Development of ABC Course Module – Seismic Connections

Link to Latest Report: June 2019 Progress Report

Background:

The great majority of ABC bridges are built using components that need to be connected on site. The size of the components, and therefore the number of connections, varies according to the ABC method used.  For example, in construction using SPMTs, the entire superstructure is typically brought to the site in a single piece. In bridges constructed from precast concrete beams and columns, many more connections may be needed. However, in all cases connections are an integral part of the methodology.

They are most conveniently located at the intersection of linear elements, such as beams and columns, which also happen to be the usual location of the largest bending moments.  Thus, the on-site connection must be designed to be easy and quick to complete, which usually implies the need to accommodate dimensional discrepancies, but at the same time be sufficiently robust to sustain severe inelastic deformations due to the seismic loading. Those characteristics of constructability and robustness are nearly mutually exclusive, so designing to achieve both simultaneously constitutes a significant challenge.

In the past two decades, great strides have been made in developing such connections, and they have made ABC viable even in severe seismic regions.  Efforts have been made to standardize some of the results, and to create Guide Specifications for their design and construction (NCHRP 12-102, NCHRP 12-105).  However, they have been developed by many different agencies, and their variations are legion, with the result that an engineer may find difficulty in determining their relative advantages and shortcomings, and therefore in selecting the connection most appropriate for the job.

Objective:

The objective is to create an educational module that will explain the nature of the different connection types, their strengths and weakness, and the circumstances in which they are likely to provide the greatest benefits.  This will require careful categorization of the different types so that they can be presented in a clear and logical way.

Scope:

The following tasks will be performed to achieve the project objective:

  • Task 1 – A review of the many different ABC connections that have been developed to date
    • The NCHRP 12-102 and 12-105 projects will form a good starting point, but other connections are being developed on almost a daily basis. These will be sought through web searches, personal contacts and other means.
  • Task 2 – Sorting the connections into logical categories for presentation
  • Task 3 – Selecting suitable connections to be included
    • This task will be done in collaboration with the other partner universities, with the goal of achieving a common approach and style of presentation.
  • Task 4 – Preparation of audio-visual aids for inclusion in the course module
    • This may require the assistance of a graphic artist or drawing technician.

Research Team:

Principal Investigator:  Dr. John Stanton
Co-Principal Investigators: Paolo M. Calvi
Research Assistant:  N/A