Engineering Commons^™

Evaluation Of Ndot’S Sediment Barrier Practices Using Performance Data, Michael A. Perez, Wesley N. Donald, J. Blake Whitman, Brian G. Roche

Nebraska Department of Transportation: Research Reports

To protect waterways adjacent to construction projects with disturbed land, a 50 ft (15 m) vegetated buffer or equivalent sediment controls are required. However, there is little guidance on the effectiveness of vegetated buffers in removing sediment or how sediment barriers can aid shorter buffers or replace buffers. A modeling methodology was developed and used to determine the performance of 11,664 50 ft (15 m) vegetated buffer configurations with Nebraska conditions; sediment capture averaged 92.6% and ranged from 18.5% to 99.5%. To determine the performance of Nebraska Department of Transportation standard and modified sediment barrier installations, a large-scale testing methodology …

Development Of Guideline For The Use Of Geosynthetics In Different Roadway Layered System In Nebraska, Jongwan Eun, Seunghee Kim, Daniel Robertson, Yusuf Alhowaidi, Hung Van, Laith Ibdah

Nebraska Department of Transportation: Research Reports

This study evaluated the design properties of the geosynthetic reinforced soils for the roadway pavement and compared the reinforcing performance depending on different geosynthetics and soil types, particularly for a subgrade layer in Nebraska. The results obtained from a large direct shear test, pullout test, and soil chamber test with a dynamic cone penetrometer (DCP) showed that geosynthetic improves soil properties associated with the pullout and interface shear resistance, strength related parameters. The Large Scale Tracking Wheel Test also showed how the performance of biaxial geogrid reinforced pavement improved the strength/stiffness and reduced the total permanent deformation and pressure acting …

Low-Cement Concrete Mixture For Bridge Decks And Rails, Soumitra Das, George Morcous Ph.D., Jiong Hu

Nebraska Department of Transportation: Research Reports

Right after construction, drying shrinkage of restrained concrete bridge decks and rails causes early-age cracking, insertion of water and chemicals, and corrosion of reinforcing steel that eventually leads to delamination and spalling of concrete. The main objective of this research is to control early-age shrinkage cracking by reducing cementitious material content in bridge deck and rail concrete mixtures. Several reduced cementitious materials concrete (RCMC) mixtures were developed by optimizing aggregate particle packing and conducting overall performance evaluation. This evaluation was carried out in three phases. The first phase investigated the feasibility of new RCMC mixtures by testing workability, compressive strength, …

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

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

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

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

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

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 …

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 …

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

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 …

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. …

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 …

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 …

Research And Education For Optimizing The Development And Implementation Of An Unmanned Aircraft Program At The Nebraska Department Of Transportation, Wayne Woldt, Jon Starr, Christopher M. U. Neale

Nebraska Department of Transportation: Research Reports

This report describes the development and implementation of an Unmanned Aircraft System Program at the Nebraska Department of Transportation (NDOT). The project involved the selection and purchase of appropriate UAS and imaging systems for NDOT, education and training for NDOT personnel with classroom and hands-on operation of UAS with the goal of obtaining proficiency and pilot licenses. In addition, the development of policy for the use of UAS within NDOT was accomplished as well as standard operating procedures (SOP) documentation and the development of example case studies of interest to NDOT using the purchased systems and technology.

Low-Cost Modal Identification Sensors For Bridge Field Testing, Daniel Linzell, Saaed Eftekhar Azam, Samira Ardani, Ahmed E Rageh

Nebraska Department of Transportation: Research Reports

This report provides a framework for experimental load rating of bridges via inclusion of low-cost dynamic sensors and dynamic tests. Currently 25% of the bridges in Nebraska are posted for live load. According to the National Bridge Inventory (NBI) in 2012, 93% of all postings in the US were based analytical load ratings, 7% were posted using field evaluation and engineering judgement, and 1% were posted using experimental load rating methods.

Instrumentation costs and traffic interruptions can be problematic when load testing is necessary to accurately assess in-situ bridge live load capacity. Recent advances in (i) sensing technology and (ii) …

Feasibility And Implementation Of Balanced Mix Design In Nebraska, Gabriel Nsengiyumva, Yong-Rak Kim, Jiong Hu

Nebraska Department of Transportation: Research Reports

Balanced mixture design is an alternative asphalt concrete design method that incorporates the performance of mixtures during the design. Balanced mixture design consists of performance test methods and performance criteria. Compared to the existing Superpave design method which mostly relies on volumetrics to design mixtures, balanced mixture design is more suited to account for performance improvements originating from reclaimed asphalt pavement and other foreign additives such as rejuvenators, warm- mix asphalt additives, polymers, and anti-stripping agents. This study investigated the feasibility of the implementation of balanced mixture design in Nebraska mixtures by exploring appropriate test methods (i.e., for fracture and …

Colloidal Silica: Cement Enhancing Admixture Product Evaluation, Lieska Halsey, David Hansen

Nebraska Department of Transportation: Research Reports

As Class F- fly ash (F-ash) becomes scarce, PCC engineers will look to other supplemental cementitious materials (SCM) to replace F-ash and its ASR mitigating properties. Colloidal silica (CS), or nano-silica, has been shown to mitigate ASR at certain replacement levels; however, CS cannot be a full replacement of F-ash. Engineers at the Nebraska Department of Transportation (NDOT) learned of CS from a presentation given by Intelligent Concrete, Inc. at the 2019 Nebraska Concrete Professionals Association Conference and decided to investigate the potential use of CS in NDOT concrete mix designs.

Evaluation Of Mixtures And Pavement Performance For Rehabilitation Methods, Mohammad Rahmani, Gabriel Nsengiyumva, Yong-Rak Kim, Jiong Hu

Nebraska Department of Transportation: Research Reports

Pavement rehabilitation practice involves milling an asphalt surface and placing a new layer. The incorporation of reclaimed asphalt pavement (RAP) mixtures brings cost savings and preserves the environment and natural resources. However, the use of recycled materials can compromise pavement performance, in particular, RAP can contribute to cracking because the mixtures with recycled materials become more brittle. In Nebraska, pavement rehabilitation has mostly been conducted by milling old 4-in. asphalt surface and placing a new 4-in. layer. Due to the potentially increased use of RAP mixtures for pavement rehabilitation, it is necessary to look into potential applications of RAP-induced overlay …

Supporting Bridge Management With Advanced Analysis And Machine Learning, Joshua Steelman, Francisco Garcia

Nebraska Department of Transportation: Research Reports

A supplemental Artificial Neural Network (ANN)-based tool was developed to support the Nebraska Department of Transportation (NDOT) in optimizing bridge management investments when choosing between refined modeling, field testing, retrofitting, or bridge replacement. Load ratings typically increase by approximately 15% to 20% when using detailed finite element analysis (FEA) instead of AASHTO approximate analysis methods. The ANN tool is implemented in an Excel spreadsheet to accept ten input parameters readily available to NDOT engineers performing typical load ratings, and predicts FEA- equivalent critical girder distribution factors (GDFs), removing unnecessary conservativism from approximate AASHTO GDFs, potentially justifying load posting removal for …

Research On School Zone Safety, Aemal Khattak, Yashu Kang

Nebraska Department of Transportation: Research Reports

This research investigated different aspects of school zone safety including the effects of speed differentials on drivers’ speeds in active school zones, the effects of school and surrounding characteristics on drivers’ speeds in active school zones, and the safety benefits and costs associated with active school zones. The research team identified 18 schools in Nebraska for data collection that consisted of drivers’ speed data, school and surrounding characteristics, and 2014-2018 reported crash data. The 18 schools were categorized by the school zone speed limit differentials: 35 to 25 mph, 40 to 25 mph, 30 to 25 mph, and 35 to …

Prototype System For Implementing The Ultrasonic Guided Wave Method On The Field, Ece Erdogmus, Eric Garcia, Michael Schuller, Ahmad Shoaib Amiri

Nebraska Department of Transportation: Research Reports

This report presents the latest improvements in a recently developed nondestructive testing (NDT) technique for early detection of various flaws such as corrosion, delamination, and concrete cracking in reinforced concrete (RC) bridge decks. The method, named Ultrasonic Guided Wave Leakage (UGWL) method by the developing authors, involves use of internal steel reinforcement (rebar) as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy at the surface of the concrete. This report builds upon the progress made in the previously published phases of the project (M029 and M066), and aims to further explore the …

Application Of Internal Curing To Improve Concrete Bridge Deck Performance, Arman Abdigaliyev, Yong-Rak Kim, Jiong Hu

Nebraska Department of Transportation: Research Reports

Due to the relatively high cement content and low water-to-cement ratio (w/c) used, bridge deck concrete is prone to premature cracking. Internal curing has been found to greatly reduce the chance of premature cracking as well as concrete deterioration. This research project was intended to develop internally cured bridge deck concrete based on a local mix design in Nebraska. Four different lightweight fine aggregate (LWFA) as internal curing agents were evaluated, and their effects on fresh, mechanical, durability, and shrinkage properties of concrete were studied. To identify the most effective LWFA dosage for shrinkage reduction, different replacement rates of sand …

Synthesis Of Repair Practices Of Damaged Precast/Prestressed Concrete Girders, George Morcous, Richard L. Wood, Antony Mohsen Kamal Masoud Kodsy

Nebraska Department of Transportation: Research Reports

Bridge girders are constantly subjected to various types of damage during their service life. There is currently limited knowledge or guidelines provided by the NDOT Bridge Office Policies and Procedures (BOPP) regarding the assessment and repair procedures of damaged precast/prestressed concrete girders. This report aims to develop a comprehensive repair manual for precast/prestressed concrete girders subjected to damage caused by over-height vehicular collision and damage located at the girder ends. Over-height vehicular collision damage typically occurs at the middle portion of the exterior girders and the primary concerns are focused on flexural deficiencies. Girder end damage can occur due to …

Improvement Of Low Traffic Volume Gravel Roads In Nebraska, Richard L. Wood, Yong-Rak Kim, Yijun Liao, Mohammad E. Mohammadi

Nebraska Department of Transportation: Research Reports

In the state of Nebraska, over one-third of roadways are unpaved, and consequently require a significant amount of financial and operational resources to maintain their operation. Undesired behavior of surface gravel aggregates and the road surfaces can include rutting, corrugation, and ponding that may lead to reduced driving safety, speed or network efficiency, and fuel economy. This study evaluates the parameters that characterize the performance and condition of gravel roads overtime period related to various aggregate mix designs. The parameters, including width, slope, and crown profiles, are examples of performance criteria. As remote sensing technologies have advanced in the recent …

Early Detection Of Near-Surface Void Defects In Concrete Pavement Using Drone Based Thermography And Gpr Methods, Zhigang Shen, Ece Erdogmus, George Morcous, Chngsheng Cheng, Zhexiong Shang, Theresa Mccabe, Antony Mohsen Kamal Masoud Kodsy

Nebraska Department of Transportation: Research Reports

The goal of this research is to evaluate the feasibility and the performance of using UAV-mounted infrared thermography (IRT) and ground penetration radar (GPR) to detect sub-surface voids caused by consolidation issues in concrete pavement. The motivation of the study is to identify the consolidation defects as early as the initial set of concrete to avoid having this problem in large pavement sections, which is costly and time consuming to repair. Using the two technologies in combination to detect subsurface voids in the concrete initial set stage is new and aims to take advantage of the strengths and minimize the …

Evaluation Of Tie-Bar Anchoring Methods: Non-Shrink Grout Vs. Epoxy, Wally Heyen, Lieska Halsey, Tim Krason, Brandon Varilek, David Hansen

Nebraska Department of Transportation: Research Reports

Tie bars are epoxy coated steel bars that connect the longitudinal joints in concrete pavement. Tie bars prevent faulting and joint separation between lanes Tie bars can be placed into the plastic concrete or inserted after curing by drilling and anchoring with epoxy or non-shrink grout. The specification for the tie bars requires the use of a No. 5 bar, 18 inches long and shall meet ASTM A775 / A775M [1], Section 1020.The Nebraska Department of Transportation “Standard Specifications for Highway Construction,” (Section 603.03) requires contractors to mechanically insert tie bars into the face of pavements during construction. Tie bars …

Development Of An Ndt Tool For In-Situ Assessment Of Prestress Loss, Bibo Zhong, Jinying Zhu, George Morcous

Nebraska Department of Transportation: Research Reports

The research objective is to develop a non-destructive testing (NDT) method to evaluate the prestress loss in prestressed concrete bridge girders using ultrasonic waves. The work principle is based on acoustoelastic effect - ultrasonic wave velocity varies with stress level in prestressed concrete. A self-reference test setup was proposed to measure wave velocity in two orthogonal directions (prestress and unstressed directions) in the girder. This setup will be able to reduce effects of material variation and temperature change.

The concept was first validated on small concrete specimens (cylinders and beams) in laboratory. A signal analysis algorithm was developed to reliably …

Feasibility Study Of Development Of Ultra-High Performance Concrete (Uhpc) For Highway Bridge Applications In Nebraska, Flavia Ribeiro Furtado De Mendonca, Mostafa Abo El-Khier, George Morcous, Jiong Hu

Nebraska Department of Transportation: Research Reports

Ultra-high performance concrete (UHPC) is a new class of concrete that has superior mechanical, durability, and workability properties that far exceed those of conventional concrete. To achieve these properties, a specific mix design with a very dense internal structure, fiber reinforcement, and low water-to-binder ratio (w/b) is commonly used. The goal of this research is to develop a non-proprietary UHPC mix with constituent materials that are readily available in the state of Nebraska for bridge construction applications. In developing this mix, the particle packing model is used, and an experimental study of the impact of various design parameters on the …