Validation of the New Mix Design Process for Cold In-Place Rehabilitation Using Foamed Asphalt, 2007

Asphalt pavement recycling has grown dramatically over the last few years as a viable technology to rehabilitate existing asphalt pavements. Iowa's current Cold In-place Recycling (CIR) practice utilizes a generic recipe specification to define the characteristics of the CIR mixture. As CIR continues to evolve, the desire to place CIR mixture with specific engineering properties requires the use of a mix design process. A new mix design procedure was developed for Cold In-place Recycling using foamed asphalt (CIR-foam) in consideration of its predicted field performance. The new laboratory mix design process was validated against various Reclaimed Asphalt Pavement (RAP) materials to determine its consistency over a wide range of RAP materials available throughout Iowa. The performance tests, which include dynamic modulus test, dynamic creep test and raveling test, were conducted to evaluate the consistency of a new CIR-foam mix design process to ensure reliable mixture performance over a wide range of traffic and climatic conditions. The “lab designed” CIR will allow the pavement designer to take the properties of the CIR into account when determining the overlay thickness.

Effective Shoulder Design and Maintenance, 2007

Granular shoulders are an important element of the transportation system and are constantly subjected to performance problems due to wind- and water-induced erosion, rutting, edge drop-off, and slope irregularities. Such problems can directly affect drivers’ safety and often require regular maintenance. The present research study was undertaken to investigate the factors contributing to these performance problems and to propose new ideas to design and maintain granular shoulders while keeping ownership costs low. This report includes observations made during a field reconnaissance study, findings from an effort to stabilize the granular and subgrade layer at six shoulder test sections, and the results of a laboratory box study where a shoulder section overlying a soft foundation layer was simulated. Based on the research described in this report, the following changes are proposed to the construction and maintenance methods for granular shoulders: • A minimum CBR value for the granular and subgrade layer should be selected to alleviate edge drop-off and rutting formation. • For those constructing new shoulder sections, the design charts provided in this report can be used as a rapid guide based on an allowable rut depth. The charts can also be used to predict the behavior of existing shoulders. • In the case of existing shoulder sections overlying soft foundations, the use of geogrid or fly ash stabilization proved to be an effective technique for mitigating shoulder rutting.

Iowa Uniform Crime Report, 2004

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

Iowa Uniform Crime Report, 2003

SERIOUS CRIMES: the rate decreased 6.6 percent from 3,669 crimes per 100,000 population in 2002 to the adjusted rate of 3,427 crimes per 100,000 population in 2003. Also known as the Crime Index, serious crimes include the violent crimes of murder, forcible rape, robbery and aggravated assault and the property crimes of burglary, larceny and motor vehicle theft. VIOLENT CRIMES: decreased 5.2 percent from 2002 to 2003, violent crimes dropped from an adjusted rate of 313.8 crimes per 100,000 population reported in 2002 to 297.4 crimes per 100,000 population in 2003. PROPERTY CRIMES: decreased 6.7 percent from an adjusted rate of 3,355 crimes per 100,000 population in 2002 to 3,131 crimes reported in 2003.

Iowa Uniform Crime Report, 2005

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

Iowa Uniform Crime Report, 2006

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

Iowa Uniform Crime Report, 2007

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

Iowa Uniform Crime Report, 2008

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

Iowa Uniform Crime Report, 2009

The National Uniform Crime Reporting System began with 400 cities representing 20 million inhabitants in 43 states on January 1st, 1930. Since the establishment of the Uniform Crime Reporting Program, the volume, diversity, and complexity of crime steadily increased while the UCR program remained virtually unchanged. Recognizing the increasing need for more in-depth statistical information and the need to improve the methodology used for compiling, analyzing, auditing, and publishing the collected data, an extensive study of the Uniform Crime reports was undertaken. The objective of this study was to meet law enforcement needs into the 21st century. The result of the study was NIBRS (National Incident Based Reporting System). Adoption of the NIBRS system took place in the mid 1980’s and Iowa began organizational efforts to implement the system. Conversion to IBR (Incident Based Iowa Uniform Crime Reporting) was completed January 1, 1991, as part of a national effort to implement incident based crime reporting, coordinated by the Federal Bureau of Investigation and the Bureau of Justice Statistics of the U.S. Department of Justice. Iowa was the fifth state in the nation to be accepted as a certified “reporting state” of incident based crime data to the national system.

A Computerized Method for the Hydrologic Design of Culverts, February 1974

Nationwide, about five cents of each highway construction dollar is spent on culverts. In Iowa, average annual construction costs on the interstate, primary, and federal-aid secondary systems are about $120,000,000. Assuming the national figure applies to Iowa, about $6,000,000 are spent on culvert construction annually. For each one percent reduction in overall culvert costs, annual construction costs would be reduced by $60,000. One area of potential cost reduction lies in the sizing of the culvert. Determining the flow area and hydraulic capacity is accomplished in the initial design of the culvert. The normal design sequence is accomplished in two parts. The hydrologic portion consists of the determination of a design discharge in cubic feet per second using one of several available methods. This discharge is then used directly in the hydraulic portion of the design to determine the proper type, size, and shape of culvert to be used, based on various site and design restrictions. More refined hydrologic analyses, including rainfall-runoff analysis, flood hydrograph development, and streamflow routing techniques, are not pursued in the existing design procedure used by most county and state highway engineers.

An Integrated Study of Pervious Concrete Mixture Design for Wearing Course Applications, July 2011

This report presents the results of the largest and most comprehensive study to date on portland cement pervious concrete (PCPC). It is designed to be widely accessible and easily applied by designers, producers, contractors, and owners. The project was designed to begin with pervious concrete best practices and then to address the unanswered questions in a systematic fashion to allow a successful overlay project. Consequently, the first portion of the integrated project involved a combination of fundamental material property investigations, test method development, and addressing constructability issues before actual construction could take place. The second portion of the project involved actual construction and long-term testing before reporting successes, failures, and lessons learned. The results of the studies conducted show that a pervious concrete overlay can be designed, constructed, operated, and maintained. A pervious concrete overlay has several inherent advantages, including reduced splash and spray and reduced hydroplaning potential, as well as being a very quiet pavement. The good performance of this overlay in a particularly harsh freeze-thaw climate, Minnesota, shows pervious concrete is durable and can be successfully used in freeze-thaw climates with truck traffic and heavy snow plowing.

Safer Construction and Maintenance Safer Construction and Maintenance Practices to Minimize Potential Liability by Counties from Accidents, September 1979

Tort claims resulting from alleged highway defects have introduced an additional element in the planning, design, construction, and maintenance of highways. A survey of county governments in Iowa was undertaken in order to quantify the magnitude and determine the nature of this problem. This survey included the use of mailed questionnaires and personal interviews with County Engineers. Highway-related claims filed against counties in Iowa amounted to about $52,000,000 during the period 1973 through 1978. Over $30,000,000 in claims was pending at the end of 1978. Settlements of judgments were made at a cost of 12.2% of the amount claimed for those claims that had been disposed of, not including costs for handling claims, attorney fees, or court costs. There was no clear time trend in the amount of claims for the six-year period surveyed, although the amount claimed in 1978 was about double the average for the preceding five years. Problems that resulted in claims for damages from counties have generally related to alleged omissions in the use of traffic control devices or defects, often temporary, resulting from alleged inadequacies in highway maintenance. The absence of stop signs or warning signs often has been the central issue in a highway-related tort claim. Maintenance problems most frequently alleged have included inadequate shoulders, surface roughness, ice o? snow conditions, and loose gravel. The variation in the occurrence of tort claims among 85 counties in Iowa could not be related to any of the explanatory variables that were tested. Claims appeared to have occurred randomly. However, using data from a sub sample of 11 counties, a significant relationship was shown probably to exist between the amount of tort claims and the extensiveness of use of warning signs on the respective county road systems. Although there was no indication in any county that their use of warning signs did not conform with provisions of the Manual on Uniform Traffic Control Devices (Federal Highway Administration, Government Printing Office, Washington, D.C., 1978), many more warning signs were used in some counties than would be required to satisfy this minimum requirement. Sign vandalism reportedly is a problem in all counties. The threat of vandalism and the added costs incurred thereby have tended to inhibit more extensive use of traffic control devices. It also should be noted that there is no indication from this research of a correlation between the intensiveness of sign usage and highway safety. All highway maintenance activities introduce some extraordinary hazard for motorists. Generally effective methodologies have evolved for use on county road systems for routine maintenance activities, procedures that tend to reduce the hazard to practical and reasonably acceptable levels. Blading of loose-surfaced roads is an example of such a routine maintenance activity. Alternative patterns for blading that were investigated as part of this research offered no improvements in safety when compared with the method in current use and introduced a significant additional cost that was unacceptable, given the existing limitations in resources available for county roads.

Design Procedures and Field Monitoring of Submerged Barbs for Streambank Protection, June 2007

The main objective of this study was to evaluate the hydraulic performance of riprap spurs and weirs in controlling bank erosion at the Southern part of the Raccoon River upstream U.S. Highway 169 Bridge utilizing the commercially available model FESWMS and field monitoring. It was found based on a 2 year monitoring and numerical modeling that the design of structures was overall successful, including their spacing and stability. The riprap material incorporated into the structures was directly and favorably correlated to the flow transmission through the structure, or in other words, dictated the permeable nature of the structure. It was found that the permeable dikes and weirs chosen in this study created less volume of scour in the vicinity of the structure toes and thus have less risk comparatively to other impermeable structures to collapse. The fact that the structures permitted the transmission of flow through them it allowed fine sand particles to fill in the gaps of the rock interstices and thus cement and better stabilize the structures. During bank-full flows the maximum scour hole was recorded away from the structures toe and the scourhole size was directly related to the protrusion angle of the structure to the flow. It was concluded that the proposed structure inclination with respect to the main flow direction was appropriate since it provides maximum bank protection while creating the largest volume of local scour away from the structure and towards the center of the channel. Furthermore, the lowest potential for bank erosion also occurs with the present set-up design chosen by the IDOT. About 2 ft of new material was deposited in the area located between the structures for the period extending from the construction day to May 2007. Surveys obtained by sonar and the presence of vegetation indicate that new material has been added at the bank toes. Finally, the structures provided higher variability in bed topography forming resting pools, creating flow shade on the leeward side of the structure, and separation of bed substrate due to different flow conditions. Another notable environmental benefit to rock riprap weirs and dikes is the creation of resting pools, especially in year 2007 (2nd year of the project). The magnitude of these benefits to aquatic habitat has been found in the literature that is directly related to the induced scour-hole volume.

Design and Evaluation of a Single-Span Bridge Using Ultra- High Performance Concrete, September 2009

Research presented herein describes an application of a newly developed material called Ultra-High Performance Concrete (UHPC) to a single-span bridge. The two primary objectives of this research were to develop a shear design procedure for possible code adoption and to provide a performance evaluation to ensure the viability of the first UHPC bridge in the United States. Two other secondary objectives included defining of material properties and understanding of flexural behavior of a UHPC bridge girder. In order to obtain information in these areas, several tests were carried out including material testing, large-scale laboratory flexure testing, large-scale laboratory shear testing, large-scale laboratory flexure-shear testing, small-scale laboratory shear testing, and field testing of a UHPC bridge. Experimental and analytical results of the described tests are presented. Analytical models to understand the flexure and shear behavior of UHPC members were developed using iterative computer based procedures. Previous research is referenced explaining a simplified flexural design procedure and a simplified pure shear design procedure. This work describes a shear design procedure based on the Modified Compression Field Theory (MCFT) which can be used in the design of UHPC members. Conclusions are provided regarding the viability of the UHPC bridge and recommendations are made for future research.

Design Manual for Low Water Stream Crossings, October 1983

The purpose of this manual is to provide design guidelines for low water stream crossings (LWSCs). Rigid criteria for determining the applicability of a LWSC to a given site are not established since each site is unique in terms of physical, social, economic, and political factors. Because conditions vary from county to county, it is not the intent to provide a "cook-book" procedure for designing a LWSC. Rather, engineering judgment must be applied to the guidelines contained in this manual.