The monitoring of a precast, prestressed girder bridge during fabrication and service provided the opportunity to observe temperature variations and to evaluate the accuracy of calculated strains and cambers. The use of high curing temperatures during fabrication affects the level of prestress because the strand length is fixed during the heating, the coefficients of thermal expansion of steel ...

16. Abstract Four scale microconcrete model bridges were tested. Experimental variables included span, skew angle, stiffness, location and number of diaphragms. Service load level behavior was studied under static, cyclic and impact loads with successive removal of diaphragms. Behavior at overload and ultimate load conditions was documented from ultimate static and impact load tests. Characteri...

Concrete has been prestressed traditionally with high-strength steel. The vulnerability of such material to corrosion calls for alternate materials, if thin-sheet products are to be prestressed. A research project at Columbia University is investigating the feasibility of using aramid fiber mesh for such purpose. This paper explores the chemical and mechanical properties of aramid in the form o...

and findings of laboratory and field tests of a new generation of precast composite piles used for the first time in the construction of the Route 40 highway bridge over the Nottoway River in Virginia. The piles consisted of 24.6 in. (625 mm) diameter concrete-filled glass fiber reinforced polymer (GFRP) circular tubes, with a 0.21 in. (5.3 mm) wall thickness. The composite piles extended above...

On November 5, 1993, the City of Calgary completed the construction of the first smart prestressed concrete highway bridge built in Canada. A total of six pretensioned girders of a continuous two span skew highway bridge were prestressed using carbon fibre composite cables (CrCC) developed by Tokyo Rope, and Leadline rods produced by Mitsubishi Kasei, Japan. This paper describes the constructio...

Seven state-of-the-art machine learning techniques for estimation of construction costs reinforced-concrete and prestressed concrete bridges are investigated in this paper, including artificial neural networks (ANN) ensembles ANNs, regression tree (random forests, boosted bagged trees), support vector (SVR) method, Gaussian process (GPR). A database design characteristics 181 prestressed-concre...

The use of heavier trucks demanded upgrading of a twenty-seven year old bridge in Winnipeg, Manitoba, Canada. Analysis of the precast prestressed concrete girders using the current AASHTO Code indicates a deficiency in the shear capacity. Shear strengthening using Carbon Fibre R_einforced Polymer (CFRP) sheets provides a low-cost solution by increasing the speed of construction and reducing tra...

Spliced joints are used widely in retrofitting traditional timber structures, especially in heritage conservation applications where as much original material as possible needs to be retained. However, in practice this method is mainly applied based on experience, and there is a lack of understanding and quantification of the mechanical behaviour of retrofitted timber members. This paper presen...