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Articles 31 - 60 of 283

Full-Text Articles in Civil and Environmental Engineering

Erosion Resistant Rock Shoulder, Chung R. Song, Richard L. Wood, Basil Abualshar, Mark O'Brien, Bashar Al-Nimri, Mitra Nasimi Oct 2023

Erosion Resistant Rock Shoulder, Chung R. Song, Richard L. Wood, Basil Abualshar, Mark O'Brien, Bashar Al-Nimri, Mitra Nasimi

Nebraska Department of Transportation: Research Reports

Highway shoulder rocks are exposed to continuous erosion force due to unexpected floodings caused by climate change. The evaluation methods of the erosion resistance of highway shoulder rocks are not currently well-developed. This study developed a new large-scale testing device, the University of Nebraska-Lincoln Erosion Testing Bed (UNLETB), which has the capability of testing the shoulder gravels. Different gradations were tested using UNLETB, and the results distinguished a high-resistant group and a low-resistant group. The low resistant group was treated with different binding agents: Ammonium Lignosulfonate (LIGNO10), Soybean Soap Stock, and DirtGlue. The treated samples showed better erosion resistance based …


Energy Dissipation Optimization For Circular Culverts, David M. Admiraal, Chi Zhang Sep 2023

Energy Dissipation Optimization For Circular Culverts, David M. Admiraal, Chi Zhang

Nebraska Department of Transportation: Research Reports

Two types of energy dissipation devices at circular culvert outlets were investigated: full-length weirs and staggered weirs. Related literature was reviewed; a model broken-back circular culvert and dissipation basin was built; instrumentation was installed to measure discharge, piezometric head, and velocities; and four sizes of full-length and staggered weirs were tested over a range of discharges and tailwaters. Weir heights ranged from D/8 to 4D/8, in which D was the culvert diameter. The two weir types were subjected to two styles of tests: (1) tests unaffected by tailwater and (2) tailwater-influenced tests. For tall full-length weirs (3D/8 and 4D/8), basin …


Truck Platooning Effects On Girder Bridges: Phase Ii-Service, Joshua Steelman, Jay Puckett, Daniel Linzell, Bowen Yang Aug 2023

Truck Platooning Effects On Girder Bridges: Phase Ii-Service, Joshua Steelman, Jay Puckett, Daniel Linzell, Bowen Yang

Nebraska Department of Transportation: Research Reports

Truck platooning—wirelessly linking two or more trucks to travel in a closely spaced convoy—is federally promoted to save fuel, improve the environment, and improve traffic operations. Platooning places trucks much closer than current design codes anticipate. While this strategy can provide higher fuel efficiency, it also can potentially overload structures. Previous reliabilitybased studies (Steelman et al., 2021; Yang et al., 2021) have focused on the Strength I limit state and have shown that trucks can operate at weights exceeding standard legal load limits even with short headways at operating-level reliability. However, service limit states in the AASHTO LRFD Bridge Design …


Crashworthy Perforated Square Steel Tube (Psst) Mailbox Support – Phase I, Robert W. Bielenberg, Cody S. Stolle, Ronald K. Faller Jul 2023

Crashworthy Perforated Square Steel Tube (Psst) Mailbox Support – Phase I, Robert W. Bielenberg, Cody S. Stolle, Ronald K. Faller

Nebraska Department of Transportation: Research Reports

Federal requirements have made it mandatory that safe mailbox support systems be designed to yield or breakaway whenimpacted by a vehicle. The Nebraska Department of Transportation (NDOT) has previously used a non-proprietary, U-channel post mailbox support that was evaluated at the Midwest Roadside Safety Facility (MwRSF) in the 1980's. NDOT desires that the mailbox support be updated to meet MASH 2016 TL-3 safety performance criteria and be redesigned to use perforated square steel tubing (PSST) for the mailbox support post.

The objective of this research project is to develop a non-proprietary mailbox support using PSST support posts that is MASH …


Inventory, Operations, And Safety At Free Right-Turn Ramps, Aemal Khattak, Jonathon Camezind, Mm Shakui Haque May 2023

Inventory, Operations, And Safety At Free Right-Turn Ramps, Aemal Khattak, Jonathon Camezind, Mm Shakui Haque

Nebraska Department of Transportation: Research Reports

This research focused on traffic safety and operational performance of rural, minor approach stop-controlled intersections with free right-turn (FRT) ramps. The objectives of the research were to:

  • Create a statewide inventory of rural FRT ramp intersections and provide to the Nebraska Department of Transportation (NDOT),
  • Using NDOT 10-year crash data, conduct statistical safety analysis of rural FRT intersections extending ¼-mile in each direction from the intersection,
  • Study vehicular operations at rural intersections with and without FRT ramps including a comparison of vehicular conflicts, and
  • Develop guidelines for operations and safety tradeoffs to assist with NDOT projects on maintaining similar locations, …


Nebraska Balanced Mix Design – Phase I, Farzad Yazdipanah, Mahdieh Khedmati, Hamzeh Haghshenas May 2023

Nebraska Balanced Mix Design – Phase I, Farzad Yazdipanah, Mahdieh Khedmati, Hamzeh Haghshenas

Nebraska Department of Transportation: Research Reports

Balanced mix design (BMD) is an alternative concept for designing asphalt mixtures that mainly focuses on performance of mixtures rather than only volumetric analysis. Using this concept, it would be possible to account for the incorporation of recycled asphalt mixtures, warm technology, polymers, rejuvenators, and other foreign additives, as well as external effective factors on the mix design such as environmental effects. This project sought to investigate performance-based methodologies for the asphalt mix design by taking a step to develop a preliminary Nebraska BMD framework. With that, selection of appropriate performance tests, finding a functional laboratory aging protocol, and defining …


Columbus, Nebraska: Southern Housing Development Design Proposal, Ryan Weyers, Caiden Dynek, Alex Papa, Brexton Robertson, Kaden Perala May 2023

Columbus, Nebraska: Southern Housing Development Design Proposal, Ryan Weyers, Caiden Dynek, Alex Papa, Brexton Robertson, Kaden Perala

Honors Program: Senior Projects (Public)

The following paper proposes the design and creation of a new housing development in the city of Columbus, Nebraska in a lot to the south of the city and directly north of the Columbus wastewater treatment plant. The goal of this proposal is to provide readers with confidence that our company is the most qualified to complete the project and will create the safest, most comfortable, most efficient, and most cost-effective final design. This proposal seeks to offer a solution to the lack of affordable housing for the growing workforce in Columbus. In order to arrive at this solution, each …


The Effect Of Four Decades Of Deregulation On Competition And Productivity Of The U.S. Freight Transportation Industry, Seungjae Shin May 2023

The Effect Of Four Decades Of Deregulation On Competition And Productivity Of The U.S. Freight Transportation Industry, Seungjae Shin

Theses and Dissertations

This study reviews the competition and productivity of the U.S. freight transportation industry for the past 41 years. This study investigated the trends of HHI market concentration index values and labor productivity values of rail and truck sectors and tried to find any relationships between the two values in the separate periods before and after the abolishment of the ICC. This study also investigated how the existence of a regulatory body impacted productivity of the freight transportation industry by using a Cobb Douglas production function on annual financial statement data in the U.S. stock exchange market. This study found that: …


Feasibility Study: Application Of Steel Sheet-Piles For The Abutment Of Water-Crossing Bridges In Nebraska, Seunghee Kim, Jongwan Eun, Chung R. Song, Chungwook Sim, Hung Phi Van, Basil Abualshar, Ramin Ziaei Tabari May 2023

Feasibility Study: Application Of Steel Sheet-Piles For The Abutment Of Water-Crossing Bridges In Nebraska, Seunghee Kim, Jongwan Eun, Chung R. Song, Chungwook Sim, Hung Phi Van, Basil Abualshar, Ramin Ziaei Tabari

Nebraska Department of Transportation: Research Reports

The overall goal of this study is to investigate the anticipated performance of steel sheet-pile bridge abutments to encourage its wider application to not only new construction but also repair and replacement of existing water-crossing bridges in Nebraska. For this purpose, this study first reviewed several bridge cases with axially loaded sheet pile abutments, as well as previous in-depth studies related to the bearing capacity of sheet piles. Then, this study conducted the large-scale direct shear tests to better understand the interaction between sheet pile and soil. As a result, about four-fifths of the internal friction angle of fill sand …


Impacts Of Diagonal Crosswalk Misuse, Elizabeth Francis May 2023

Impacts Of Diagonal Crosswalk Misuse, Elizabeth Francis

Civil Engineering Undergraduate Honors Theses

A diagonal crosswalk paired with an all-red phase traffic signal is an effective approach to manage intersections with high pedestrian volume. This allows pedestrians to cross both north-south and east-west bound roads at the same time. However, ineffective diagonal crosswalk marking, and lack of signs reduces the use of diagonal crosswalks which in turn results in jaywalking, often in unsafe capacities. The objective of this study is to determine the impacts of pedestrian-caused delay and safety impacts due to the misuse of a diagonal crosswalk. To better understand the impacts, a camera-based data collection was conducted during a four-hour period …


Establishment Of Wildflower Islands To Enhance Roadside Health, Ecological Value, And Aesthetics Phase Ii, Jackson Ebbers, Heidi L. Hillhouse, John A. Guretsky, Thomas J. Weissling Mar 2023

Establishment Of Wildflower Islands To Enhance Roadside Health, Ecological Value, And Aesthetics Phase Ii, Jackson Ebbers, Heidi L. Hillhouse, John A. Guretsky, Thomas J. Weissling

Nebraska Department of Transportation: Research Reports

No abstract provided.


Performance Of High Early-Strength Materials Used In Concrete Bridge Repair, Zina Ebrahim, Fray F. Pozo-Lora, Zachary Benson, Mohammad Mastali, Marc Maguire, Jiong Hu Mar 2023

Performance Of High Early-Strength Materials Used In Concrete Bridge Repair, Zina Ebrahim, Fray F. Pozo-Lora, Zachary Benson, Mohammad Mastali, Marc Maguire, Jiong Hu

Nebraska Department of Transportation: Research Reports

High early-strength materials are widely used for rapid concrete patching projects to limit road closure time and traffic obstruction. This research investigated the field performance of multiple high early-strength materials used in maintenance projects across Nebraska. Data from high early-strength products included in the state’s approved product list were collected and compared to field performance. In addition, a survey was prepared and distributed to the surrounding states to understand standard practices related to appropriate specifications of these materials that can be later used to develop specifications for the utilization of high early strength materials in Nebraska based on experimental and …


Uhpc Decked I-Beam For Accelerated Bridge Construction, George Morcous, Maher K. Tadros Mar 2023

Uhpc Decked I-Beam For Accelerated Bridge Construction, George Morcous, Maher K. Tadros

Nebraska Department of Transportation: Research Reports

Ultra-High-Performance Concrete (UHPC) is an excellent material for bridge construction due to its exceptional durability and superior mechanical properties. Several Departments of Transportations (DOTs), including NDOT, have limited the use of UHPC in bridge construction to joints and connections between bridge components due to the relatively high materials cost of commercially UHPC products. Recently, NDOT has sponsored a research project to develop a non-proprietary UHPC using local materials to reduce materials cost and ensure its availability to local contractors and precast producers. The project was completed successfully and an economical UHPC mix that satisfied all workability, durability, and strength requirements …


An Analysis Of The Effect Of Temperature On Asphalt Paving In South Dakota, S M Rahat Rashedi Jan 2023

An Analysis Of The Effect Of Temperature On Asphalt Paving In South Dakota, S M Rahat Rashedi

Electronic Theses and Dissertations

Temperature is an important parameter to consider for asphalt paving since this work is generally susceptible to weather due to outdoor construction. The South Dakota Department of Transportation (SDDOT) developed working day weather charts in 1998 to address the expected adverse weather days. This thesis investigated the effect of temperature on adverse weather days for asphalt paving and compared them to the value reported in the 1998 SDDOT study. Moreover, the thesis also examined how closely the maximum temperature data from project sites' weekly progress reports (WPR) matched the data from the closest weather stations. When the maximum temperature (TMAX) …


Effect Of Varying Amounts Of Sandstone On The Performance Of Asphalt Mixtures In Arkansas, David Murphy Aug 2022

Effect Of Varying Amounts Of Sandstone On The Performance Of Asphalt Mixtures In Arkansas, David Murphy

Graduate Theses and Dissertations

There are many different species and subspecies of aggregate used across the state of Arkansas, and the rest the country. However, it cannot be presumed that the amount and type of these aggregates will be compatible with the commonly used asphalt binder of an area; this can lead to performance issues and premature pavement damage. It has been suspected in Arkansas that an excessive amount of sandstone in asphalt mixtures may be a culprit of some of these premature pavement damage issues, especially regarding the moisture susceptibility of a pavement. This study aimed to analyze the performance effects of using …


Phased Construction Bridges: Monitoring And Analysis For Traffic-Induced Vibration, Khalid Al-Kady, Christine E. Wittich, Richard L. Wood, George Morcous Jun 2022

Phased Construction Bridges: Monitoring And Analysis For Traffic-Induced Vibration, Khalid Al-Kady, Christine E. Wittich, Richard L. Wood, George Morcous

Nebraska Department of Transportation: Research Reports

Phased construction is a common technique utilized to allow bridges to remain partially open to traffic throughout the construction process. The segment of the bridge deck that is constructed second cures under the effect of traffic-induced vibration transmitted from the adjacent bridge-deck segment, which is open to traffic. However, subjecting bridge decks to traffic-induced vibration during early-age curing raises concerns about the durability of the decks. The primary goal of this study is to generate a fundamental understanding of the transmission of traffic-induced vibration, the extent of degradation on phased construction bridge decks, and the impact of potential mitigation measures. …


Measuring Accessibility For Pedestrians, Bicyclists, And Transit Riders To Grocery Stores In The Excelsior/Outer Mission Neighborhoods Of San Francisco, Alexandra Lee-Gardner Jun 2022

Measuring Accessibility For Pedestrians, Bicyclists, And Transit Riders To Grocery Stores In The Excelsior/Outer Mission Neighborhoods Of San Francisco, Alexandra Lee-Gardner

Master's Theses

Grocery stores are an important amenity in neighborhoods and access to grocery stores is important for health and well-being. While grocery store accessibility is a popular topic of research, studies measuring access for pedestrians, bicyclists, and transit riders are extremely rare. When a new store opened in the Excelsior/Outer Mission districts of San Francisco on a street lacking basic infrastructure for pedestrians, bicyclists, and transit riders, the importance of this study became apparent. The Excelsior/Outer Mission neighborhood has a shocking number of collisions (over 1,100 between 2015 and 2019), elevated levels of walking, biking, and transit ridership, and minimal safe …


Our Streets: Increasing Equity In Active Transportation Planning Through Community Outreach, Jordan Hoy May 2022

Our Streets: Increasing Equity In Active Transportation Planning Through Community Outreach, Jordan Hoy

Master's Projects and Capstones

ABSTRACT Significant research has demonstrated that active transportation infrastructure is essential for the growth and livability of San Francisco: it increases access to economic opportunities, promotes overall improved public health, encourages mobility without contributing to roadway congestion, prevents traffic injuries and fatalities, and supports the sustainability goals of the city. Despite the fact that communities of color will benefit the most from active transportation infrastructure development, historical disenfranchisement in tandem with a lack of diverse representation within public participation contributes to an inequitable distribution of walking and biking investments throughout the city of San Francisco. While research shows that Black …


Transformational Leadership And The Adoption Of Sustainability And Asset Management Practices In Ground Transportation Organizations, Mohammad M. Bushahri May 2022

Transformational Leadership And The Adoption Of Sustainability And Asset Management Practices In Ground Transportation Organizations, Mohammad M. Bushahri

Dissertations - ALL

The unprecedented challenges the infrastructure domain has been facing for the past few decades are forcing the authorities and owners of relevant organizations, particularly within the ground transportation sector, to introduce more innovative measures and to mitigate risks by embracing and adopting sustainability and asset management practices. This study examined the relationship between transformational leadership and the embracing and adopting of sustainability and asset management practices in the U.S. ground transportation sector. Further, this study assessed the mediation effect of organizational innovation on the relationship between transformational leadership style and the leaders' perception in terms of adaptation of sustainability and …


Design And Analysis Of Efficient Freight Transportation Networks In A Collaborative Logistics Environment, Vishal Badyal May 2022

Design And Analysis Of Efficient Freight Transportation Networks In A Collaborative Logistics Environment, Vishal Badyal

All Dissertations

The increase in total freight volumes, reducing volume per freight unit, and delivery deadlines have increased the burden on freight transportation systems of today. With the evolution of freight demand trends, there also needs to be an evolution in the freight distribution processes. Today's freight transportation processes have a lot of inefficiencies that could be streamlined, thus preventing concerns like increased operational costs, road congestion, and environmental degradation. Collaborative logistics is one of the approaches where supply chain partners collaborate horizontally or/and vertically to create a centralized network that is more efficient and serves towards a common goal or objective. …


Estimating System And Traveler Costs Due To Lane Closures During Construction And Maintenance Operations, Ernest Tufuor, Li Zhao, Mm Haque, Laurence Rilett Ph.D., John Anderson, Eric Thompson May 2022

Estimating System And Traveler Costs Due To Lane Closures During Construction And Maintenance Operations, Ernest Tufuor, Li Zhao, Mm Haque, Laurence Rilett Ph.D., John Anderson, Eric Thompson

Nebraska Department of Transportation: Research Reports

Lane closures are used to facilitate activities related to road construction and maintenance or operations. However, there are economic costs associated with lane closures and these may accrue to both the traveling public as well as to traffic agencies. The Nebraska Governor’s office has identified maximizing the effectiveness of lane closures as a priority for the Nebraska Department of Transportation (NDOT). The goal of this project is to assist NDOT in effectively managing the operations of work zones to maximize the effectiveness of lane closures under Nebraska conditions. This report summarizes the findings of the current state of the practice …


Determining Earthquake Impacts On Arkansas' Roadway Network: An Application Of Hazus., Simon Rothwell May 2022

Determining Earthquake Impacts On Arkansas' Roadway Network: An Application Of Hazus., Simon Rothwell

Civil Engineering Undergraduate Honors Theses

Natural hazards are a dangerous and unpredictable aspect of life on earth. They can cause devastating damage to our surroundings that makes movement of people, goods, and emergency services difficult. There is a need to plan for these disasters to ensure that damages to our infrastructure and people are minimized. It can be difficult for planners to determine which parts of a roadway network are most vulnerable to a specific disaster and what their impact on the rest of the network may be. This thesis uses a nationally available natural disaster estimation tool developed by FEMA called “Hazus” (FEMA, 2020). …


Community Transportation Needs And Willingness To Use Shared Micromobility: A Case Study Of Fort Smith, Arkansas, Anthony Michael Kammerer May 2022

Community Transportation Needs And Willingness To Use Shared Micromobility: A Case Study Of Fort Smith, Arkansas, Anthony Michael Kammerer

Civil Engineering Undergraduate Honors Theses

Shared micromobility is utilized in “targeted service areas with the usage generally intended for short trips such as "first- and last-mile" connections to complete trips made via other modes, including transit” (Price et al., 2021). In the United States, this practice has especially taken off with the implementation of sharing-based systems. This is evidenced by ridership numbers in the United States growing from 84 million riders nationwide in 2018 to 136 million riders in 2019 (NACTO, 2020). Users often use their smart phone or another similar device to unlock the vehicle after paying a fee on the device through their …


Research On High-Rap Mixtures With Rejuvenator - Field Implementation, Nitish R. Bastola, Mahdieh Khedmati, Hamzeh Haghshenas Dec 2021

Research On High-Rap Mixtures With Rejuvenator - Field Implementation, Nitish R. Bastola, Mahdieh Khedmati, Hamzeh Haghshenas

Nebraska Department of Transportation: Research Reports

The use of Rejuvenating Agents (RAs), as Recycled Asphalt Pavement (RAP) modifiers, has been increasing over the past years. However, the field performance of asphalt mixtures containing high-RAP materials and modified with RAs has raised some concerns regarding the long-term performance of RAs. This study evaluated the laboratory and field performance of high-RAP mixtures with and without bio-oil RA. Three sets of plant-produced specimens were collected: 1) laboratory-compacted; 2) field-compacted and cored after paving; and 3) field-compacted and cored after one and two years. The Hamburg Wheel Tracking (HWT) test was used to evaluate the specimens' resistance to rutting and …


Data-Driven Operational And Safety Analysis Of Emerging Shared Electric Scooter Systems, Qingyu Ma Dec 2021

Data-Driven Operational And Safety Analysis Of Emerging Shared Electric Scooter Systems, Qingyu Ma

Computational Modeling & Simulation Engineering Theses & Dissertations

The rapid rise of shared electric scooter (E-Scooter) systems offers many urban areas a new micro-mobility solution. The portable and flexible characteristics have made E-Scooters a competitive mode for short-distance trips. Compared to other modes such as bikes, E-Scooters allow riders to freely ride on different facilities such as streets, sidewalks, and bike lanes. However, sharing lanes with vehicles and other users tends to cause safety issues for riding E-Scooters. Conventional methods are often not applicable for analyzing such safety issues because well-archived historical crash records are not commonly available for emerging E-Scooters.

Perceiving the growth of such a micro-mobility …


Complete Streets, Jim Speer Aug 2021

Complete Streets, Jim Speer

2021 Spring Reports (Sullivan)

The City of Sullivan enacted a Quality of Life plan to address multiple improvements to their city, including some of the city’s infrastructure. Mayor Clint Lamb’s goal is to connect the city via roadways and trail systems that are accessible for all transportation methods and attractive for community members and tourists. ENVI460 students provided recommendations based off the city’s need for improvements to road systems and attractiveness. Students recommended a new roadway design for the Main Street section, sustainable infrastructure additions and buffer zones, and green space for attraction sites.


Assessing The Impact Of Health Benefits And Carbon Footprint In Student Parking Decisions At A University Campus, Emiliano Ruiz Aug 2021

Assessing The Impact Of Health Benefits And Carbon Footprint In Student Parking Decisions At A University Campus, Emiliano Ruiz

Open Access Theses & Dissertations

In the student parking location problem, traditionally, the parking permit cost, the last-mile travel time, and the ease of finding an available parking stall are the only decision criteria driving permit purchases. However, a studentâ??s choice of parking location has associated walking health benefits and sustainability impacts. These impacts are related to the walking distance from the parked vehicle to the final destination on campus, in addition to the location effect on the carbon footprint of a vehicle-trip taken to campus. As such, this Thesis examined a multi-criteria decision approach to a university studentâ??s choice of parking location. This approach …


Signal Processing And Data Analysis For Real-Time Intermodal Freight Classification Through A Multimodal Sensor System., Enrique J. Sanchez Headley Jul 2021

Signal Processing And Data Analysis For Real-Time Intermodal Freight Classification Through A Multimodal Sensor System., Enrique J. Sanchez Headley

Graduate Theses and Dissertations

Identifying freight patterns in transit is a common need among commercial and municipal entities. For example, the allocation of resources among Departments of Transportation is often predicated on an understanding of freight patterns along major highways. There exist multiple sensor systems to detect and count vehicles at areas of interest. Many of these sensors are limited in their ability to detect more specific features of vehicles in traffic or are unable to perform well in adverse weather conditions. Despite this limitation, to date there is little comparative analysis among Laser Imaging and Detection and Ranging (LIDAR) sensors for freight detection …


Understanding And Efficiently Managing Right-To-Take Challenges In Kentucky, Pam Clay-Young, Steve Waddle, Bryan Gibson Jun 2021

Understanding And Efficiently Managing Right-To-Take Challenges In Kentucky, Pam Clay-Young, Steve Waddle, Bryan Gibson

Kentucky Transportation Center Research Report

Executive Summary

Kentucky constitutional and statutory law requires that a fair process be in place to let a property owner challenge a condemnor’s right to acquire private property, including a right to appeal the initial decision. Property acquired by a condemnor must be for public use, and property owners have the right to an immediate and expedited hearing on right-to-take. Two of these requirements will remain in place regardless of statutory revisions: the requirement that property must be needed (i.e., not arbitrary) for public use, and the right to one appeal. Only an amendment(s) to the Kentucky Constitution would alter …


Design And Detailing Of Cast-In-Place And Precast Concrete Approach Slabs, George Morcous, Mostafa Abo-Elkhier May 2021

Design And Detailing Of Cast-In-Place And Precast Concrete Approach Slabs, George Morcous, Mostafa Abo-Elkhier

Nebraska Department of Transportation: Research Reports

Approach slab is a structural concrete slab that spans from the backwall of the abutment (i.e. end of the bridge floor) to the beginning of the paving section. The purpose of the approach slab is to carry the traffic loads over the backfill behind the abutments to avoid differential settlement that causes bumps at the bridge ends. Cast- in-place concrete approach slab is the current practice in US with various spans, reinforcement, thicknesses, joints, and concrete covers. NDOT has observed premature cracking in a significant number of approach slabs, which could result in a shorter service life and costly repairs/replacements …