While Holland Charter Township’s trail system covers portions of the Township on either side of I-196, connectivity between the two sides was limited. While developing a plan with Zeeland Charter Township and Ottawa County to connect the non-motorized pathway network of the Holland area with that in Grand Rapids, the need for a highway crossing over Adams Street became very evident and made the most sense. However, the existing Adams Street vehicular bridge is a high traffic, five lane thoroughfare with only 3’ wide shoulders. "A separate non-motorized bridge over I-196 became the lynchpin to finalize this proposed connectivity," said Scott Post, P.E., Project Manager with Prein&Newhof (P&N), the consulting engineer.
Contech Engineered Solutions designed a 236’ x 14’ Gateway®-style Continental® truss bridge, completely spanning the east and west bound lanes of I-196 and the clear zones outside of the shoulders in order to minimize the risk of vehicles hitting the abutments. In order to address Michigan Department of Transportation’s (MDOT) concerns that citizens might throw objects off the bridge into the traffic below, a cage was designed to envelop the bridge and deter unlawful behavior. The bridge was pre-manufactured in Minnesota and then shipped to the site where it was bolted together and lowered into place via crane.
"This was a unique project, building a pedestrian bridge over a state highway," added Post. "Contech representatives went out of their way to ensure the bridge met the specific standards for MDOT construction. This bridge project was the critical link to provide regional non-motorized connectivity between the communities Holland and Grand Rapids, and beyond. Not only does it provide an important pedestrian connection for the community, but it is also destined to become a community landmark for generations to come."
P&N’s engineers designed the foundations on either end of the bridge using the critical reaction values provided by Contech. To further expedite the construction timeline of the project, P&N incorporated Contech’s precast abutment wall system. Each abutment was designed as a two panel system measuring 25’ tall and over 8’ wide. The abutments were set in one day allowing Midwest Bridge, the project’s contractor, to pour the foundation floor the following day.
Due to the unique nature of an independent bridge for non-motorized use over one of their interstate highways, MDOT was initially concerned with the concept. However, MDOT recognized the value of the crossing and the proposed Continental bridge met MDOT’s highway design standards. The new Adams Street pedestrian crossing allows users to enjoy Holland Charter Township’s entire trail system without risking their lives crossing the dangerous, vehicular Adams Street Bridge. It also provides a key strategic link between the lakeshore trail networks in Holland Township and the City of Holland (including connected non-motorized access to existing routes south to Saugatuck and north to Whitehall) and the Fred Meijer Kenowa Trail. Cyclists can now ride over 40 miles to Grand Rapids and beyond on designated non-motorized pathways, making this a very significant link in the regional trail system. Holland Charter Township expects this new bridge to increase trail use within and beyond its own system.
"Contech offered a complete turn-key package that no other bridge supplier could offer for this type of project," concluded Post. "The technical support, design expertise and on-site support helped drive this project from concept to installation to bridge approval by MDOT. In the end, our goal as a consulting engineer is to bring concepts to reality for our clients at the best value and to the highest standards. Contech was vital in making this happen."