Anchor Bolt Patterns for Mechanically Fastened FRP Plates

Contributing USMA Research Unit(s)

Center for Innovation and Engineering, Civil and Mechanical Engineering

Publication Date


Publication Title

Journal of Composites for Construction

Document Type



This paper examines the results of material testing of hybrid carbon and glass fiber-reinforced polymer (FRP) plates for use in prestressed mechanically fastened applications. The small-scale material tests were conducted in three phases: (1) uniaxial tension without holes, (2) uniaxial tension with open holes, and (3) uniaxial tension with single- and multibolt connections. In all three phases of testing, Digital Image Correlation (DIC) was used to obtain continuous strain data, showing holistic strain field development through failure. A total of 89 tests were conducted across 17 treatment groups to develop an anchor pattern and fastener spacing which is optimized with respect to maximum capacity and behavior under anticipated service load conditions. The tests presented comprise the initial phase of a larger project that aims to employ prestressed mechanically fastened FRP (MF-FRP) plates as a retrofit repair solution for deteriorated prestressed concrete bridge superstructures. Results conclude that 2 lines of 11 bolts with diameters of 12.7 mm, with longitudinal spacing of 100 mm and transverse spacing of 38 mm, provide an end-region anchor pattern with an ultimate capacity of 206 kN which is 89% of the ultimate capacity for the examined FRP plate with holes.

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