Developing a methodology to account for commercial motor vehicles using microscopic traffic simulation models

The collection and interpretation of data is a critical component of traffic and transportation engineering used to establish baseline performance measures and to forecast future conditions. One important source of traffic data is commercial motor vehicle (CMV) weight and classification data used as input to critical tasks in transportation design, operations, and planning. The evolution of Intelligent Transportation System (ITS) technologies has been providing transportation engineers and planners with an increased availability of CMV data. The primary sources of these data are automatic vehicle classification (AVC) and weigh-in-motion (WIM). Microscopic traffic simulation models have been used extensively to model the dynamic and stochastic nature of transportation systems including vehicle composition. One aspect of effective microscopic traffic simulation models that has received increased attention in recent years is the calibration of these models, which has traditionally been concerned with identifying the "best" parameter set from a range of acceptable values. Recent research has begun the process of automating the calibration process in an effort to accurately reflect the components of the transportation system being analyzed. The objective of this research is to develop a methodology in which the effects of CMVs can be included in the calibration of microscopic traffic simulation models. The research examines the ITS data available on weight and operating characteristics of CMVs and incorporates this data in the calibration of microscopic traffic simulation models. The research develops a methodology to model CMVs using microscopic traffic simulation models and then utilizes the output of these models to generate the data necessary to quantify the impacts of CMVs on infrastructure, travel time, and emissions. The research uses advanced statistical tools including principal component analysis (PCA) and recursive partitioning to identify relationships between data collection sites (i.e., WIM, AVC) such that the data collected at WIM sites can be utilized to estimate weight and length distributions at AVC sites. The research also examines methodologies to include the distribution or measures of central tendency and dispersion (i.e., mean, variance) into the calibration process. The approach is applied using the CORSIM model and calibrated utilizing an automated genetic algorithm methodology

OPERATIONAL METHODS FOR THE ASSESSMENT AND MANAGEMENT OF AGING INFRASTRUCTURE

The aims and scope of the Handbook is to provide designers with a general methodology for the assessment of existing structures, which is illustrated step by step, referring to the selected case studies. The case studies have been chosen not only in order to cover as much as possible the actual variety of infrastructures and materials, but also different building periods, from the sixteenth century to the most recent past. In this way, it is possible to consider structures designed according to different approaches; in fact, while recent structures have been designed according to Codes, Standards, Guidelines or theoretical models, the most ancient ones have been designed according to empirical rules or architectural canons, therefore the understanding of original design ideas often requires that survey and in-situ measurements and investigations are supplement with historical studies. In the presentation of case studies, beside the reference to the general procedures provided by modern Codes and ISO 13822 in particular, the above mentioned necessity of understanding original design ideas and the significance of the engineering judgement in the diagnosis of the structural decays are emphasized, aiming to communicate to the reader a correct way to approach existing structures. The references mentioned in each chapter provide additional background materials, further guidance and information, allowing to widen the significance and the field of application of the assessment methods illustrated for each case study

Advanced assessment methods for elderly bridges. State-of-the-art and justification based on LCA

[ANGLÈS] Many of the existing bridges do not satisfy the structural requirements specified in design codes for new bridges. However, many of these bridges must remain in service and therefore decisions must be made in order to maintain their safety. In the design of new bridges, it is accepted “to be on the safe side” inherent in the standards; but for an assessment of an elderly bridge this procedure should be removed in order to have a more realistic understanding of the state of the structure. Otherwise, the decisions made, being too conservative, can result in unnecessary costs. The main problem is that many existing bridges near to the end of their live under conventional evaluation methods give results which imply or the replacement of the bridge or a high investment for repair it to bring it back to the performance level stipulated in the current standards. The existing advanced methods of structural assessment allow evaluating the actual state of the structure. It has been shown in many cases that better results can be obtained with advanced methods than with conventional methods because the advanced ones evaluate the structure decreasing as much as possible the existing uncertainties. This implies to move from a structure that initially seemed to require heavy investments or to be replaced, to a structure which would have acceptable conditions of behaviour at least for a certain period of time, with a much lower investment and an optimized repair and maintenance. Current methods of advanced evaluation are based on probabilistic methods of reliability through the updating of the variables that which contains uncertainty (traffic solicitations, etc.). This updating is carried out by site‐specific data taken with Structural Health Monitoring systems. Load tests also can be included within the advanced methodologies of evaluation. These evaluation methods have a great impact on the life‐cycle assessment of a bridge because apart from reducing the maintenance and repair costs allow, with a more accurate assessment, extend the lifespan of a structure while maintaining adequate levels of performance and safety. The present thesis aims to synthesize the state‐of‐the‐art of the mentioned advanced assessment methods used in bridges. It also highlights the involvement, influence and direct relationship of these methods with the different aspects which are currently considered in Life‐Cycle Assessment of existing bridges.[CASTELLÀ] Muchos de los puentes existentes no satisfacen los requerimientos estructurales especificados en los códigos de diseño para nuevos puentes. Sin embargo, muchos de estos puentes deben mantenerse en servicio y, por tanto, deben tomarse decisiones respecto a mantener su nivel de seguridad. Para el diseño de puentes nuevos, se acepta el “estar del lado seguro” inherente en las normativas; pero para una evaluación de un puente de avanzada edad dicho proceder debe eliminarse para poder tener un conocimiento más real del estado de la estructura. De lo contrario, las decisiones que se tomen, por demasiado conservadoras, pueden dar lugar a gastos innecesarios. El problema principal reside en que muchos puentes existentes cercanos al fin de su vida útil bajo métodos de evaluación convencional arrojan resultados que implicarían o la sustitución del puente o una inversión de reparación muy elevada para llevarlo de nuevo al nivel de comportamiento estipulado en las normativas actuales. Los métodos avanzados de evaluación estructural existentes, permiten evaluar el estado real de la estructura. Se ha demostrado en muchos casos que con métodos avanzados se obtienen mejores resultados que con los métodos convencionales ya que se evalúa la estructura disminuyendo al máximo posible las incertidumbres existentes. Ello conlleva pasar de una estructura que en un principio parecía requerir una inversión muy elevada o ser sustituida, a una estructura que volvería a estar en condiciones aceptables de comportamiento al menos durante un determinado periodo de tiempo, con una inversión mucho menor y optimizada de reparación y mantenimiento. Los métodos actuales de evaluación avanzada se basan en métodos probabilísticos de fiabilidad a través de la actualización de las variables que encierran incertidumbre (solicitación del tráfico, etc.). Dicha actualización se lleva a cabo con datos tomados in situ mediante sistemas “Structural Health Monitoring”. Las pruebas de carga también pueden englobarse dentro de las metodologías avanzadas de evaluación. Estos métodos de evaluación tienen un gran impacto en la evaluación del ciclo de vida de un puente puesto que aparte de reducir los costes de mantenimiento y reparación permiten, mediante una evaluación más precisa, alargar la vida útil de una estructura manteniendo unos niveles de comportamiento y seguridad adecuados. La presente tesis presente sintetizar el estado del arte de los métodos avanzados de evaluación estructural mencionados utilizados en puentes. También incide directamente en la implicación, influencia y relación directa de dichos métodos con los distintos aspectos que se consideran actualmente en la evaluación del Ciclo de Vida de los puentes existentes

Development of a Long-term, Multimetric Structural Health Monitoring System for a Historic Steel Truss Swing Bridge

The bridge stock across the United States is ageing, with many bridges approaching the end of their design life. The situation is so dire that the American Society of Civil Engineers gave the nation’s bridges a grade of “C+” in the 2013 edition of their Report Card on America’s Infrastructure. In fact, at the end of 2011, nearly a quarter of all bridges in the United States were classified as either structurally deficient or functionally obsolete. Thus, the nation’s bridges are in desperate need of rehabilitation and maintenance. However, limited funds are available for the repair of bridges. Management of the nation’s bridge infrastructure requires an efficient and effective use of available funds to direct the maintenance and repair efforts. Structural health monitoring has the potential to supplement the current routine of scheduled bridge inspections by providing an objective and detailed source of information about the status of the bridge. This research develops a framework for the long-term monitoring of bridges that leverages multimetric data to provide value to the bridge manager. The framework is applied to the Rock Island Arsenal Government Bridge. This bridge is a historic, steel truss, swing bridge that spans the Mississippi River between Rock Island, IL and Davenport, IA. The bridge is owned and operated by the US Army Corps of Engineers (USACE) and is a vital link for vehicular, train, and barge traffic. The USACE had a system of fiber optic strain gages installed on the bridge. As part of this research, this system was supplemented with a wireless sensor network that measured accelerations on the bridge. The multimetric data from the sensor systems was collected using a program developed in the course of this research. The data was then analyzed and metrics were developed that could be used to determine the health of the structure and the sensor networks themselves. Statistical process control methods were established to detect anomalous behavior in the short and long term time scales. Methods to locate and quantify the damage that has occurred in the structure once an anomaly has been detected were demonstrated. One of the methods developed as part of this research was a first order flexibility method. The SHM system this research develops has the desirable characteristics of being continuous temporally, multimetric, scalable, robust, autonomous, and informative. By necessity, some aspects of the developed SHM framework are unique and customized exclusively for the Rock Island Government Bridge. However, the principles developed in the framework are applicable to the development of an SHM system for any other bridge. Application of the SHM framework this research develops to other bridges has the potential to increase objectivity in the evaluation of bridges and focus maintenance efforts and funds on the bridges that are most critical to the public safety.Financial support for this research was provided in part by the Army Corps of Engineers Construction Engineering Research Laboratory (CERL) through a subcontract with Mandaree Enterprise Corporation.Ope

SMARTI - Sustainable Multi-functional Automated Resilient Transport Infrastructure

The world’s transport network has developed over thousands of years; emerging from the need of allowing more comfortable trips to roman soldiers to the modern smooth roads enabling modern vehicles to travel at high speed and to allow heavy airplanes to take off and land safely. However, in the last two decades the world is changing very fast in terms of population growth, mobility and business trades creating greater traffic volumes and demand for minimal disruption to users, but also challenges, such as climate change and more extreme weather events. At the same time, technology development to allow a more sustainable transport sector continue apace. It is within this environment and in close consultation with key stakeholders, that this consortium developed the vision to achieve the paradigm shift to Sustainable Multifunctional Automated and Resilient Transport Infrastructures. SMARTI ETN is a training-through-research programme that empowered Europe by forming a new generation of multi-disciplinary professionals able to conceive the future of transport infrastructures and this Special Issue is a collection of some of the scientific work carried out within this context. Enjoy the read