Dynamic behaviour of underspanned suspension road bridges under traffic loads

Underspanned suspension bridges are structures with important economical and aesthetic advantages, due to their high structural efficiency. However, road bridges of this typology are still uncommon because of limited knowledge about this structural system. In particular, there remains some uncertainty over the dynamic behaviour of these bridges, due to their extreme lightness. The vibrations produced by vehicles crossing the viaduct are one of the main concerns. In this work, traffic-induced dynamic effects on this kind of viaduct are addressed by means of vehicle-bridge dynamic interaction models. A finite element method is used for the structure, and multibody dynamic models for the vehicles, while interaction is represented by means of the penalty method. Road roughness is included in this model in such a way that the fact that profiles under left and right tyres are different, but not independent, is taken into account. In addition, free software {PRPgenerator) to generate these profiles is presented in this paper. The structural dynamic sensitivity of underspanned suspension bridges was found to be considerable, as well as the dynamic amplification factors and deck accelerations. It was also found that vehicle speed has a relevant influence on the results. In addition, the impact of bridge deformation on vehicle vibration was addressed, and the effect on the comfort of vehicle users was shown to be negligible.

Road Dust Emission Sources and Assessment of Street Washing Effect

Although previous studies report on the effect of street washing on ambient particulate matter levels, there is a lack of studies investigating the results of street washing on the emission strength of road dust. A sampling campaign was conducted in Madrid urban area during July 2009 where road dust samples were collected in two sites, namely Reference site (where the road surface was not washed) and Pelayo site (where street washing was performed daily during night). Following the chemical characterization of the road dust particles the emission sources were resolved by means of Positive Matrix Factorization, PMF (Multilinear Engine scripting) and the mass contribution of each source was calculated for the two sites. Mineral dust, brake wear, tire wear, carbonaceous emissions and construction dust were the main sources of road dust with mineral and construction dust being the major contributors to inhalable road dust load. To evaluate the effectiveness of street washing on the emission sources, the sources mass contributions between the two sites were compared. Although brake wear and tire wear had lower concentrations at the site where street washing was performed, these mass differences were not statistically significant and the temporal variation did not show the expected build-up after dust removal. It was concluded that the washing activities resulted merely in a road dust moistening, without effective removal and that mobilization of particles took place in a few hours between washing and sampling. The results also indicated that it is worth paying attention to the dust dispersed from the construction sites as they affect the emission strength in nearby streets.

ICT Road map for supporting energy systems in smart cities

This paper introduces a road map for ICTs (Information and communication technologies) supporting planning, operation and management of energy systems in smart cities. The road map summarises different elements that form energy systems in cities and proposes research and technical development (RTD) and innovation activities for the development and innovation of ICTs for holistic design, planning and operation of energy systems. In addition, synergies with other ICT systems for smart cities are considered. There are four main target groups for the road map: 1) citizen; 2) building sector; 3) energy sector; and 4) municipality level. As an example for enabling active participation of citizens, the road map proposes how ICT can enable citizens? involvement among others into building design. The building sector roadmap proposes how ICTs can support the planning of buildings and renovations in the future, as well as how to manage building energy systems. The energy sector road map focuses on city?s energy systems and their planning and management, including e.g. demand side management, management of different district level energy systems, energy performance validation and management, energy data models, and smarter use of open energy data. Moreover, the municipality level road map proposes among others ICTs for better integration of city systems and city planning enabling maximised energy efficiency. In addition, one road map section suggests development needs related to open energy data, including among others the use of energy data and the development and harmonisation of energy data models. The road map has been assembled in the READY4SmartCities project (funded by EU 7th Framework Programme), which focuses on the energy system at the city level, consisting of centralised energy systems and connections to the national level energy grids, as well as interconnections to the neighbourhood and building level energy systems.

Interregional trade changes in Spain caused by the introduction of a road fee charge for heavy goods vehicles

The introduction of a homogeneous road charging system according to the Directive 2011/76/EU for the use of roads is still under development in most European Union (EU) member states. Spain, like other EU members, has been encouraged to introduce a charging system for Heavy Goods Vehicles (HGVs) throughout the country. This nationwide charge has been postponed because there are serious concerns about their advantages from an economic point of view. Within this context, this paper applies an integrated modeling approach to shape elastic trade coefficients among regions by using a random utility based multiregional Input- Output (RUBMRIO) approach and a road transport network model in order to determine regional distributive and substitutive economic effects by simulating the introduction of a distance-based charge (?/km) considering 7,053.8 kilometers of free highways linking the capitals of the Spanish regions. In addition, an in-depth analysis of interregional trade changes is developed to evaluate and characterize the role of the road charging approach in trade relations among regions and across freight intensive economic sectors. For this purpose, differences in trade relations are described and assessed between a base-case or ?do nothing? scenario and a road fee-charge setting scenario. The results show that the specific amount of the charge set for HGVs affect each region differently and to a different extent because in some regions the price of commodities and the Generalized Transport Cost will decrease its competiveness within the country.

Evaluating the spatial and social equity effects of road pricing in the European urban context: the Madrid Metropolitan Area.

The paper explores the spatial and social impacts arising from implementation of a road-pricing scheme in the Madrid Metropolitan Area (MMA). Our analytical focus is on understanding the effects of the scheme on the transport accessibility of different social groups within the MMA. We define an evaluation framework to appraise the accessibility of different districts within the MMA in terms of the actual and perceived cost of using the road infrastructure "before" and "after" the implementation of the scheme. The framework was developed using quantitative survey data and qualitative data from focus group discussions with residents. We then simulated user behaviors (mode and route choice) based on the empirical evidence from a travel demand model for the MMA. The results from our simulation model demonstrated that implementation of the toll on the orbital metropolitan motorways (M40, M30, for example) decreases accessibility, mostly in the districts where there are no viable public transport alternatives. Our key finding is that the economic burden of the road-pricing scheme particularly affects unskilled and lower income individuals living in the south of the MMA. Consequently lower income people reduce their use of tolled roads and have to find new arrangements for these trips: i.e. switch to the public transport, spend double the time for their commuter trips or stay at home. The results of our research could be applicable more widely for anyone wishing to better understand the important relationship between increased transport cost and social equity, especially where there is an intention to introduce similar road-pricing schemes within the urban context.

An integrated modeling approach to assess the impact on road freight transport demand of allowing longer and heavier vehicles (LHVs) in Spain

The assessment on introducing Longer and Heavier Vehicles (LHVs) on the road freight transport demand is performed in this paper by applying an integrated modeling approach composed of a Random Utility-Based Multiregional Input-Output model (RUBMRIO) and a road transport network model. The approach strongly supports the concept that changes in transport costs derived from the LHVs allowance as well as the economic structure of regions have both direct and indirect effects on the road freight transport system. In addition, we estimate the magnitude and extent of demand changes in the road freight transportation system by using the commodity-based structure of the approach to identify the effect on traffic flows and on pollutant emissions over the whole network of Spain by considering a sensitivity analysis of the main parameters which determine the share of Heavy-Goods Vehicles (HGVs) and LHVs. The results show that the introduction of LHVs will strengthen the competitiveness of the road haulage sector by reducing costs, emissions, and the total freight vehicles required.

Optimized HOG for on-road video based vehicle verification

Vision-based object detection from a moving platform becomes particularly challenging in the field of advanced driver assistance systems (ADAS). In this context, onboard vision-based vehicle verification strategies become critical, facing challenges derived from the variability of vehicles appearance, illumination, and vehicle speed. In this paper, an optimized HOG configuration for onboard vehicle verification is proposed which not only considers its spatial and orientation resolution, but descriptor processing strategies and classification. An in-depth analysis of the optimal settings for HOG for onboard vehicle verification is presented, in the context of SVM classification with different kernels. In contrast to many existing approaches, the evaluation is realized in a public and heterogeneous database of vehicle and non-vehicle images in different areas of the road, rendering excellent verification rates that outperform other similar approaches in the literature.

Road to 1966 : caminos hacia "complejidad y contradicción en la arquitectura", en la cultura arquitectónica de la segunda posguerra en EE.UU

Complejidad y contradicción en la arquitectura ha resultado ser una de las referencias capitales más aludidas, citadas y reproducidas de la literatura arquitectónica de los tiempos recientes. No en vano, en la introducción de la propia obra, Vincent Scully afirmó que «probablemente es el texto más importante sobre arquitectura desde ‘Vers une Architecture’, escrito por Le Corbusier en 1923». Sin embargo, sus fuentes parece que están inexploradas o, al menos, no examinadas. Por ello, Road to 1966 se plantea como un trabajo de investigación con tres objetivos de partida fundamentales: (1) el interés en estudiar el debate arquitectónico candente, creado con las fricciones surgidas entre los protagonistas de unos años que cambiaron el estado de lo que se consideraba una obra legítima en arquitectura; (2) se pretende ampliar la cronología del desarrollo intelectual de un texto, el de Venturi, que marcó la segunda mitad del siglo xx, de manera retroactiva hasta los años de la II Guerra Mundial, cuando parece que empezaban a ser coherentes y reconocibles unas nuevas posiciones desde las que aproximarse a las cuestiones de la práctica, la teoría y la historia de la arquitectura; (3) poder ofrecer una nueva interpretación de dicho texto de Venturi, entendido no como el origen primigenio de parte de las grandes transformaciones de la arquitectura reciente (de los últimos cincuenta años), sino como el resultado necesario de esa cronología intelectual previa. La arquitectura norteamericana de estos años de posguerra ha resultado ser crucial en su posterior desarrollo, y, especialmente, en relación al libro de Venturi. De hecho, Scully en la introducción de la edición original de Complejidad y contradicción, señalaba que «el principal argumento del libro está expuesto a finales de los cincuenta». Que la arquitectura del siglo xx tiene en la Norteamérica de los años sesenta -cuando se consolida la figura de Venturi- uno de sus capítulos más decisivos, frecuentemente asumido como el paso siguiente a la importada modernidad heroica europea, hoy parece no ser discutido por casi nadie. Ahora bien: ¿qué ocurre con los años intermedios? ¿Qué acontece entre el final de la II Guerra Mundial y esos años sesenta? La posible carencia de una postura dominante y clara quizás haya sumido esta etapa en un cierto olvido o descuido por parte de historiadores y críticos. Así, este trabajo se estructura alrededor del papel que ocupa el texto venturiano, sin ser éste su único protagonista. Tomado más bien como excusa, la tesis va profundizando de manera deductiva en el conjunto de circunstancias que pudieron llevar a su autor hacia las conclusiones que desarrolló, detectando los ambientes biográficos y formativos, pensamientos compartidos e influencias epistemológicas y profesionales mutuas, que justificarían una novedosa interpretación de dicho texto como el corolario necesario de un panorama de crisis y cambios - éste sí protagonista en este trabajo-, al contrario de cómo habitualmente se ha venido entendiendo dicha obra. La investigación se centra predominantemente en el rastreo de las fuentes citadas por el propio Venturi en su libro, así como de los textos de mayor difusión (generalmente revistas profesionales no exclusivamente académicas, además de libros, catálogos de exposiciones, actas de simposios…), y no tanto en las obras construidas o proyectadas; sí, quizás, en los términos en los que dichas obras fueron publicadas, comentadas o reseñadas. Así, se ha adoptado una aproximación concebida sub specie bibliotecae, donde se han aplicado unos métodos de trabajo caracterizados por su componente cronológica, y, después, analítico-comparativa: dicho de otro modo, un método historiográfico-periodístico capaz de relacionar las historias o cursos de ciertas ideas o nociones, dentro de un contexto general más amplio en sus derivadas arquitectónicas, estéticas, socio-generacionales, culturales, filosóficas, científicas, políticas, literarias… Con ello, se pretende establecer una relectura del primer libro de Venturi y sus años de gestación desde unas nuevas concepciones, más modernas que postmodern(ist)as, proponiendo una posible evolución en la arquitectura más reciente cuyas raíces, a fin de cuentas, tendrían su origen en la Norteamérica de 1946 a 1966. ABSTRACT Complexity and Contradiction in Architecture has proved to be one of the capital, alluded references cited and reproduced in the architectural literature of the recent times. Not surprisingly, in the Introduction to the book, Vincent Scully wrote that "yet it is probably the most important writing on the making of architecture since Le Corbusier´s ‘Vers une Architecture’, of 1923". However, its sources seem to be unexplored or at least not examined. Therefore, Road to 1966 is presented as a research with three fundamental starting objectives: (1) first, the interest in studying the burning architectural debate, created within the arising frictions among the protagonists of the years that changed the status of what was considered a legitimate work in architecture; (2) second, it seeks to extend the chronology of the intellectual background of the book written by Venturi, which marked the second half of the twentieth century, in a retroactive manner to the years of the World War II, when it seems that some new positions from which to approach the issues of practice, theory and history of architecture began to be consistent and recognizable; (3) lastly, to offer a new interpretation of Venturi’s text, now understood not as the primal source of the great transformations of the recent architecture (of the last fifty years), but as the necessary result of that background intellectual chronology. The American architecture of these post-war years has proved to be crucial in its later stages, and especially in relation to the book of Robert Venturi. In fact, Scully in the Introduction to the first edition of Complexity and Contradiction, noted that "the major argument of this book was laid out in the late fifties". The fact that the architecture of the twentieth century –when the leading figure of Venturi was consolidated- has in the North America of the sixties one of its most decisive chapters, (often assumed as the next step to the imported European heroic modernism) today seems to be discussed by almost anyone. Now, what about the intervening years? What happens between the end of the World War II and the sixties? The potential lack of a clear dominant position of this stage may have plunged it into oblivion or oversight by historians and critics. Thus, this research is structured around the role that occupies Venturi’s work, whereas this is not its only subject. Rather taken as an excuse, the thesis deepens deductively in the set of circumstances that could lead its author to the conclusions he developed in 1966, detecting biographical and academic environments, shared thoughts and epistemological and mutual professional influences, that would justify a new interpretation of this book as a necessary corollary of an outlook of crisis and change (this major and center subject in this dissertation), contrary to what has been commonly understood upon this work. The research focuses predominantly on tracing the sources cited by Venturi himself in his book, as well as other texts of wider dissemination and outreach (usually professional journals not exclusively academic, as well as books, catalogs of exhibitions, symposia proceedings...), and not so much in the buildings or unbuilt projects; but also, perhaps, it is focused in the terms in which these works were published, commented or reviewed. Hence an approach conceived sub specie bibliotecae has been adopted, with working methods characterized by their chronological component, and then the analytical-comparative one: in other words, a historiographicaljournalistic method able to relate stories or courses of certain ideas or notions, within a broader general context in its architectural, aesthetic, sociological-generational, cultural, philosophical, scientific, political, literary... sides. This approach intends to establish a re-reading of Venturi’s first book and its years of gestation, from some new understandings, more modern than postmodern(ist), proposing a possible evolution of the latest architecture whose roots, after all, would have their origin in the North America of 1946-1966.

Understanding how to reduce road transport emissions : modelling the impact of eco-driving

Entre los problemas medioambientales más trascendentales para la sociedad, se encuentra el del cambio climático así como el de la calidad del aire en nuestras áreas metropolitanas. El transporte por carretera es uno de los principales causantes, y como tal, las administraciones públicas se enfrentan a estos problemas desde varios ángulos: Cambios a modos de transporte más limpios, nuevas tecnologías y combustibles en los vehículos, gestión de la demanda y el uso de tecnologías de la información y la comunicación (ICT) aplicadas al transporte. En esta tesis doctoral se plantea como primer objetivo el profundizar en la comprensión de cómo ciertas medidas ICT afectan al tráfico, las emisiones y la propia dinámica de los vehículos. El estudio se basa en una campaña de recogida de datos con vehículos flotantes para evaluar los impactos de cuatro medidas concretas: Control de velocidad por tramo, límites variables de velocidad, limitador de velocidad (control de crucero) y conducción eficiente (eco‐driving). Como segundo objetivo, el estudio se centra en la conducción eficiente, ya que es una de las medidas que más ahorros de combustible presenta a nivel individual. Aunque estas reducciones están suficientemente documentadas en la literatura, muy pocos estudios se centran en estudiar el efecto que los conductores eficientes pueden tener en el flujo de tráfico, y cuál sería el impacto si se fuera aumentando el porcentaje de este tipo de conductores. A través de una herramienta de microsimulación de tráfico, se han construido cuatro modelos de vías urbanas que se corresponden con una autopista urbana, una arteria, un colector y una vía local. Gracias a los datos recogidos en la campaña de vehículos flotantes, se ha calibrado el modelo, tanto el escenario base como el ajuste de parámetros de conducción para simular la conducción eficiente. En total se han simulado 72 escenarios, variando el tipo de vía, la demanda de tráfico y el porcentaje de conductores eficientes. A continuación se han calculado las emisiones de CO2 and NOx mediante un modelo de emisiones a nivel microscópico. Los resultados muestran que en escenarios con alto porcentaje de conductores eficientes y altas demandas de tráfico las emisiones aumentan. Esto se debe a que las mayores distancias de seguridad y las aceleraciones y frenadas suaves hacen que aumente la congestión, produciendo así mayores emisiones a nivel global. Climate change and the reduced air quality in our metropolitan areas are two of the main environmental problems that the society is addressing currently. Being road transportation one of the main contributors, public administrations are facing these problems from different points of view: shift to cleaner modes, new fuels and vehicle technologies, demand management and the use of information and communication technologies (ICT) applied to transportation. The first objective of this thesis is to understand how certain ICT measures affect traffic, emissions and vehicle dynamics. The study is based on a data collection campaign with floating vehicles to evaluate the impact of four specific measures: section speed control, variable speed limits, cruise control and eco‐driving. The second objective of the study focuses on eco‐driving, as it is one of the measures that present the largest fuel savings at an individual level. Although these savings are well documented in the literature, few studies focus on how ecodrivers affect the surrounding vehicles and the traffic, and what would be the impact in case of different eco‐drivers percentage. Using a traffic micro‐simulation tool, four models in urban context have been built, corresponding to urban motorway, urban arterial, urban collector and a local street. Both the base‐case and the parameters setting to simulate eco‐driving have been calibrated with the data collected through floating vehicles. In total 72 scenarios were simulated, varying the type of road, traffic demand and the percentage of eco‐drivers. Then, the CO2 and NOx emissions have been estimated through the use of an emission model at microscopic level. The results show that in scenarios with high percentage of co‐drivers and high traffic demand the emissions rise. Higher headways and smooth acceleration and decelerations increase congestion, producing higher emissions globally.

Implementation of road dust resuspension in air quality simulations of particulate matter in Madrid (Spain)

An evaluation of the concentration levels of Particulate Matter (PM) was carried out in Madrid (Spain) by introducing the emissions from road dust resuspension. Road dust resuspension emission factors (EF) for different types of vehicles were calculated from EPA-AP42, a global resuspension factor of 0.097 g veh−1km−1 as described in Amato et al. (2010) and a rain-dependent correction factor. With these resuspension EFs, a simulation at street canyon level was performed with the OSPM model without rainfall. Subsequently, a simulation using the CMAQ model was implemented adding resuspension emissions affected by the rain. These data were compared with monitored data obtained from air quality stations. OSPM model simulations with resuspension EFs but without the effect of rainfall improve the PM estimates in about 20gm−3μ compared to the simulation with default EFs. Total emissions were calculated by adding the emissions estimated with resuspension EFs to the default PM emissions to be used by CMAQ. For the study in the Madrid Area, resuspension emissions are approximately of the same order of magnitude as inventoried emissions. On a monthly scale, rain effects are negligible for resuspension emissions due to the dry weather conditions of Spain. With the exception of April and May, the decrease in resuspension emissions is not >3%. The predicted PM10 concentration increases up to 9μ gm−3 on annual average for each station compared to the same scenario without resuspension. However, in both cases, PM 10 estimates with resuspension are still underestimating observations. It should be noted that although that accounting for resuspension improves the quality of model predictions, other PM sources (e.g., Saharan dust) were not considered in this study.

The rocky road ahead to peace : the Arab Uprisings and the conflict in Libya

Peer reviewed