Engineering : Construction


Health Monitoring and Imaging System for Concrete Structures

An assistant professor in civil engineering at the University of Wisconsin-Platteville in partnership with an electrical engineer from New Mexico State University, has developed a comprehensive monitoring system capable of identifying interior defects and stress in concrete structures such as bridges. By combining sensor technology with an ultrasound signal generator, multi-channel data acquisition and proprietary data processing algorithms, the interior conditions in any cross section of a bridge can be visualized in 3D. With this technology, small stress changes in the order of 0.1Mpa and cracks as thin as a human hair are detected. Such a combined system provides competitive advantage over existing methods that solely measure stress changes and rely on installation of strain gauges on the surface or inside concrete structures. These methods only provide for measurement of stress changes at the locations where sensors are placed, creating gaps in the evaluation of stress change. In addition, with current technology, holes must be drilled and patched for sensor placement and bridges must be taken out of service during testing. The proposed technology provides for a more absolute evaluation of not only changes in stress but also identification of cracks, does not require drilling of holes and can be used on in-service bridges, saving time, money and providing a more comprehensive assessment of bridge health.

Environmentally Green Glue

UW–Madison researchers have developed a process to transform soy flour into a strong, environmentally safe wood adhesive.

In the process, a suitable reagent is used to phosphorylate the flour’s lysine amino acid residues. The phosphorylated flour then is mixed with an oxidizing agent that drives the formation of cross-linking bonds. This improves the flour’s adhesive properties. Unwanted salts created in the process can be removed.

Flours of other legumes and/or oil seed crops (e.g., flax, canola) are suitable as well.

Portable and Lightweight Interlocking Crowd Control Barrier

UW-Madison researchers have developed a barricade connector that allows adjacent supports to be interlocked to prevent crowds from pushing the barricades apart. The newly-devised interlocking connector utilizes one of the two openings in any A-frame barrier structure to facilitate simple but effective connection of two barrier units. By connecting the units via one of the openings and using a typical barrier board in the other opening, pedestrians are unable to separate the individual barrier units or access the blocked area. The image below clearly illustrates the structure and function of the connector and barrier board. The barrier system is lightweight and portable, easy to manufacture and weather resistant.

Splice System to Connect Reinforcement Bars in Concrete Assemblies

UW-Madison researchers have developed a method for connecting multiple rebars, including steel, metallic and/or fiber-reinforced rebars, with a polymeric tube.  The tube is specially reinforced to provide the strength and stiffness needed to transfer tension force from the first bar to the tube, and then from the tube to the second bar.  Force is transferred between the reinforced tube and the bars by filling the space in the tube between the bars with a strong cementitious grout.  In addition, a special method of treating the inner surface with locking structures provides a strong bond between the tube and the grout.

This system and method provides a rebar splicing system made at least partially from non-metallic, corrosion-resistant materials, which can be used for reinforcing concrete with a relatively long use life in highly corrosive environments. The splicing system may be especially attractive for joining precast components by using the durable polymer tube in combination with non-corroding FRP reinforcement bars in connection regions that are particularly susceptible to corrosion.

Structural Reinforcement Using Composite Strips

UW-Madison researchers have developed a method of using a powder-actuated fastener gun to send fasteners through a reinforcing strip to affix it to a structure. Several advantages of this technology over currently available methods are listed below.