Precast Concrete Elements for Accelerated Bridge Construction Final Report Volume 3. Laboratory Testing, Field Testing, and Evaluation of a Precast Concrete Bridge: Black Hawk County,v January 2009

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa DOT Office of Bridges and Structures. Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBISB) system for use with accelerated construction. A typical PMBISB is comprised of five to six precast MBISB panels and is used on low volume roads, on short spans, and is installed and fabricated by county forces. Precast abutment caps and a precast abutment backwall were also developed by BHC for use with the PMBISB. The objective of the research was to gain knowledge of the global behavior of the bridge system in the field, to quantify the strength and behavior of the individual precast components, and to develop a more time efficient panel-to-panel field connection. Precast components tested in the laboratory include two precast abutment caps, three different types of deck panel connections, and a precast abutment backwall. The abutment caps and backwall were tested for behavior and strength. The three panel-to-panel connections were tested in the lab for strength and were evaluated based on cost and constructability. Two PMBISB were tested in the field to determine stresses, lateral distribution characteristics, and overall global behavior.

Roadway Lighting and Safety: Phase II – Monitoring Quality, Durability and Efficiency, November 2011

This Phase II project follows a previous project titled Strategies to Address Nighttime Crashes at Rural, Unsignalized Intersections. Based on the results of the previous study, the Iowa Highway Research Board (IHRB) indicated interest in pursuing further research to address the quality of lighting, rather than just the presence of light, with respect to safety. The research team supplemented the literature review from the previous study, specifically addressing lighting level in terms of measurement, the relationship between light levels and safety, and lamp durability and efficiency. The Center for Transportation Research and Education (CTRE) teamed with a national research leader in roadway lighting, Virginia Tech Transportation Institute (VTTI) to collect the data. An integral instrument to the data collection efforts was the creation of the Roadway Monitoring System (RMS). The RMS allowed the research team to collect lighting data and approach information for each rural intersection identified in the previous phase. After data cleanup, the final data set contained illuminance data for 101 lighted intersections (of 137 lighted intersections in the first study). Data analysis included a robust statistical analysis based on Bayesian techniques. Average illuminance, average glare, and average uniformity ratio values were used to classify quality of lighting at the intersections.

Effect of Mix Times on PCC Properties, HR-1066, 1998

The objectives of this research were the collection and evaluation of the data pertaining to the importance of concrete mixing time on air content and distribution, consolidation and workability for pavement construction. American Society for Testing and Materials (ASTM) standard C 94 was used to determine the significance of the mixing time on the consistency of the mix being delivered and placed on grade. Measurements of unit weight, slump, air content, retained coarse aggregate and compressive strength were used to compare the consistency of the mix in the hauling unit at the point of mixing and at the point placement. An analysis of variance was performed on the data collected from the field tests. Results were used to establish the relationship between selected mixing time and the portland cement concrete properties tested. The results were also used to define the effect of testing location (center and side of truck, and on the grade) on the concrete properties. Compressive strength test concepts were used to analyze the hardened concrete pavement strength. Cores were obtained at various locations on each project on or between vibrator locations to evaluate the variance in each sample, between locations, and mixing times. A low-vacuum scanning electron microscope (SEM) was used to study air void parameters in the concrete cores. Combining the data from these analysis thickness measurements and ride in Iowa will provide a foundation for the formulation of a performance based matrix. Analysis of the air voids in the hardened concrete provides a description of the dispersion of the cemtitious materials (specifically flyash) and air void characteristics in the pavement. Air void characteristics measured included size, shape and distribution.

Iowa's Renewable Energy and Infrastructure Impacts, TR-593, 2010

The federal government is aggressively promoting biofuels as an answer to global climate change and dependence on imported sources of energy. Iowa has quickly become a leader in the bioeconomy and wind energy production, but meeting the United States Department of Energy’s goal having 20% of U.S. transportation fuels come from biologically based sources by 2030 will require a dramatic increase in ethanol and biodiesel production and distribution. At the same time, much of Iowa’s rural transportation infrastructure is near or beyond its original design life. As Iowa’s rural roadway structures, pavements, and unpaved roadways become structurally deficient or functionally obsolete, public sector maintenance and rehabilitation costs rapidly increase. More importantly, costs to move all farm products will rapidly increase if infrastructure components are allowed to fail; longer hauls, slower turnaround times, and smaller loads result. When these results occur on a large scale, Iowa will start to lose its economic competitive edge in the rapidly developing bioeconomy. The primary objective of this study was to document the current physical and fiscal impacts of Iowa’s existing biofuels and wind power industries. A four-county cluster in north-central Iowa and a two-county cluster in southeast Iowa were identified through a local agency survey as having a large number of diverse facilities and were selected for the traffic and physical impact analysis. The research team investigated the large truck traffic patterns on Iowa’s secondary and local roads from 2002 to 2008 and associated those with the pavement condition and county maintenance expenditures. The impacts were quantified to the extent possible and visualized using geographic information system (GIS) tools. In addition, a traffic and fiscal assessment tool was developed to understand the impact of the development of the biofuels on Iowa’s secondary road system. Recommended changes in public policies relating to the local government and to the administration of those policies included standardizing the reporting and format of all county expenditures, conducting regular pavement evaluations on a county’s system, cooperating and communicating with cities (adjacent to a plant site), considering utilization of tax increment financing (TIF) districts as a short-term tool to produce revenues, and considering alternative ways to tax the industry.

Transportation and Iowa's Economic Future, 1993

This is a study of how transportation policy can be fashioned to improve Iowa's long-term economic prospects. The research focuses on the state level and covers pricing, resource allocation, investment, and other issues that directly affect the performance of public facilities that support transportation of goods and people to and from points in Iowa. Chapter 1 is an introduction. Chapter 2 begins with an assessment of how Iowa's economy is changing, both functionally and spatially. Commuting patterns and methods of goods movement are then discussed. The purpose of this analysis is to provide a context for the exploration of transportation policy issues in subsequent chapters. In Chapter 3 a framework is established for evaluating changes in transportation policies. A working definition of economic development is given and the role of government policies in making an area more attractive to economic activity is considered. Chapter 4 analyzes public policy options for Iowa's roads and highways. These policy options are intended to help the state compete for economic activity. Chapter 5 assesses alternative investment strategies for major navigational facilities on the upper Mississippi River. Chapter 6 examines major transportation policy issues in Iowa's agricultural sector. The current magnitude of agricultural shipments and the roles of several modes are presented. After focusing on issues related to railroad competitiveness, the analysis turns to how Iowa's rural roads should be financed. The need for joint investment and pricing decisions affecting waterways, railroads, and rural roads is stressed. Chapter 7 examines the current status of freight transportation in Iowa. An assessment is made of issues related to trucking and of intermodal transportation and its potential for cost-effective shipping to and from businesses in Iowa. Chapter 8 summarizes the key findings of this study, offering ten recommendations. These recommendations relate to transportation as a means of facilitating economic development.

The Mormon Trail: Historic Byway Inventory and Evaluation, 1998

A three-step approach was used to do the study of the Mormon Trail. These involved research, field data collection and evaluation of the project corridors. Step one involved research on the location of the Trail, associated sites and the historic land use near the Trail between 1846 and 1868. The next step involved defining roads to be inventoried and the actual field survey. Step three involved evaluation of the inventoried corridors. This evaluation procedure was based on the methodology currently used by Iowa DOT to evaluate candidate scenic byway routes but involved different evaluation factors. The numeric results of the two analyses can be directly compared. The results of the field survey and evaluation are shown in detail by county. Inventory and evaluation procedures for historic and cultural byways are discussed in Appendix A.

Automated Collection of Sign Inventory Information by Integrating Global Positioning System (GPS) with Videologging Data Collection Activities, 1995

Advances in communication, navigation and imaging technologies are expected to fundamentally change methods currently used to collect data. Electronic data interchange strategies will also minimize data handling and automatically update files at the point of capture. This report summarizes the outcome of using a multi-camera platform as a method to collect roadway inventory data. It defines basic system requirements as expressed by users, who applied these techniques and examines how the application of the technology met those needs. A sign inventory case study was used to determine the advantages of creating and maintaining the database and provides the capability to monitor performance criteria for a Safety Management System. The project identified at least 75 percent of the data elements needed for a sign inventory can be gathered by viewing a high resolution image.

Coordination of Transit and School Busing in Iowa, Final Report, December 2003

The 2003 Iowa General Assembly asked the Iowa Department of Transportation (Iowa DOT) to conduct a study of Iowa public policy regarding coordination of public transit services and school transportation. This report describes the efficiencies that may be obtained by coordinating transit management and maintenance systems in the areas of school transportation, public transit, and other forms of public transportation. The Center for Transportation Research and Education (CTRE) at Iowa State University studied these issues and prepared this report for the Iowa DOT.

Iowa Department of Transportation Strategic Plan, January 2003 Through December 2006, June 2004

To provide safe and modern transportation systems and services to individuals who travel in Iowa, the Iowa Department of Transportation has identified three broad-based and far-reaching strategic goals: accessibility, responsiveness and accountability. These goals are outlined in this plan, which is aligned with the Accountable Government Act. In addition, the plan specifically addresses strategic needs to serve our customers, and to respond to trends of a growing population and the ever changing need to enhance and expand Iowa's transportation systems. This plan is a living document, and therefore, will be updated periodically.

The Iowa Sex Offender Registry and Recidivism, 2000

The Iowa Division of Criminal and Juvenile Justice Planning (CJJP) received funding through the Bureau of Justice Statistics’ (BJS) State Justice Statistics (SJS) Program for the purpose of collection and analysis of data related to implementation of the Iowa Sex Offender Registry. The research had two specific goals: · To enhance understanding of the State’s Sex Offender Registry through collection and analysis of data on sex offenders before and after the Registry’s implementation. · To develop and validate a unique Iowa Sex Offender Risk Assessment tool to assist in identifying those offenders who constitute the highest risk to re-offend. Few studies have addressed the impact of a Sex Offender Registry program on recidivism rates or other variables. It was the purpose of this first study to examine and compare two groups of individuals to determine what effect, if any, the requirement to register as a sex offender had on recidivism rates over a 3-4 year period.

Iowa Department of Transportation Office of Contracts Letting Summary - July 1, 2003, thru June 30, 2004

A summary of the 12 regularly scheduled lettings and three emergency/special lettings held by the Iowa Department of Transportation for construction and maintenance work during the period July 1, 2003, through June 30, 2004.

Iowa Department of Transportation Strategic Plan Revised, January 2003 Through December 2006, June 2004

To provide safe and modern transportation systems and services to individuals who travel in Iowa, the Iowa Department of Transportation has identified three broad-based and far-reaching strategic goals: accessibility, responsiveness and accountability. These goals are outlined in this plan, which is aligned with the Accountable Government Act. In addition, the plan specifically addresses strategic needs to serve our customers, and to respond to trends of a growing population and the ever changing need to enhance and expand Iowa's transportation systems. This plan is a living document, and therefore, will be updated periodically.

Development of In-Situ Detection Methods for Materials-Related Distress (MRD) in Concrete Pavements, July 2003

The purpose of this research was to summarize existing nondestructive test methods that have the potential to be used to detect materials-related distress (MRD) in concrete pavements. The various nondestructive test methods were then subjected to selection criteria that helped to reduce the size of the list so that specific techniques could be investigated in more detail. The main test methods that were determined to be applicable to this study included two stress-wave propagation techniques (impact-echo and spectral analysis of surface waves techniques), infrared thermography, ground penetrating radar (GPR), and visual inspection. The GPR technique was selected for a preliminary round of “proof of concept” trials. GPR surveys were carried out over a variety of portland cement concrete pavements for this study using two different systems. One of the systems was a state-of-the-art GPR system that allowed data to be collected at highway speeds. The other system was a less sophisticated system that was commercially available. Surveys conducted with both sets of equipment have produced test results capable of identifying subsurface distress in two of the three sites that exhibited internal cracking due to MRD. Both systems failed to detect distress in a single pavement that exhibited extensive cracking. Both systems correctly indicated that the control pavement exhibited negligible evidence of distress. The initial positive results presented here indicate that a more thorough study (incorporating refinements to the system, data collection, and analysis) is needed. Improvements in the results will be dependent upon defining the optimum number and arrangement of GPR antennas to detect the most common problems in Iowa pavements. In addition, refining highfrequency antenna response characteristics will be a crucial step toward providing an optimum GPR system for detecting materialsrelated distress.

Using the Air Void Anal Analyzer for Real-Time Quality Control Adjustments in the Field, November 2004

The air void analyzer (AVA) with its independent isolation base can be used to accurately evaluate the air void system—including volume of entrained air, size of air voids, and distribution of air voids—of fresh portland cement concrete (PCC) on the jobsite. With this information, quality control adjustments in concrete batching can be made in real time to improve the air void system and thus increase freeze-thaw durability. This technology offers many advantages over current practices for evaluating air in concrete.

2006-2010 Iowa Transportation Improvement Program

This document provides the planned investments in Iowa's transportation system for the five-year period of 2006-2010. It encompasses aviation, railroads, rivers, trails, state parks and institutional roads, roadways, and public transit.