No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

A new method has been developed for strengthening reinforced concrete beams for flexure which uses multiple mechanical fasteners to attach a fiber reinforced polymer (FRP) strip to the member. This study investigates the behavior of the method on full scale concrete T beams of three different steel reinforcement levels. The beams were strengthened without surface preparation, and the strips were attached with only four man-hours of labor per beam. The strengthened beams resulted in increases of up to 11.7 % in the yield moment and up to 27.2 % in the moment capacity at a deflection of L/135. The beams exhibited large amounts of ductility, before failure.

Existing precast concrete railroad crossings in the state of Indiana are experiencing too short a life expectancy. This study proposes methods that can be used to produce durable concrete railroad crossings with satisfactory rideability, durability, and longevity. Thirty-two precast concrete railroad crossings were visited in central and northern Indiana. Failures were determined to belong to three major categories: structural capacity causes, environmental causes, and material property causes. A concrete mix was evaluated at three different polyolefin fiber contents and without fibers. Beams were tested in flexure, and modulus of rupture and first crack deflection were recorded for each beam. Cylinders were cast for compressive testing and splitting tensile testing. Modulus of rupture was increased by the addition of fibers. The spread in data was observed to increase with an increase in fiber content. Compressive strength and splitting tensile strength were increased slightly by the addition of fibers. Panels are currently being produced that utilize post tensioning. These panels are less likely to crack under extreme loading conditions. If a crack forms, it closes upon removal of the load.