Eleven decked bulb T beams were constructed, instrumented, and tested under shear loading to failure. Nine beams were reinforced and prestressed with carbon-fiber composite cable (CFCC) strands, whereas one beam was prestressed with conventional lowrelaxation steel strands and one beam was reinforced with non-prestressed CFCC strands. Half the span of each beam was reinforced with CFCC stirrups, whereas the other half was reinforced with conventional steel stirrups. Both ends of each beam were tested to evaluate the performance of CFCC stirrups versus that of steel stirrups. The investigation addressed the shear performance with respect to several shear parameters, including shear-span-to-depth ratio, stirrup spacing, prestressing force, and type of longitudinal and transverse reinforcement. All test beams failed by crushing of concrete in either the web or the top flange. No rupture of CFCC stirrups was experienced in any of the test beams. The performance of CFCC stirrups was analogous to that of steel stirrups with the exception that steel stirrups demonstrated a yield plateau before concrete failure. Beam ends with CFCC stirrups attained cracking and ultimate shear capacities similar to those attained in ends with steel stirrups. Results from the experimental investigation were compared with the theoretical values predicted using some available shear design guidelines for steel and CFCC reinforcement. In addition, modifications for current AASHTO LRFD shear design equations and its possible implementation in the ACI shear design guidelines are proposed based on the experimental results.

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Carbon fi ber-reinforced polymer (CFRP) composite material has been widely studied and applied in bridge engineering as an alternative solution to the corrosion-related problems posed by steel reinforcement. Nevertheless, adoption of CFRP reinforcement to replace conventional steel reinforcement in highway bridges has not been fully realized yet in the fi eld. Therefore, large-scale experimental investigations on bridges with CFRP reinforcement are essential to encourage its widespread application in highway bridges. This paper presents an experimental investigation conducted on a one-third-scale AASHTO-type bridge model prestressed with carbon fi ber composite cable (CFCC) strands. The bridge model was designed, constructed, instrumented, and tested to thoroughly investigate its fl exural behavior, strain response, and ultimate load failure. A separate one-third-scale single AASHTO-type I-beam was also constructed and tested to study its fl exural and shear behavior as a control beam. In general, both the control beam and the bridge model experienced compression-controlled failure as anticipated. Signifi cant cracking and defl ection were experienced prior to failure. The ultimate strength of the control beam and the bridge model were in close agreement with the values estimated using the Unifi ed Design Approach.

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Metal Matrix Composite containing Fe2Tb0 .3Dy0.7 particles in Al matrix is strengthened by the effect of magnetostriction. The composite is fabricated by powder metallurgy, and the average diameter and the volume fraction of the particle are 2um and 5%, respectively. The magnetostriction induced by the magnetic field is relaxed at high temperature. Turning off the magnetic field at room temperature produces the residual stress. It is found that the compressive stress induced in the matrix develops the large tensile strength.