CLOSE OVERLAY
Project Details
STATUS

In-Progress

PROJECT NUMBER

22-829, TR-816

START DATE

11/01/22

END DATE

04/30/25

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CP Tech Center
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Peter Taylor

Director, CP Tech Center

Co-Principal Investigator
Dan King

Research Engineer, CP Tech Center

Co-Principal Investigator
Halil Ceylan

Director, PROSPER

About the research

Fiber-reinforced concrete (FRC) has become more widely used in thin concrete overlays in recent years. It is well known that synthetic macro-fibers increase the fracture toughness and residual strength of concrete, which mitigates cracking and improves the fatigue life of concrete overlays. Some of the other benefits of fiber-reinforcement could further benefit the performance and service life of concrete overlays by improving joint behavior, load transfer, and pavement smoothness. However, the performance benefits of these mechanisms are not well-quantified and are not considered in current concrete overlay design procedures. This study will take comprehensive performance measurements at a number of FRC overlay test sections that have been built in Iowa in recent years. The analysis will provide more insight into the full benefits of fiber-reinforcement and how they impact design choices and overlay service life. With a more complete understanding of the performance benefits of using fibers in concrete overlays, agencies would be able to optimize their FRC overlay designs, better predict long-term performance, and use resources more efficiently for maintaining Iowa’s roadway network.

Project Details
STATUS

In-Progress

PROJECT NUMBER

22-818, TR-818

START DATE

10/01/22

END DATE

03/31/24

FOCUS AREAS

Safety

RESEARCH CENTERS InTrans, CTRE, Iowa LTAP
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Keith Knapp

Director, LTAP

Co-Principal Investigator
David Veneziano

Safety Circuit Rider, LTAP

About the research

Each year a city public works focus group is convened the day before the spring conference of the Iowa Chapter of the American Public Works Association (APWA). Approximately five years ago, an idea was proposed at this focus group that responded to an identified need for more useful guidance related to the overall and elemental conversion of four-lane undivided roadway to three lanes (i.e., one lane in each direction and a two-way left-turn lane [TWLTL]). A literature review by the Iowa Department of Transportation (DOT) showed that a significant amount of material has been created on this subject. In fact, there has been so much documentation that it can be a challenge to practitioners. It was concluded by the project development team there was a need to combine this information in a more useful manner. The tasks in this project were designed to respond to this continuing need.

Project Details
STATUS

In-Progress

PROJECT NUMBER

22-830, TR-817

START DATE

10/17/22

END DATE

02/28/23

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CTRE
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Jeramy Ashlock

Faculty Affiliate

About the research

The Central Iowa Expo facility is located in Boone, Iowa. The Iowa DOT initiated a research project (IHRB Project TR-671) to implement foundation stabilization technologies (Phase I), construction of the pavement layers using intelligent compaction technology (Phase II), and non-destructive evaluation of pavement systems right after construction (Phase III).

Falling Weight Deflectometer (FWD) tests were performed on the pavement layer and ground penetrating radar tests were performed to evaluate thickness of the asphalt layer and moisture conditions of the base layer. This project includes an assessment of those tests.

Project Details
STATUS

In-Progress

PROJECT NUMBER

22-828, TR-815

START DATE

11/01/22

END DATE

10/31/24

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Alice Alipour

Structure and Infrastructure Engineer, BEC

About the research

Traffic signal structures are an integral part of the transportation infrastructure system, ensuring the safety of motorists and pedestrians. These structures, however, have been found to perform poorly due to fatigue-related issues in their connections. This mostly originates from the large-amplitude vibrations caused under galloping, vortex shedding, and natural wind and truck-induced gusts. The inherent dynamic properties of these structures, especially their low mechanical damping (0.1%-0.4%), is proven to be a key contributing factor, further exacerbating the fatigue-related issues. While most of investigations performed to date have been focused on the development of vibration mitigation strategies or the design of fatigue-rated connections, much less attention has been given to a more fundamental solution, stemming from the modification of the aerodynamic characteristics of this category of structures, addressing the issues at their roots.Considering the large number of traffic signal structures used for traffic control, their cost of repair and reinstallation can add up fast, while their potential failure can pose an immediate risk to the traveling public. This has led to a growing need to develop more cost-effective solutions to mitigate the large-amplitude vibrations of both new and existing traffic signal structures.

Project Details
STATUS

Completed

PROJECT NUMBER

05-232, TR-546

START DATE

07/01/05

END DATE

07/31/09

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CTRE, SUDAS
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Neal Hawkins

Associate Director, InTrans

About the research

Changes in technology have an impact on standard practice, materials, and equipment. The traffic signal industry is constantly producing more energy-efficient and durable equipment, better communications, and more sophisticated detection and monitoring capabilities. Accordingly, this project provides an update to the traffic signal content within the Statewide Urban Design and Specifications (SUDAS) Design Manual and Standard Specifications.

This work was completed through a technical advisory committee with a variety of participants representing contractors, the Iowa Department of Transportation, cities, consultants, vendors, and university research and support staff.

Project Details
STATUS

Completed

PROJECT NUMBER

19-717, TR-779

START DATE

07/15/19

END DATE

09/30/22

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Justin Dahlberg

Director, BEC

Co-Principal Investigator
Brent Phares

Bridge Research Engineer

About the research

The primary goal for this project was to evaluate the efficacy of A709 Grade QST 65 steel for use in Iowa bridge projects. The objectives of the project were as follows:

  • Identify the current state of use of A709 Grade QST 65 steel in bridge projects
  • Identify the ductility and strength characteristics of A709 Grade QST 65 steel through full-scale laboratory testing
  • Identify the fatigue characteristics of A709 Grade QST 65 steel through cyclic fatigue testing
  • Observe and compare bridge construction similarities and differences to conventional steel construction using a new bridge planned over Sand Creek in Buchanan County, Iowa
  • Compare relative costs of using A709 Grade QST 65 steel versus conventional steel
  • Measure the live load response at various points in time on the Sand Creek Bridge, which was constructed using A709 Grade QST 65 steel

The ductility and strength of the steel was observed through the various laboratory tests completed for this project as well as the testing performed by others. Minimum requirements for this steel grade have been established, and the results of this study indicate that the requirements were met and surpassed.

The modified design of this first-in-the-nation bridge using Grade QST 65 steel over Sand Creek allowed for a reduction in beam size for this relatively short-span, low-traveled bridge due to the increased strength of the steel beams. The total steel cost for these beams resulted in a 20% material cost savings.

The results should give confidence to engineers considering use of this steel grade on bridge construction projects with longer spans and higher traffic counts.

Project Details
STATUS

In-Progress

PROJECT NUMBER

22-820

START DATE

09/12/22

END DATE

09/30/27

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, PROSPER
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Halil Ceylan

Director, PROSPER

Co-Principal Investigator
Sunghwan Kim

Associate Director, PROSPER

Co-Principal Investigator
Bo Yang

About the research

Cape seals, which have been applied in several countries as well as the United States for many years, have never before been used by counties in the State of Iowa. As part of the Clinton County Pilot Demonstration Project of Cape Seals endorsed by the Iowa Highway Research Board (IHRB) serving as Iowa’s State Transportation Innovation Council (STIC), this study will (1) perform data collection and monitoring activities at the Cape Seal Pilot Demonstration Project site in Clinton County and (2) collect before and after stakeholder input to measure perceptions about the project and cape seal performance. This will be achieved through the execution of the following primary tasks: (1) documenting construction activities and executing a showcase/open house during project construction, (2) monitoring and evaluating pavement performance regarding the effectiveness of the innovations, (3) executing subsequent technology transfer and information dissemination activities and developing implementation plans with recommendations, and (4) publishing final research project documents. This research project would be highly helpful in scientifically documenting the performance of cape seal application over its service life and in providing the necessary data for the Iowa Department of Transportation (DOT) and Iowa counties who are considering deploying cape seals as standard pavement preservation practices (if the deployment is successful).

Project Details
STATUS

In-Progress

PROJECT NUMBER

TR-792

START DATE

10/13/21

END DATE

02/28/24

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, CTRE
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board
University of Iowa

Researchers
Principal Investigator
Antonio Arenas Amado
Co-Principal Investigator
Larry Weber
Co-Principal Investigator
Marian Muste

Research Engineer

Co-Principal Investigator
Ibrahim Demir

About the research

The goal of this study is to complete a comprehensive evaluation of the flood reduction benefits of existing on-road structures (ORS). This work will be performed in five selected HUC12s in Iowa. To accomplish this objective the research team will use the process-based hydrologic model GHOST to run multi-year continuous simulations using both historic precipitation conditions as well as increased precipitation conditions that represent the projected changes in heavy precipitation by the mid-and late-21st century.

Project Details
STATUS

Completed

PROJECT NUMBER

18-660, TR-752

START DATE

07/01/18

END DATE

06/30/22

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, BEC
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Brent Phares

Bridge Research Engineer

Co-Principal Investigator
Katelyn Freeseman

About the research

Longitudinal joints are thought to provide relief from expansion and contraction of the bridge deck resulting from temperature change, shrinkage, and live loads. Historically, however, these joints have been known to leak, allowing chloride-laden water to reach the bottom of the deck overhang and even the exterior girders.

One of the primary conclusions from the previous Phase I project was that the development of cracking in bridge decks appears to be less dependent on the total width of the deck and more dependent on restraint of the abutment to temperature changes and, in particular, temperature gradients. Based on the results of that research, a 115 ft long, 228 ft wide, bridge in Black Hawk County, Iowa was selected and designed to incorporate a thermal isolation barrier.

The objective of this research was to follow and document the design, construction, and performance of the bridge in Black Hawk County with a specific focus on the success of the deck crack mitigation efforts. To achieve this objective, the newly constructed bridge on Viking Road over IA 58 was selected for this study.

A nearly two-year-long monitoring period enhanced by multiple bridge inspections was conducted. In addition, an analytical study was conducted to investigate the efficacy of the isolation barrier on resisting the cracking at the end of the deck for an integral abutment bridge.

The results confirmed the findings from the Phase I research that development of cracking in bridge decks seems less dependent on the total width of the deck. The finite element model results indicated the maximum deck strain to be 46% greater without the effects of the thermal isolation barrier. This indicated that, without the thermal isolation barrier, the Viking Road Bridge could see cracking at the end of its deck.

The researchers recommend the use of a thermal isolation barrier between the abutment and backfill soils for wide integral abutment bridges as one way to lengthen the service life of these bridge decks while reducing maintenance, rehabilitation, and/or replacement costs as well.

Project Details
STATUS

In-Progress

PROJECT NUMBER

22-795, TR-810

START DATE

05/01/22

END DATE

10/31/23

FOCUS AREAS

Infrastructure

RESEARCH CENTERS InTrans, PROSPER
SPONSORS

Iowa Department of Transportation
Iowa Highway Research Board

Researchers
Principal Investigator
Halil Ceylan

Director, PROSPER

Co-Principal Investigator
Sunghwan Kim

Associate Director, PROSPER

About the research

Iowa ranks as number one in the nation in egg production, and the Iowa Egg Council reports that between September 2019 and August 2020, Iowa produced nearly 16 billion eggs, meaning that each year Iowa egg industries are responsible for about 1 of 5 eggs consumed in the United States. Egg production adds significantly to the Iowa economy by contributing more than $2 billion in total sales. The cost of distributing in-shell eggs from Iowa to highly populated areas on the east and west coasts represents Iowa’s primary competitive disadvantage, so to reduce freight costs and compete more effectively against other states (e.g., Pennsylvania and California), Iowa has employed a production strategy of delivering approximately 70% of its eggs in liquid or dried-egg form, processed through integrated packing and breaking facilities to food manufacturers and other customers. Based on this strategy, increased liquid or dried-egg production is expected to ensure the price competitiveness of the Iowa egg industry. Consequently, while large amounts of eggshells are also generated from Iowa egg industries, they lie unused as value-added products and get dumped into landfills. Eggshells mainly consist of calcium carbonate (CaCO3) (i.e., up to 94%), identified as the primary element of calcium-based stabilizer materials (CSMs) with the capability for binding soil and aggregates through hydration, cation exchange, flocculation, pozzolanic reaction, and carbonation. The concept of using eggshells as bio-based cementing materials has therefore been investigated and successfully demonstrated overseas, targeting their use as new value-added products (e.g., cement replacement, soil stabilizer, masonry blocks, bone, and dental implants, etc.). Such proven success in other countries suggests the desirability of research in identifying effective and practically-implementable ways of using Iowa eggshell waste to improve engineering properties of Iowa geo-materials (e.g., frost-susceptible soils and low-quality local aggregates) used in either pavement or gravel road systems. It is hypothesized that such an innovative and sustainable approach may lead to the achievement of stronger and more durable pavement foundation and gravel road systems in Iowa.

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