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Over the last 15 years, microbially induced calcite precipitation (MICP) has emerged as a possible solution to mitigate coastal erosion. To date, most MICP soil treatments that have been studied involve column injection using a pump. In recent years, MICP application through surface percolation has gained traction as an alternative technique, but data using this technique are limited. More recently, a new treatment recipe/technique was developed, and this technique was termed bioslurry. Like most MICP studies, research with bioslurry has concentrated on the column injection method, and surface percolation has received very limited attention. This paper discusses the treatment of Florida beach sand by surface percolating bioslurry. Researchers experimented with variations of the bioslurry recipe to optimize erosion resistance, which was assessed using a pocket erodometer combined with physical measurements. In addition, treated specimen morphology was preliminarily examined using X-ray diffraction and scanning electron microscopy. Results showed that erosion resistance was maximized when 15% to 25% of the specimens' pore volumes were filled with bioslurry and that this erosion resistance may be sufficient to withstand worst-case storm events after only one treatment. In addition, previous researchers always used a relatively long (i.e., ∼12 h) stir time when preparing bioslurry. Results presented here show that it may be possible to produce comparable data with much shorter stir times (i.e., 1 to 2 h). [ABSTRACT FROM AUTHOR]

The global COVID-19 pandemic had an unprecedented impact on transportation worldwide. Significant decreases in transportation across all modes were evident and sustained as governments worldwide implemented various countrywide closures and quarantine restrictions to slow the spread of the virus. This paper quantifies and assesses daily vehicle counts by Federal Highway Administration (FHWA) vehicle classifications during the COVID-19 pandemic in New York and Florida throughout 2020. The study found that duringMarch and April of 2020, traffic among all investigated FHWA categories was significantly reduced in both Florida and New York. However, commodity carriers in both states were able to recover faster and remained more consistent than passenger vehicles. This pattern was also observed in both urban and rural communities in Florida. The findings of this work demonstrate how commodity carrier movements, assessed through FHWA vehicle category counts, were less impacted by the governmental restrictions during the pandemic than passenger transportation. While overall traffic volume dropped by more than half in most places at the height of the pandemic, larger commodity-carrying vehicles remained nearly unchanged from the prior year by June of 2020. This was likely because of the critical need to maintain trucking movements to sustain populations. Understanding how truck traffic and freight movements more broadly were impacted during the COVID-19 pandemic is critical in preserving the continuity of service and preventing supply shortages in the event of future outbreaks. [ABSTRACT FROM AUTHOR]

Since the Ronan Point collapse in the UK in 1968, the progressive collapse analysis of residential buildings has gradually drawn the attention of civil engineers and the scientific community. Recent advances in computer science and the development of new numerical methodologies allow us to perform high-fidelity collapse simulations. This paper assesses different scenarios that could have hypothetically caused the collapse of the Champlain Tower South Condo in Surfside, Florida, in 2021, one of the most catastrophic progressive collapse events that has ever occurred. The collapse analysis was performed using the latest developments in the Applied Element Method (AEM). A high-fidelity numerical model of the building was developed according to the actual structural drawings. Several different collapse hypotheses were examined, considering both column failures and degradation scenarios. The analyses showed that the failure of deep beams at the pool deck level, directly connected to the perimeter columns of the building, could have led to the columns' failure and subsequent collapse of the eastern wing of the building. The simulated scenario highlights the different stages of the collapse sequence and appears to be consistent with what can be observed in the footage of the actual collapse. To improve the performance of the structure against progressive collapse, two modifications to the original design of the building were introduced. From the analyses, it was found that disconnecting the pool deck beam from the perimeter columns could have been effective in preventing the local collapse of the pool deck slab from propagating to the rest of the building. Moreover, these analyses indicate that enhancing the torsional strength and stiffness of the core could have prevented the collapse of the eastern part of the building, given the assumptions and initiation scenarios considered. Building catastrophic collapses can cause significant lives and economic losses. Poor design and maintenance, in combination with aging, will more likely increase, in the next years, the number of buildings potentially vulnerable to the risk of collapse, due to either seismic, accidental, or degradation actions. This research focuses on the analysis of the Champlain Tower South condo collapse, which occurred in Surfside, Florida, in 2021. Different hypothetical collapse scenarios were simulated, comparing the analysis results with the actual evidence of the collapse. The analyses have shown that the degradation of the pool deck slab, due to corrosion, may have contributed to the collapse of the building. Finally, two different minor revisions of the original design of the building were analyzed to reduce the risk of failure and understand how the collapse of similar residential buildings could be prevented. [ABSTRACT FROM AUTHOR]

Small wastewater systems serving less than 10,000 population equivalents (p.e.) face a wide range of challenges due to technical and managerial capacity issues, limited resources, and the need to reduce environmental impacts. Based on the wide range of challenges of small systems, the authors of this manuscript developed the social, environmental, and economic wastewater decision support tool (SEE WWDST) to aid decision makers in comparing the sustainability of treatment alternatives. The tool uses multi-criteria decision analysis to produce a single SEE impact score that assesses 12 sustainability metrics across three larger categories: economic performance (e.g., net present worth of costs, affordability), environmental performance (e.g., carbon footprint, eutrophication, water reclaimed), and social performance (e.g., maintenance time, employee training, degree of automation, operator certification requirement, system intrusiveness, daily, and seasonal resilience). This paper compares the performance of three onsite wastewater treatment systems in Florida. The three systems evaluated include: (1) a passive septic tank effluent biofilter (STEB) system, (2) a mechanized aerobic treatment unit (ATU) system, and (3) a passive clay, sulfur, and shell biofilter (CSSB) system. The passive CSSB system was found to be the preferred system due to its lower present worth of cost, lower carbon footprint and eutrophication potential, and better performance for various social factors (e.g., maintenance time, degree of automation, system intrusiveness). The passive STEB system was the second preferred alternative, despite having a worse social performance and the highest present worth of cost. The systems were then assessed using even, social, environmental, and economic weighting preferences and a sensitivity analysis was conducted. In spite of shifts in weighting preference and changes to input data parameters to assess sensitivity, the passive CSSB system was found to be the preferred alternative. This paper highlights the importance of using triple bottom line sustainability metrics to assess small wastewater treatment alternatives using a novel decision support tool. [ABSTRACT FROM AUTHOR]

A rectangular rapid flashing beacon (RRFB) is a pedestrian crosswalk countermeasure system that cautions drivers by providing them with real-time warning about the presence of pedestrians in an upcoming crosswalk. This paper investigated the safety effectiveness of existing RRFBs installed in the state of Florida between 2013 and 2018. Additionally, traffic volume, roadway characteristics, and land-use mix were included as explanatory variables. The study evaluated 154 treated sites with RRFB installations and 158 control sites with similar characteristics. Safety performance functions (SPF) were developed, and crash modification factors (CMF) were calculated using the empirical Bayes (EB) methodology for various crash types. A CMF of 0.31 for total pedestrian crashes was estimated, showing that RRFBs have the potential to reduce 69% of total pedestrian-involved crashes. CMF for total vehicular crashes and rear-end crashes were also investigated to ascertain whether RRFBs have adverse effects on rear-end crashes. CMF for total vehicular crashes was found to be 1.14, showing that RRFBs do not have positive effect in reducing total vehicular crashes. Similarly, it was observed that CMF for the rear-end crashes was 1.11, indicating RRFBs might have adverse effect on rear-end crashes because vehicles needs to slow down or stop due to the presence of pedestrians. CMFunctions for significant variables for pedestrian, rear-end, and total crash models were also estimated in this study. An economic analysis indicated that the implementation of RRFBs will yield a benefit to cost ratio (calculated over 3 years) of approximately 85.5 with a 4% discount rate. [ABSTRACT FROM AUTHOR]

Even with the continuous development of coating technologies, coating systems are susceptible to corrosion-induced premature failures and unable to meet the anticipated service life. Coating premature failures will negatively impact the safety, integrity, and longevity of steel bridge structural elements. The advancement of the data analytics approach (e.g., machine learning) offers an opportunity to leverage the wealth of historical bridge inspection and maintenance data collected by Departments of Transportation to evaluate coating conditions of steel bridges effectively and efficiently. This paper focuses on presenting a data-driven study that analyzes the conditions of coating systems of steel bridges in the state of Florida. Three machine learning algorithms were used in developing models that can be used to analyze steel bridge coating conditions based on data collected from the Bridge Management System of the Florida Department of Transportation. The result showed that the machine learning–based models were able to effectively predict steel bridge coating conditions. The k -nearest neighbor (KNN) regression algorithm offered the best performance. Although the approach was currently applied to the steel bridges of Florida, it can be easily replicable for similar data sets from other states. The research contributes to the body of knowledge by offering a data-driven understanding of coating performance of steel bridge elements. The research has the potential to offer a valuable decision-making tool for transportation agencies to effectively and easily analyze or predict steel bridge coating conditions. [ABSTRACT FROM AUTHOR]

Rock coring is an essential method of geotechnical site characterization for foundations supported by rock, in which three possible phases of operation exist: inefficient, optimized, and destructive. When operating within the optimized phase, core recoveries and the rock quality designation reflect the strata encountered. However, the optimized phase is rarely achieved in practice, leading to deficiencies in strength assessment and geotechnical site characterization. This paper identifies the operational limits that separate each phase of rock coring by using measuring while drilling (MWD) and quantifies the increased energy that results from an inadequate depth of cut (Phase 1), the effects of breaking rock particles into smaller sizes, and the damage that occurs to core specimens from increased frictional resistance (Phase 3), as well as the effect rock strength and bit geometry have on mechanical efficiency. Drilling parameter interdependencies are discussed and detailed guidelines to assess rock strength in situ via MWD are provided. Finally, recommended coring guidelines are established through MWD which optimize the quantity and quality of strength assessments collected to improve geotechnical site characterization. [ABSTRACT FROM AUTHOR]

Although there is extensive work related to design and implementation of model-driven optimal groundwater management, evaluation of the performance of those models is less reported. This hinders transferability of lessons learned and wide adoption of specific policies. This paper reports a study designed to evaluate the effectiveness of a real-time optimal groundwater management tool, optimized regional operations plan (OROP), used in the Tampa Bay region (located on the west coast of Florida in the United States) since 1998. The overarching question in this study is how different groundwater levels would have been at monitoring sites if such an operational decision-supporting tool was not implemented. The proposed framework is comprised of multiple steps, including generating a non-OROP groundwater pumping scenario that would have happened without the decision support tool in place, running a modified optimization model in retrospective mode, and comparing water level between OROP-based and non-OROP–based pumpage scenarios. The framework is applied to historical data in the past decade (2010–2019). In generating an alternative pumpage scenario, realistic model constraints (e.g., pump capacity, pipeline hydraulics, and network) were used to generate wellfield pumpage to meet demands. Wellfield pumpage is then disaggregated at individual wells. Differences in resulting water levels at monitoring wells, at multiple timescales, between the OROP and non-OROP pumpage scenarios were calculated. Results reveal that although at a weekly timescale the effectiveness of OROP seems minimal over the region, the cumulative effectiveness at the monthly and annual timescales is remarkable. It is also found that benefit of using OROP is even higher during dry seasons when groundwater levels are more critical in maintaining wetland health. The proposed framework presented in this study can be applied to other areas in evaluating groundwater management strategies. [ABSTRACT FROM AUTHOR]