<p> As population and traffic increase, improvements in the paving industry including roadways, parking lots, and sidewalks are desired. Pavements have a key effect on the quantity and quality of rainwater runoff and reserved ground water. More so, regulations towards constructing and paving these new areas are becoming stricter especially in urban areas where available land is becoming limited. Permeable pavements are more common than ever, and are a solution to rainwater runoff, recharging ground water, and reducing the costs associated with treating storm water. </p><p> Permeable pavements are available alternative to conventional pavements and are becoming more applicable and more widespread. Unlike conventional pavements, permeable pavements have major obstacles to acceptance and use since there is limited research on these types of pavements, with only a handful of guidelines and properties for users to follow. </p><p> This research incorporates two technical concepts on two topic areas. The first topic can be used to assist decision makers, planners, and owners in selecting their pavement type for their intended use by analyzing and comparing the life-cycle cost for four pavement types. Two of these are conventional impermeable pavements: Hot-Mix Asphalt and Portland Cement Concrete and two are permeable pavements: Porous Asphalt and Pervious Concrete. This first topic area will also summarize tables of advantages and limitations for each pavement type. The second topic area of this paper will help initiate guidelines on how to design, mix, batch, place, cure, and test pervious concrete.</p>

<p> Recent earthquakes devastated lives and destroyed a great stock of buildings. As a result, the earthquake-impacted regions incurred huge business and operation interruption losses. To minimize the business interruption losses through Performance-Based Seismic Design, there is an obvious need for a validated downtime model that would cover a large spectrum of building sizes and types. Building downtime consists of securing finances, mobilizing contractors, engineers and supplies, and the time to perform the actual repair, i.e., repair time. This study focuses on developing a model to characterize the repair time contribution to the downtime as an extension to FEMA P-58 Loss Assessment Methodology. The proposed repair time model utilizes the Critical Path Method for repair scheduling and realistic labor allocations that are based on the amount and severity of building damage. The model is validated on a significant sample of data collected through case studies from previous earthquakes, interviews with contractors, engineers, and inspectors. The proposed model also has a capability of scheduling resources to meet resource limitations that can either come from labor congestions or from a surge in demands following a disaster. The proposed resource scheduling method provides an efficient way of reducing the number of workers during labor congestions while minimizing its effect on the project duration. The final outcome is a realistic estimation of repair time associated with an earthquake.</p>

This dissertation presents the formulation and implementation of the variational multiscale enrichment computational framework for scale inseparable multiscale modeling of structures subjected to extreme environments. In the presence of structures with elasto-viscoplastically behaved heterogeneous materials, the framework includes the variational multiscale enrichment (VME) method, the reduced order variational multiscale enrichment (ROVME) method for mechanical and thermo-mechanical problems, and the hybrid integration for reduced order variational multiscale enrichment (HROVME) method. First, the variational multiscale enrichment method for elasto-viscoplastic problems is developed for the scale inseparable multiscale modeling. VME is a global-local approach that allows accurate fine scale representation at small subdomains whereas the response within far-fields is idealized using a coarse scale representation. The scale inseparable character is represented by the relatively insignificant scale size difference and strong coupling effect between the scales. A one-parameter family of mixed boundary conditions that range from Dirichlet to Neumann is employed to study the effect of the choice of boundary conditions at the fine scale on accuracy. Second, the reduced order variational multiscale enrichment method for elasto-viscoplastic problems is developed to improve the computational efficiency of the VME method. By eliminating the requirement of direct fine scale discretization and repetitive evaluation of the microscale equilibrium state, the computational effort associated with the VME method is significantly reduced. Third, the reduced order variational multiscale enrichment method for coupled thermo-mechanical problems is presented which extends the ROVME method to model structures with temperature sensitive constituent properties. The temperature-dependent coefficient tensors of the reduced order approach are approximated in an efficient manner, retaining the computational efficiency of the reduced order model in the presence of spatial/temporal temperature variations. Last, the hybrid integration for reduced order variational multiscale enrichment method is developed to further improve the computational efficiency of the proposed framework. Considering the coupled transport-thermo-mechanical effects, it employs the key ideas of the ROVME and the computational homogenization approaches to directionally consider scale separation within the structures. The HROVME method also extends the ROVME approach to microstructures with periodic boundary conditions and improves the stability of the ROVME method by avoiding the potential hourglass modes. Numerical verifications are performed to demonstrate the high accuracy, computational efficiency and capability of the proposed computational framework.

Wireless communication through automated and connected vehicles is an evolving technology. This ameliorates the driving conditions, reduces time spent in traffic and curtails the crash occurrences. One of the most challenging areas, where these interactions can be most useful, are freeway merge ramps. Both the drivers on mainline and the drivers merging would be skeptical about their decisions at this location. The drivers who want to merge to the freeway mainline would seek to find an appropriate gap to enter the mainline of the freeway. While the technology of connected and automated vehicles is being promoted, the reality now is that for the foreseeable future, the traffic would not comprise 100% of such connected and automated vehicles. In other words, there will be a mixed traffic of manually-driven and connected/automated vehicles, with various levels of automation in the latter types of vehicles. Capturing the driver behavior at the merge locations into a freeway with such mixed traffic, will be useful in learning and improving safety on the roadways. The Driving Simulator is a useful device in capturing driver behaviors. In this study scenarios are developed in the Driving Simulator which allows mixed traffic on mainline and also observe the driver behaviors from the ramp onto the merge. Overall there were three variations in the mixed traffic flow for the mainline freeway: 0%, 50% and 75% penetration rates. The freeway traffic was generated for the mixed traffic by first developing a mixed probability distribution which assumes exponential distributions for the inter-arrival times of manually-driven vehicles and a constant headway (uniform distribution) is assumed between connected vehicles. The mixed distribution was then used to randomly generate vehicles through Monte Carlo simulation, with assigned headways in the Driving Simulator for the various connected vehicle penetration rates. The subject driver’s speed along the ramp is monitored, as well as the speeds of those vehicles on the freeway. The gaps between freeway vehicles, which were accepted by the subject driver, were recorded for the various situations and scenarios. There were a total of 41 participants, with 29 young drivers (younger than 65 years) and 12 elderly drivers (65 years and older, amongst which 2 were between 55 and 65 years old). Three scenarios were presented to the drivers. The first driving task was to determine headway gap acceptance for the three penetration rates, based on the perception of the subject drivers (without driving). The second test involved the subjects actually driving on the ramp and implementing a suitable gap to merge on the freeway traffic at each ramp. From the data collected, the critical gaps were estimated based on perception. The gaps accepted while driving were also tabulated analyzed. It was observed that the critical gap for the young drivers in 0%, 50%, 75% penetrations rate are 2.9 sec, 1.8 sec, and 1.7 sec respectively. The critical gaps observed for elderly drivers aged over 65 are 3.5 sec, 2.0 sec, and 1.9 sec respectively. Based on an Analysis of Variance (ANOVA), there is no evidence to prove the equality of means for different groups classified by age, gender and driving experience in both perception and actual driving conditions for 0% and 50% penetration rates. It was observed that the headway gaps accepted by young and drivers, both by perception and driving in 0% penetration rate were 2.39 sec and 2.35 sec respectively. The headway gaps accepted by elderly drivers both by perception and driving in 0% penetration rate were 2.4 sec and 2.72 sec respectively. When the ANOVA was performed between the 0% and 50% penetration rates of driving conditions, it was observed that there is a lot of variation in the mean headway gaps accepted. The values of average headway gaps accepted for young drivers were estimated as 2.36 sec and 1.53 sec respectively, in the 0% and 50% penetration rates. For the elderly drivers the average headway gap values observed were 2.72 sec and 1.55 sec respectively, in the 0% and 50% penetration rates traffic. The results also indicated the subject driver acceleration and deceleration behavior at the merge ramp. The results also showed that when the (aggressive) drivers accelerated to match the velocity of mainline traffic and merged in between connected-automated vehicles with the shortest gap, effects were noticed on the mainline traffic, where the main line traffic had to decelerate rapidly. Overall, it was observed that the subject drivers accepted shorter headway gaps as the penetration rates increases. / A Thesis submitted to the Department of Civil Engineering in partial fulfillment of the Master of Science. / Summer Semester 2017. / July 18, 2017. / Includes bibliographical references. / John O. Sobanjo, Professor Directing Thesis; Eren Erman Ozguven, Committee Member; Lisa Spainhour, Committee Member.

Taller wind turbines with big wheel area have been proposed for low wind speed sites, where conventional 80m tower cannot produce enough electricity. Hub height of 140m gives the potential to all 50 states to produce power from wind. However, it is not clear which tower (steel, concrete or hybrid) is economically attractive beyond 80m, or which design parameter is most critical in enabling tall yet economic tower. The aim of this paper is to come up with optimum designs for steel, concrete and hybrid towers while minimizing wind turbine cost and maximizing power production and then study the influence of changing one design variable on optimum designs. Also, it was of interest to study the effect of defining rotor dimeter of turbine as an independent design variable or as function of height. Multiple optimal solutions were obtained, which are called Pareto-optimal solutions. The design variables were chosen to be diameter, thickness, height of tower and blade radius. Design constraints were buckling, yielding, shear stresses for steel tower and ultimate and service limit states for the concrete tower. Those constraints have been used to control the stability of the tower. Different linear constraints have been applied for each tower, e.g. radius of the rotor should be less than the height of the tower. The design problem is conceptual design so detailed design is beyond scope of this research, such as the flange for the steel tower, connection between the concrete parts, and connection between the steel and concrete for the hybrid tower. Nonetheless, the cost of these parts was added to the design problem. Due to the highly constrained, non-convex and non-linear nature of the design problem, Genetic algorithm has been chosen as a solver for the problem. The towers were analyzed for operational and nonoperational aerodynamic conditions according to IEC 61400-1. A comparison of steel, concrete and hybrid towers was analyzed for heights ranging (80m-150m). Results showed that up to 95m, the cost difference was negligible between all towers options. Beyond 95m hybrid towers were dominating the solutions. For 150m hub height, concrete tower saved 12% when it is compared to its steel counterpart. Concrete base diameter decreases to less than 10m, industry preferred, when average concrete wall thickness was equal or greater than 0.4m or compressive strength of concrete increases. Increasing compressive strength of concrete by 10% also resulted in cost reduction of 2.18% for 150m hub height. Results showed that defining rotor diameter as a design variable was better than defining it as a function of height because the optimization problem had fewer constraints. / A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the Master of Science. / Summer Semester 2017. / June 19, 2017. / Genetic algorithm, Optimization, power, wind turbine tower / Includes bibliographical references. / Sungmoon Jung, Professor Directing Thesis; Michelle Rambo-Roddenberry, Committee Member; Lisa Spainhour, Committee Member.

As the strategy of green building becomes more and more popular due to a combination of environmental and economic concerns, there develops a need for clearly being able to understand the potential implications for choosing green strategies over conventional building practices. Some of the regions of interest consist of the additional upfront costs associated with green practices, potential life-cycle benefits associated with green building components, potential energy savings, and the ability to reduce emissions. Many of these areas can potentially be forecasted with a fair degree of certainty (e.g. energy consumption, additional upfront costs); however, some elements of green building are less well defined. One such area consists of the ability of green buildings to improve the productivity and well-being of its inhabitants through an improved indoor environmental quality (IEQ). It is difficult to grasp just how much a healthier and cleaner environmental can impact a person’s cognitive functions, mental state, and physical health. Several studies shown in the literature review of this paper lead show a positive correlation between green buildings and reductions in asthma symptoms, depression symptoms, improved well-being due to reductions in contaminants, a reduction in sick building syndrome (SBS) and building related illness (BRI). This paper aims to do what many have done before in attempting to quantify the potential impact that sustainable buildings can have on its occupants; however, the scope and methods to determine these potential correlations will differ. Perhaps the most noticeable difference will be in the paper’s focus on attempting to measure the potential impact that LEED (Leadership in Energy and Environmental Design) accredited schools have on their student occupants by measuring their productivity via the use of standardized test scores and attendance rates compared to those students in conventional (non-LEED) schools. To develop a balanced analysis, the paper will control for various school-related and socio-economic factors (e.g. economic status, race, percent of teachers with a Master’s degree or higher). To make a judgement on the effect that sustainability has on academic achievement and student wellbeing, 2 sample t-tests, regression analysis, and M5P decision trees will be implemented to determine if there are significant differences between LEED and conventional schools and to determine the relationship between LEED and non-LEED parameters on student achievement and wellbeing metrics. To ensure that a large population of students from across the nation are accounted for, the study intends on investigating at least three states-worth of student data. These states (Florida, New York and Virginia) are in different climates, thus allowing for an examination of the potential differences between the various climate zones and building codes. Lastly, a case study building information model (BIM) of College Park Elementary School (located in Virginia) will be run through the energy modeling (EM) software, Ecotect, to provide information related to the school’s annual energy consumption, acoustics, and daylight and lighting values. An optimization equation, developed using previous literature and findings from this study, will use information from the case study in an attempt to optimize its academic performance. The equation will attempt to minimize construction and operational costs while maximizing student performance metrics. The optimization equation will be run through NEOS server’s Nonlinearly Constrained Optimization, Knitro. The purpose of this study is to inform those decision-makers involved in the construction of schools, and who may be interested in obtaining LEED certification for the school, to what extent the LEED schools benefit the school’s student academic achievement levels. Accounting for soft benefits (e.g. productivity, morale, general wellbeing) in a cost-benefit analysis invites an element of risk due to the difficulties in soliciting, obtaining, and accurately measuring these performance metrics. When considering fields involving knowledge work, accurately measuring productivity is an inexact science that normally requires building occupants to perform self-examinations. The results from these examinations are reliant on the occupant’s perceptions and could be open to bias. This study avoids self-assessments through its use of standardized testing as a measure for productivity. The proposed outcome of this paper is that the impacts of LEED schools on their occupants’ academic achievement, health, and wellbeing will be better understood and easier to quantify. The authors hypothesize that LEED schools will outperform conventional schools, which can be attributed to improved IEQ due to tighter building envelopes, increased ventilation rates, better filtration, a reduction in building or cleaning products containing volatile organic compounds, etc. An absence of this data could point to the inability of LEED schools to directly impact their students in a meaningful way, particularly its Indoor Environmental Quality credits, which means that LEED could have to rethink its standards if it wishes to truly improve the productivity and wellbeing of its occupants. / A Dissertation submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Summer Semester 2018. / May 29, 2018. / Indoor Environmental Quality, LEED, Machine Learning, Optimization, Sustainable Design / Includes bibliographical references. / Walter Boot, University Representative; John O. Sobanjo, Committee Member; Lisa Spainhour, Committee Member.

This project evaluates using traffic simulation, the performance of a mixed traffic composition of Connected and Autonomous Vehicles (CAV) and conventional or human-driven vehicles, in comparison with the performance of the existing traffic composition of only conventional vehicles on a freeway segment. The introduction of CAVs into the existing transportation system is a phase in the evolution of automobile traffic currently generating a lot of concerns and questions that needs to be answered before the full deployment of these vehicles. Traffic simulation presents a safer and cost-effective approach to evaluating this innovative technology when compared with real world testing. Connected and autonomous vehicles (CAV) are designed to improve traffic operations, as the difference in their driving behavior from regular vehicles suggests a reasonable tendency to change the traffic flow pattern. However the issue being examined in this project is whether there would be a significant change in traffic operations resulting from their deployment, and also to verify whether the change is an improvement of the existing traffic condition in terms of performance measures used for the evaluation. Data was collected from the I-95 Freeway in South Florida, and used in the development of a traffic microsimulation model, in VISSIM. The model was calibrated using minimum error algorithm implemented in MATLAB to determine the optimal value of the two model parameters considered -- stand still distance (CC0), and headway time (CC1). The calibrated model was used as the base model and CAVs are incorporated into the base model in 10% increment, to examine their effect on the base model. The performance measures are average hourly speed, hourly traffic volume, travel time, delay, and safety. Findings show that for every increment in CAV market penetration, there is a change of 6.52% - 48% in the capacity of the freeway, 40% reduction in travel time, more than 30% reduction in delay per vehicle, more than 26% increase in average speed of the traffic at high demand volumes. / A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2018. / July 9, 2018. / Connected technology, Freeway, VISSIM / Includes bibliographical references. / John O. Sobanjo, Professor Directing Thesis; Eren Erman Ozguven, Committee Member; Maxim Dulebenets, Committee Member.

As it stands, many of Florida’s roads have already reached their designed service life and are now in the process of being renewed. The current method in rehabilitation of concrete pavement requires the expired piece of pavement to be cut and removed, place new dowel bars, and then epoxied into the surrounding slabs. Once the slab area has been prepared, fresh concrete is poured, and finished. The concrete is then cured and monitored to achieve a strength requirement of 2,200 psi in the shortest possible time before the lanes can be opened for traffic. This event has been known to take a long time and on major highways lane where lane closure may not exceed 8 hours. This restriction limits the number of slabs that can be replaced. The types of concrete used on these projects are also problematic. In the past, high amounts of cementitious material was used and this can lead to premature cracking. To improve production levels, accelerate construction time at a reduced cost, and provide long lasting pavement, the current research study presents an alternative method of using precast slab panels and self-consolidating concrete. This was accomplished by testing several SCC mixes in the laboratory to achieve concrete with high workability without, high early strength and without segregation. Then, precast panels were designed and built for quick installation and removal. This study also necessitated full scaled field tests where precast slab panels with the proper SCC mix were used. The slabs were tested by a loaded truck moving over it repeatedly and the slab was monitored for any movement and displacements caused by driving and braking on it. After the data was collected from the precast panels, the slabs were then removed and fresh SCC was then poured into the empty pit. The SSC slab was left to cure and the maturity of the concrete was monitored to achieve the required strength for lane opining. In this study, three techniques were used to monitor the concrete maturity. These techniques involved the use of the conventional thermocouples, thermal camera, and laser gun. The traffic load was then applied by driving a dump truck loaded to 25000 pounds over the track for 100 laps. The SCC mix behaved as designed and presented in this study. It achieved a high workability and retained a high slump for nearly an hour. It also exceeded the required FDOT strength requirement of 2200 psi for lane opening. The precast panels proved to be highly durable during the installation, testing, removal and can be reused for other similar applications. Results from this study proved proved that using this method has several benefits including greater productivity, reduced maintenance of traffic, shorter project completion time. Further, it may reduce the case of premature cracking due to the increase amount of curing time. / A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Summer Semester 2018. / July 23, 2018. / Includes bibliographical references. / Kamal Tawfiq, Professor Directing Thesis; Michelle Rambo-Roddenberry, Committee Member; Lisa Spainhour, Committee Member; Raphael Kampmann, Committee Member.

The National Design Specification for Wood Construction (NDS) outlines different factors and equations necessary for designing structures exploiting timber. While analyzing a timber shear wall there are several specific equations and restraints that the design must satisfy. These limitations come from not only the NDS, but also the Minimum Design Loads for Buildings and Other Structures (ASCE7), the Florida Building Code (FBC), and the International Residential Code (IRC). ASCE7, paired with the NDS, provide a standard design methodology. The FBC and IRC focus their framework around the minimum requirements. These manuals focus on the design strength of the individual components, rather than how they react once affixed to one another. The sheathing is the foremost structural component which combats against the wind loads. Several different types of sheathing, as well as nail sizes and patterns were analyzed as a connected structure. The methodology used was similar to that of reinforced concrete, in that the properties of the nails and sheathing were transformed into that of the sawn lumber stud. This facilitated an analytical comparison between the standard design method and that of a "composite I-beam". Increases and decreases in strength were found, due to the complexity of the design equations, the addition of the sheathing component did not always enable a higher wall capacity. Deflection as the ultimate failure of the member still rang true for the new method of design. / A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science. / Fall Semester 2018. / November 6, 2018. / Includes bibliographical references. / Michelle Rambo-Roddenberry, Professor Directing Thesis; Sungmoon Jung, Committee Member; Raphael Kampmann, Committee Member; Lisa Spainhour, Committee Member.

The aging population is expected to increase substantially in the future. The fatal crash rates (per mile traveled) involving older drivers (65+) are considerably higher than those of younger drivers. This research involved conducting computational experiments involving dummy models to investigate the biomechanics of older drivers in vehicular crashes. Before conducting these experiments, the concepts of biological changes in older populations needed to be addressed. This allowed us to first find out what makes the older drivers different from younger drivers. It was found that driving posture is one of the two key differences between the two age groups. The Hybrid III computational dummy model was used to investigate the effect of driving posture. The other key finding shows that older drivers are affected by aging factors such as material properties decrease and thickness decrease of bones. The Total Human Model for Safety (THUMS) was used because it can be modified to represent an aged driver to be used in the crash simulations. For the posture investigation, the idea is that driving posture for older drivers tend to be closer to the steering wheel whereas younger drivers are more laid back was incorporated. All computational work was completed in LS-DYNA; a finite element code used for non-linear impact analysis. The Finite Element (FE) simulation was validated by comparing the FE results with physical crash test results. These results were found in the Federal Motor Vehicle Safety Standards and Regulations (FMVSS) Report 208 for Frontal Crash Test. For subsequent simulations, posture changes based on the idea of aging according to literature review were implemented. For the Head Injury Criteria, the extended shoulders of an older driver yielded percent differences as high as 16%. The arms acted like braces to restrain the torso while the head continued forward. The extended knees also yielded a 16% increase in head injury. As for the chest acceleration, the extended hip and torso joints showed increased values. It was concluded that sitting closer was beneficial for the Head Injury Criteria but the opposite was true for the chest acceleration. The posture changes did not affect the pelvis acceleration. This investigation gave us a better understanding of what occurs in automobile accidents specific to older occupants. This knowledge can be useful in designing engineering approaches to mitigate injuries. Using the aged model, the material properties decrease yielded the highest chest deflection of 13.3%. For the bone thickness decrease, the chest acceleration showed the highest increase of 12.5%. The head acceleration and chest deflection showed noticeable increases. Overall with all three aging factors in place, the head and chest accelerations yielded high increases. Whereas for the deflection, it remains the same. The thoracic rotation increased the head resultant acceleration. The rotation decreased the deflection of the thorax because the ribs were more in line with the force imposed by the crash. It can withstand more force when the ribs are more parallel with the force. As for the chest acceleration, no significant change was present. It can be concluded that the older drivers in rear impacts experienced higher (Neck Injury Criterion) NICmax than younger drivers as much as 6.9% percent for the material property decrease and bone thickness decrease. The thorax rotation yielded a 4.7% decrease in NICmax. It is possible that this aging factor caused the thorax to conform more into the seatback thus reducing the injury. The bone thickness decreased affected the NICmax greatly whereas the material property decreased did show signs of minimal positive influence. The material property decreased yielded 0.8% increase while the thickness decreased yielded a 3.0% increase. / A Dissertation submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester 2017. / November 8, 2017. / Includes bibliographical references. / Sungmoon Jung, Professor Directing Dissertation; Changchun Zeng, University Representative; John Sobanjo, Committee Member; Kamal Tawfiq, Committee Member.