MassDOT’s 93FAST14 Project | Innovative Bridge Technologies/Accelerated Bridge Construction

November 4, 2014 N/A

The 2014 in-depth web training features the Massachusetts DOT's 93FAST14 project. In this project ABC was used in the replacement of 14 bridges on Interstate 93 in Medford, Middlesex Country. The bridge superstructures were installed during 55-hour weekend closures over a 10 weekend period during the summer of 2011.

Module 1: Introduction

by Tom Donald, P.E., Director of Bridge Project Management, MassDOT

Module 1 Presentation

MassDOT’s Accelerated Bridge Program
Overview of 14 bridge replacements in 10 weeks
Decision to use Design Build
Post-construction inspection and performance

Module 2: Planning and Preliminary Design

by Mike Culmo, P.E., Vice President, Transportation and Structures, CME Associates, Inc.

Module 2 Presentation

History of project development
Project priorities
Decision for use of ABC vs conventional construction
Cost implications of ABC vs. Conventional
Overall project timeline / schedule
Prefabrication options and preliminary design approach
Preliminary Substructure Analysis
Performance specification for closure pours
Roles and responsibilities

Module 3 :Design Details – Substructure Rehabilitation

by Joe Gill, P.E., President, Gill Engineering

Module 3 Presentation

Design requirements
Substructure analysis
- Issues with applying LRFD to existing substructure
- Rational approach used
Bearing seat modifications
- Requirements for shallower beams
- Different beam spacing
- Shoring and beam end removal for beam seat modifications
Abutment modifications
- Use of approach slabs as dead-men

Module 4: Design Details – Superstructure Replacement

by Joe Gill, P.E., President, Gill Engineering

Module 4 Presentation

Design requirements
- No real design differences
- Designed as simple spans with link slabs
- Minimize beam depth to improve vertical clearance
- Complications associates with large skews
Diaphragms
- Minimize the number of diaphragms
- Use of diaphragms on closure pour bays
Cast-in-place barriers
- Why not precast?
- Use of shoulders for work zone.
Construction issues
- Crane picks controlled most sites
- Minimize weight on PBUs
Closure pour issues
- High early strength
- Control of shrinkage to minimize cracking
- Details and reinforcing
- Design for interim strength
Link slab design – jointless deck
Slab details at abutments
Diaphragms
Bearing layout and design
- Floating Bridge Concept
- Use of sliding bearings to control seismic forces
- Deck protection – HMA and waterproofing vs. exposed deck