Iowa Department of Transportation : A Design for Growth, 1971

This report has been prepared to provide a succinct documentation of the results of an intensive "finding" as to the requirement for an Iowa Department of Transportation, the recommended general organizational characteristics, and the implementation process requisite to instituting an Iowa Department of Transportation. This report specifies, in summary, the systematic procedure employed in the analysis, followed by a presentation of the fundamental concepts associated with a department of transportation and documentation of the "need" for a state department of transportation. The majority of the report is devoted to presentation of a best judgment as to how an Iowa Department of Transportation should be organized and implemented. The report concludes with a discussion of a recommended approach to the implementation of the department, and issues and recommendations for review.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, June 21, 2016; With Addendums

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Iowa Department of Transportation Major Items - Preliminary Quantity Report, July 19, 2016; With Addendums

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State-of-the-Art Methods for Design of Integral Bridge Abutments, HR-227, 1981

The routine use of integral abutments to tie bridge superstructures to foundation piling began in this country about 30 years ago. Kansas, Missouri, Ohio, North Dakota, and Tennessee were some of the early users. This method of construction has steadily grown more popular. Today more than half of the state highway agencies have developed design criteria for bridges without expansion joint devices.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, August 16, 2016; With Addendums

Weekly letting report

Dynamic Simulation Methods for Evaluating Motor Vehicle and Roadway Design and Resolving Policy Issues, 1990

This study had three objectives: (1) to develop a comprehensive truck simulation that executes rapidly, has a modular program construction to allow variation of vehicle characteristics, and is able to realistically predict vehicle motion and the tire-road surface interaction forces; (2) to develop a model of doweled portland cement concrete pavement that can be used to determine slab deflection and stress at predetermined nodes, and that allows for the variation of traditional thickness design factors; and (3) to implement these two models on a work station with suitable menu driven modules so that both existing and proposed pavements can be evaluated with respect to design life, given specific characteristics of the heavy vehicles that will be using the facility. This report summarizes the work that has been performed during the first year of the study. Briefly, the following has been accomplished: A two dimensional model of a typical 3-S2 tractor-trailer combination was created. A finite element structural analysis program, ANSYS, was used to model the pavement. Computer runs have been performed varying the parameters defining both vehicle and road elements. The resulting time specific displacements for each node are plotted, and the displacement basin is generated for defined vehicles. Relative damage to the pavement can then be estimated. A damage function resulting from load replications must be assumed that will be reflected by further pavement deterioration. Comparison with actual damage on Interstate 80 will eventually allow verification of these procedures.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, July 19, 2016; With Addendums

Weekly letting report

Evolution of Design Practice at the Iowa State Highway Commission for the Determination of Peak Discharges at Bridges and Culverts, 1971

This paper carries the rather weighty title of "Evolution of Design Practice at the Iowa State Highway Commission for the Determination of Peak Discharges at .Bridges and Culverts." Hopefully, this evolving process will lead to a more precise definition of a peak rate of runoff for a selected recurrence interval at a particular site. In this paper the author will relate where the Highway Commission has been, is now, and will be going in this art of hydrology. He will then offer some examples at a few sites in Iowa to illustrate the use of the various methods. Finally, he will look ahead to some of the pitfalls still lying in wait for us.

Highway Location Reference Procedure Project, 1990

The purpose of the proposed Highway Location Reference Procedure is stated in the contract as follows: "Establishment of a highway network locational reference process that will primarily allow for the proper correlation of pavement management data, and secondarily provide the basis for other existing and future data base integration and for the planned Iowa DOT Geographic Information System. In addition, the locational reference process will be able to correlate network applications with a statewide spatial location method to facilitate the relationship of Iowa DOT data to that of other agencies and to allow for the graphic display of the network in map form." The Design Specifications and Implementation Plan, included in this Final Report, are intended to provide the basis for proceeding with immediate development and implementation of the pavement management system. These specifications will also support the future Iowa DOT implementation of other integrated data bases and/or the planned Geographic Information System.

Review of Geometric Design Criteria and Lighting Design Criteria, 1968

The investigations for this report were initiated in October, 1967, to perform the following: l. Review the current Iowa State Highway Commission roadway geometric design standards and criteria for conformance with national policies and recent research findings with special attention to high way safety. 2. Review the current Iowa State Highway Commission roadway lighting design standards and criteria for conformance with national policies and recent research findings with special attention to high way safety

Iowa Department of Transportation Major Items - Preliminary Quantity Report, September 20, 2016; With Addendums

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Validation of Gyratory Mix Design in Iowa, TR-667, 2016

The design number of gyrations (Ndesign) introduced by the Strategic Highway Research Program (SHRP) and used in the Superior Performing Asphalt Pavement (Superpave) mix design method has been commonly used in flexible pavement design throughout the US since 1996. Ndesign, also known as the compaction effort, is used to simulate field compaction during construction and has been reported to produce air voids that are unable to reach ultimate pavement density within the initial 2 to 3 years post-construction, potentially having an adverse impact on long-term performance. Other state transportation agencies have conducted studies validating the Ndesign for their specific regions, which resulted in modifications of the gyration effort for the various traffic levels. Validating this relationship for Iowa asphalt mix designs will lead to better correlations between mix design target voids, field voids, and performance. A comprehensive analysis of current Ndesign levels investigated the current levels with existing mixes and pavements and developed initial asphalt mix design recommendations that identify an optimum Ndesign through the use of performance data tests.

Iowa Department of Transportation Major Items - Preliminary Quantity Report, October 18, 2016; With Addendums

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Iowa Department of Transportation Major Items - Preliminary Quantity Report, November 15, 2016; With Addendums

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Iowa Department of Transportation Major Items - Preliminary Quantity Report, December 20, 2016; With Addendums

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