Structural Engineering Commons^™

Bridge Deck Overhang Design: Effective Vehicle Impact Loads, Ultimate Strength, And Implications On Bridge Rail Performance, Andrew Eric Loken

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

When an errant vehicle strikes a bridge railing on a typical girder bridge, impact loads are transmitted downward through the railing and inward through the deck overhang to the primary superstructure elements. In this research effort, design demands for deck overhangs supporting concrete railings were characterized using physical testing and complementary modeling in LS-DYNA. Physical test and modeling results were also used to better characterize the ultimate strength of overhangs supporting post-and-beam railings. Ultimately, a novel design methodology for deck overhangs was developed and proposed for adoption to the AASHTO LRFD Bridge Design Specifications (BDS).

For overhangs with solid concrete …

Meta-Analysis Of Insulated Concrete Wall Panel Design Methods For Shear And Flexure Behavior, Maryam Al-Bayati

Durham School of Architectural Engineering and Construction: Dissertations, Thesis, and Student Research

Insulated Concrete wall panels have been designed and constructed since the early 1950s with various shear ties, dimensions, and methods; nonetheless, thermal bridging and rational design are still a concern. Many companies have recently developed plastic connectors that have gradually replaced solid concrete sections and steel connectors due to their superior thermal efficiency and strength. However, there is no generally accepted method for predicting the behavior of sandwich wall panels in structural engineering practice or codes, but many methods have been used since the early 1920. This study aims to evaluate the accuracy of current methods for predicting the flexural …

Investigation And Modification Of Single-Post Aluminum Sign Supports For Mash Crashworthiness, Rodrigo Quintero

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Traffic signs are used to display information to drivers and are one of the most commonly encountered roadside structures. Although they are a vital traffic control device, signs can pose a significant safety risk to errant drivers due to their extensive placement and proximity to the roadway. Therefore, traffic signs and their supports must be designed with crashworthiness in mind to reduce the likelihood of injury in the event of a vehicle impact. Prior to 2009, these systems were evaluated using the crash testing criteria found in the National Cooperative Highway Research Program (NCHRP) Report No. 350 [1]. Currently, they …

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

Honors Theses

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 …

Three-Dimensional Structural Analysis Of Temple 16 And Rosalila At Copan Ruinas, Luis Tuarez

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Temple 16 is an ancient Maya structure located at the heart of the Copán Ruinas Acropolis in Western Honduras. Temple 16 contains several earlier structures within it that were built on top of each other throughout Copán’s history. One of these earlier structures, Rosalila, is one of the most culturally significant structures within the Acropolis due to its preservation. An intricate series of archeological tunnels have been excavated throughout Temple 16 to allow for its study. However, significant cracking has been observed within Rosalila and several tunnels have experienced partial collapse. This not only poses a life safety issue for …

Assessment Of Bridge Pier Response To Fire, Vehicle Impact, And Air Blast, Chen Fang, Qusai Alomari, Daniel G. Linzell

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Highway bridges exposed to intentional or unintentional fire followed by combined vehicle impact and air blast are at risk of significant damage and, possibly, collapse. Limited studies examining the complex effects of these extreme demands on bridge support elements and parametrizing their response and damage are found in the open literature. Research that is presented is part of an ongoing numerical investigation examining round, multi-column, reinforced concrete (RC), bridge pier behavior subject to multi-hazard scenarios involving fire, vehicle impact, and air blast. Detailed nonlinear finite element analysis models of single columns and multi-column piers supported by a pile foundation system …

Science Club, Danielle Gibson, Krista Andersen

Honors Expanded Learning Clubs

Honors After School program for elementary age children to engage with scientific principles. Students performed hands-on experiments to explore various STEM fields. Each weekly lesson consisted of a different concept to be learned or explored by early elementary aged students.

Inter-Wythe Slip Design Criteria For Non-Composite Insulated Walls, Abdelrahman Awawdeh, Fray F. Pozo-Lora, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

Non-composite insulated wall connector design is governed by ICC-ES AC320. This standard works entirely in the loading domain, asking the engineer to prevent connector failure due to tension and shear loading. In this paper, the authors discuss additional criteria related to thermal loading and out-of-plane wind loading that create displacement demand in the non-composite connectors. Loads suitable for such analyses are not well defined. Loads are assumed and demonstrated herein and shown to cause significant displacement demand on connectors. Limited non-composite wythe connector testing is available, and some results are presented here. A comparison indicates that outright failure of non-composite …

Design Of Wythe Connectors For Concentrated Out-Of-Plane Loading Of Insulated Walls, Ammar Al-Maabreh, Fray F. Pozo, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

Partially composite concrete insulated wall panels must be designed to handle different types of loading, including out-of-plane concentrated loads. Currently, there is a lack of information that describes and helps engineers analyze the mechanics of axial load transfer for insulated wall panels for concentrated out-of-plane loads that may occur from lifting, handling, or floor/roof reactions. Such loading generates axial and shear forces in the wythe connectors, making it important to choose the type and quantity of connectors in the design process. This paper aims to develop a better understanding of out-of-plane point load mechanics on concrete sandwich wall panels. A …

Reducing Early-Age Shrinkage Cracks Of Bridge Decks And Rails, Soumitra Das, George Morcous, Jiong Hu

UNL Student Research Days Posters, Graduate

Early-age shrinkage cracking of concrete bridge decks and rails accelerates the penetration of water and chemicals which leads to reinforcement corrosion, delamination, and eventually spalling. All this results in shorter service life, road closure, and costly repair. Development of Low-cement concrete(LCC) mix to reduce early age shrinkage crack through aggregate grading optimization was done in this research work. This approach also reduces concrete cost ($15-$20/cyd) (15–25%) and its carbon footprint (≈15%).

North 14th Street Corridor Improvements Project, Ashley Nguyen, Samantha Corey, Maricela Paramo Reyes, Pooja Rajeev

Honors Theses

The following project report was a study of the North 14^th Street corridor ranging from Adams Street to Virginia Street conducted by University of Nebraska-Lincoln students for a senior design capstone project. Main focuses of the project were the intersection of Adams and 14^th Street and the 14^th Street bridges over Cornhusker Highway and Oak Creek. Study of this area included work in transportation, traffic, structural, geotechnical, water resources, and environmental engineering. However, this report done by students should not take the place of work done by licensed professional engineers.

This project was done in collaboration with …

Effects Of Friction On The Dynamic Behavior Of Flexible Rocking Bodies, S. Mohammadreza Farooghi Mehr, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

Flexible rocking bodies are freestanding structures that are free to deform and rock, potentially overturning, when subject to ground excitation. Prior research on the seismic behavior of this type of structure typically assumed sufficient friction at the ground surface to avoid sliding motion. However, experimental observations showed that this assumption was often violated and structures demonstrated non-negligible sliding during their responses. The overarching goal of this study is to evaluate the impact of sliding on the overturning response of flexible rocking bodies. To this end, a two-dimensional analytical model was developed in a Lagrangian formulation, which is presented in this …

Probabilistic Seismic Vulnerability Assessment Of Freestanding Historic Monuments, Marie E. Wagner

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Seismic events can cause significant damage to structures, especially to freestanding structures which are not fixed to the ground and are free to rock independently. This thesis will study the response of freestanding statues and monuments to ground motions and develop probabilistic models for overturning, in order to assist in retrofitting and repair efforts. To do this, single and dual block system models were created with a variety of sizes, aspect ratios, and asymmetries, then subjected to several historic ground motions to determine whether they overturn using three-dimensional distinct element analysis as a result of rocking, sliding or twisting in …

Prioritization Of Research On Bridge Railings For Use On Timber Deck Bridges And Development Of Two Glulam Bridge Railing Systems, Jared Duren

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

In the past, many timber bridge railings, bridge railings for use on timber deck bridges, and approach guardrail transition systems to accompany these railings, have been developed to meet different impact safety criteria. Through an extensive literature review, the design details of these systems were identified and organized. A survey was then developed and distributed to multiple government agencies and timber industry members to identify their desire for these bridge railing and approach guardrail transition systems to be developed to meet current American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) impact safety criteria. …

Fragility Functions Of Manufactured Houses Under Earthquake Loads, Shuyah Tani Aurore Ouoba

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Manufactured homes are factory-built homes made of wooden structural members, then transported and installed on a given site. Manufactured housing is used in many countries, such as in Australia, and in New Zealand but remain mostly popular in the United States. In 2020, nearly 22 million people were estimated to live in manufactured homes in the United States, with an increase of more than fifty percent in the shipment over the past seven years. However, performance observations from the last decades have shown the vulnerability of manufactured homes to extreme events, like windstorms and earthquakes. Damage assessments and post-event evaluations …

Analysis Of Laminated Beams: A Bibliometric Review, Arati Waghmare, Sanjay Kulkarni

Library Philosophy and Practice (e-journal)

In this paper statistical analysis of literature on “Analysis of Laminated Beams” using Scopus and Web of Science database is done. Reason behind bibliometric study of literature is to understand the extent of research in this particular area. Since Scopus and Web of Science indexing are known as the most reliable sources amongst all the peer reviewed journals, literature from Scopus and Web of Science database only is taken into consideration. Benchmarks used for the analysis are publications in a year, published articles of different authors, citations of authors etc. Considered period is from 2000 to 2020. It is found …

Evaluation Of Permanent Concrete Barriers To Mash 2016, Samuel Elias Hovde

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

The objective of this research project was to develop evaluation criteria for permanent concrete barriers to MASH 2016 TL-3 and TL-4 without crash testing and then to evaluate permanent concrete barrier standards provided by the sponsoring agencies of the Midwest Pooled Fund Program. A literature review was conducted to determine evaluation criteria for stability, shape, strength, and anchorage, and a database of permanent concrete barrier crash tests was compiled. A survey was conducted to collect barrier standards from the members of the Midwest Pooled Fund Program, and barriers were selected and evaluated according to the determined methodology. A total of …

Advanced Concrete Composites For Improved Performance: A Bibliometric Survey, Dhruv Patel, Aryan Tiwari, Nishnat Nikhare, Rohit Shinde, Ashutosh Dubey, Manan Shah, Shalaka Hire, Sayali Sandbhor

Library Philosophy and Practice (e-journal)

Concrete is the core component of any civil engineering construction. Conventional concrete can be modified depending upon the needs and requirements of the construction. Such concrete is called advanced concrete and this report aims to study advanced concrete and its composites. The main objective of this report is to perform a bibliographic survey on the latest research literature available under the domain of advanced concrete composites for improved performance. Timespan considered for the survey is from the year 2015 to 2020. The bibliographic survey consists of literature from online platforms such as the Web of Science (WoS) and Scopus database. …

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) …

Semi Real-Time Detection Of Subsurface Consolidation Defects During Concrete Curing Stage, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Subsurface consolidation defect is a common issue in concrete pavement construction, and the hidden defects often require costly repairs after project delivery. Therefore, being able to identify this type of defect during construction will enable contractor to conduct quick repairs to avoid costly post-construction rework. In this paper a semi real-time detection approach using infrared thermography is introduced. The developed approach utilizes the hydration heat during curing time to identify the subsurface voids based on the regional temperature contrast. Experimental studies were conducted using artificial void-defect in different sizes and depths. The thermographic analysis is employed to locate the void-defects …

Automatic Delamination Segmentation For Bridge Deck Based On Encoder-Decoder Deep Learning Through Uav-Based Thermography, Chongsheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Concrete deck delamination often demonstrates strong variations in size, shape, and temperature distribution under the influences of outdoor weather conditions. The strong variations create challenges for pure analytical solutions in infrared image segmentation of delaminated areas. The recently developed supervised deep learning approach demonstrated the potentials in achieving automatic segmentation of RGB images. However, its effectiveness in segmenting thermal images remains under-explored. The main challenge lies in the development of specific models and the generation of a large range of labeled infrared images for training. To address this challenge, a customized deep learning model based on encoder-decoder architecture is proposed …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

Probabilistic Analysis Of Slide-Rocking Structures Under Earthquake Loads, Taylor J. Knickerbocker

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Estimates of rare seismic hazard are essential for the resilience of critical infrastructure and facilities. However, these estimates are highly uncertain at long return periods due to the lack of observed earthquake records. Several ground motion prediction equations have been proposed to close this gap and estimate rare seismic demands; however, these models were developed based on more moderate earthquake records and can yield physically unrealizable ground motions when extrapolated to long return periods. For this reason, seismologists have proposed using precariously balanced rocks (PBRs) as a way to constrain rare seismic hazard. PBRs are a type of fragile geologic …

Unl-Cc Outdoor Education Center Master Plan, Marie Wagner

Honors Theses

The following report contains the work done by the group Griswold Engineering in completion of the Senior Design requirements for Civil Engineering and the Honors Requirements of the Project Manager. As the project manager, my job was to organize the project as a whole and to work alongside the Structural Engineer on the project. One of the main problems to overcome was the division of labor amongst the group. The project was originally conceived as a group project with one project manager and five other students to serve as the project engineers in each subdiscipline. Since this group only had …

Development Of Post-To-Deck Connections For Use In A Mash Tl-4 Steel-Tube Bridge Rail, Pascual Mauricio

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

A new post-to-deck connection was designed for mounting an upcoming Manual for Assessing Safety Hardware (MASH) Test Level 4 steel-tube bridge rail to the side of the bridge deck to limit impact load transferred to the deck and to minimize the propensity for deck damage during impacts. With preference for the bridge rail system to be compatible for use on all deck configurations, the Illinois and Ohio Departments of Transportation desired the new system to attach to bridge decks comprised of concrete slabs or precasted prestressed, concrete box-beam girders.

A new post-to-deck connection for a new MASH 2016 TL-4 steel-tube …

Civil Engineering Design Of Cornhusker Council's Outdoor Education Center, Kelly Weiler

Honors Theses

A team of geotechnical, structural, hydraulic, environmental, and transportation experts collaborated to provide engineering solutions to the Cornhusker Council in an effort to solve the current problems facing their Outdoor Education Center. This results of this project provided the structural design of three bridges on the property, transportation plans for two parking lots and roadway design, geotechnical recommendations for soil testing and erosion prevention, and an environmental and hydraulic analysis of the property. A major challenge in the design of this project is the consideration of the dangers and regulations that accompany the floodway and floodplain regions on site. Various …

Bridge Deck Delamination Segmentation Based On Aerial Thermography Through Regularized Grayscale Morphological Reconstruction And Gradient Statistics, Chongsheng Cheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Environmental and surface texture-induced temperature variation across the bridge deck is a major source of errors in delamination detection through thermography. This type of external noise poises a significant challenge for conventional quantitative methods such as global thresholding and k-means clustering. An iterative top-down approach is proposed for delamination segmentation based on grayscale morphological reconstruction. A weight-decay function was used to regularize the reconstruction for regional maxima extraction. The mean and coefficient of variation of temperature gradient estimated from delamination boundaries were used for discrimination. The proposed approach was tested on a lab experiment and an in-service bridge deck. The …

Exploring Engineering Club, Samantha Corey, Stephen Yaghmour

Honors Expanded Learning Clubs

Exploring Engineering Club provides an introduction to a variety of engineering problems and piques the students’ interest in engineering by accompanying the information with hands-on problem solving activities mainly related to structural engineering. The activities will often be done in teams which will teach good teamwork skills, as well as problem solving and critical thinking.

Post-Earthquake Assessment And Numerical Modeling Of Freestanding Heritage Structures, M. Khalid Saifullah, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

Historic and heritage structures are particularly vulnerable to earthquakes, where damage or collapse can not only lead to loss of a structure but also the loss of irreplaceable heritage. Many heritage structures can be classified as freestanding (detached) structures, including unreinforced masonry walls, classical multi-drum columns, and statue-pedestal systems. However, the seismic response of freestanding structures (sliding, rocking, rock-slide, overturning) is poorly predicted by existing methods due to geometric non-linearities as well as sensitivity to interface conditions and modeling parameters. Previous studies have focused on analytical modeling of simplified systems and/or experimentation under controlled laboratory conditions. In contrast, this paper …

Damage Assessment Of A Sixteen Story Building Following The 2017 Central Mexico Earthquake, Yijun Liao, Richard L. Wood, M Ebrahim Mohammadi, Kanchan Devkota, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

The 2017 M7.1 Central Mexico Earthquake caused significant infrastructural damage in the Mexico City area. The earthquake contained a significant pulse in the long period, resulting in numerous buildings severely damaged or collapsed. This paper discusses a reinforced concrete building which was still partially occupied post-earthquake. The building’s interior walls were examined to have substantial damage, including some extensive cracking. In January 2018, the authors visited the structure and collected detailed assessment data. The data collection included ground-based lidar scans and recorded ambient vibrations of the damaged structure using accelerometers. Eleven scans were collected from the four exterior facades to …