ABSTRACT
High Performance Materials in Bridge Construction
M. Myint Lwin, Director, Office of Bridge Technology, FHWA
Presented: Thursday, May 13
11:30 am - 12:15 pm
High-performance materials have been developed to assure long life, fast construction and cost-effectiveness in infrastructure renewable. Several market-ready high-performance materials are discussed in this presentation.
High-performance concrete (HPC) is one of over 60 products investigated and advanced under the Strategic Highway Research Program (SHRP) in the 1990's. HPC is denser, stronger and less permeable. The advantages of HPC are longer bridge spans, increased durability and improved engineering properties. With HPC we can design and build bridges and highways to achieve 100-year life.
High-performance steel (HPS) is the outcome of a cooperative research program between the Federal Highway Administrative (FHWA), the U.S. Navy, and the American Iron and Steel Institute (AISI) launched in 1994. In about three years, the research program developed HPS with improved weldability, excellent corrosion resistance, high crack tolerance and very high strength. The combination of these improved properties of HPS leads to cost-effective applications in bridge design and construction. Over 40 states are already taking advantage of these properties in new bridge construction to improve long-term performance, lower first cost and reduce life-cycle cost.
Fiber reinforced polymer (FRP) is very high strength, light weight, corrosion resistance, and high in toughness. It is a popular material choice for bridge strengthening, repair and seismic retrofit. In recent years, FRP has been used for rebar, prestressing strands in concrete structures, wraps and shells for seismic retrofit, and beams and shapes for bridge elements and systems.
Accelerated construction technology (ACT) is aimed at exploring innovative ways to reduce construction time on major highway projects, improving construction quality and site safety, and reducing adverse impacts on the traveling public. FHWA in collaboration with the AASHTO Technology Implementation Group (TIG) conducts Accelerated Construction Technology Transfer (ACTT) workshops across the country to states apply the principles and practices of ACT to major projects.
Self-compacting/consolidating concrete (SCC) offers many advantages, some of which include no vibration, low noise, and faster construction. Japan has developed and used SCC since the early 1990's. In the last few years, a number of SCC bridges, walls and tunnel linings have been constructed in Europe. In the U.S., SCC is gaining interest and use, especially by the precast concrete industry. Some precast plants have retooled and invested in SCC mixing plants to cost-effectively produce precast elements of all shapes and sizes, and level of intricacy. Ready-mixed SCC is being used in columns, walls, piers and crossbeams of congested reinforcement. Properly engineered SCC flows into and completely fills intricate and complex forms under its own weight, passes through and bonds to congested reinforcement under its own weight, and is highly resistant to segregation.
High-performance materials and innovative construction methods are essential to our success in building faster, safer, more durable and cost-effective bridges in our national transportation network.
