American Society of Civil Engineers

Flexural Behavior of an Ultrahigh-Performance Concrete I-Girder

by Benjamin A. Graybeal, Ph.D., P.E., M.ASCE, (Res. Struct. Engr., Fed. Highway Administration, Turner-Fairbank Highway Res. Ctr., 6300 Georgetown Pike, McLean, VA 22101. E-mail:

Journal of Bridge Engineering, Vol. 13, No. 6, November/December 2008, pp. 602-610, (doi:

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Document type: Journal Paper
Abstract: The flexural behavior of an ultrahigh-performance concrete (UHPC) was investigated through the testing and related analysis of a full-scale prestressed I-girder. A 28 ksi (193 MPa) compressive strength steel fiber reinforced concrete was used to fabricate an 80 ft (24.4 m) long AASHTO Type II girder containing 26 prestressing strands and no mild steel reinforcement. Intermediate and final behaviors, including cracking, flexural stiffness, and moment capacity, were investigated. Test results are compared to predictions based on standard analytical procedures. A relationship between tensile strain and crack spacing is developed. The uniaxial stress-strain response of UHPC when subjected to flexural stresses in an I-girder is determined and is verified to be representative of both the stress and flexural stiffness behaviors of the girder. A flexural design philosophy for this type of girder is proposed.

ASCE Subject Headings:
Concrete structures
Concrete beams
Prestressed concrete
Flexural strength
High-strength concrete