Principal Investigator: George Morcous
About this Project
Brief Project Description & Background
Several bridge decks are reaching the end of their service life and/or need to be replaced due to insufficent width or capacity. For those decks on precast/prestressed concrete I-girders with wide and thin top flanges, there is a significant risk of damaging girder flanges during deck removal. Therefore, several deck removal methods need to be evaluated with respect to their impact on bridge I-girders as well as cost, duration, risk on workers and traveling public, and environmental compliance.
The objective of this project is to determine the most efficient deck removal method in precast/prestressed concrete I-girder bridges. This efficiency is determined based on their impact on the structural performance of girders, cost of removal and repair, duration of removal and repair, safety of workers and traveling public, noise level, impact on the surrounding environment.
The expected outcome of this project will be a list of feasible bridge deck removal methods and the severity/extent of damage to I-girders from each method as well as their impact on the project cost, duration, safety, and environment. This information will allow allow bridge owners to select optimal method regarding the removal of concrete decks for given project conditions.
Current concrete bridge I-girders, such as NU girders, have unique characteristics compared to the standard AASHTO I-girders. These girders have wide and thin top flange to improve lateral stability of long span girders during erection, provide adequate platform for workers, shorten deck span, and reduce girder weight. However, these features made the top flange more susceptible to damage during deck removal operations, which will be inevitably encountered shortly as several of bridges will require re-decking for structural and functional reasons in the near future. Therefore, there is an urgent need nationwide to determine the optimal deck removal method(s) with respect to their impact on girder top flange and shear connectors. These methods also need to be evaluated considering cost, time, noise, safety, and environmental criteria to ensure rapid construction, sustainability, optimal use of federal funds, and safety of workers and traveling public. The main objective of this project is to identify the deck removal method that are optimal for use in precast/prestressed concrete I-girder bridges, which represent over 50% of the bridges constructed in the last few decades. These methods include, but not limited to: saw cutting, jackhammering, hydro-blasting, and combinations. The Eastbound of Camp Creek Bridge in Lancaster County, Nebraska, is scheduled for demolition in Fall 2012. The proposed deck removal methods will be applied to this bridge. After deck removal, several girders will be inspected for damage, repaired, re-decked, and tested at the structural laboratory to evaluate their residual flexural and shear capacities.