Selected Research Projects

Contact Dr. Head for more information.

Determination of Bridge Element Weights Based on Data-Driven Models

PI: Dr. Monique Head (UD); co-PI: Dr. Yoojung Yoon (West Virginia University)
Master’s Student: Qozeem Abiona
Sponsor: USDOT, University Transportation Center (UTC), CIAMTIS @PennState

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Bridges are made up of several parts acting as a unit and this complexity makes it important to know which elements have more influence in the optimum performance of the bridge. The increase in bridge element-level data collection by the Departments of Transportation (DOTs) in the United States makes it pertinent to consider a more efficient use of these data for an improved bridge and asset management. The weight or importance of the bridge elements influences the maintenance, repair, and replacement (MRR) schedule of the DOTs and the resource allocation to the structures. The DOTs currently use a cost-based approach to assign weight to bridge elements which can be in terms of the loss accrued during downtime or the amount needed for the replacement of the element. However, this approach does not consider the structural relevance of the bridge element to the overall performance of the major component. The project explores innovative data-driven approaches that are based on Stochastic and Machine Learning (ML) models for determining the weight (or importance) of individual bridge elements.

Vulnerability Assessment of Existing Bridges in the Pacific Northwest Region Subjected to Long-Duration Earthquakes

PI: Dr. Monique Head (UD)
PhD Student: Shaymaa Obayes
Sponsor: University of Delaware

Brief project description: Limited studies to date have specifically focused on assessing the vulnerability of multi-span precast concrete girder (MSPCG) bridges subjected to long duration earthquakes in high seismic regions that may perform inadequately compared to today’s design standards. The primary objective of the study is to accurately quantify the risk and structural vulnerability of these bridges typical in the Pacific Northwest (PNW) region using fragility curves based on predefined damage states that correspond to four performance levels to determine the likelihood of bridge collapse during a long-duration or mega earthquake. The four damage states are established to capture minor cracking and minor spalling, moderate shear cracking and moderate spalling, shear failure – (column structurally unsafe), and column collapse. MSPCG bridge types are examined first in this study and modeled in OpenSees. The bridge model is subjected to a suite of simulated M9 ground motions and nonlinear time history analyses are conducted. Preliminary results show that the fragility curves for the MSPCG bridges suggest a higher fragility level than presented in HAZUS-MH in terms of slight, moderate, and extensive damage states; however, the fragility level for the collapse damage state presented in HAZUS-MH was significantly higher than the model results. The expected results can be used to prioritize bridge retrofit and asset management based on the likelihood of these events and its impact on critical infrastructure and society.

DEEDS: Building Coastal Community Resilience with Nature-based Shoreline Solutions

Co-PI: Dr. Monique Head (UD)
PhD Student: Waqas Iqbal
Sponsor: US Department of Defense

Brief project description: For centuries, hardened shoreline materials like rip rap, bulkheads, and concrete have been used to reduce the impact of waves and storm surges to protect coastal infrastructure. However, their effectiveness decreases over time as they begin to erode, which has become a growing concern as climate change amplifies coastal conditions. As concern for coastal resiliency has increased over the past few decades, new types of environmentally sustainable shoreline stabilization tools, like living shorelines (LSs), have become more popular. There are two widely used approaches, including non-structural and hybrid. Hybrid LS approaches, which include fiber logs, marsh toe revetment, marsh sills, oyster reefs, breakwaters, and wave attenuation devices, are applied to coasts with greater hydrodynamic forcing and storm surges because they include stronger materials that protect delicate vegetation. Owing to the multi-dimensional problem, this project involves different stakeholders from landscape architecture, environmental engineering, ecology, geography, and spatial sciences, and structural engineering. As a part of the structural engineering group, our aim is to perform a detailed vulnerability analysis to identify critical infrastructure and critical evacuation routes at military installations near Aberdeen (MD) and the state of Delaware (DE). In-situ water level sensors will be utilized to study wave profiles across APG and DE for calculating expected demands on coastal structures across existing and proposed hybrid shorelines. Although hybrid LSs are effective in wave attenuation in some cases, overcoming the impacts of natural hazards on critically deteriorated infrastructure has been a great challenge, especially because climate change and SLR are causing more frequent hurricanes. Highway codes specify minimum design load demands for coastal structures but there is a need to investigate the structural demands of bridge piers using detailed fluid-structure interaction analysis. While calculating the structural demands, deterioration models will also be included to capture the structural response of deteriorated bridge piers using detailed FSI analysis to contribute towards resilient infrastructure and resilient communities.

Predictive modeling and simulation of chloride-induced damage to concrete coastal infrastructure

PI: Dr. Monique Head (UD)
Master’s Student: KJ Olsen
Sponsor: US Department of Defense

Brief project description: With the increased frequency of weather events, more existing and soon-to-be-built transportation-based structures are expected to be exposed to higher levels of salinity than initial design life estimations. To prevent excessive destructive testing that can physically disrupt the condition of the structures, predictive modeling of concrete subjected to high levels of chloride-induced damage can be used to complement field and laboratory testing. A series of tests will be conducted at varying chloride concentrations and temperatures to develop accurate deterioration models for service life monitoring. To simulate extensive aged chloride-based deterioration of the sample sets, accelerated heated high salinity exposure will be used to determine the rates at which concrete roadway and deck surfaces become susceptible to damage over time. Ultimately, the laboratory results will be used to cross-correlate with actual chloride-induced damage based on in-situ measurements, field observations, and predicted salinity levels. New chloride profiles as a function of age, the composition of the material, and crack formation will be analyzed to inform predictive deterioration models that can guide more sustainable and data-driven asset management strategies. 

Experimental Usage of Recycled Plastics in Cementitious Materials

PI: Dr. Monique Head (UD) and Dr. Suresh Advani (UD, Dept. of Mechanical Engineering)
UD Undergraduate Student: KJ Olsen
Sponsor: University of Delaware

Brief project description: With increased attention on sustainable infrastructure and providing greener alternative materials, there is a need to address the large quantities of plastics that lurk in landfills. Many of these plastics include non-degrading, thermoset plastics and composites from items such as decommissioned airplanes and wind blades  that cannot be melted down or remolded. However, when grinded and mixed with concrete, the material has the potential to be reused and repurposed for transportation surfaces such as pavements or overlays as long as the addition of these plastics do not contribute to degradation of minimum criteria for structural performance. Therefore, the main objective of this research is to analyze the effects of adding plastics to concrete, which minimizes landfill waste material while potentially offering a new class of sustainable, green material that can be used as an alternative construction material, if successful.

Estimating Peak Floor Acceleration Using Artificial Neural Networks

PI: Dr. Monique Head (UD)
UD Graduate Student: Wael Aloqaily
Sponsor: University of Delaware

Brief project description: This study aims to predict peak floor acceleration (PFA) for a particular building when subject to a given ground motion using artificial neural networks (ANNs). PFA can be an effective engineering demand parameter for lifelines via inspection and recovery assessment. By guiding evacuation from buildings with invisible (e.g. non-structural) damage that can pose a hazard to human life and optimizing inspection resources. To quickly predict PFA, machine learning (ML) is utilized to learn patterns from time-history analysis results. ML approach can swiftly provide the PFA response, to some degree of accuracy, without the need to run time-consuming time history analysis (THA). Preliminary results from linear analysis and performance of the model have been obtained to date.

Bridge Load Rating and Evaluation Using Digital Image Measurements

PI: Dr. Monique Head (UD); co-PIs: Dr. Harry Shenton (UD), Dr. Michael Chajes (UD), and Dr. David Lattanzi (George Mason University)
UD Graduate Student: Luke Timber
Sponsor: USDOT, University Transportation Center (UTC), CIAMTIS @PennState

Brief project description: The objective of the research is to develop and implement a procedure for load rating based on field testing using digital image measurements. Field testing of a bridge is a relatively simple procedure, yet it is still only done on a very, very small fraction of bridges in the U.S. inventory.  To properly allocate resources to determine whether a bridge repair, rehabilitation or replacement is needed, the actual load carrying capacity is needed from field testing and not an analytical model alone.  We propose having a low-cost, nondestructive and reliable means to conduct field testing for bridge load rating and evaluation using image-based measurements.  Replacing multiple discrete strains measurements with digital image correlation opens the door to making bridge testing easier, less expensive, and much more common as a solution to address the grand challenge of determining how and what is needed to properly allocate resources for deteriorating and aging bridges.

Optimized Performance of UHPC for Bridge Joints and Overlays

PI: Dr. Monique Head (UD); co-PIs: Dr. Paramita Mondal (UD) and Dr. Farshad Rajabipour (PennState)
UD Graduate Student: Tyler Dennis
Sponsor: USDOT, University Transportation Center (UTC), CIAMTIS @PennState

Brief project description: The use of ultra-high performance concrete (UHPC) for connections between prefabricated bridge elements (i.e., bridge deck panels) offers fast construction and increased durability, and is gaining momentum across the United States. In addition, UHPC overlays can be used for effectively repairing deteriorating concrete bridge decks. UHPC offers significant advantages over conventional concrete both short and long-term.  The objective of this research is to capitalize on the existing knowledge and literature by compiling various UHPC mix design strategies and establishing empirical composition-property relationships that can be used to develop UHPC mixtures for expansion joints and overlays with optimum durability and structural performance. In addition, we will address a critical knowledge gap of linking formulation and rheology of UHPC mixtures with different fiber types, which allow designing highly flowable mixtures. The resulting optimum UHPC mixtures will be laboratory tested and further improved. Potential impact on the state of practice could be significant by promoting the use of low-cost non-proprietary UHPC to extend the life of concrete bridges, and by familiarizing the industry and transportation agencies in the region with this valuable technology.

Design of Anchors for Repair and Rehabilitation of Bridges with Externally Wrapped Carbon Fiber Reinforced Polymers

PI: Dr. Monique Head (UD); co-PI: Dr. Jovan Tatar
UD Graduate Student: Christian Viniarski
Sponsor: USDOT, University Transportation Center (UTC), CIAMTIS @PennState

Brief project description: Externally bonded fiber reinforced polymer (FRP) composites, particularly carbon FRP (CFRP), have been instrumental in the flexural strengthening of concrete bridges because of their high strength-to-weight ratio, corrosion resistance, rapid and easy application, and reduced cost compared to complete or partial bridge replacement. Even though CFRP composites are durable when faced with external environments typical for bridges, their bond to concrete is susceptible to degradation under moisture. CFRP-concrete bond deterioration was found to often lead to an early onset of debonding, and can limit the overall effectiveness (i.e. desired ultimate capacity and performance under service loads) of concrete bridges externally bonded with CFRP as evidenced by our previous work. Improved performance of externally bonded CFRP can be achieved with the addition of post-installed U-wrap and fiber anchors on the beam soffit to enhance the CFRP-concrete bond capacity. However, no design guidelines to date covering anchored CFRP exists due to limited experimental data covering a broader range of geometric and material properties, which significantly limits implementation of anchored CFRP in transportation structures. The project team will address this knowledge gap, and develop a modified design equation for flexural strengthening of anchored externally bonded CFRP concrete beams.

Dynamic Plant Monitoring to Inform Structural Design Models

PI: Dr. Erin Sparks (College of Agriculture); co-PI: Dr. Monique Head (UD)
UD Graduate Student: Shaymaa Obayes
Sponsor: UDRF-SI

Brief project description: A key strategy to meet the food production needs of a growing world population is to limit preventable crop losses. One of these preventable losses is mechanical failure, which accounts for up to 66% of crop losses worldwide. Plant mechanical failure has been studied in separate contexts based on the point of failure – stalk or root mechanical failure. To date there is no structural model that has been developed to inform whole plant mechanics. The UDRF-SI proposal here aims to ameliorate this gap in knowledge by combining the expertise of a plant biologist with a structural engineer. Using this combined expertise, we aim to adapt structural monitoring equipment for corn plant analyses, and develop whole plant mechanical models to inform plant structural design that will limit crop loss due to mechanical failure. 

Structural Performance Verification of Structural Pipe Liners for Corrugated Metal Pipes

PI: Dr. Monique Head (UD); co-PIs: Dr. Harry Shenton (UD), Dr. Jovan Tatar (UD), and Dr. Michael Chajes (UD)
UD Graduate Student: Tyler DuBose
Sponsor: Delaware Department of Transportation (DelDOT)

Brief  project description: The objective of this project is to verify the structural performance of structural pipe liners with varying thicknesses applied to corrugated metal pipes through full-scale testing.  Testing is needed to validate the ultimate strength and failure modes of these liners, which are believed to provide adequate resistance in the absence of the host conduit due to corrosion. The proposed research program is divided into seven tasks: (1) kick-off meeting, (2) literature review, (3) materials testing, (4) structural analysis, (5) full-scale testing, and (6) structural verification, and (7) reporting and dissemination. The project team will build upon the existing knowledge and results provided by the Transportation Pooled Fund Program on Structural Design Methodology for Spray Applied Pipe Liners in Gravity Storm Water Conveyance Conduits (with several partner states including Delaware) to provide additional experimental and analytical results that can support the development of a national design standard, which does not currently exist for applied structural spray liners. The research team is qualified and excited to perform the proposed tasks and collaborate with DelDOT personnel on a critical maintenance strategy that can be cost-effective with potential widespread use by other DOTs once verified.

Synthesis Study of Jointless Bridge Design and Details

PI: Dr. Harry Shenton (UD); co-PIs: Dr. Monique Head (UD), and Dr. Michael Chajes (UD)
UD Graduate Student: Hannah Power
Sponsor: Delaware Department of Transportation (DelDOT)

Brief  project description: The objective of the proposed research is to evaluate the current state-of-knowledge and -practice of the design of jointless bridges, with the goal to develop guidelines and recommendations for the design of such bridges in Delaware. The Delaware Department of Transportation has implemented jointless bridge designs in the recent past, to take advantage of the many benefits this approach offers in the long-term performance and maintenance of the bridge. The research will provide an independent assessment of current procedures and recommendations for future projects that will lead to improved performance and economic savings for the State.

Bonding of Overlays to Ultra-High Performance Concrete

PI: Dr. Jovan Tatar (UD); co-PIs: Dr. Paramita Mondal (UD), Dr. Monique Head, and Dr. Michael Chajes (UD)
UD Graduate Student: Abass Okeola
Sponsor: Delaware Department of Transportation (DelDOT)

Brief  project description: DelDOT has implemented innovative ultra-high performance concrete (UHPC) in a state-owned bridges. UHPC offers significant cost-savings for the state due to its superior mechanical properties that allow for thinner structural components, excellent durability properties, and strong bonding to the conventional concrete substrate. However, the bonding quality between UHPC components and typical overlay materials used by DelDOT, such as latex modified concrete (LMC), polyester polymer concrete (PPC), and thin epoxy overlay. Existing literature also does not address this concern. Main aim of the proposed work is to elucidate the bonding characteristic between the typical overlay materials used in the state bridge projects, and propose a set of guidelines for implementation. To achieve the project aim, the research program was divided into four tasks: (1) literature review, (2) field evaluation of overlay bonding, (3) laboratory pull-off experiments to determine UHPC-overlay bond strength and failure mode; and (4) reporting and dissemination.

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