Louis N. Triandafilou, Federal Highway Administration
Since the fall of 1997, the Mid-Atlantic States Prestressed Concrete Committee for Economic Fabrication (PCEF) has been meeting twice a year to carry out its mission: “To encourage and promote economy, quality, and uniformity in the design, manufacture, and construction of high performance, prestressed concrete bridge members.” The reference to high performance concrete (HPC) in the mission statement emphasizes the direction that the FHWA, state DOTs, and industry are taking to ensure improved durability, permeability, and strength in concrete bridges.
The PCEF consists of FHWA bridge engineers, industry representatives, and DOT bridge designers and materials engineers from Delaware, the District of Columbia, Maryland, Pennsylvania, Virginia, and West Virginia. Recent meetings have also included representatives from the DOTs in New Jersey, New York, and North Carolina, and the FHWA Eastern Federal Lands Highway Division. The precast, prestressed concrete suppliers that provide bridge members to these states are an integral part of the group. The PCEF is structured with subcommittees on standardization, design parameters, materials and quality control/quality assurance, construction/production, and contracting practices. The first critical actions taken by the PCEF to promote uniformity, quality, and economy were to adopt two recommendations. Recommendation No. 1 was that, “HPC with a 28-day compressive strength of 8,000 psi (55 MPa) shall be used in prestressed concrete whenever it is economical. Prestressed concretes with strengths from 8,000 to 10,000 psi (55 to 70 MPa) may be used with approval of the State Bridge Engineer.” Recommendation No. 2 deals with corrosion protection: “Concrete for piles, beams, and slabs shall contain 3.5 gal of calcium nitrite per cu yd of concrete, conforming to… unless granulated iron blast-furnace slag (minimum 40 percent by weight of cement) or silica fume (minimum 7 percent by weight of cement) conforming to… is used. Concrete for structures over tidal water, beams and slabs within 15 ft of mean high water, and all exposed piles shall contain either 5.4 gal of calcium nitrite per cu yd concrete, conforming to… or 2.0 gal of calcium nitrite per cu yd of concrete with granulated iron blast-furnace slag (minimum 40 percent by weight of cement) or silica fume (minimum 7 percent by weight of cement) conforming to…”
The PCEF has adopted a family of bulb-tee shapes that are interchangeable with the recently developed New England bulb-tees. The proposed sections are very versatile with nine girder depths, three web thicknesses, three top flange widths, and two bottom flange thicknesses providing a total of 162 possible shapes. The needs of every state and precaster should be satisfied within this framework that uses one set of form pieces to produce any of the girder shapes.
In summary, the Mid-Atlantic States PCEF is a dedicated group of professionals working hard toward the ultimate goal of enhancing the economy of prestressed concrete bridges through standardization and uniformity of design and fabrication practices. The group is an excellent example of the FHWA, state and local DOTs, and industry working together to adopt quality and economical measures through a consensus process. Positive effects have been achieved by tying the group’s mission to the national emphasis on HPC. At each PCEF meeting, the states identify more and more activities on the implementation of HPC.
Further Information
More information about PCEF meetings, subcommittees, and the full committee roster can be found at the FHWA website www.fhwa.dot.gov/resourcecenters/eastern/infrastr/hipma.htm. Or, contact the author at [email protected] or 410-962-3648.