East River Drive Barrier Rail and Wall Project, Davenport, Iowa

2007 ACEC Iowa Engineering Achievement Award

Originally constructed in 1934, the East River Drive retaining wall and barrier rail project began as a 380-foot reinforced concrete section built as part of the realignment and widening of what is now known as US 67. 

This project included removal of approximately 2000 feet of stone barrier rail and replacement with reinforced concrete barrier rail and reinforced paved shoulder along East River Drive (US Hwy 67) in the City of Davenport, Iowa. This project also included:  88,200 Lbs. of epoxy coated reinforcing steel, reconstruction of intake top, 2.2 stations of pavement markings and 6 squares of sod.  Traffic was maintained on East River Dr. on at least one lane northbound and two lanes southbound during construction.

The Iowa River Pedestrian Bridge over the Iowa Dam, Coralville, IA

2006 ACEC Outstanding Civil Engineering Project Achievement

The existing Iowa River Dam and Spillway connecting Iowa City and Coralville, was built in 1922 for power generation.  The rock filled timber crib structure with concrete encasement served power to a population of 12,500 until 1968.

During recent inspection divers observed water flowing from the downstream face.  The existing abutments are in structurally poor condition and the bridge piers have experienced significant abuse by large trees and high water.  The two municipalities deemed this critical to maintain as the upstream Iowa City water plant requires stable river elevation and Coralville’s recreation access is one mile upstream.

NNW proposed an examination of the inside of the dam to determine its structural integrity.  The interior consisted primarily of the minimally reinforced concrete shell and spacious caverns where the timber had rotted away and settled.  NNW prepared plans and specification for filling the interior of the dam with flowable mortar and replacing the bridge with a two-span pre-fabricated bridge with one pier at the middle of the dam.  Included in the renovation were handicapped access, new abutments as well as additional piers to continue the bridge across the spillway.  The project is currently being constructed with completion anticipated in the summer of 2004.

2000-2001 Iowa Quality Initiative Award
For Superior Quality of Workmanship

Riverside Drive / Arts Campus

2004 ACEC Engineering Excellence Honor  Award
2000 Iowa Quality Initiative Award
For Best Cast-In-Place Culvert In Iowa

The drainage area of 200 urban acres and proximity to the Iowa River continually flooded the North Riverside Drive/ University of Iowa Arts Campus area.  The area was closed for several moths during the flood of 1993.  This project took advantage of the ancient idea of using natural head of the surrounding hills to drive storm water to the river via large culverts (750’ long).  In addition, two small (20,000 gpm) pumping stations were installed.

River Street

Iowa City, Iowa

The project included the relocation and installation of sanitary sewer, watermain, chilled water piping and storm sewer.  This project was implemented in three phases in partnership with the University and the City of Iowa City.  Being near a residential neighborhood NNW was instrumental in maintaining public relations.

Melrose Avenue Bridge over Iowa Interstate R.R.

City of Iowa City Design of new 210-foot long, 70-foot wide, three-span, steel stringer bridge. Project included 800 feet of urban approach roadway with storm sewer and utility relocation. Extensive traffic control and staging greatly complicated the project.

1997 Iowa Quality Initiative Structures Award

Kent Park Disiltation

Johnson County

The state of Iowa desired to remove and dispose of sediment from the bottom of the lake.  NNW designed a dredging and decanting system utilizing two settling ponds.  This method allows for reclamation of the holding area using sediment soils mixed with natural soil, quick completion of the project and return of the lake to full use and a cost efficient, safe way to obtain the project goal.

In addition, NNW recommended constructing smaller permanent silt detention ponds at the entrance to the lake that can easily and regularly be cleaned by smaller equipment and prevent heavy siltation in the main body of the lake.  This project successfully removed 60,000 cubit yards of siltation in 7 months at a cost of approximately $230,000.

Capitol Street Utility Tunnel Rehabilitation

University of Iowa

Design and Construction Management of rehabilitation of 600-foot long underground utility tunnel while utilities remain in service, including high-pressure steam.

Oakdale Campus Utility Tunnel Rehabilitation

Design and Construction Management of rehabilitation of 200-foot long underground utility tunnel.

Rienow Residence Hall - Utility Tunnel Restoration

Design of restoration system of 5-foot wide by 6-foot high box culvert like structure.