Development of LRFD Procedures for Bridge Pile Foundations in Iowa Volume III: Recommended Resistance Factors with Consideration of Construction Control and Setup, TR-584, 2012

The Federal Highway Administration (FHWA) mandated utilizing the Load and Resistance Factor Design (LRFD) approach for all new bridges initiated in the United States after October 1, 2007. As a result, there has been a progressive move among state Departments of Transportation (DOTs) toward an increased use of the LRFD in geotechnical design practices. For the above reasons, the Iowa Highway Research Board (IHRB) sponsored three research projects: TR-573, TR-583 and TR-584. The research information is summarized in the project web site (http://srg.cce.iastate.edu/lrfd/). Two reports of total four volumes have been published. Report volume I by Roling et al. (2010) described the development of a user-friendly and electronic database (PILOT). Report volume II by Ng et al. (2011) summarized the 10 full-scale field tests conducted throughout Iowa and data analyses. This report presents the development of regionally calibrated LRFD resistance factors for bridge pile foundations in Iowa based on reliability theory, focusing on the strength limit states and incorporating the construction control aspects and soil setup into the design process. The calibration framework was selected to follow the guidelines provided by the American Association of State Highway and Transportation Officials (AASHTO), taking into consideration the current local practices. The resistance factors were developed for general and in-house static analysis methods used for the design of pile foundations as well as for dynamic analysis methods and dynamic formulas used for construction control. The following notable benefits to the bridge foundation design were attained in this project: 1) comprehensive design tables and charts were developed to facilitate the implementation of the LRFD approach, ensuring uniform reliability and consistency in the design and construction processes of bridge pile foundations; 2) the results showed a substantial gain in the factored capacity compared to the 2008 AASHTO-LRFD recommendations; and 3) contribution to the existing knowledge, thereby advancing the foundation design and construction practices in Iowa and the nation.

Improving Concrete Overlay Construction, TR-600, 2010

Several road construction projects involving concrete overlays at the state and county levels in Iowa in 2009 were studied for construction techniques and methods. The projects that were evaluated consisted of sites in four Iowa counties: Osceola, Worth, Poweshiek, and Johnson counties. The construction techniques and methods that were studied included concrete overlays and material usage. By evaluating these methods, highway agencies can explore different ways of making road construction less costly and can minimize the amount of time that the traveling public is exposed to road construction.

Implementation Manual — 3D Engineered Models for Highway Construction: The Iowa Experience; RB33-014, 2015

3D engineered modeling is a relatively new and developing technology that can provide numerous benefits to owners, engineers, contractors, and the general public. This manual is for highway agencies that are considering or are in the process of switching from 2D plan sets to 3D engineered models in their highway construction projects. It will discuss some of the benefits, applications, limitations, and implementation considerations for 3D engineered models used for survey, design, and construction. Note that is not intended to cover all eventualities in all states regarding the deployment of 3D engineered models for highway construction. Rather, it describes how one state—Iowa—uses 3D engineered models for construction of highway projects, from planning and surveying through design and construction.

Material and Construction Optimization for Prevention of Premature Pavement Distress in PCC Pavements, Phase III Final Report, 2008

Mixture materials, mix design, and pavement construction are not isolated steps in the concrete paving process. Each affects the other in ways that determine overall pavement quality and long-term performance. However, equipment and procedures commonly used to test concrete materials and concrete pavements have not changed in decades, leaving gaps in our ability to understand and control the factors that determine concrete durability. The concrete paving community needs tests that will adequately characterize the materials, predict interactions, and monitor the properties of the concrete. The overall objectives of this study are (1) to evaluate conventional and new methods for testing concrete and concrete materials to prevent material and construction problems that could lead to premature concrete pavement distress and (2) to examine and refine a suite of tests that can accurately evaluate concrete pavement properties. The project included three phases. In Phase I, the research team contacted each of 16 participating states to gather information about concrete and concrete material tests. A preliminary suite of tests to ensure long-term pavement performance was developed. The tests were selected to provide useful and easy-to-interpret results that can be performed reasonably and routinely in terms of time, expertise, training, and cost. The tests examine concrete pavement properties in five focal areas critical to the long life and durability of concrete pavements: (1) workability, (2) strength development, (3) air system, (4) permeability, and (5) shrinkage. The tests were relevant at three stages in the concrete paving process: mix design, preconstruction verification, and construction quality control. In Phase II, the research team conducted field testing in each participating state to evaluate the preliminary suite of tests and demonstrate the testing technologies and procedures using local materials. A Mobile Concrete Research Lab was designed and equipped to facilitate the demonstrations. This report documents the results of the 16 state projects. Phase III refined and finalized lab and field tests based on state project test data. The results of the overall project are detailed herein. The final suite of tests is detailed in the accompanying testing guide.

Developing an Effective Construction Training Program for Hispanic and American Supervisors and Craft Workers, 2007

Hispanics are a large and growing part of the United States workforce. Projections of the U.S. Census Bureau (2001) state that, by the year 2050, Hispanics will account for 25% of the population. For the Midwest in particular, the Hispanic population is expected to increase 35% by the year 2025. The construction industry is expected to experience a greater percentage increase of its Hispanic population, due to the labor-intensive nature of the industry. This study addresses the expected increase of Hispanic workers in the construction industry by testing the best approaches for delivering training to construction crews with Hispanic workers as well as American supervisors and laborers in the state of Iowa. The research methodology consisted of assessing the effects on communication, safety, work environment, and productivity as a result of the integration training. Results show that integration on-site training decreases workers’ desire to move and increases quality of work and productivity. Most importantly, experimental design was used to show the increasing levels of direct construction communication due to the Toolbox Integration Course for Hispanic Workers and American Supervisors (TICHA) designed as part of this project. This study recommends the creation of a quasi-governmental or association program that can offer continuous research and training that can benefit the construction industry as well as society as a whole. The industry involvement in this process is crucial for contractors. Not only do contractors benefit from reduced insurance premiums when workers act safely, but workers with better communication skills are more productive.

Developing an Effective Construction Training Program for American Supervisors with Hispanic Craft Workers, 2005

In the construction industry, Hispanics have the highest rate of fatal work injuries among the racial/ethnic groups, and productivity in the field is limited by the language barrier between Hispanic workers and their supervisors and the level of education of many Hispanic craft workers. This research developed a training program designed to facilitate the integration process between American supervisors and Hispanic craft workers in a practical and cost-effective way, thus improving productivity and lowering fatality rates. The Iowa State University research team conducted a survey of 38 American supervisors, representing 14 Iowa construction companies. Survey results confirm that communication is the main problem experienced by American supervisors in the job site. Many American supervisors also use or depend on a link-person (an individual who interprets tasks to the rest of the Hispanic crew) to communicate to the Hispanic crew members. Research findings show that language differences affect productivity and workplace safety in the construction industry. Additionally, the educational levels of Hispanic workers indicate that they may not have the literacy skills necessary to understand training materials. This research developed two training courses designed to expand the Spanish communication skills of American supervisors. The research team modified the English-as-a-second-language course developed in Phase I into the Spanish as a Second Language (SSL) Survival Course. A series of technical training courses were also developed, titled Concrete Pavement Construction Basics (CPCB), that cover general practices in concrete pavement construction. They are much shorter and more specialized than the SSL course. The CPCB courses provide American supervisors simple and practical communication tools on a variety of topics to choose from according to their specific needs.

Electronic Construction Collaboration - Phase 1, 2009

Bridge construction projects are becoming increasingly complex as the demand for context-sensitive solutions, aesthetic designs, and accelerated bridge construction becomes more prevalent. In addition, the Iowa Department of Transportation (Iowa DOT) is entering a phase of design and construction of large border bridges, such as the I-80 (let 2008 for $56 million) and US 34 bridges over the Missouri River and I-74 over the Mississippi River. Compared to typical construction projects, these bridges generate more contractor Requests for Information (RFIs), Value Engineering (VE) proposals, Requests for Changes (RFCs), and shop drawings. Management of these submittals is a significant challenge for Resident Construction Engineers (RCEs) and other Iowa DOT staff. In addition, some submittals require cross-departmental and project consultant reviews. Commercially available software exists for managing submittals and project collaboration teams; in-house solutions may also be possible. Implementation is intended to speed construction submittal review time, reduce incidence of delay claims, and free up Iowa DOT staff from project management administrative tasks. Researchers from Iowa State University working with the Iowa DOT conducted a multi-pronged approach to indentify a web-based collaboration solution for Iowa DOT bridge projects. An investigation was launched to determine the functional needs of the Iowa DOT. Commercially available software programs were also evaluated to find what functionality is currently available. A Request for Proposals (RFP) was written to select a commercial web-based collaboration solution for pilot testing. In the second phase of research, a solution will be selected and implemented on two pilot projects. Lessons learned from these pilot projects will assist the Iowa DOT in developing and implementing a long-term solution to improve the management of Iowa DOT bridge projects.

FY2015 Highway Construction Program Expenditures/Obligations

This report describes the highway construction program, actual expenditures of the program and contractual obligations of the program for FY 2015.

Report of the Workshop on Intelligent Construction for Earthworks: April 14-16, 2009

The objectives of this workshop were to update the strategies identified during the 2008 workshop; provide a collaborative exchange of ideas and experiences; share research results; increase participants' knowledge; develop research, education, and implementation initiatives for intelligent compaction (IC) and automated machine guidance (AMG) technologies; and develop strategies to move forward. The 2 1/2 day workshop was organized as follows: Day 1: Review of 2008 workshop proceedings, technical presentations on IC and AMG technologies, and participating state department of transportation (DOT) briefings. Day 2: Industry/equipment manufacturer presentations and breakout interactive sessions on three topic areas. Day 3: Breakout session summary reporting and panel discussion involving state DOT, contractor, and industry representatives. The results of the breakout sessions on day 2 were analyzed to identify the priorities for advancement in each of the three topic areas. Key issues for each topic were prioritized by reviewing the recorder's notes in detail, finding common topics among sessions, and summarizing the participant votes.

Demonstration and Field Evaluation of Alternative Portland Cement Concrete Pavement Reinforcement Materials, Construction Report, HR-1069, 1998

The function of dowel bars is the transfer of a load across the transverse joint from one pavement slab to the adjoining slab. In the past, these transfer mechanisms have been made of steel. However, pavement damage such as loss of bonding, deterioration, hollowing, cracking and spalling start to occur when the dowels begin to corrode. A significant amount of research has been done to evaluate alternative types of materials for use in the reinforcement of concrete pavements. Initial findings have indicated that stainless steel and fiber composite materials possess properties, such as flexural strength and corrosion resistance, that are equivalent to the Department of Transportation specifications for standard steel, 1 1/2 inch diameter dowel bars. Several factors affect the load transfer of dowels; these include diameter, alignment, grouting, bonding, spacing, corrosion resistance, joint spacing, slab thickness and dowel embedment length. This research is directed at the analysis of load transfer based on material type and dowel spacing. Specifically, this research is directed at analyzing the load transfer characteristics of: (a) 8-inch verses 12-inch spacing, and (b) alternative dowel material compared to epoxy coated steel dowels, will also be analyzed. This report documents the installation of the test sections, placed in 1997. Dowel material type and location are identified. Construction observations and limitations with each dowel material are shown.

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.

Low Cost Fly Ash - Sand Stabilization Roadway, Construction Report, HR-259, 1986

Fly ash, a by-product of coal-fired electricity generating plants, has for years been promoted as a material suitable for highway construction. Disposal of the large quantities of fly ash produced is expensive and creates environmental concerns. The pozzolanic properties make it promotable as a partial Portland cement replacement in pc concrete, a stabilizer for soil and aggregate in embankments and road bases, and a filler material in grout. Stabilizing soils and aggregates for road construction has the potential of using large quantities of fly ash. Iowa Highway Research Board Project HR-194, "Mission-Oriented Dust Control and Surface Improvement Processes for Unpaved Roads", included short test sections of cement, fly ash, and salvaged granular road material mixed for a base in western Iowa. The research showed that cement fly ash aggregate (CFA) has promise as a stabilizing agent in Iowa. There are several sources of sand that when mixed with fly ash may attain strengths much greater than fly ash mixed with salvaged granular road material at little additional cost

Practical Data Collection: Establishing Methods and Procedures for Measuring Water Clarity and Turbidity of Storm Water Run-Off from Active Major Highway Construction Sites, 2014

In anticipation of regulation involving numeric turbidity limit at highway construction sites, research was done into the most appropriate, affordable methods for surface water monitoring. Measuring sediment concentration in streams may be conducted a number of ways. As part of a project funded by the Iowa Department of Transportation, several testing methods were explored to determine the most affordable, appropriate methods for data collection both in the field and in the lab. The primary purpose of the research was to determine the exchangeability of the acrylic transparency tube for water clarity analysis as compared to the turbidimeter.

Image Analysis for the Characterization of Materials for Highway Construction : Phase I, Progress Report, HR-346, 1992

The major objective of this project is to evaluate image analysis for characterizing air voids in Portland cement contract (PCC) and asphalt concrete (AC) and aggregate gradation in asphalt concrete. Phase 1 of this project has concentrated on evaluation and refinement of sample preparation techniques, evaluation of methods and instruments for conducting image analysis, and finally, analysis and comparison of a select portion of samples. Preliminary results suggest a strong correlation between the results obtained from the linear traverse method and image analysis methods for determining percent air voids in concrete. Preliminary work with asphalt samples has shown that damage caused by a high vacuum of the conventional scanning electron microscope (SEM) may too disruptive. Alternative solutions have been explored, including confocal microscopy and low vacuum electron microscopy. Additionally, a conventional high vacuum SEM operating at a marginal operating vacuum may suffice.

Bond Contribution to Whitetopping Performance on Low Volume Roads, Construction Report, HR-341, 1993

This research was initiated in 1991 as a part of a whitetopping project to study the effectiveness of various techniques to enhance bond strength between a new Portland cement concrete (PCC) overlay and an existing asphalt cement concrete (ACC) pavement surface. A 1,676 m (5,500 ft) section of county road R16 in Dallas County, Iowa was divided into 12 test sections. The various techniques used to enhance bond were power brooming, power brooming with air blast, milling, cement and water grout, and emulsion tack coat. As a part of these bonding techniques, two pavement thicknesses were placed; two different concrete proportions were used; and two sections were planed to a uniform cross-slope.