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<br />needed to sacrifice durability for function. Our concept for the Bridge Park achieves the complex <br />geometry, span demand, and aesthetic finish with concrete elements that do not require expensive <br />structural coatings. Steel coatings such as high-performance paint or metalizing have a finite life span <br />requiring complete overcoating or removal and reapplication in approximately 15 – 25-year intervals, <br />depending on the coating system utilized and quality of application. The removal and reapplication of the <br />coating system will require lengthy lane closures and costs on the order of one million dollars per <br />recoating. In addition, the coating system appearance will deteriorate with flaking or chalking as the <br />system approaches the useful life. Prestressed concrete will maintain durability without the need to <br />maintain a coating system. <br />Comparison of Concrete and Steel Box Superstructures <br />Key Issue Steel Box Girders Concrete Box Girders <br />Initial Costs +$1M relative to concrete boxes (see <br />Construction Cost Estimate) <br />Low cost relative to steel girders. <br />Many fabricators can provide. <br />Structural <br />Coating Cost <br />+$500k relative to concrete No structural coating required. <br />Structural <br />Coating <br />Maintenance <br />Structural coatings can be expected to last <br />approximately 15 years in the Bridge Park <br />environment. Replacement of coating <br />system requires complete removal, full <br />containment, and lane closures. <br />Prestressed concrete beams do not <br />require any structural coatings. <br />Inspectability <br />Requires access hatches, ventilation, lighting <br />inside of box, and hands-on access to <br />fracture critical steel elements. Cladding <br />cannot be provided on steel girders since the <br />need to be fully accessible to inspect. <br />FUB does not require access or <br />lighting or ventilation and all <br />surfaces are accessible from below <br />or in maintenance vault. No fracture <br />critical elements. <br />Maintainability <br />Requires maintenance of lighting and <br />ventilation systems. Requires maintenance <br />of steel coating system that will be replaced <br />multiple times over the life of the bridge. <br />No maintenance of FUBs required. <br />Aesthetics <br />Steel coating systems will deteriorate over <br />time and since cladding cannot cover the <br />steel girder there will not be a consistent <br />finish for most of the structure’s life. <br />Concrete elements will provide a <br />consistent look throughout the life <br />of the iconic Bridge Park. <br />