The existing bridge over the Wakarusa River on County Route 1057 was deemed structurally deficient and in need of rehabilitation or replacement. To determine the best solution, Douglas County contracted BG Consultants to study the existing structure and identify the most cost-effective rehabilitation alternatives.
Various rehabilitation options were considered, but due to bearing capacity limitations of the existing substructure, BG determined replacement of the entire structure to be the most cost-effective option. Before selecting the size for a new structure, a detailed hydraulic analysis was performed utilizing HEC-RAS software. The analysis evaluated different size structures in combination with varying approach roadway profiles and existing upstream water surface elevations.
BG was retained to design a three-span, 120’ – 170’ – 120’ composite welded plate girder structure. The girders were made of weathering steel, which develops its own protective coating and never needs painting. The replacement structure provides improved safety for the traveling public with its increased load carrying capacity, a wider deck than the existing superstructure could have provided, and a life expectancy in excess of 50 years. In addition to structural evaluation, hydraulic analysis, and structural design, BG Consultants obtained all required permits and provided surveying, approach roadway design, and grading plans.
Douglas County, Kansas