Award-Winning Projects
Over the years, WHKS & Co. has had the privilege of designing projects that have been honored by the American Council of Engineering Companies of Iowa and have received several Engineering Excellence Awards on their behalf.
Engineering Excellence Award 2024
Ioway Creek Flood Mitigation | Ames, Iowa
WHKS designed flood mitigation and stream restoration measures for a 2,000-foot reach of Ioway Creek on either side of the Duff Avenue Bridge in the City of Ames. WHKS assisted the City with completion of the FEMA Flood Mitigation Assistance grant application process, securing $4.5 Million to fund improvements.
The stream corridor was modeled using 2D software to determine channel velocities and flood elevations. WHKS analyzed alternatives to open the flows under the Duff Avenue bridge and minimize impacts to the parking area in the southwest corner of a commercial development on Buckeye Avenue. The site layout for a 300′ x 12′ modular block retaining wall was constructed to accommodate slope grading. The addition of a berm diverts flows at the northeast corner of the Duff Avenue Bridge.
The selected design kept the channel as-is near the Duff Avenue Bridge, with a second stage area constructed to divert water during heavy rainfall. To restrict flows at the bridge, the end spans were designed with open velocities to prevent build up of sediment. The high velocities through the bridge prevent sediment from returning to the channel.
The City acquired two buildings to accommodate the improvements. WHKS prepared right-of-way plats for acquisition and met with property owners to coordinate right-of-way and easement needs.
Several of the trees cleared along the channel were reused as root wads to stabilize the bank. Root wads and boulder clusters also provide areas for fish habitat. Rock deflectors slow the water during flooding events and maintain normal flows to the center of the stream to reduce meandering.
Wetland delineations were conducted within the project corridor to meet permitting requirements. A seeding plan focusing on pollinators was developed in the pocket wetlands.
The project received the Honor Award (Second Place) in the Special Projects Category in the 2024 Engineering Excellence Awards Competition.
Engineering Excellence Award 2020
Mill Pond Park Trail and Bridge | Nora Springs, Iowa
The Mill Pond Park Trail and Bridge is a 700 foot, multi-use path with a two-span steel prefabricated bridge beginning at Hooker Avenue North, crossing the Shell Rock River, and ending on the west side of the existing walking bridge in Nora Springs. The bridge unites two parts of the City, creating a safer and easier passage for residents.
The steel truss bridge spans 360 feet and was designed to be maintenance-free to provide for years of sustainable use. The bridge features an ADA-compliant walkway and a central lookout platform for pedestrians to take in the scenic views of the Shell Rock River. Concrete walking trails connect the bridge to the parking areas on both sides of the river. At night, the trail and bridge are illuminated with 57 approach trail lights and 33 bridge walkway lights. The project was completed in four phases.
The project received the Grand Place Award in the Special Projects Category.
Engineering Excellence Award 2016
US 34 Ramp B Repair | Burlington, Iowa
After an over-height vehicle struck the US 34 E-S Ramp B bridge and severely damaged the girder, WHKS provided an evaluation, conducted an analysis, and provided repair design for replacement of the damaged section.
The project was completed in two phases to accommodate a local festival. Phase 1 included temporary support design and the construction necessary to open the ramp in time for Steamboat Days. Phase 2 replaced the damaged girder section. WHKS devised a plan to use a strong back beam under a two-phase placement method. In Phase 1, the temporary beam was placed directly over and connected to the damaged girder to allow ample room for vehicles while supporting necessary bridge weight and live loads from bridge traffic. Phase 2 involved moving the strong back a few feet off-center of the girder to allow for the replacement of the damaged girder and reconstruction of the deck and barrier.
Traditionally, the strong back beam has been used as temporary support during repair operations only when the roadway is closed to traffic. WHKS designers created an analytical model combining the temporary beam with the existing structure to form a hybrid structural system with free-flowing traffic.
The construction of the new hybrid structural system subjected the existing structure to loads not covered in the bridge’s original design. WHKS designed a plan to “pre-tension” the threaded rods connecting the strong back to the existing girder to induce off-setting differential deflections to maximize the utilization of the strong back beam’s strength. The Ramp B Bridge was reopened 26 days after the initial impact.
The project received the Grand Place Award in the Transportation Category and was the Grand Conceptor (overall winner of all entries).
Engineering Excellence Award 2014
MRT Heritage Trail Pedestrian Overpass and Trail Extension | Dubuque, Iowa
WHKS provided survey and design for the construction of a pedestrian overpass structure over US Highway 52/3 and the HMA paving extension of 1.05 miles of pedestrian trail from Rupp Hollow Road to John Deere Road.
The structure included design of a single-span bridge over US 52 and the adjoining MSE wall approaches. The paved trail is located on Dubuque County right-of-way, which is the abandoned Chicago and Great Western Railroad right-of-way corridor. Plans for the trail and bridge were prepared in accordance with Iowa DOT Standard Specifications. The project required an extensive hydraulic and hydrologic analysis for property located in the floodplain requiring coordination with various agency representatives.
The project received a Second Place Honor Award in the Special Projects Category.
Engineering Excellence Award 2013
Trout Run Trail Bridge over State Highway 9 | Decorah, Iowa
The City of Decorah developed a system of trails that encompass the City. As part of the final segment, the City wanted to construct a “signature” pedestrian bridge where the trail crosses State Highway 9.
WHKS performed a feasibility study that evaluated various bridge options. After considering several structure types, the City selected a concrete post-tensioned frame type bridge. The project was one of the first bridges in the state of Iowa to utilize a longitudinally posttensioned concrete frame structural system.
WHKS performed the structural design and created final plans for the three-span bridge. Unique features of the bridge to include the thin concrete deck slab with curved arches and the post-tensioning system in the slab. The superstructure and piers are made with high strength concrete.
The project received a 2nd Place Honor Award in the Transportation Category.
