Page 49 - Bridge and Highway Structure Rehabilitation and Repair

24 SECTION 1 ADMINISTRATIVE ISSUES

2. Construction materials may be classified as traditional, new, or emerging. The goal is to fully
employ these, and even newer optimized materials, by exploiting the potential and properties
of materials, including life-cycle performance. Their advantages and limitations need to be
understood. The objectives are:
• Assessment of real and perceived barriers to deployment of various elements of optimized
structural systems.
• Development of appropriate state criteria for the use of these materials, details, compo-
nents, and structures for adoption into the LRFD specifi cations.
• Quantification of the impact of increased traffic volume and loads, nondestructive tests,

methods for protection, preventing salt ion intrusion, and new materials and techniques
for deck construction and repairs.
1.8.5 Use of Construction Systems Such as Accelerating Bridge Construction (ABC)
and Design-Build Construction (DBC)
Many states have legislation that mandates minimizing traffi c disruption during construc-
tion. Innovative construction methods, materials, and systems are needed for reducing on-site
construction time. Accelerated bridge construction results in projects being completed more
quickly and therefore the impact to users may be lessened.
Projects can be completed while maintaining traffic capacity including little impact to peak

traffic. Selection of the most effective techniques, the most promising emerging techniques, and

benefit/cost parameters is required to indicate when accelerated construction is appropriate.
Accelerated bridge design and construction research will advance technology by develop-
ing improved prefabricated structural systems using enhanced details, materials, and foundation
systems, using modern technology such as high capacity cranes and tractor trailers.
The organization of a combined contractor-consultant team has reduced some of the fric-
tion and lack of coordination between contractors and consultants. Traditional systems have

been refined by contractors playing a greater role as team members, which has resulted in more
realistic construction related design, better use of contractor’s resources, and a faster turnout in
construction.
1.8.6 Extending Service Life

1. Using efficient repair methods and improved retrofi ts.
It is important to understand the processes that decrease the serviceability of existing struc-
tures and to determine the optimum time to apply the preservation methods. There is a need
to develop approaches to preserve, maintain, or rehabilitate the existing system by managing
these processes. An outcome would be to develop strategies that would extend the service
life of the existing inventory of bridges and highway structures.
2. Main load carrying members are the core of any bridge. They require :
• Repair and strengthening methods, improved retrofit and replacement of bearings. The

majority of retrofits are in the form of upgrading the bearings, scour countermeasures,
and use of crash tested parapets. Details are provided in Section 2 of this book.
• Methods to eliminate expansion joints and bearings
• Corrosion mitigation techniques including coatings.
3. Substructures would require methods for strengthening piers and abutments.
4. Deployment of the most promising emerging preservation methods would be required.
These concepts are provided in design techniques covered in Section 2 of this book.
5. Modernizing structural details such as using jointless decks.
Integral and semi-integral abutment bridges are being used extensively to eliminate the prob-
lematic deck joint. Jointless bridge systems result in more durable bridges since combined