In a 2001 study, Paul M. Goodrum examined the impact of equipment technology on productivity in the U.S construction industry between 1976 and 1998. This research and its results have been included in a larger discussion about productivity trends in the U.S, since then. The objective of this research is to extend the Goodrum study to the period between 1995 and 2009, so that further insight into long term trends and effects can be obtained. The study begins with a brief review of the research that has been completed in the last ten years with respect to the analysis of construction productivity trends in the U.S., Canada, and other developed countries. Then the study examines the characteristics common to all construction projects and factors affecting construction productivity, because an accurate understanding of the correlation between these factors will lead to improved productivity. A statistical significance test (t-test) is used as a method of measuring the validity of the observed changes in productivity between 1995 and 2009. The main finding of this research is that there is a slight improvement in partial factor productivity in the United States between 1995 and 2009 as measured using the Means estimating manuals while the labor productivity remains almost the same between 1995 and 2009. Through statistical significant test (t-test), it is found that the construction partial factor productivity have changed significantly between 1995 and 2009.Finally, samples of construction typical projects were taking as an example to show how the mentioned productivity improvements will affect the construction industry in the United States. The result of this study can be used as a guideline for planners, decision makers, owners, engineers, and contractors to develop insight with respect to the challenge of improving productivity in the North American construction industry. The implementation of the findings of this study will also be helpful for any specific project, because the duration of the project can be decreased and the productivity of the construction increased. The research provides some recommendations which may assist others who are interested in working in this area.

Corrosion is the number one deterioration mechanism that decreases the service life of the concrete structures. Many structures in severe environments have experienced an unacceptable loss in serviceability earlier than anticipated due to corrosion. Advanced composite materials in the form of externally bonded fiber reinforcing polymer (FRP) sheets have been successfully used for rehabilitation and strengthening of infrastructure in lieu of traditional repair techniques such as steel plates bonding. FRPs are used because of their light weight, ease of application, non-corrosiveness material, and high strength. The current study comprised of testing eighteen reinforced concrete beams to investigate the confinement provided by carbon fiber-reinforced polymer (CFRP) sheets on the bond strength of corroded tension lap splices under static loading. The beams were 200mm wide by 300mm high by 2000mm. Each beam was reinforced on the tension side with two steel bars (2 M 15 or 2 M20 steel bars) spliced at mid span in the constant moment region. The nominal concrete strength was 43 MPa and the yield stress of the steel reinforcement was 400MPa. The test variables were the concrete cover to bar diameter ratio (c/d) which varied from 1.5 to 2.67, the level of corrosion (0% and 2.5% mass loss), and the presence or absence of transverse CFRP wrapping. The corrosion in the steel bars was induced by means of accelerated technique withan impressed current density of 150mA/cm2. The specimens were instrumented by strain gauges on the steel reinforcement, concrete, and CFRP sheets. Linear variable differential transformer (LVDT) was used to measure mid span deflection. The specimens were tested to failure in four point bending. The test results showed that all beams failed by bond splitting. The reduction in the ultimate bond strength due to a 2.5% corrosion level ranged between 16% and 25% depending on the c/d ratio. The reduction in the ultimate bond strength due to a 5.0% corrosion level ranged between 20% and 45% depending on the c/d ratio. FRP wraps were effective in confining the tension splice region. The failure in the FRP repaired beams was more ductile and more gradual although the final mode of failure was splitting of the concrete cover. A new, (Ktr,f,) accounting for the presence and amount of FRP confining tension lap-splice was proposed.

Capital renewal is an essential decision in sustaining the serviceability of infrastructure. Effectively allocating limited renewal funds amongst numerous asset components represents a large-scale combinatorial optimization problem that is difficult to solve. While various mathematical optimization techniques have been presented in the published literature, they are not very effective in handling the complexities and huge calculations related to large scale problems. More recently new evolutionary-based techniques, such as genetic algorithms (GA) have been introduced for finding near-optimum solutions to large-scale problems. Experimenting with this technique for asset renewal problems has revealed that GAs performance rapidly degrades with problem size. For instance, a previous research by Hegazy and Elhakeem (2010), could improve fund allocation for only a portion of total existing components (maximum of 8000 asset components) with degradation in optimization performance by increasing number of components. To address larger scale problems, this research investigates both evolutionary and advanced mathematical optimization techniques and seeks a goal of handling models consist of at least 50,000 asset components. To enhance the performance of GAs for large-scale optimization problems, three aspects were considered: (1) examining different problem formulations such as integer, on-shot-binary, and step-wise binary formulation; (2) experimenting with commercial GA-based tools; and (3) introducing an innovative segmentation method to handle groups of smaller size problems, and then integrating the results. To identify the best segmentation method, similarity-based segmentation is compared to random segmentation and was found to have superior performance. Based on the results of numerous experiments with different problem sizes and comparison with previous results obtained by Hegazy and Elhakeem (2010) from the same prototype used in this study, the GAs + Segmentation approach is found to handle a problem size of 50,000 components, with better solution quality (improved optimum solution), and no noticeable degradation of optimization performance by increasing the problems size. In addition to evolutionary algorithms, performance of one of the advanced mathematical programming tools (GAMS), and its powerful optimization engine (CPLEX), are investigated. For the mathematical representation of the asset renewal problem, best formulation is selected with regard to the definitions of easy-to-solve integer programming (IP) formulations. To reduce internal calculations, the GAMS mathematical model is coded to interact with original spreadsheet data by using GAMS data exchange (GDX) files. Based on experimentations, using advanced mathematical tools with strong (easy-to-solve) IP formulations, improved the solution quality even further in compare to GA + Segmentation. In conclusion, this research investigated both evolutionary and advanced mathematical optimization techniques in handling very large-scale asset renewal problems, and introduced effective models for solving such problems. The developed models represent a major innovative step towards achieving large cost savings, optimizing decisions, and justifying fund allocation decisions for infrastructure asset management. While the focus of this research is on educational buildings, the developed optimization models can be adapted to various large-scale asset management problems.

The temperature of 0°C, the phase change point of water-ice, is among the most influential factors on the hydrology of the temperate regions that experience winter. Many cryospheric processes, such as snow and ice melt, avalanches, freshwater ice breakup, and ice jam floods, are triggered by the arrival of the above-0°C air temperatures. Moreover, such 0°C based changes can have significant cascading impacts on other parts of the physical environment as well as related socio-economic activities. This research adopts an extensive analytical approach to examine the changes in the sign of mean JFM (January-February-March) and MAM (March-April-May) air temperatures, in the 0.5° × 0.5° land grid cells of the Northern Hemisphere (20.25°N-89.75°N), during the period 1901-2009. The goal is to identify grid cells in which JFM or MAM temperatures used to be primarily below freezing, however, changed sign permanently some time during 1901-2009 due to an advancement in the arrival timing of the annual above-0°C temperature. Considering that air temperature fluctuates and can cross 0°C several times during the entire period of study, four different modelling techniques are employed to detect the shift points in the trend function as well as mean level of the time series and to determine the year when the model rises above 0°C (y₀) in a given location. Model-specific criteria are set to determine y₀ in cases of multiple positive 0°C crossings. The techniques applied include i) trend shift detection techniques: Model 2 and Model 3 (Perron and Yabu, 2009b; Kim and Perron, 2009), ii) Multivariate Adaptive Regression Splines (Friedman, 1991), and iii) the R method (Rodionov, 2004,2006). This thesis provides a thorough discussion of these techniques and reviews their strengths and weaknesses relative to the research goals. In addition to y₀, the time of the onset of warming that causes a time series to permanently rise above 0°C (y_w) is identified. The applied methods divide the entire domain of the time series into sub-regions in which the data are approximated by polynomials of degree zero or one. The segment which encompasses y₀ is termed the 'segment of interest' (S_interest). The combination of S_interest and the segment(s) with positive slope that immediately follows S_interest forms a section referred to as the 'section of total warming' (S_W_total ). The non-parametric Mann-Kendall test, following the modified trend-free pre-whitening approach (Burn et al., 2004), is conducted to examine if the warming during S_interest, which causes the temperature to turn positive, is significant. The same test is applied to S_W_total to determine if the total warming subsequent to y_w is significant. Only the locations with significant warming during S_interest and S_W_total are selected. A bootstrap analysis (Cunderlik and Burn, 2002), conducted to determine the field significance of the results, indicates that local trends are also globally significant. 
A thorough comparative evaluation of all the above-mentioned techniques determines that Model 2 is the technique that best meets the analysis goals. Analytical results indicate that during JFM, y₀ most commonly takes place in the following zones (referred to as 'transition area'). It should be noted that only the grid cells with significant warming during S_interest and S_W_total are considered: i) North America, western U.S; ii) Europe, highest density in central Europe; iii) southwestern and central Asia, a small region consisting of some parts of Uzbekistan, Kazakhstan, and Iran; iv) central-eastern Asia, a small area in western China most of which lies in the Taklamakan Desert; v) easternmost Asia, some grid cells from east-central China, South Korea, and Japan. During MAM, over North America, the transition area of Model 2 is principally located in Canada and extends from northeastern British Columbia to the Atlantic regions. In Eurasia, northern Europe, European Russia, southern Russia, northern Mongolia, and northeastern China form the great portion of the transition area. It should be noted that except for a few high-elevation regions located in lower latitudes, the grid cells with y₀ taking place during MAM are located north of those with y₀ occurring during JFM. Results also indicate that y₀ of the majority of locations occurs during the 1960-2008 interval. During MAM, the transition area of Model 2 in east-central Canada and Eurasia exhibits a clear pattern of increase in y₀ values with latitude. This characteristic is also observed in some regions during JFM. The y_w values are most commonly distributed over the period 1901-1980 with a peak during 1960-1980. The rate of warming over S_interest and S_W_total generated by Model 2 is 0.01-0.1(°C/year). The spatial and temporal variability in the results is believed to be related to variations in climate, elevation effects, and/or large-scale atmosphere and ocean circulations, all of which require further evaluation for proper attribution of effects.

This study proposes a seismic design optimization method for steel building frameworks following the capacity design principle. Currently, when a structural design employs an elastic analysis to evaluate structural demands, the analysis results can be used only for the design of fuse members, and the inelastic demands on non-fuse members have to be obtained by hand calculations. Also, the elastic-analysis-based design method is unable to warrant a fully valid seismic design since the evaluation tool cannot always capture the true inelastic behaviour of a structure. The proposed method is to overcome these shortcomings by adopting the most sophisticated nonlinear dynamic procedure, i.e., Nonlinear Time- (or Response-) History Analysis as the evaluation tool for seismic demands. The proposed optimal design formulation includes three objectives: the minimum weight or cost of the seismic force resisting system, the minimum seismic input energy or potential earthquake damage and the maximum hysteretic energy ratio of fuse members. The explicit design constraints include the plastic rotation limits on individual frame members and the inter-story drift limits on the overall performance of the structure. Strength designs of each member are treated as implicit constraints through considering both geometric and material nonlinearities of the structure in the nonlinear dynamic analysis procedure. A multi-objective Genetic Algorithm is employed to search for the Pareto-optimal solutions. The study provides design examples for moment resisting frames and eccentrically braced frames. In the examples some numerical strategies, such as integrating load and resistance factors in analysis, grouping design variables of a link and the beams outside the link, rounding-off the objective function values, are introduced. The design examples confirm that the proposed optimization formulation is able to conduct automated capacity design of steel frames. In particular, the third objective, to maximize the hysteretic energy ratio of fuse members, drives the optimization algorithm to search for design solutions with favorable plastic mechanisms, which is the essence of the capacity design principle. For the proposed inelastic-analysis-based design method, the seismic performance factors (i.e., ductility- and overstrength-related force reduction factors) are no longer needed. Furthermore, problem-dependent capacity design requirements, such as strong-column-weak-beam for moment resisting frames, are not included in the design formulation. Thus, the proposed design method is general and applicable to various types of building frames.

The history of engineering knowledge with regards to bamboo is surprisingly recent, with the major work on bamboo having been completed by Janssen (1981) and Acre (1993) of the University of Eindhoven, The Netherlands. In their research, both noted that splitting is the dominant limit state in structural applications, which agrees with the authors experience (during our May 2008 visit to India) and that of other researchers. It is because of this dominant limit state that this research focused on the development of an appropriate method of characterizing the splitting strength of bamboo culms. This document focuses on developing and calibrating an appropriate (but simple to conduct) test method for assessing the splitting capacity of full culms. The proposed split-pin fracture test is founded on a fundamental fracture mechanics approach. This method, while simple to conduct, can account, in a consistent manner, for the high degree of variability present in bamboo geometric and material properties. In order to demonstrate the validity of the proposed test method, a series of tests were performed on a sample of Bambusa Stenostachya (Tre Gai) bamboo. In addition to the proposed fracture test, shear and compression tests were performed in accordance with existing ISO standards (ISO 2004b). Of the three test types performed, the compression test had the lowest variability, the shear test had the highest, and the proposed fracture tests had a variability that fell between the two. Thus the fracture test demonstrated that it yields reliable results. Utilizing the values obtained from both this series of tests as well as those carried out by other institutions, a comparison of common design values was made between Tre Gai and the select-structural grade of two commonly encountered woods, Douglas Fir and Southern Pine. While the design values for bamboo obtained from different institutions varied considerably, Tre Gai generally exhibited performance superior to that of the two timber species referenced. It can be concluded that Tre Gai, when grown, harvested, and preserved correctly, is a competitive, or in some cases, a superior alternative to wood.

Computer simulation has become a very useful and flexible tool in the planning process of passenger facilities. By this means the probability of queues, congestion and delays can be determined, and different design concepts and operational disciplines can be considered experimentally. Within this thesis two different check-in disciplines, restricted flight system, and common system are compared. The stochastic simulation models developed to evaluate the performance of the alternative check-in systems examined the impact of 1) changes in the number of passengers boarding per flight, 2) reduction in the number of counters, and 3) different time value to the passengers. Input to the model including 1) service times, 2) passengers rate of arrivals, 3) characteristics of the passenger groups, etc. allowed for testing both alternatives. Output from the model included 1) queuing times, 2) number of persons in queue, 3) density of crowds, and 4) counter utilization. After calibrating the model with data gathered at Knoxville's airport, it was found that the common system has better performance than the restricted system. Also it was determined that the restricted system became inefficient for a large number of persons checking in per flight. Finally, by assigning monetary value to the passenger time, it was possible to select the number of counters which represented the minimum cost to the airlines, the airport operator, and the passengers.

Speed limits for large trucks have been reduced at many locales for air quality and safety reasons. To realize an improvement in air quality and safety, however, diligent enforcement and fitting punishment have to be implemented. This may put a strain on already tight resources and manpower for state and local agencies. To this end, this paper presents a license plate recognition (LPR) technology based heavy vehicle speed enforcement system that requires relatively minimal initial investment and no increase in enforcement personnel, cruisers, or pursue/pull-over activities. The efficiency of the system is achieved by catching speeding trucks in the act and then enforcing the law at weigh stations, which all trucks, with few exceptions, are required to enter.The configuration of the system for the Knoxville, TN study site is presented. Strategic placement of LPR units on I-40 and I-75 enables the speed tracking and enforcement process. Identified trucks are checked against the CVEIW national database for additional inspection, enforcement, and citation activities.

The behavior of a novel pile framed retaining wall developed by the Tennessee Department of Transportation (TDOT) is investigated using a 2D non-linear finite element (FE) analysis for. The wall design eliminates the need for a construction right of way behind the wall; thus it is ideal for urban areas. The design concept consists of vertical and battered H pile sections as the structural frame, and a concrete facing that is installed as the soil is excavated during top-down construction. Vertical tie-down anchors and a concrete cap and facing are used to counteract overturning moments. A 2-D FE analysis of the wall system was conducted to understand how the earth pressures are applied to the sloped wall, and how the loads are distributed throughout the piling frame. An increased understanding of the performance of this new system will lead to more economic pile sections and spacing under service loads. In addition, the construction sequence was modeled to investigate the non-linear response of the wall system. Parametric studies were conducted to investigate wall performance for different soil conditions, boundary conditions, wall heights, and tie-down forces. The results show that active earth pressures are adequate for design and that TDOT’s original design was conservative.

Increased globalization has caused large increases in truck traffic on the nation’s interstate system, with much additional growth expected in the coming years. This growth has elevated interest in developing new strategies to address rising levels of truck traffic, especially in dense and congested urban areas. This thesis focuses on the evaluation of several alternative lane management configurations as they compare to the current lane configuration in search of the best fit for operational improvement. This task was performed in two ways – survey and simulation. A survey of 500 long-haul truck drivers was administered in Knoxville, Tennessee, at the crossroads of major north-south and east-west interstate highways. The dataset was evenly divided between owner-operators and truck-company employed drivers. The survey suggested the alternative truck lane management configurations and most of the respondents supported moving truck lanes to the inside travel lanes to avoid merging and lane changing cars, either through traditional truck lanes restrictions or truck only lanes. The alternative lane configurations and the current lane configuration were simulated in VISSIM. Parameters such as speed, travel time, delay, and lane change were used for evaluating the configurations during simulation. A statistical test was applied to the results of the simulations. Each configuration yielded significantly different results in most cases and a few insignificant changes in other cases. One of the configurations – the optional truck only lane configuration, stood out as the best fit for operational improvements by offering high speeds, shorter travel times, smaller delay times and greater delay cost savings, and increased highway safety. Such configuration could potentially address the challenges faced by increasing truck traffic in congested urban areas.