The structural feasibility of using welded steel mesh in bridge decks.

摘要

In spite of the economical and structural benefits of using welded steel mesh (WSM) as reinforcement in concrete bridge decks, structural engineers have been reluctant to use it in highway structures. Their main concern, which arises from their lack of knowledge of the properties and behavior of this material, is poor fatigue strength due to welded intersections. Nevertheless, there are many benefits to be gained from using WSM in bridge decks (i.e. considerable savings through reduced construction time, improved bond, anchorage and serviceability performance, small probability of error in placement in comparison with conventional reinforcement, non-requirement of highly skilled laborers for placement). This dissertation establishes the necessary information of the properties of WSM and examines the behavior of structural elements utilizing this material. The experimental testing program included tensile, chemical composition, fatigue, flexure, splice, pullout, and punching shear tests. The material used in the experimental program was taken from United States, German, and Canadian WSM manufacturers. The specimens included steel composed of rods, smooth wires, deformed wires, epoxy-coated deformed wires, tempered and non-tempered WSM and non-tempered bars without weld.;As a result of the experimental and analytical investigations, information regarding material properties has been established, with recommendations on material and the manufacturing process which may yield the best ductility and behavior. The structural element behavior has been explained and recommendations to assure the material's best performance (reinforcement ratio limitation, splice length equation, splice detail, orientation of the transverse wires) are presented. Finally, the proposed analytical method for deflection and rotation calculations has been found to be accurate based on the experimental results of this study.;The results of the investigation show that WSM performs well with respect to all the experimental tests with the exception of the simply supported slab in the flexure test, where the slab had less ductility than an equivalent slab reinforced with conventional reinforcement. However, the WSM reinforced slab deformed sufficiently and showed clear signs of distress before failure, a behavior which can provide visual warning of imminent failure. Thus, WSM can be used, with proper engineering judgment, as reinforcement of bridge decks.