It has been a long time coming, however the entire four bridge replacement program of North Center Street received a big boost on June 3 with concrete pouring onto the deck for the biggest bridge, specifically the one spanning the Iowa River.

A new pier and abutments were built several months ago. Those were followed by concrete pre-stressed beams which were set in place. Construction crews from PCI built forming supports for the deck and another crew installed re-bar over the entire structure.

Wednesday was the appointed time to pour concrete for the deck. In total 290 cubic yards of concrete was brought to the site. Pumper trucks at either end of the bridge supplied fed the pumper trucks. Crews from PCI worked diligently to get the concrete mixture in place. The work started at approximately 7 a.m. at the north end of the structure. By 11:10 a.m., the last load was in place.

According to Paul Geilenfeldt, county engineer, the plans called for pouring 290 cubic yards for the deck. Each cubic yard weighs 4,050 pounds. North Center Street’s bridge deck over the Iowa River weighs approximately 1.2 million pounds. The deck surface is 200 feet long and 50 feet wide.

PCI employees were aided by machinery specifically designed and built to make large pour projects easier. Precise thickness of concrete is imperative. Even with all the assistance the machinery provides, hand work and skills of the workers is still a requirement as attention to detail is achieved.

Remaining work related to the river bridge is extensive. It will include concrete vehicle barrier walls, pedestrian sidewalk and reconstruction and paving of approaches to the bridge. Existing roadway

surfaces between bridges will be torn out and new paving poured. And a large water main will also be built to carry potable water to the city from the water treatment plant. That large pipe system will rest on its own concrete beam along the north edge of the river bridge.

Concrete on a bridge deck must be allowed to cure slowly to gain strength over time. The entire deck system is now covered with burlap and kept moist with water spray.

Later this summer, when approach work and road paving is completed to the Water Works Plant, bridge work will shift to the two remaining smaller overflow bridges. After those bridges are finished, paving of that portion of the roadway will take place. The entire package of bridges and roadway paving may, if weather cooperates and work goeswell, be completed in late 2021.

County Engineer Geilenfeldt may be contacted for updates on the time line for the entire four bridge project of North Center Street.

Concrete is heavy and to get it easily in place, pumper trucks utilize a long boom and pipe system to put the mixture where it needs to be. An operator for the boom truck hose accomplishes his task by a remote control hand held box. This saves considerable time and makes for efficient work by deck crews.