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Bridge Design and Construction: The Ultimate Construction Kit
DP-99 Bridge Design and Analysis
      BRASS
      BRUFEM
DP-102 Bridge Construction
AP-44 Bridge Technology Workshops
TE-36 High-Performance Concrete
As with many other segments of civil engineering, bridge design has evolved from early art forms to a sophisticated science. A hundred years of experience have been assimilated into the engineering practice. Now modern research and development findings have been re-examined, tested, proven in service, and codified into bridge specifications and practice. Traditional design philosophies and methods, such as Working Stress Design (WSD) and Ultimate Strength Design (USD), are still used in bridge design, but recent developments in bridge design specifications have departed from the traditional approaches to incorporate more rational methods.

Load Factor Design (LFD) was a first step toward implementing a bridge design code based on statistical factors that account for variability of loads, lack of accuracy in analysis, and the probability of simultaneous occurrence of different loads. Load and Resistance Factor Design (LRFD) extended the philosophy to include resistance factors that account for the variability of material properties, structural dimensions and workmanship, and uncertainty in the prediction of resistance. Properly applied, the LRFD code is expected to lead to more rational bridge designs that will produce more economical and durable highway bridges. A concerted effort to train bridge designers in the concept of load and resistance factors, as well as their applications to bridge design, is crucial to the successful implementation of the new codes.

The LRFD specifications are ideal for assimilating new developments in bridge materials and construction methods, such as electroslag welding and high-performance concretes, since resistance factors can be modified as necessary to represent uncertainties in material properties. Part of this project will involve promoting new bridge materials and construction methods and will include implementing the LRFD code in bridge design software.
Recent innovative developments in bridge design codes, bridge materials, and construction methods have led to the establishment of 10 milestones:
  1. Develop and initiate formal training sessions for the design of bridge superstructures and bridge foundations using the LRFD code.
  2. Develop and initiate formal training sessions for the use of nondestructive load testing to determine load ratings of bridges.
  3. Develop and initiate a formal demonstration project on electroslag welding for steel bridges.
  4. Approve the LRFD specifications as the sole AASHTO code for design of highway bridges.
  5. Upgrade major bridge design, analysis, and rating software with LRFDcode: BRASS, AASHTO BDS.
  6. Use High-Performance Concrete in a prestressed concrete bridge in Virginia.
  7. Prepare Technology Transfer material and conduct a regional seminar on the use of High-Performance Concrete in a prestressed concrete bridge in Texas.
  8. Use High-Performance Concrete in parallel structures; conventional concrete in one, HPC in the other.
  9. Establish an equipment loan program for SHRP-developed High-Performance Concrete test equipment.
  10. Establish design and construction guidelines for High-Performance Concrete.


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