Protection of Structural Concrete Substructures, HR-220, Progress Report, 1984

The corrosion of reinforcing steel within concrete has always been a problem in construction of bridge decks. With low slump concrete and epoxy rebar, progress has been made in controlling the corrosion. There is concern, however, that the chloride also attacks the substructures, specifically the pier columns. They are subject to chloride attack by chemical deicers in the drainage from the bridge deck. Piers supporting grade separation bridges are also subject to chlorides contained in the direct splash from the lower level traffic. In this project, a field evaluation was conducted to evaluate the effectiveness of commercially available products in preventing chloride intrusion.

Use of Longitudinal Subdrains in the 3R Program, Final Report, HR-509, 1981

Construction of the interstate highway system began in 1956. This U.S. network of highway consists of more than 41,000 miles with 790 miles in Iowa. There have been many benefits of the controlled access roadway, but probably the most significant is the improved safety for the motorist. In Iowa, we have always endeavored to utilize quality locally available materials in our construction using the most economical or cost effective methods. Obviously when the effort is to build a cost effective system, there will be some portions of the network that will not perform as well as expected. In the design of our interstate, the main consideration for base construction under the pavement was structural capacity. The material was dense graded with the aim of supporting the pavement and distributing the load as it is transferred to the underlying grade. The drainage characteristic of the base was apparently not given adequate consideration. On jointed portland cement concrete (pcc) pavement, the water that is trapped immediately beneath the pavement causes severe problems. The traffic causes rapid movement of the water resulting in the hydraulic pressures or "pumping" (movement and redeposit of base fine material) resulting in faulting between individual slabs. Recognizing the need for maintaining this large national highway network, the Federal Highway Administration has initiated a funding program for resurfacing, restoration and rehabilitation (3R). Many miles of the system are more than 20 years old and in need of major maintenance. This new 3R Program necessitated a complete inventory of the Iowa interstate system to establish priorities and to identify those sections in need of immediate remedial treatments.

Dynamic Deflections for Determining Structural Rating of Flexible Pavements, HR-178, 1979

The Road Rater is a dynamic deflection measuring apparatus for flexible base pavements. The Road Rater replaces the Benkelman Beam which was last used by the Iowa DOT in 1977. Road Rater test results correlate reasonably well (correlation coefficient = 0.83) with Benkelman Beam test data. The basic differences between the Road Rater and Benkelman Beam are as follows: 1. The Benkelman Beam uses a static 18,000 lb. load while the Road Rater uses a dynamic 800 to 2,000 lb. loading. 2. The Road Rater tests much faster and more economically than the Benkelman Beam. 3. The Road Rater better simulates a moving truck than the Benkelman Beam. The basic operating principle of the Road Rater is to impart a dynamic loading and measure the resultant movement of the pavement with velocity sensors. This data, when properly adjusted for temperature by use of a nomograph included in this report, can be used to determine pavement life expectancy and estimate overlay thickness required. Road Rater testing will be conducted in the spring, when pavements are in their weakest condition, until seasonal correction factors can be developed. The Road Rater does not have sufficient ram weight to effectively evaluate load carrying capacity of rigid pavements. All rigid pavements react similarly to Road Rater testing and generally deflect from 0.65 to 1.30 mils. Research will be contined to evaluate rigid pavements with the Road Rater, however. The Road Rater has proven to be a reliable, troublefree pavement evaluation machine. The deflection apparatus was originally front-mounted,but was rear-mounted during the winter of 1977-78. Since that time, van handling has greatly improved, and front suspension parts are no longer overstressed due to improper weight distribution.

Structural Characterization of UHPC Waffle Bridge Deck and Connections, TR-614, 2014

The AASHTO strategic plan in 2005 for bridge engineering identified extending the service life of bridges and accelerating bridge construction as two of the grand challenges in bridge engineering. These challenges have the objective of producing safer and more economical bridges at a faster rate with a minimum service life of 75 years and reduced maintenance cost to serve the country’s infrastructure needs. Previous studies have shown that a prefabricated full-depth precast concrete deck system is an innovative technique that accelerates the rehabilitation process of a bridge deck, extending its service life with reduced user delays and community disruptions and lowering its life-cycle costs. Previous use of ultra-high performance concrete (UHPC) for bridge applications in the United States has been considered to be efficient and economical because of its superior structural characteristics and durability properties. Full-depth UHPC waffle deck panel systems have been developed over the past three years in Europe and the United States. Subsequently, a single span, 60-ft long and 33-ft wide prototype bridge with full-depth prefabricated UHPC waffle deck panels has been designed and built for a replacement bridge in Wapello County, Iowa. The structural performance characteristics and the constructability of the UHPC waffle deck system and its critical connections were studied through an experimental program at the structural laboratory of Iowa State University (ISU). Two prefabricated full-depth UHPC waffle deck (8 feet by 9 feet 9 inches by 8 inches) panels were connected to 24-ft long precast girders, and the system was tested under service, fatigue, overload, and ultimate loads. Three months after the completion of the bridge with waffle deck system, it was load tested under live loads in February 2012. The measured strain and deflection values were within the acceptable limits, validating the structural performance of the bridge deck. Based on the laboratory test results, observations, field testing of the prototype bridge, and experience gained from the sequence of construction events such as panel fabrication and casting of transverse and longitudinal joints, a prefabricated UHPC waffle deck system is found to be a viable option to achieve the goals of the AASHTO strategic plan.

Synthetic Fabric to Improve Structural Capacity in Asphalt Overlays, HR-516, 1984

Iowa's first field application of synthetic engineering fabrics was on research project HR-158, "Prevention of Reflective Cracking in Asphalt Overlays". This research placed in September 1971 used three different engineering fabrics. A final report concluding generally favorable performance was distributed in May 1977. There have been a number of Iowa engineering fabric installations since that initial project.

Hydro-Surface Preparation and Coating for Painted Structural Steel, TR-407, 1999

Cities and counties in Iowa have more than 8,890 steel bridges, most of which are painted with red lead paint. The Iowa Department of Transportation (Iowa DOT) maintains less than 35 bridges coated with red lead paint, including seven of the large border bridges over the Mississippi and Missouri Rivers. Because of the federal and state regulations for bridge painting, many governmental agencies have opted not to repaint, or otherwise maintain, lead paint coatings. Consequently, the paint condition on many of these bridges is poor, and some bridges are experiencing severe rusting of structural members. This research project was developed with two objectives: 1) to evaluate the effectiveness of preparing the structural steel surface of a bridge with high pressure water jetting instead of abrasive blasting and 2) to coat the structural steel surface with a moisture-cured polyurethane paint under different surface preparation conditions.

Lake Restoration 2007 Report and 2008 Plan, December 28, 2007

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2008 Report and 2009 Plan, December 30, 2008

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2009 Report and 2010 Plan, December 30, 2009

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2010 Report and 2011 Plan, December 30, 2010

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2011 Report and 2012 Plan, December 30, 2011

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2012 Report and 2013 Plan, December 31, 2012

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2013 Report and 2014 Plan, December 31, 2013

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Lake Restoration 2014 Report and 2015 Plan, December 31, 2014

The Department of Natural Resources (IDNR) Lake Restoration Program focuses on restoring impaired lakes to improve the quality of life for Iowans. Communities are rallying around their water resources as they seek population growth and economic success. Communities of the Iowa Great Lakes Region, Storm Lake, Crystal Lake, Creston and Clear Lake are obvious examples, but other communities including Lake View and Brighton are identifying the importance of lakes for their futures as well. The distribution and nature of Vision Iowa grants, Community Attraction and Tourism grants, and now, Great Places, all further emphasize the importance of water to community, quality of life and economic growth.

Protection of Structural Concrete Substructures, Construction Report, HR-220, 1981

It is the objective of this project to determine, via field tests, the long term effectiveness of several available systems as their ability to protect concrete surfaces against the intrusion of chloride ions. Early concepts of this project included utilizing personnel from several offices within the Highway Division of the Iowa Department of Transportation. Cooperation and coordination with regularly scheduled activities were considered imperative. A meeting for this purpose was held on April 16, 1980. This meeting was attended by the investigators, Mr. Bernard C. Brown, Office of Materials, Mr. Richard Merritt, District 6 Materials Engineer, Mr. John Saunders, District 6 Maintenance Engineer, and Mr. James Phinney, Resident Maintenance Engineer.