task 6 – Draft and Final Report
    • A comprehensive draft final report including the activities performed in the previous tasks will be prepared and submitted first for review by the research advisory panel (RAP). After incorporating the comments received from RAP, the final report will be submitted.

Research Team:
Principal Investigator:  Dr. Armin Mehrabi
Research Assistant:  Seyed Saman Khedmatgozar Dolati

Previous Progress Reports: