Enhanced Camber Calculations for Prestressed Concrete Bridge Girders

The objective of this study was to develop accurate prestressed girder camber calculations and validate them with available data. The project team conducted a thorough literature review and analyzed recent girder camber research efforts in other states. The team collected existing data on 189 Missouri bridge girders as well as field data and cylinder samples from four girders during fabrication. The camber prediction equations and parameters were evaluated and compared to the field data.  

The study found that the current prediction method under-predicted the initial camber measured in the field on average by about 25%. However, investigation also found that the field measurements may have had error due to sag in the measurement string line. It was also found that the effect of the overhang (girder length past storage support locations) affects the camber. Temperature effects were found to be another source of camber error. The current camber calculations were modified to include the effect of the girder overhang and a continuous time-dependent prediction of camber. In addition, guidelines for camber measurement were developed. The modifications to the camber prediction reduced the underprediction of camber to less than 4% on average and decreased the variability to within ±25%. The proposed method was implemented into a computer spreadsheet for easy calculation.

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Report number: cmr 21-011
Published: December 2021
Project number: TR202101
Authors: Dr. Sarah Orton, Dr. Vellore Gopalaratnam, Ali Elawadi, John Holt, Dr. Maria Lopez, Dr. Thomas Murphy

Performing organization: University of Missouri-Columbia

Optimizing Work Zone Zipper Merge Using Federated Driving Simulators

Several departments of transportation have implemented the zipper merge to counter the issues of wasted capacity and queue jumping that surface at early merge work zones. This project researched four issues related to zipper merge operations and offered practical suggestions for the deployment of zipper merge. 

A main result is that public education is vital since many drivers either do not understand zipper merge or are averse to changing from the long-held practice of early merging. Specific recommendations are provided for the deployment of educational materials, including video and written bulletins. 

Drivers prefer for zipper merge to operate under lower traffic speeds and higher traffic flow conditions. However, simulator results show that zipper merge works even under higher speeds and moderate traffic flow conditions. The placement of the last CMS sign in the zipper merge system near the taper is preferred to produce more desirable driver behavior. This placement can be specified in the MoDOT Engineering Policy Guide. The adoption of these recommendation supported by research could improve zipper merge acceptance and operations in Missouri.

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Report number: cmr 21-010
Published: December 2021
Project number: TR202009
Authors: Carlos Sun, Praveen Edara, Sabreena Anowar, and Casey Canfield

Performing organization: University of Missouri-Columbia

Snow and Ice Treatment Products Evaluation

The Missouri Department of Transportation (MoDOT) Maintenance Division uses different materials to reduce the negative impact of snow and ice on the friction performance of state travelways. These materials include abrasives (sand or cinders), rock salt (sodium chloride), and other chemical deicers that emerged in recent years. The use of chemicals and abrasives (in addition to plowing) for highway winter maintenance operations is an essential strategy for ensuring a reasonably high level of service, yet the performance of such materials has to be balanced with their cost effectiveness, and potentially detrimental effects on transportation infrastructure, the natural environment, and motor vehicles. 

Currently, there are considerable data gaps when it comes to the quantification of their performance and impacts and comprehensive assessment for decision making. This study conducted a comprehensive and quantitative evaluation of snow and ice control chemicals currently used by various MoDOT districts for highway maintenance operations based on laboratory tests. An evaluation matrix to assess the cost-effectiveness and potential impacts under a holistic and multi-criteria framework was developed. The results indicated that products #5 (“Clear Lane” Produce), #7 (Calcium Chloride (liquid) Treated Rock Salt) and #3 (“Snow Slicer” Treated Rock Salt) scored above 60 out of 100. Product #5 with a score of 67 is the first priority, then product #7 with a score of 66 is the second priority, and finally product #3 with a score of 64 is the third priority.

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Report number: cmr 21-009
Published: December 2021
Project number: TR202002
Authors: Jenny Liu, Jun Liu, Xianming Shi, and Mehdi Honarvarnazari 

Performing organization: Missouri University of Science & Technology and Washington State University

Airport Design-Build Bid Documents and Agency Guidance

Design-build project delivery has been embraced across several states and local agencies for large and small public transportation projects. This delivery method has also been used extensively in the construction of privately owned and operated hangars to accelerate schedule and reduce construction cost. The State of Missouri launched this research project to determine how the design-build model can be effectively utilized by general aviation airport operators in the State of Missouri in the construction of hangars using Federal Aviation Administration grant funding.

Literature review and interviews demonstrated the need for additional design-build guidance and documentation for general aviation airports in Missouri. Interviews were conducted with Department of Transportation staff, airport sponsors, consultants, and contractors to garner feedback on project concerns and lessons learned for design-build projects. The interviews demonstrated a desire by the general aviation airport operators to utilize design-build project delivery methods.

Based on these results, a design-build manual, templated documents, and checklists were generated for use by the sponsor and Missouri Department of Transportation to procure and deliver hangar projects at Missouri’s general aviation airports using design-build.

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Report number: cmr 21-008
Published: October 2021
Project number: TR202105
Authors: Glenn Goldstein, Richard Hoffman, Nicholas Patterson, and Philip Schwab

Performing organization: RS&H, Inc.

Understanding and Improving Heterogeneous, Modern Recycled Asphalt Mixes

A comprehensive research investigation was carried out to investigate the use of recycled materials in Superpave asphalt mixtures in Missouri. The investigation involved sampling of aggregates, binders, plant-produced mixtures, and field cores followed by a rigorous lab testing program. Lab testing included an extensive binder extraction and recovery (E & R) experiments, followed by a comprehensive suite of advanced binder tests. 

An attempt was made to shed light on effective strategies to iterate existing mix designs into more ‘balanced mix designs’ for modern, heterogeneous recycled mixtures in the Midwest. Different strategies were employed, such as the use of a softer virgin binder, the addition of a rejuvenator, and the employment of 5% to 20% of dry-process, engineered crumb rubber by weight of total binder. These mixes were subjected to a suite of cracking and rutting mixture performance tests to establish baseline performance, followed by four additional mix design iterations per mix (for a total of 10 investigated mixtures). The DC(T), I-FIT, IDEAL-CT, and Hamburg wheel tracking tests were used in the performance testing suite. 

Based on the results of the study, it was found that RAP, and particularly RAS, drive the need for the use of softer virgin binders to be used in modern, recycled asphalt mixtures in Missouri. Recommendations are provided with respect to the selection of softer virgin binder grades based on recycled material type and amount. Recommendations for balancing mixes with the use of rejuvenators and ground tire rubber are also provided.

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Report number: cmr 21-007
Published: October 2021
Project number: TR201807
Authors: William G. Buttlar, Magdy Abdelrahman, Hamed Majidifard, and Eslam Deef

Performing organization: University of Missouri-Columbia and Missouri University of Science & Technology

Evaluation of Alternatives to Calcined Bauxite for Use in High Friction Surface Treatment (HFST) in Missouri

High Friction Surface Treatments (HFST) applications are used to reduce roadway crashes on risky locations and horizontal curves. Currently, Calcined Bauxite (CB) is the primary aggregate used for HFST in Missouri. Calcined Bauxite has very limited sources, which makes it more expensive than locally available aggregates. 

This research evaluated CB's feasible alternative aggregates through a comprehensive experimental program for use in HFST applications. The alternative aggregates were Earthworks, Meramec River, Steel Slag, Rhyolite, Black Diabase, Quartzite, Flint Chat, and Potosi Dolomite aggregate sources. 

Three categories of testing were followed in the experimental program: the first category was for the physical properties testing, the second category was for durability testing, and the third category was for performance testing. Two main conclusions related to aggregate sources in HFST applications were noted: the availability of alternative aggregate sources that compare to Calcine Bauxite quality and the applicability of performance testing to evaluate aggregate sources. A Life-Cycle-Cost simple program was developed to conduct cost analysis based on performance of the tested aggregate sources. The study recommended to construct HFST field sections using the selected alternative aggregates.

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Report number: cmr 21-006
Published: September 2021
Project number: TR202005
Authors: Eslam Deef-Allah, Korrenn Broaddus, and Magdy Abdelrahman, Ph.D.  

Performing organization: Missouri University of Science & Technology

Pollinator Habitat Along Highway Right of Way

Pollinators are important components of our ecosystems, as well as being important contributors to agricultural production. Highway right of way (ROW) is one potential habitat for pollinators. The objectives of this study were to assess existing practices of other agencies for promoting pollinator habitat within the ROW and to identify potential locations for pollinator habitat in Missouri. 

The study methodology included a review of academic and practitioner literature, survey of state departments of transportation (DOTs), DOT interviews, and geographic information system (GIS) analysis. The literature review found that various practitioner resources are available regarding site assessment, best management practices (BMPs), planting guidance, and other topics related to promoting pollinator habitat within the ROW. The literature addresses the suitability of a particular site for pollinator habitat based on various factors such as cover and health of existing vegetation, mowing frequency, soil texture and pH, land use, site size, sunlight, water availability, and accessibility. Survey results indicated that the most frequently utilized methods for promoting pollinator habitat in the highway ROW are planting native species that benefit pollinators, limiting the frequency of mowing, and vegetation management practices. DOTs perceive the designation of right of way on DOT facilities and reclassification of existing habitat as the most effective methods for promoting pollinator habitat. GIS was used to analyze multiple data layers (including ROWs, public lands and bodies of water, and land use/land cover) to quantify potential available land for pollinator habitat development and connectivity with other natural landscapes. A 500’ buffer around the ROW parcels was used to identify potential intersections with parks, natural areas and bodies of water. 

GIS files transmitted with this report will allow MoDOT to examine the locations of upcoming projects to identify those warranting further consideration as pollinator habitat.

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Report number: cmr 21-005
Published: July 2021
Project number: TR202104
Authors: Kathleen M. Trauth, Noel R. Aloysius, Henry Brown, Lauren L. Sullivan

Performing organization: University of Missouri-Columbia

Wireless Crack Sensing Systems for Bridges

The main objective of this research was to develop and deploy a wireless crack sensing system that can measure and monitor cracks for both concrete and steel bridge structures. This system contains the sensing unit, wireless data transmitting system, as well as a data processing unit. 

The sensing unit consists of single or arrays of advanced thin film-based sensing nodes that are capable of measuring crack-induced strains in bridge structures. This thin film sensing node contains soft polymer film (polyvinylidene difluoride, PVDF) embedded with conductive nanoparticles (graphene) or atomically thin films. Both the Poisson’s effect and contact mechanism were considered to covert the strain to electrical resistance of the sensing unit. This sensing unit is also connected to a wireless transmitting system to broadcast the signal wirelessly. The wireless transmitting system utilizes a blue-tooth technology that can enable the sensing unit to broadcast electronic signals in terms of electrical resistance. These signals were received by a mobile device (laptop or cellphone) that can convert the electrical resistance information into the measured stains. These measurements are processed using the data processing unit. The data processing unit  receives the electrical resistance data and converts it into measured strains. The machine learning approach was also taken to train the software to be able to automatically detect the abnormalities in the measured strain for critical crack growth detection.

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Report number: cmr 21-004
Published: June 2021
Project number: TR202008
Authors: Chenglin Wu, PhD

Performing organization: Missouri University of Science & Technology

HFST Before and After Analysis

Due to its high potential for safety improvement, MoDOT had deployed High Friction Surface Treatments (HFST) since 2013, at several areas experiencing high crash rates. To determine if the HFSTs are providing the expected results and if MoDOT’s HFST program is effective, this study was conducted with the primary objective of evaluating MoDOT’s existing HFST sections with regard to their overall effectiveness (i.e., reduction in crashes) and benefit (i.e., return on investment). 

Statistical modeling of before/after crashes from MoDOT’s HFST sections showed that the HFST reduced crashes, with the reduction ranging from 13.7 percent to 79.5 percent and an overall reduction of 53.3 percent. The Benefit-Cost Analysis (BCA) carried out subsequently showed that MoDOT may expect a benefit-cost ratio (B/C) ranging from 2.3 to 409.1, with an overall average of 52.6. Based on these results, it is concluded that MoDOT’s HFST program is effective in reducing crashes with a high rate of return. Concrete filled pultruded FRP tubes repair was not able to recover the strength of the virgin piles.

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Report number: cmr 21-003
Published: April 2021
Project number: TR201909
Authors: Jay Bledsoe, P.E. and  Hyung Lee, Ph.D., P.E.

Performing organization: Applied Research Associates, Inc.

Behavior and Repair of Corroded Steel H-Piles

This report summarizes the details of experimental work and finite element modeling conducted to evaluate: 1) the remaining axial capacity of H-piles having different corrosion severity and extension levels, and 2) the performance of repaired corroded H-piles. Seventeen full-scale H-piles were investigated under concentric and eccentric loads. The piles had milled cross sections to represent the loss of a cross-sectional area due to corrosion. Three different repair solutions were investigated: concrete filled pultruded fiber reinforced polymer tubes (CFPTs), ultra-high-performance concrete (UHPC) plates, and concrete jackets encased in fiber reinforced polymer. Push-out of thirty-eight specimens was carried out to optimize the three repair techniques. This was followed by repairing nine full-scale H-piles using the three different methods. Furthermore, finite element and analytical models were developed for the virgin and repaired specimens. Corrosion changed the mode of failure of the investigated piles from global buckling to local buckling which triggered global buckling. The AISC (P-Δ) analytical approach was the best approach to predict the strengths of the corroded piles. Both the UHPC plates and concrete encased in FRP jackets repair solutions were able to recover the strength of the corroded piles. The UHPC, however, represented a fast solution for repair. Concrete filled pultruded FRP tubes repair was not able to recover the strength of the virgin piles.

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Report number: cmr 21-002
Published: March 2021
Project number: TR201809
Authors: Mohanad M. Abdulazeez, Amro Ramadan, Binod Shrestha, Eslam Gomaa, Tousif Mahmood, Ahmed Gheni, and Mohamed A. ElGawady

Performing organization: Missouri University of Science and Technology 

Predictive Deep Learning for Flash Flood Management

This research was completed in tandem as a project funded through MoDOT and the Mid-America Transportation Center. It used deep learning methods, along with weather information from NOAA/National Weather Service and geospatial data from the USGS National Map and other public geospatial data sources, to develop forecasting tools capable of assessing the probability of flash flooding in high risk areas. These tools build on existing models developed by the USGS, FEMA, and others and were used to determine evacuation routing and detours to mitigate the potential for loss of life during flash floods. The project scope included analysis of publicly available data in Greene county in and around Springfield, MO as part of a pilot project in Missouri. This data was then used to determine the probability of flash flooding in order to model evacuation or detour planning modules that can be implemented to assure the safety of the community and highway personnel. These modules used existing rainfall data and weather forecasts in a three-day sliding window to include soil moisture in the flash flood predictions. The transportation safety or disaster planner can use these results to produce planning documents based on geospatial data and information to develop region-specific tools and response methods to potential flash flood events.

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Report number: cmr 21-001
Published: January 2021
Project number: TR202023
Authors: Steven Corns, Suzanna Long, Jacob Hale, Bhanu Kanwar, Lauren Price

Performing organization: Missouri University of Science and Technology