Search

A sewer system is a principal element of infrastructure in modern cities, accounting for massive amounts of public investments. Corrosion of manholes in the sewer system is a global issue, and millions of dollars are being spent on the maintenance, restoration, and replacement of deteriorated sewer networks. Concrete manholes in the sewer system are deteriorating due to the attack of sulfuric acid produced by microorganisms in a process termed microbial induced concrete corrosion (MICC), which reduces the lifespan of concrete sewer elements. The objective of this paper is to investigate the correlation between the gas- and liquid-phase sewer environmental factors and hydrogen sulfide concentration in the gas phase. The production, emission, and build-up of hydrogen sulfide gas in manholes is identified as a major cause of MICC in manhole shafts. The field study was conducted in more than 200 manholes in the City of Arlington (Texas, US). The data was collected every minute for 48 h to understand the trends of liquid- and gas-phase parameters such as hydrogen sulfide (H2S concentration), liquid and gas temperature, pH, DO, and relative humidity. The study also examines how gas-phase H2S concentrations vary with season; manhole design, including manholes' depth, slope, and presence of drop; and sewer flow conditions such as velocity and turbulence. Although no strong linear correlation was found between liquid-/gas-phase parameters, the manhole categories were found to play a significant role in H2S generation. The manholes with hydraulic jump generated the highest average H2S concentrations, followed by manholes with drops. High turbulence zones were observed in manholes of both categories, leading to H2S stripping from liquid to gas phase. The highest H2S concentration was recorded in summer, suggesting that higher liquid temperature resulted in increased bacterial activity, which generated greater liquid-phase sulfide. Greater Henry's law constants in summer, due to high temperatures, would have favored transfer of liquid-phase sulfide to the gas phase. [ABSTRACT FROM AUTHOR]

Connected vehicle (CV) data in this paper refer to the in-vehicle telematic data, including trajectories and driving events (e.g., hard braking) collected by vehicle manufacturers when vehicles are moving. Recently manufactured vehicles are equipped with cellular modems and Internet of Things (IoT) devices to collect vehicle data. Such data, after removing personal information, are being redistributed to third-party organizations. Compared to other probe vehicle data, the CV data has a higher penetration rate, ubiquitous coverage, and almost lane-level positioning accuracy. These features pave the road for novel transportation applications in transportation planning and traffic operations. In this paper, we represent a novel framework to estimate the regional link volumes based on the CV data and a deep neural network (DNN) model. The training data are generated according to the link volumes (targeted model output) and the corresponding CV counts (input features) at the same locations. The DNN model's performance was compared with other estimation methods like linear regression and random forest and showed superior performance. The trained DNN model takes ubiquitous CV counts from other locations to estimate the corresponding link volumes. As a case study, the proposed DNN model was trained with a large training data set derived from CV data and time-dependent link counts collected at over 1,200 locations on freeways in the Dallas FortWorth, Texas, area. The results reveal good accuracy and robustness. [ABSTRACT FROM AUTHOR]

In February 2021, Texas was hit by a severe winter storm. The extreme cold weather triggered an unprecedented increase of electricity demand and simultaneous failure of multiple electricity grid components. The dual effect caused a widespread power outage that left millions of Texans without power for days. This paper estimates the indirect economy-wide cascading impact of that power outage. It utilized historical make and use tables between 1997 and 2019 in an inoperability input-output analysis–based economic impact assessment model to quantify the expected indirect cost of the power outage in terms of the loss of gross domestic product of Texas. This research found that expected loss to be approximately $664 million in 2019 values. It also found that in Texas industries such as oil and gas extraction, petroleum, coal products, and so on are particularly vulnerable to such weather-related prolonged power outages. The outcomes of this paper can be used in planning for strategies to make the grid robust, reliable, and resilient to severe weather events. The identification of vulnerable industries can also help in planning for auxiliary capacities so the cascading economic impacts of the weather-related power outages can be reduced. [ABSTRACT FROM AUTHOR]

In this paper, the authors present their efforts in exploring a new type of traffic data, referred to as internet-connected vehicle (ICV) data, for traffic congestion management and operational planning. Most currently manufactured vehicles contain onboard GPS and cellular modules, and they constantly connect to automobile manufacturers' clouds via cellular networks and upload their status. Some automobile manufacturers have recently redistributed the nonpersonal part of such data, such as geolocation, to third-party organizations for innovative applications. Compared with the traditional vehicle GPS data, the ICV data contain high-resolution GPS waypoints accompanied with the vehicles' abnormal moving events (e.g., hard braking). The ICV data also have huge potential in congestion management and operational planning. They explore to identify and analyze traffic congestion on both freeways and arterials using the ICV data. The ICV data adopted for this research are redistributed by Wejo Data Service, representing 10%–15% of all moving vehicles in the Dallas–Fort Worth (DFW) area in Texas. Through one case study for a freeway segment and one for an arterial segment, new traffic performance metrics based on the characteristics of ICV data have been presented. The highlights of these efforts are as follows: (I) queue length and propagation at freeway bottlenecks can be directly measured based on where and when most internet-connected vehicles slow down and join the queue; (II) an internet-connected vehicle's actual delay time on arterials can be directly measured according to its slow movement percentage, without assuming the nondelay travel speed; and (III) the ICV data set are also combined with the high-resolution traffic signal events to generate a ground-truth time-space diagram (TSD) on arterials—a common visualization of arterial signal performance for transportation planning and operations. [ABSTRACT FROM AUTHOR]

Bridge deterioration is inevitable in service, and the inspection and maintenance of bridges are needed to ensure structural integrity. To make cost-effective inspection plans, bridge management departments need degradation models to predict future condition ratings of bridges. Although there have been studies on bridge degradation, the input features of models are selected mostly based on engineering experience, and no effective method has been proposed. Meanwhile, most models based on machine learning (ML) and deep learning (DL) only predict the degradation of bridges in a single year and cannot cover a complete inspection cycle (usually 2 years), providing limited decision support for the transportation departments. Besides, more accurate models are needed to predict the degradation trend of bridges. In response to these problems, an improved ReliefF algorithm is proposed to select features of bridges in the paper. Meanwhile, a new degradation model combining recurrent neural network (RNN) and convolutional neural network (CNN) is established. Historical data of bridges in the US state of Texas from 1992 to 2019 are employed to verify the proposed methods. The result shows that the improved ReliefF algorithm selects the appropriate feature set as the input of the prediction model, and the model accurately predicts the future condition ratings of bridges in the next 3–4 years. The research is beneficial to infrastructure management departments in allocating bridge inspection and maintenance resources reasonably. [ABSTRACT FROM AUTHOR]

Inspecting and assessing existing utility poles has become increasingly important for reducing the vulnerability of power distribution infrastructure systems in disaster situations, which can enhance community resilience. Although vision-based systems have been applied to detect faults in power distribution infrastructures, little research currently exists on assessing component- and network-level failures of utility poles based on their geometric and environmental information. This paper aims to propose a new data-driven approach to support risk-informed decision-making for utility maintenance under extreme wind conditions. Large-scale open-source imagery from Google Street View is used to assess geometric properties of utility poles (i.e., leaning angle). Then the failure probability of utility poles is analyzed under varying conditions (e.g., age, leaning angle, and wind loads) in a three-dimensional virtual city model. The proposed method is tested through case studies in Texas to (1) validate an algorithm for estimating leaning angles of utility poles and (2) understand the progress of failures of leaning utility poles from a network perspective. The outcomes of the case studies demonstrate that the proposed method has the potential to leverage large-scale open-source visual data to assess the vulnerability of utility pole networks that may lead to cascading failures in power distribution infrastructure systems. Based on the proposed virtual environment, the method is expected to enable practitioners to facilitate risk-informed decision-making against disaster situations, which creates an opportunity for prioritizing maintenance tasks regarding power distribution infrastructures. [ABSTRACT FROM AUTHOR]

Assessing the stability of rock slopes is essential to ensuring the typical performance of adjacent transportation infrastructures but simulating the existing field topography and boundary conditions for stability analysis is challenging. This paper describes a case study in which highly weathered rock slopes adjacent to a railroad track in Texas were analyzed using close-range photogrammetry data obtained from an unmanned aerial vehicle with close-range photogrammetry (UAV-CRP). A highly weathered rock mass with low intact strength was considered as a single continuum that undergoes circular failure and was analyzed using Spencer's two-dimensional (2D) and three-dimensional (3D) limit equilibrium method (LEM) analyses. A 3D critical slip surface was obtained to identify the critical sections on which to conduct the individual 2D stability analysis and obtain a safe resloping angle. These angles were further used to reslope the whole rock slopes and conduct a 3D analysis to arrive at a safe and economic slope angle for each side of the rock-cut. The realistic geometrical slopes developed from the aerial imagery were used to develop a framework for comprehensively analyzing the stability of a rock slope undergoing circular failure. [ABSTRACT FROM AUTHOR]

Reports that Jose M. Rosset and James T. P. Yao, professors at the Texas A&M University in College Station, were presented the 1999-2000 Best Paper Award of the periodical `Journal of Professional Issues in Education and Practice' for their paper titled `Roles of Civil Engineering Faculty.'

This paper presents findings from a side-by-side operational comparison of granular road salt (RS) and MeltDown 20 (MD) deicing chemicals for snow and ice control from the perspective of "the maintenance worker in the truck." The field test site, near Canyon, Texas, was divided into sixteen 305 m (1,000 ft) sections that were either untreated controls or received treatment with RS or MD at nominal Texas Department of Transportation (TxDOT) application rates of 85 kg/lane km (300 lb/lane mile) and 42 kg/lane km (150 lb/lane mile), respectively. Three storms met pre-established criteria for snow accumulation, and field test sections were subject to cycles of plowing, deicing treatment, and slushing. Video and still-image data facilitated estimation of visible pavement, and vehicle-based decelerometer tests measured pavement friction. Overall results showed that granular RS outperformed MD in 5/20 data events (25%) and RS outperformed untreated control in 9/20 data events (45%). In contrast, MD never outperformed RS and outperformed control in only 5/20 data events (25%). Further, TxDOT maintenance management data indicate the operational cost to apply MD (corrosion-inhibited) is 3.5× higher than RS (noninhibited), raising questions about cost-effectiveness given the road, climate, and temperature conditions characteristic of the north Texas latitude. [ABSTRACT FROM AUTHOR]

This paper presents a seismic slope stability assessment study of an inherently heterogeneous hydraulic fill dam in Texas. Extensive cone penetration soundings conducted at the dam site were interpreted to estimate different dam material properties. Eight sections distributed along the length of the dam were considered for the slope stability assessment to incorporate the effect of variations in material properties on the hydraulic fill dam. The conventional pseudostatic analysis method was modified to account for the differences in the behavior of the dam materials during static and seismic loading conditions. The current state of practice considers the same critical slip surface for both static and pseudostatic analyses. A modified pseudostatic slope stability analysis was performed to identify other possible critical slip surfaces with lower factors of safety values than the critical slip surface obtained from the static stability analysis. A reliability-based approach was then adopted to incorporate the effect of uncertainty on the estimation of shear-strength parameters of the dam materials, and the expected performance during different seismic events was evaluated. Two hypothetical earthquake events were also considered for the postearthquake deformation and serviceability assessment studies. The approach adopted in this research study facilitates identifying the critical sections of a dam that the conventional analysis method may not consider. Hence, this new approach would be integral toward developing guidelines for evaluating the seismic resilience of earthen dams. [ABSTRACT FROM AUTHOR]

An explosion occurred at a fertilizer plant in the town of West, Texas, on Wednesday, April 17, 2013, devastating a populated neighborhood. A total of 15 people were killed, and approximately 160 more people were injured. Approximately 150 buildings were damaged in the explosion, and the damage to affected homes and businesses was estimated to exceed $100 million. This research documents the building damages caused by the unprecedented explosion and evaluates the technical information for the explosion. The Part I paper of this research focused on the building damage documentation and air-blast incident overpressure calculations. As a companion paper, this manuscript (Part II) primarily focuses on the study of blast-induced ground-shock effects. The ground shock-induced building damages and ground vibration peak particle velocities (PPVs) are analyzed. With a combined consideration of these two types of blast loadings, the air-blast incident overpressures and ground shocks, the field investigated damages caused by the West Fertilizer plant explosion are explained in a more precise manner. The air-blast incident overpressure is identified as the dominant factor for the damages of both wood light-frame buildings and engineering buildings. The ground shock is the secondary factor but is still important. Concluding the research outcomes in the Part I and Part II papers, this study proposes a four-scale blast-induced damage severity evaluation system, demonstrates efficient blastloading calculation methods for both the air-blast incident overpressure and ground-shock PPV, and provides a correlation between the blast loadings and the blast-induced damages for the West Fertilizer plant explosion case. The documentation and analyses that resulted from this research could serve as a good case study for better understanding of the blast loadings and building structural responses. [ABSTRACT FROM AUTHOR]

An explosion occurred at a fertilizer plant in the town of West, Texas, on Wednesday, April 17, 2013, devastating a populated neighborhood. A total of 15 people were killed, and approximately 160 people were injured. Approximately 150 buildings were damaged in the explosion. The damage to affected homes and businesses was estimated to exceed $100 million. The purpose of this study was to collect on-site technical data of the explosion and gain knowledge of blast loadings and structural responses from this unprecedented explosion. Specifically, this research documented the building damages caused by the West Fertilizer plant explosion and the affected buildings' construction and materials and evaluated the technical information for the explosion, including the blast loadings, i.e., the air-blast incident overpressures and ground shocks, on different buildings with respect to the standoff distances. A total of two technical papers have been prepared. The Part I paper (this manuscript) focused on the building damage documentation and air-blast incident overpressure estimation for the West Fertilizer plant explosion case. The Part II paper focused on the effects of the ground shock caused by this West Fertilizer plant explosion. [ABSTRACT FROM AUTHOR]

Highway maintenance and rehabilitation (M&R) planning is a multifaceted decision-making process that requires the consideration of multiple but often conflicting objectives. Traditionally, state highway agencies (SHAs) have focused on maximizing the condition of a pavement network or minimizing agency costs needed to keep the network at an acceptable physical and functional level of service. However, other objectives like minimizing the road user costs and greenhouse gas (GHG) emissions are seldom factored into the M&R decision-making process. In this paper, a mixed integer program that accounts for these three objectives is presented. The proposed model is then implemented on a subset network in Texas consisting of 100 pavement sections. The results demonstrate the Pareto-optimal relationships that exist between the road condition improvements, road user costs, and GHG emissions. Notably, there is a positive relationship between condition score improvements and the observed marginal GHG emissions from the case network implementation. Furthermore, this network's results indicate that GHG emissions from materials and construction contribute to the most significant proportion of the total estimated GHG emissions. The results of the sensitivity analysis confirm the observed trends in the network case examined and provide valuable insights concerning the impact of variability in the budget size. The principal contribution of this study is in providing an approach for highway decision-makers to perform trade-offs in road condition improvements, road user costs, and GHG emissions of alternate pavement M&R programs or policies. [ABSTRACT FROM AUTHOR]

Lean construction (LC) holds potential benefits for project labor productivity; however, the impact on the industry has not been significant. Among other factors, the self-interested behavior of stakeholders, called autonomous agents (AAs) in game theory, has affected LC performance. AAs make decisions for their own benefit rather than for the sake of the project. This paper presents an exploration of the potential impacts that the behavior of subcontractors, as AAs, have had on the performance of LC tools, such as the last planner system (LPS). A qualitative approach was used to collect data through personal interviews with 74 participants in eight projects, built by four construction companies, throughout Texas. A quantitative approach was used to analyze the interviews. The findings were as follows: (1) subcontractors behaved as AAs; (2) the LPS did not prevent the behavior of subcontractors AAs, but it supported the management of issues by the behavior of the subcontractors as AAs; and (3) the behavior of subcontractors as AAs affected LPS performance. This study contributes to the body of knowledge on engineering management by identifying a problem affecting LC, prompting academics and practitioners to investigate solutions that will benefit the labor productivity of the industry. [ABSTRACT FROM AUTHOR]

The goal of this paper was to develop a performance measurement-based approach for transportation agencies, such as state departments of transportation, to evaluate and enhance sustainability. This research proposes a performance measurement-based framework and evaluation methodology for sustainable transportation, linked to agency strategic planning goals. The methodology was applied and tested for the Texas Department of Transportation (TxDOT). This sustainability enhancement methodology is implemented within the highway-corridor planning process. The research identified 12 performance measures, including measures of congestion, safety, alternative modes, and air quality, to address the goals and objectives in TxDOT's strategic plan. The multiattribute utility theory (MAUT) decision-making approach was applied to quantify and normalize the selected performance measures and calculate sustainability index values for current and predicted future corridor conditions. This paper also presents the results from a pilot application of the methodology for a section of US-281 in San Antonio, Texas. The findings made it possible to identify specific performance measures and specific portions of the corridor that needed improvement to enhance the overall sustainability. This research provides a useful tool to assess the relative sustainability of transportation corridors now and in the future. [ABSTRACT FROM AUTHOR]

A cold-formed steel framed shear wall may fail in shear buckling of the sheathing, local buckling or distortional buckling of the framing member under compression forces or connection failures. An unusual distortional buckling mode on boundary studs under uplift forces was recently observed in a shear wall test program conducted at the University of North Texas. It was found in monotonic pushover shear wall tests that the flanges of the boundary studs undertaking uplift forces were distorted at the bottom area of the studs near the hold-down. This paper presents the test program and analysis of the unique distortional buckling mode. The paper also provides procedures for predicting the distortional buckling strength of the boundary studs, as well as the construction details to mitigate the damage by this unexpected distortional buckling mode. [ABSTRACT FROM AUTHOR]

This paper discusses various water management issues facing federal, state, and local agencies charged with managing the water resources of the Rio Grande River Basin and its major tributaries. The Rio Grande—3,058 km (=1,900 mi) long—is the fourth longest river in the United States. The river's basin is 870,236 km2(=336,000 mi2) and for roughly two-thirds of its length it forms the United States–Mexican border. It is a major recreational resource providing world class trout fishing near its headwaters in Colorado's San Juan Mountains and shoreline, angling, and boating opportunities near the Colorado–New Mexico border. The Rio Grande is the principal tourist attraction of Big Bend National Park and flows through downtown Albuquerque and El Paso. Many reaches are wide and broad, but almost all are relatively shallow and not navigable by commercial ships. Nevertheless, it is one of the most important renewable water resources of the southwestern United States and North America. The issue of the “manageability” of the river in the face of social forces and disparate administrative jurisdictions that adversely impact Rio Grande flows is a thread linking various sections of the paper together. The length of the river; the fact that major reaches lie in Colorado, New Mexico, and Texas; and its unique role as an international boundary pose complex management problems. The allocation status quo formed by the complex nexus of existing river laws make it difficult to reshape Rio Grande management. [ABSTRACT FROM AUTHOR]

Gravel aggregates have been used extensively in the Houston District for continuously reinforced concrete (CRC) pavements construction for many years. However, some of these pavements have been subject to early-age delamination and eventual spalling damage. A series of studies since the early 1990's have been conducted to gain a better understanding of mechanisms, material properties, and construction practices related to delamination and spalling. This paper describes a systematic and methodical approach for selecting construction measures to counter the negative effects of using gravel aggregates in concrete paving as it pertains to minimizing early-age delamination distress. The approach was developed based on laboratory measures and practices, numerical approaches for assessing delamination potential, and test sections established in the Houston District, Texas. The testing programs in the laboratory and the field, as well as the analytical results, are presented in this paper. The analysis of the results leads to a step-by-step approach for evaluating and selecting construction measures. [ABSTRACT FROM AUTHOR]

This paper reports the results of a chip seal research project in Texas where the researchers are using both quantitative and qualitative means to evaluate chip seal performance on rural roads. The team is making specific use of the Transit New Zealand (TNZ) T/3 “sand circle” test to measure the change in average texture depth over time and applying those measurements to the TNZ P/17 performance specification for allowable surface texture deterioration over the first year of chip seal performance. The results demonstrate the value of quantitatively characterizing the preseal surface condition as a benchmark against which to compare new chip seal performance. Those roads that had poor preseal surface conditions as exhibited by low macrotexture as measured by the T/3 sand circle test showed early loss of macrotexture and premature flushing after a new seal had been applied and failed the specified P/17 1-year texture loss performance criteria. Thus, the paper concludes that not only is having a quantitative metric essential to be able to accurately assess the performance of new seals but also that the use of the TNZ T/3 sand circle test furnishes an easy, cost-effective means to quantitatively characterize preseal surface texture. [ABSTRACT FROM AUTHOR]

This paper proposes a framework for using business and organizational scenario-planning techniques for regional strategic transportation-planning purposes. The paper provides a brief history of scenario planning as it emerged from business-strategic planning activities and gives an overview of its goals and limitations. The paper then reviews the context for scenario planning in regional transportation planning as well as precedents of its application in this field. The paper continues with a presentation of a scenario-planning framework for transportation as refined and applied to the Houston metropolitan area. The major findings and lessons from this application are discussed, together with conclusions and observations regarding further potentials and refinements. [ABSTRACT FROM AUTHOR]

Current materials and construction specifications for pavement preservation treatments are predominantly prescriptive and rarely correlate the initial quality of the treatment to its future performance. As a result, it is difficult for highway agencies to account for the performance lost or gained due to differences between the as-designed treatment and as-constructed treatment. Also, these specifications may not incentivize contractors to focus on factors that affect the treatment's long-term performance. To account for these limitations, this paper provides a simulation-based performance-related specification (PRS) methodology for pavement preservation treatments, with application to thin hot-mix asphalt (HMA) overlays. Through performance prediction models and lifecycle cost analysis, this methodology determines pay factors based on the probability distributions of the total lifecycle costs of the as-designed and as-constructed treatments and the unit bid price. The developed PRS methodology was applied to four Long-Term Pavement Performance sections in Texas, Idaho, Florida, and New Jersey that received thin HMA overlay treatments. These case studies demonstrated the applicability of the developed methodology and provided insights into the relationships between the initial quality of thin HMA overlays and expected pay factors. [ABSTRACT FROM AUTHOR]

Owing to the 2008 economic downturn in the United States, the construction industry lost 632,000 jobs nationally, of which approximately 100,000 were in Texas. In response to the economic recession, a stimulus package known as the American Recovery and Reinvestment Act (ARRA), was signed by President Obama on March 6, 2009. This paper presents the results of a study examining the construction employment impact of ARRA spending on Texas transportation projects. The primary goal of this study was to estimate direct employment in the construction industry from spending on construction projects. By using regression analysis, the study assesses employment from data on Texas Department of Transportation projects that used ARRA funds, showing that employment generated by construction projects depends on project type, size, and location urbanization. The findings can be useful to policy makers in allocating funds on construction projects when employment stimulation is an objective. [ABSTRACT FROM AUTHOR]

The Texas DOT (TXDOT) is concerned about the widening gap between pavement preservation needs and available funding. Thus, the TXDOT Austin district pavement engineer (DPE) has investigated methods to strategically allocate available pavement funding to potential projects that improve the overall performance of the district and Texas highway systems. The primary objective of the study presented in this paper is to develop a network-level project-screening and ranking method that supports the Austin district 4-year pavement-management plan development. The writers developed candidate-project selection and ranking algorithms that evaluated pavement conditions of each project candidate using data contained in the Pavement Management Information System (PMIS) database, incorporated insights from Austin district pavement experts, and implemented the developed method and supporting algorithm. This process previously required weeks to complete, but now requires about 10 min, including data preparation and running the analysis algorithm, which enables the Austin DPE to devote more time and resources to conducting field visits, performing project-level evaluations, and testing candidate projects. The case study results show that the proposed method assisted the DPE in evaluating and prioritizing projects and allocating funds to the right projects at the right time. [ABSTRACT FROM AUTHOR]

The North American specifications for the design of cold-formed steel (CFS) structural members provides equations for determining the sheet shear strength in bolted connections when standard holes are used. In applications of oversized holes, the specification requires experimental analysis to be conducted to ensure satisfactory performance. A research project was recently completed at the University of North Texas to investigate the behavior and performance of CFS bolted connections using oversized holes. This paper presents the findings on the sheet shear strength for oversized hole applications. The studied parameters in this research included the following: sheet thickness from 0.762 to 2.997 mm; connection type of single shear and double shear with a single bolt; and bolt diameters of 6.4, 9.5, 12.7, and 15.9 mm. The experimental results indicate that the use of oversized holes without a washer did not significantly weaken the sheet shear strength. Recommendations are provided for predicting the nominal sheet shear strength. [ABSTRACT FROM AUTHOR]

Many of the older bridges in the United States have no original contract documents available, and about 26,000 bridges that are rated as scour critical have unknown foundation conditions. Thus, no information is available regarding the type, depth, geometry, or material of these scour critical bridge foundations. The unknown bridge foundations pose a significant problem to bridge owners because of safety concerns. This paper presents the determination of an unknown bridge foundation depth at Forth Worth, Texas. The bridge was supported by driven steel H-piles. Three nondestructive testing (NDT) techniques were utilized: (1) the parallel seismic (PS) method, (2) the sonic echo (SE) method, and (3) resistivity imaging (RI). The main objective of this present study was to compare the suitability of NDT techniques to determine the unknown bridge foundation depth. Based on the field test results, both PS and RI methods provided foundation depth close to actual foundation depth. However, the SE method was determined to be unsuitable for determining the unknown steel H-pile depth. [ABSTRACT FROM AUTHOR]

An extensive set of in situ and laboratory test data is presented for a footing load test site east of Houston, Texas, in desiccated Beaumont clay. The in situ test program included standard and cone penetration tests (CPTs), the latter of which was selected for statistical analysis to produce vertical and horizontal random field model parameters for corrected cone tip resistance. Given the relatively high sampling frequency of the cone tip resistance in the vertical direction, the vertical random field model parameters were determined using the modified Bartlett's test statistic with fitted autocorrelation models subject to a strict fitting criterion. Horizontal random field model parameters were generated by collapsing the two-dimensional distribution of the CPTs to a one-dimensional representation and by using less stringent evaluation of the autocorrelation. The results of this study indicate that Beaumont clay exhibits greater inherent spatial variability than previously reported at other clay sites, which is attributed to the secondary structure of the desiccated clay. A companion paper discusses the performance of a footing load test in the context of spatial and transformation uncertainty. [ABSTRACT FROM AUTHOR]

The rational method for peak discharge (Qp) estimation was introduced in the 1880s. Although the rational method is considered simplistic, it remains an effective method for estimating peak discharge for small watersheds. The runoff coefficient (C) is a key parameter for the rational method and can be estimated in various ways. Literature-based C values (Clit) are listed for different land-use/land cover (two words, no hyphen) (LULC) conditions in various design manuals and textbooks; however, these Clit values were developed with little basis on observed rainfall and runoff data. In this paper, Clit values were derived for 90 watersheds in Texas by using LULC data for 1992 and 2001; the Clit values derived from the two data sets were essentially the same. Also for this study, volumetric runoff coefficients (Cv) were estimated by using observed rainfall and runoff depths from more than 1,600 events observed in the watersheds. Watershed-median and watershed-average Cv values were computed, and both are consistent with data from the National Urban Runoff Program. In addition, Cv values were estimated by using rank-ordered pairs of rainfall and runoff depths (i.e., frequency matching). As anticipated, C values derived by all three methods (literature based, event totals, and frequency matching) consistently had larger values for developed watersheds than for undeveloped watersheds. Two regression equations of Cv versus percent impervious area were developed and combined into a single equation that can be used to rapidly estimate Cv values for similar Texas watersheds. [ABSTRACT FROM AUTHOR]

Bacterial levels in Buffalo Bayou in Houston commonly exceed contact recreation standards. Potential sources of bacteria include wastewater treatment plants, sanitary sewer overflows, septic systems, wet and dry nonpoint-source discharges via direct runoff and pipes, direct deposition, and sediment. A water-quality model in the Hydrologic Simulation Program-FORTRAN (HSPF) was calibrated and validated for hydrology, sediment, and Escherichia coli and subsequently used to evaluate the impacts of the bacterial sources in the watershed. In addition, simple estimates of bacterial loads were calculated along with source evaluations from load duration curves. Load reductions based upon the simple estimates indicated that water-quality standards were met by reducing dry-weather indicator bacterial loads by 69% and wet-weather loads by 98%. When these load reductions were implemented in the HSPF model, however, standards were not met under dry-weather conditions. Residual nonpoint-source loading was found to cause the discrepancy between simple load estimate calculations and the developed water-quality model. This paper demonstrates that runoff can play a significant role in maintaining high levels of bacteria under all flow conditions and that understanding the temporal variations in bacterial source loading is critical to ensure that load reductions will achieve water-quality standards. [ABSTRACT FROM AUTHOR]

The Bolivar Peninsula in Texas was severely impacted by Hurricane Ike with strong winds, large waves, widespread inundation, and severe damage. This paper examines the wave and surge climate on Bolivar during the storm and the consequent survival and destruction of buildings. Emphasis is placed on differences between buildings that survived (with varying degrees of damage) and buildings that were completely destroyed. Building elevations are found to be the primary indicator of survival for areas with large waves. Here, buildings that were sufficiently elevated above waves and surge suffered relatively little structural damage, while houses at lower elevations were impacted by large waves and generally completely destroyed. In many areas, the transition from destruction to survival was over a very small elevation range of around 0.5 m. In areas where waves were smaller, survival was possible at much lower elevations. Higher houses that were not inundated still survived, but well-built houses at lower elevations could also survive as the waves were not large enough to cause structural damage. However, the transition height where waves became damaging could not be determined from this study. [ABSTRACT FROM AUTHOR]

Departments of transportation in the United States are under increasing pressure to accelerate projects to meet user-defined constraints and reduce the inconvenience to the traveling public. Although there is information about acceleration projects in other industries, there has been little specifically aimed at highway projects. A domestic scan sponsored by the National Cooperative Highway Research Program was tasked with providing information in this area. The objective of this paper is to synthesize the resulting information into fundamentals that support successful planned accelerated highway project delivery. Case studies of how departments of transportation successfully accelerated the construction of four very different projects in California, Florida, and Texas serve as the basis for identifying these fundamentals. The fundamentals include upfront and detailed planning, designs that facilitate accelerated construction, a collaborative environment for project stakeholders, and incentives and disincentives to motivate construction contractors. [ABSTRACT FROM AUTHOR]

The model developed in this paper, the bacteria loading estimator spreadsheet tool (BLEST), was designed as an easy to use indicator bacteria model that can overcome the shortcomings of many of the simpler total maximum daily load (TMDL) modeling approaches by integrating spatial variation into load estimates. BLEST was applied to the Buffalo Bayou watershed in Houston, Texas and incorporated loading from point and nonpoint sources, such as wastewater treatment plants, sanitary sewer overflows, septic systems, storm sewer leaks, runoff, bed sediment resuspension, and direct deposition. The dry weather Escherichia coli load in Buffalo Bayou was estimated using BLEST to be 244 billion MPN/day and would require an overall 48% reduction to meet the contact recreation standard, while wet weather loads would need to be reduced by 99.7%. Dry weather loads were primarily caused by animal direct deposition, septic systems and discharges from storm sewers under dry weather conditions, while wet weather loads were mostly attributable to runoff and resuspension from sediment. Unlike most simple TMDL load allocation strategies, BLEST can be used to evaluate spatially variable load reduction strategies. For example, septic system load reductions implemented in less than 10% of the subwatersheds resulted in a decrease in bayou loading of more than 20%. [ABSTRACT FROM AUTHOR]

The results of a multifaceted investigation into large-amplitude vibrations of bridge stay cables are presented. The vibration of the stay cables occurred under light rain and wind conditions, and resulted in low-frequency, large-amplitude oscillations having recorded displacements of over 24 in.(0.6 m). Due to concerns about the implications of the vibrations on the integrity and durability of the stay cables and observed damage to stay-cable anchorage components, an investigation and repair program was developed. The final repair program arose from an investigation that combined the talents of practicing engineers, the Texas Department of Transportation, and representatives from four universities. Ultimately, a combination of supplemental hydraulic dampers and cable restrainers were used to mitigate the vibrations. This paper describes the results of the investigation and presents the practice-based methodology used to develop the implemented repair program. [ABSTRACT FROM AUTHOR]

In the past few years, a number of full-depth or perpetual pavements have been designed and constructed in the State of Texas. A study was conducted to examine the quality of the compaction of the thick asphalt layers within these pavements using advanced forensic tools such as X-ray computed tomography (X-ray CT) and ground penetrating radar (GPR). The GPR is a nondestructive tool for evaluating the uniformity of density in pavements at highway speed. X-ray CT is a laboratory tool that is used to conduct detailed analysis of air void distribution and uniformity in asphalt pavement cores. This paper presents the results of analyzing one of the perpetual pavements constructed in State Highway 114 (SH-114). In this project, two different structural asphalt pavement sections were placed, one included a 1 in. (25.4 mm) stone filled (SF) Superpave mix and the other included a traditional dense graded Type B material. The dense graded Type B material was found to be uniformly compacted. However, major compaction problems were identified with the coarse SF Superpave mix. The poor compaction and associated high percent air vsoids were found to permit moisture infiltration, which could potentially lead to rapid pavement deterioration. The analysis showed very good agreement between the GPR and X-ray CT results and demonstrated the efficiency of using GPR and X-ray CT in the evaluation of asphalt pavement compaction. [ABSTRACT FROM AUTHOR]

The city of Frisco, Tex., published state plane coordinates were “ground scaled” into surface coordinates for the purpose of establishing a hybrid coordinate system to be easily used by surveyors. Nineteen city monuments were found and collected by GPS observation using real-time kinematic (RTK) connected to the Texas RTK Cooperative Network. The network creates a virtual reference station near the GPS roving receiver, allowing the surveyor to use the rover unit by itself without the need for setting up a base station on the project site. Using a GPS manufacturer’s standard protocol, localizing ground-scaled GPS vectors to the city’s hybrid values yielded acceptable horizontal (H) and vertical (V) residuals over a 233 km2 network. Two out of 19 monuments observed explained maximum residual error (H=0.029 m, V=0.082 m) with no significant differences in the mean ΔN and ΔE between published grid, hybrid, and surface coordinates (P=0.77). This paper will illustrate and discuss the procedures and results of this project. [ABSTRACT FROM AUTHOR]

During the summer of 2005, a tidal creek (“Pine Gully”) within a few kilometers of the Houston Ship Channel was completely blocked by a 200 m long and 1.5 m deep plug of silt and fine sand. This paper documents and explains this unusual sedimentation event. It then presents a new method for calculating ship wave-induced sediment transport into tidal creeks. Between November 2005 and January 2006, measurements of velocity, pressure, and suspended sediment concentration were taken in the creek approximately 150 m seaward of the plug. The data indicated ship wave-induced bores (one per ship). Each bore caused a net sediment transport of approximately 0.4 m3 toward the plug, enough to explain the observed rate of sediment accumulation. Cores of the plug showed that the plug material was consistent throughout, suggesting a single pathway (from the bay). During the period of plug formation, rainfall and creek discharge were relatively low indicating a likely factor for the plugging. Model calculations showed that significant ship wave-induced sediment transport into Pine Gully would occur only when Pine Gully mean depth is less than 0.8 m. [ABSTRACT FROM AUTHOR]

This paper presents three field projects to illustrate the integrated approach to forensic investigations of roadway pavement failures used widely in Texas. In each case, the combined ground-penetrating radar (GPR) and falling weight deflectometer (FWD) data were extremely useful for identifying contributing factors, such as stripping in the hot mix or localized areas of wet or weak base. Dynamic cone penetration (DCP) is used for validating problems with base and subbase layers. Laboratory tests are often required to complete the investigation, especially if the repair strategy calls for in-place recycling of the existing structure. The extent of stripping and high porosity that caused delamination for Projects 1 and 2 was detected by GPR and verified by core samples. GPR, FWD, DCP, and field soil samples all showed indications that the existing base on Project 1 was wet and the stiffness was only about one-third that of a typical flexible base in Texas. FWD data demonstrate that the pavement structures for Projects 1 and 2 were inadequate, so a rehabilitation strategy was selected that included structural strengthening. In Project 3, GPR, lab density, and permeability tests indicate that the dramatic pavement failures were attributable to moisture entering the base through a poorly compacted asphalt concrete layer and poor longitudinal joints. The base material was found to be highly susceptible to moisture and did not meet the Texas Department of Transportation’s compressive strength requirements when subjected to capillary soaking. The repetitive triaxial test results revealed that the stiffness and load-carrying capability became inadequate when the base materials were exposed to moisture. The pavement structure had been totally replaced in 2004. [ABSTRACT FROM AUTHOR]

Researchers identified a potential methodology for obtaining the incremental societal costs and benefits from a variable pricing project and applied that methodology to the QuickRide high occupancy/toll (HOT) lanes in Texas. This is one of the longest running variable pricing projects in the United States and, as such, it provided useful historical data and trends upon which to estimate future benefits and costs. This analysis found that the incremental societal benefits of QuickRide exceeded incremental societal costs for the time period considered. A companion paper that used the same methodology to examine the benefits and costs of the SR-91 Express Lanes found similar results. However, the differences between the benefits and costs were dramatically different for the two projects, indicative of the relative size of the two projects and the number of travelers impacted. On SR-91, tens of thousands of travelers were impacted on a daily basis where QuickRide’s impact was limited to approximately 400 travelers per day. Interestingly, the benefit-cost ratios of the two projects were similar, both between 1.5 and 1.7. [ABSTRACT FROM AUTHOR]

Reflective cracking through jointed concrete pavement overlays has been a persistent problem. Several different rehabilitation strategies have been used in Texas. This paper is a summary of the performance of strategies used in the past 10 years. The performance of the crack-retarding grid has been disappointing as it has been related to several premature failures. Only one project has realized a benefit of the crack-retarding grid, where the reflective cracking was delayed by about 1 year. The writers believe the small openings in the crack-retarding grid and the lack of an effective bond may be the causes of the layer separation. A proprietary crack-retarding asphalt material has been performing well over two years of monitoring. In one experimental project, 100% of the cracks reflected through conventional overlay material in the first year. Both Petromat fabric underseal and crack-retarding asphalt material have been performing satisfactorily to retard reflective cracking. However, there is a large cost difference between these two treatments. Seven experimental treatments on a major section of US 59 were evaluated. The worst-performing section on the US 59 project was the break-and-seat method, which failed due to weak subgrade support. The weak subgrade is unable to support cracked concrete, which leads to a rocking action under traffic loads. It is concluded that for future projects, the break-and-seat method should not be applied on subgrade with a dynamic cone penetrometer penetration rate exceeding 25 mm per blow. A flexible base overlay with thin asphalt surfacing and the Arkansas (large stone) mix have performed well. Flexible base overlays were able to absorb the joint movement and eliminate the reflective cracking. The flexible base should be of top quality with very low moisture susceptibility. In Texas, this involves specifying a Texas triaxial Class 1 material with classification of “good” in suction/dielectric tests. It is also critical to provide an effective seal for the flexible base. A chip seal followed by a thin 75-mm hot mix layer is recommended. [ABSTRACT FROM AUTHOR]

Recently, a structural condition index (SCI) was developed for the Texas Department of Transportation as a screening tool to discriminate between pavements that need structural reinforcement from those that do not. For the successful implementation of the SCI concept at the network level, one of the critical issues is to determine the minimum falling weight deflectometer (FWD) testing frequency. The paper discusses how to determine the required FWD testing frequency, or the required FWD test spacing needed for implementing the SCI at the network level. In this study, the risk-based method was employed, where the variance of the SCI at the network level was assessed by randomly selecting a small sample of the pavement sections that were representative of the whole network. Due to the limited number of such sections and the lack of knowledge of underlying distribution of the SCI variances at the network level, the bootstrap method was used to obtain the mean and the confidence intervals on the mean of the SCI variances at the network level. [ABSTRACT FROM AUTHOR]

This paper focuses on the cause, possible solutions, and future prevention of pavement heave at a new construction project. We speculated that heaving on the east side of the project was caused by a reaction between the lime stabilizer and minerals in the soil. Because of a difference in soil chemistry, the west side of the project (which was still under construction) did not show evidence of heaving. A forensic investigation was initiated to test our hypothesis. The findings of the investigation concluded that the cause of the heaving on the east side of the road was related to the formation of the expansive mineral, ettringite. Ettringite formed due to the reaction of the lime stabilizer with seams of high sulfate soil on the east side. Laboratory testing did not find any effective stabilizer for the high-sulfate soils on the east side. Therefore, reconstruction would involve removing and replacing the treated layer with a select material that has less than 2,000 ppm sulfates. Test results indicate that there was no threat of sulfate heave on the west side. District personnel had performed the field conductivity tests to evaluate and monitor the concentration of the sulfate content on the remaining project. The treatment of 3%/72-h mellowing period/3% lime treatment was employed on the west side. The whole project has been completed for 1 year and no heave has been observed. [ABSTRACT FROM AUTHOR]

The Accreditation Board for Engineering and Technology has developed and implemented new criteria for accrediting engineering technology programs in the United States. The new criteria, Technology Criteria 2000 (TC2K), have changed the way that engineering technology programs conduct their business. In order to survive in the future, each program has to develop a strategy to meet the new requirements specified in the TC2K. The Department of Engineering Technology at Texas Tech University has developed a program assessment portfolio (PAP) to assess the department performance toward the attainment of TC2K Criterion 1. This paper presents 12 assessment methods within the PAP. Particularly, it demonstrates how to develop and implement one of the assessment methods, pre- and postcourse assessment, to a senior-level course. Data collected from the implementation has been analyzed and results indicate that pre- and postcourse assessment provide valuable information regarding student learning. Furthermore, the information can be used to continue improving effectiveness of teaching. [ABSTRACT FROM AUTHOR]

Allocation of water in Texas evolved historically over several centuries into an essentially unmanageable system. Water management has progressed significantly in recent years with the transition of riparian rights to a surface-water permit system. Although the “law of the biggest pump” still governs, pressure for ground-water regulation continues to intensify. Water rights have become a major consideration in water-resources development and management in the state. This paper describes the Texas experience in allocating water resources among many competing users. The evolution of the water-rights system is outlined, and key issues remaining to be resolved are noted. The strategies adopted and the complexities encountered in Texas are representative of other states as well. [ABSTRACT FROM AUTHOR]