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    <title>Transport Research International Documentation (TRID)</title>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
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      <link>https://trid.trb.org/</link>
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      <title>Technische Konzeptionierung und Umsetzung eines prototypischen externen Human-Machine-Interfaces (eHMI) zur Kommunikation automatisierter Fahrzeuge mit anderen Verkehrsteilnehmenden</title>
      <link>https://trid.trb.org/View/2487874</link>
      <description><![CDATA[Ziel ist es, im Hinblick auf die Förderung der Verkehrssicherheit ein prototypisches externes Human-Machine-Interface (eHMI) technisch zu konzipieren und prototypisch umzusetzen. Das eHMI soll zur Kommunikation autonomer (fahrerloser) Fahrzeuge mit zu Fuß gehenden Menschen dienen, während es von zusätzlich anwesenden menschlichen Fahrzeugführenden nicht missinterpretiert werden darf. Das eHMI soll spezifisch der Kommunikation an Engstellen dienen, in denen die Vorfahrt nicht eindeutig geregelt ist und ein zu Fuß Gehender die Fahrbahn in der Engstelle queren möchte. Das eHMI soll vorranging mit dem/der Fußgänger/-in kommunizieren, während es jedoch auch für andere Verkehrsteilnehmende sichtbar ist. Das eHMI soll an aktuellen Forschungsergebnissen orientiert sein. Es soll sich um ein visuelles eHMI handeln, welches aus allen relevanten Perspektiven sichtbar ist und an einem autonomen Fahrzeug angebracht werden kann. Der Nutzen des Projekts besteht darin, eine Validierungsgrundlage für eine zukünftige Bewertungsmethode für eHMIs zu schaffen. ABSTRACT IN ENGLISH: The aim is to technically design and prototypically implement a prototype external human-machine interface (eHMI) with a view to promoting road safety. The eHMI is to be used for communication between autonomous (driverless) vehicles and people on foot, while it must not be misinterpreted by human drivers who are also present. The eHMI should be used specifically for communication at bottlenecks where the right of way is not clearly regulated and a pedestrian wants to cross the carriageway in the bottleneck. The eHMI should primarily communicate with the pedestrian, while also being visible to other road users. The eHMI should be based on current research results. It should be a visual eHMI that is visible from all relevant perspectives and can be attached to an autonomous vehicle. The benefit of the project is to create a validation basis for a future evaluation method for eHMIs.
]]></description>
      <pubDate>Thu, 09 Jan 2025 10:30:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2487874</guid>
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    <item>
      <title>Kostnader för trafikbuller fördelat på olika boendemiljöer</title>
      <link>https://trid.trb.org/View/1748836</link>
      <description><![CDATA[Noise disturbance costs are based on differences in house prices for noise exposure. An important factor for which there is still no scientifically knowledgeable knowledge is the total noise cost (per person per year) distribution of the cost of noise disturbance when staying inside the dwelling or residence outside the dwelling. This distribution is still made on the basis of standard estimates previously made (ie, 50 percent of interference is in and out, respectively), but scientifically documented results are not yet available. This project aims to analyze, with empirical methods of housing prices, whether any distribution other than 50% each between different types of housing environments is more compatible with individuals' willingness to pay for reduced noise disturbances]]></description>
      <pubDate>Mon, 02 Nov 2020 14:08:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1748836</guid>
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    <item>
      <title>Roughest hour: approaches to ship hull fouling management</title>
      <link>https://trid.trb.org/View/1737772</link>
      <description><![CDATA[Submerged surfaces at sea are colonized by a high diversity of sessile (i.e. attached) life forms. As the merchant fleet capacity increases, responding to growth in demand for seaborne transport, so does the hull wetted surface area that is prone to colonization by these sessile organisms, i.e. marine biofouling. Such colonization leads to increased ship hull surface roughness, which results in both environmental and economic issues, namely fuel penalties and increased emissions to air. Improved maintenance of the hull would not only reduce these penalties, but also reduce emission of antifoulants and other paint components to the marine environment, as well as risks related to the transport of non-indigenous species on fouled hulls. The work presented in this thesis aimed at improving current approaches to the management of ship hull fouling, which typically rely on a combination of fouling-control coatings and an in-water cleaning scheme. Knowledge on the adhesive strength of fouling to minimize cleaning forces, on the one hand, and evaluation of the hull condition and hull roughness penalties, on the other hand, are therefore central to the aim of this thesis. The outcome of performed work supports a preventive approach to hull maintenance, e.g. gentle and frequent cleanings (hull grooming), or an alternative predictive approach, based on vessel performance and condition monitoring for detecting early forms of fouling. Tools are provided with potential to improve hull maintenance practices. These include minimizing cleaning forces applied during in-water hull cleaning through knowledge on adhesion strength of fouling (Papers I, III and IV), and more-accurate determination of the impact of fouling on vessel performance, namely by accounting for hull form effects (Papers II) or using a novel performance indicator that would be applicable in wider comparisons between vessels (Paper V).]]></description>
      <pubDate>Tue, 08 Sep 2020 14:37:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/1737772</guid>
    </item>
    <item>
      <title>Investigation of NVH phenomena at electric vehicles</title>
      <link>https://trid.trb.org/View/1605928</link>
      <description><![CDATA[Sound quality is one of the key interfaces customers evaluate with their vehicles. New powertrain concepts, either fully electric or hybrid, come with new NVH problems and previously unknown phenomena. The entirely different setup of electric engine and gearbox and the higher rotational speeds are now creating perceivable noises and vibrations at way higher frequencies. Further, the omission of both combustion engine and exhaust system eliminates two of the most dominant sound sources. These systems were typically masking many other sounds, which are now perceivable. Considering the whole vehicle, measurement points and used transducers can remain the same, even though the sound field itself is rather different. While exterior noise is rather exciting due to the regulatory point of view, rotational analysis is still an exciting topic and needs to be further investigated.]]></description>
      <pubDate>Thu, 25 Jul 2019 10:04:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1605928</guid>
    </item>
    <item>
      <title>EL AEROTRANSPORTE COMERCIAL ENTRE MEXICO Y LOS EE. UU. EN EL CONTEXTO DEL NUEVO ACUERDO BILATERAL</title>
      <link>https://trid.trb.org/View/1574750</link>
      <description><![CDATA[En diciembre de 2015, los gobiernos de Mexico y los Estados Unidos firmaron un nuevo acuerdo sobre transporte aereo, que entro en vigor en agosto de 2016. El nuevo acuerdo es una de las estrategias establecidas para fortalecer la integracion binacional en el marco del Tratado de Libre Comercio de America del Norte. La liberalizacion de los mercados emprendida por el gobierno mexicano en la decada de los noventa tuvo un alcance esencialmente domestico. El nuevo acuerdo extiende la apertura comercial al mercado binacional, con lo que se eliminan las restricciones respecto al numero designado de aerolineas por ruta, la asignacion de origenes y destinos, y las tarifas. Un aspecto que destaca en el acuerdo es el establecimiento de la denominada “quinta libertad” para las aerolineas de pasajeros y la “septima libertad” para las aerolineas de carga, que les otorgan mayores facilidades para articular cadenas de transporte internacional que incluyan terceros paises. En este trabajo se presenta un breve analisis de la situacion actual del transporte aereo entre Mexico y los Estados Unidos, que sirve de base para entender las razones que explican el establecimiento del nuevo acuerdo y reflexionar sobre algunos de sus posibles efectos en el mercado de servicios de transporte aereo. abstract:  On December 18th , 2015, government representatives of Mexico and the United States of America signed a new air transport agreement which has come into force on August 21th, 2016. This agreement is not an isolated economic policy instrument, but it is explicitly considered as a strategy to strengthen the binational integration defined by the North American Free Trade Agreement. The air transport markets liberalization undertaken by the Mexican Government in the 1990’s had a domestic scope. The new agreement extends the liberalization to the binational market, thus deregulating the number of participating airlines in the routes, the origin – destination assignments, and the fare control. Additionally, the agreement includes the enablement of the so-called “fifth freedom” for passenger airlines, and “seventh freedom” for cargo airlines. This report presents a brief analysis of the current situation of the air transportation between Mexico and the USA, which works as a basis to understand the reasons behind the new agreement and to think over some of its expected impacts.]]></description>
      <pubDate>Wed, 19 Dec 2018 10:42:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1574750</guid>
    </item>
    <item>
      <title>MANUAL ESTADISTICO DEL SECTOR TRANSPORTE 2017</title>
      <link>https://trid.trb.org/View/1564416</link>
      <description><![CDATA[Esta publicacion constituye la vigesima novena edicion del Manual Estadistico del Sector Transporte, producido por primera vez en 1989. Hasta la edicion 1999 se busco que el ano de actualizacion fuera el mismo para todos los temas, lo cual dio como resultado que se incluyera informacion estadistica con dos anos de atraso respecto al ano de publicacion; el presente Manual Estadistico del Sector Transporte 2017 en cambio, fue integrado con la intencion de tener actualizado a 2016 la mayoria de la informacion. El Manual Estadistico tiene como objetivo ofrecer a los interesados en la materia una perspectiva global de la evolucion reciente del transporte en Mexico (1993-2017) a traves de informacion estadistica oficial, generada dentro y fuera del Sector.]]></description>
      <pubDate>Mon, 22 Oct 2018 09:17:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1564416</guid>
    </item>
    <item>
      <title>Räfflor: effekter och konsekvenser av olika räffeltyper vid mitträffling på 2-fältsvägar</title>
      <link>https://trid.trb.org/View/1426564</link>
      <description><![CDATA[Milled rumble strips is one way to attract the drivers' attention when they involuntarily are about to leave the lane. The rumble strips provide both internal and external noise but also vibrations in the vehicle. The overall aim of this work is to elucidate the effects and consequences of the use of intermittent milled rumble strips compared to sinus milled rumble strips in the center of the road. The comparison take into account; external noise, internal noise, vibrations, damage to the road surface and the price. However, due to lack of data, vibrations and price issues are excluded here. The work is based on documentation of lessons learned in Sweden, Denmark, Norway and Finland. In Denmark, Norway and Sweden, measurements were made of the maximum external noises. There were major variations in results for both intermittent rumble strips and sinus rumble strips. The results show that the intermittent rumble strips provide an increase of external noise on the 2—8 dB (A). The corresponding figure for the sinus rumble strip is 0.0 to 4 dB (A). Further, it is found that the sinus rumble strips provide more low frequency noise (30—40Hz) compare to the intermittent rumble strips (60—160 Hz). Maximum noise from intermittent rumble strips are obtained around 80—90 km/h, and at 90 km/h the threshold for noise for those living close to the road is 90—140 meters. It is not known at what speed the sinus rumble strip provide the maximum noise. There is reason to believe that what is perceived as disturbing is not only related to the maximum noise but rather to fact that the sound deviates from the traffic noise monotonous sound. The rumble strip sound is more low frequency and not continuously. Regarding the internal noise most studies have focused on passenger cars and an increase in internal noise when driving on intermittent rumble strips varies between 13—17 dB (A). For the sinus rumble strip the corresponding values are 1—6 dB (A). If the level obtained for the sinus rumble strip is sufficient in order to attract the driver's attention is as far as we know not evaluated. However, results from simulator studies show that even low levels of internal noise is helpful for drivers who are about to leave the lane due to sleepiness. The sinus rumble strips provide not only noise but also vibrations. What the most important component to attract attention is, is not known, but most truly the vibrations create an important contributing effect. There are almost no studies available on the effects regarding drivers of trucks and buses. The coating quality is one aspect to consider and experience shows that the less areas milled, the less damage on the coating. Furthermore, there is a recommendation not to mill on surface thinner than 25 mm. The majority of tests have been on the shoulder and not in the center of the road. Evaluations from Denmark and Norway combine the sinus rumble strips with the lane marking, the so called drip flex (coating mass dropped into points near each other in a line formation) and the top of the sinus rumble strip is a bit under the surface level. This is done to protect the sinus rumble strip and the coating.]]></description>
      <pubDate>Mon, 17 Oct 2016 11:57:20 GMT</pubDate>
      <guid>https://trid.trb.org/View/1426564</guid>
    </item>
    <item>
      <title>MANUAL ESTADISTICO DEL SECTOR TRANSPORTE 2015</title>
      <link>https://trid.trb.org/View/1424950</link>
      <description><![CDATA[Esta publicacion tiene como objetivo ofrecer a los interesados en la materia una perspectiva global de la evolucion reciente del transporte en Mexico (1993-2014), a traves de informacion estadistica oficial generada dentro y fuera del Sector. Consta de 99 cuadros, acompanados de textos, figuras y croquis, que pretenden facilitar la consulta y auxiliar en la interpretacion de las series estadisticas. Se dedica un capitulo a cada tema: la participacion del transporte en la economia nacional; transporte y comercio exterior; trafico de carga contenerizada; movimiento y trafico domestico de carga; movimiento y trafico de pasajeros; infraestructura del transporte; equipo de transporte; inversiones en transporte; costos de infraestructura y equipo; transporte de petroleo y consumo de energia. Se anexa una relacion cronologica de disposiciones legales relacionadas con el funcionamiento del  transporte.]]></description>
      <pubDate>Fri, 30 Sep 2016 16:31:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1424950</guid>
    </item>
    <item>
      <title>MANUAL ESTADISTICO DEL SECTOR TRANSPORTE 2013</title>
      <link>https://trid.trb.org/View/1368887</link>
      <description><![CDATA[Esta publicacion tiene como objetivo ofrecer a los interesados en la materia una perspectiva global de la evolucion reciente del transporte en Mexico (1993-2010), a traves de informacion estadistica oficial generada dentro y fuera del Sector. Consta de 108 cuadros, acompanados de textos, figuras y croquis, que pretenden facilitar la consulta y auxiliar en la interpretacion de las series estadisticas. Se dedica un capitulo a cada tema: la participacion del transporte en la economia nacional; transporte y comercio exterior; trafico de carga contenerizada; movimiento y trafico domestico de carga;  movimiento y trafico de pasajeros; infraestructura del transporte; equipo de transporte; inversiones en transporte; costos de infraestructura y equipo; transporte de petroleo y consumo de energia. Se anexa una relacion cronologica de disposiciones relacionadas con el funcionamiento del transporte.]]></description>
      <pubDate>Fri, 25 Sep 2015 16:31:46 GMT</pubDate>
      <guid>https://trid.trb.org/View/1368887</guid>
    </item>
    <item>
      <title>Principle Other Vehicle Warning</title>
      <link>https://trid.trb.org/View/1347599</link>
      <description><![CDATA[The only possibility for a driver to avoid a collision may sometimes be to issue a warning to another driver. Connecting the horn and the headlight to an already existing sensor system could be a cost effective solution. This report covers the implementation and evaluation of such an automated warning system in a driving simulator at VTI. In this test 24 drivers with normal hearing and 24 with moderate hearing loss experienced five critical events in which four different warning signals were evaluated; sound, light, and a combination of sound and light, and no warning (as reference). A visual distraction task was used to distract the drivers and create critical situations. The results were consistent. A combined sound and light warning significantly increased cautious driving behaviour and also lead to the highest perceived criticality of the situations. With the combined warning the driver’s attention was effectively drawn from the visual distraction task. Drivers were generally positive towards the warning system, and most positive towards the combined warning presenting light and sound signals. Drivers were able to distinguish between warnings (at critical events) and greetings (at non-critical events) suggesting that the tested additional use of horn and headlight would not affect reactions to non-critical warnings or greetings. Hearing loss was associated with worse performance on the visual distraction task and less perceived realism of the driving simulator. But it was not associated with effects on any driving behaviour measures or of warning modalities. This result suggests that the evaluated system should work also for drivers with moderate hearing loss.]]></description>
      <pubDate>Fri, 27 Mar 2015 12:06:37 GMT</pubDate>
      <guid>https://trid.trb.org/View/1347599</guid>
    </item>
    <item>
      <title>Externt buller från mitträfflor</title>
      <link>https://trid.trb.org/View/1347530</link>
      <description><![CDATA[Milled centerline rumble strips are used as a safety measure by alerting the driver via sound and vibration inside the vehicle. A secondary effect is that exterior noise is generated and that is a potential cause of annoyance and sleep disturbance for inhabitants living close to the road. This report describes a series of measurements and calculations with the aim of determining how many rumble strip hits that can be expected and what sound levels can be generated. The number of hits was determined using a total of ten days of measurements from four different locations and the results show that 0.2–1.0 per cent of all vehicle passages hit the rumble strip. The percentage of vehicles that hit the strip increases during night. The noise levels that are generated during a hit were determined by controlled pass-by measurements at different speeds with three different vehicles, a car with normal tires, a car with low profile tires and a truck (towing engine of semi-trailer). These measurements where then used to predict the outdoor and indoor noise levels. The calculations show that the Swedish guideline values may be exceeded at short distances, but it may be questioned if the road traffic noise guidelines are valid for rumble strip hits, since the noise is both impulsive and tonal in character.]]></description>
      <pubDate>Fri, 27 Mar 2015 12:04:07 GMT</pubDate>
      <guid>https://trid.trb.org/View/1347530</guid>
    </item>
    <item>
      <title>Noise emission levels for electric and hybrid vehicles: first results of the FOREVER project</title>
      <link>https://trid.trb.org/View/1327824</link>
      <description><![CDATA[The FOREVER project (Future OpeRational impacts of Electric Vehicles on national European Roads), which started in January 2013, intends to identify the impact of electric and hybrid-electric vehicles on road traffic noise. Initially developed for urban situations, these vehicles can now be encountered on national road networks due to the increase of their electric range. This paper presents in a first stage results regarding the characterization of their noise emission using relevant measuring techniques and a reflection on how they could be used as input data of the CNOSSOS-EU prediction model for an environmental quantification. The data presented concerns mainly measurements carried out on light vehicles, although heavier vehicles will also be considered in the project. In a second stage, in complement to EPNL (Effective Perceived Noise Level) we analyze data obtained with a system of perceptual dimensions to assess how the variation in the character of the noise from different vehicle mixes is likely to affect annoyance levels.]]></description>
      <pubDate>Wed, 15 Oct 2014 10:40:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1327824</guid>
    </item>
    <item>
      <title>Experimentelle Untersuchungen zum Einfluss einer externen Vorspannung auf die Querkrafttragfaehigkeit vorgespannter Durchlauftraeger / Experimental investigations on the influence of an external prestressing on the shear behavior of prestressed continuous beams</title>
      <link>https://trid.trb.org/View/1290182</link>
      <description><![CDATA[Durch die gestiegene Verkehrsbelastung und Veraenderungen im Querkraftnachweis weisen viele aeltere Bruecken in Deutschland nach den aktuell gueltigen Normen rechnerische Defizite in der Querkrafttragfaehigkeit auf. Um diese Bruecken weiterhin fuer den Verkehr freizugeben, koennen zum einen durch die Anwendung verfeinerter Bemessungsansaetze die vorhandenen Tragreserven ausgenutzt und zum anderen Verstaerkungsmassnahmen durchgefuehrt werden. Beschrieben werden die Ergebnisse experimenteller Untersuchungen im Auftrag der Bundesanstalt fuer Strassenwesen (BASt) zum Einfluss einer zusaetzlichen externen Vorspannung auf die Querkrafttragfaehigkeit bestehender Spannbetonbruecken. Hierzu wurden sechs Bauteilversuche an drei Durchlauftraegern mit parabelfoermiger Vorspannung und zusaetzlicher externer Vorspannung durchgefuehrt. Nach den Versuchen liefert der derzeitige Bemessungsansatz auf Grundlage des Fachwerkmodells mit Rissreibung konservative Ergebnisse bei der Bestimmung der Querkrafttragfaehigkeit. Erweiterte Ansaetze ermoeglichen eine genauere Bestimmung der Querkrafttragfaehigkeit. (A) ABSTRACT IN ENGLISH: Many bridges in Germany exhibit calculative shear capacity deficits according to current codes due to increased traffic loads and changes in the code provisions. In order to extent their service life, the existing reserves in the design procedures can in part be used by application of refined design approaches. Furthermore, strengthening measures can be performed. The article describes the results of experimental investigations on the influence of an additional external prestressing on the shear capacity of existing prestressed concrete bridges. Within this project six tests on three continuous beams with constant parabolic post-tensioning and variable external post-tensioning were performed. The tests reveal that the current approach on the basis of a truss model with crack-friction leads to conservative design results concerning the determination of the shear capacity whereas alternative approaches yield more accurate values of the shear capacity. (A)]]></description>
      <pubDate>Tue, 28 Jan 2014 09:19:51 GMT</pubDate>
      <guid>https://trid.trb.org/View/1290182</guid>
    </item>
    <item>
      <title>Code de bonne pratique pour les revetements industriels exterieurs en beton</title>
      <link>https://trid.trb.org/View/1254108</link>
      <description><![CDATA[This publication deals with outdoor industrial pavements in concrete, which need to be discriminated clearly from indoor industrial floors mainly because they are exposed to weather agents. Whereas numerous publications, guidelines and recommendations are available for indoor industrial floors, technical literature on outdoor industrial pavements is relatively scarce. This code of good practice aims to fill this gap. The first chapter describes the field of application and the relevant terminology. The second chapter discusses the structural design of outdoor industrial pavements and the main factors to be considered. Design and construction aspects such as concrete composition, joints, reinforcements, laying method, finishing and curing are presented in detail in the third chapter – with ample allowance for weather agents. The fourth chapter is devoted to special applications such as large slabs in reinforced concrete, toppings, low-shrinkage concrete, etc. Inspections and evaluations are the subject of the fifth chapter. The sixth chapter elaborates on deficiencies and on maintenance and repairs. The final chapter explains how the principles of sustainable development can be implemented when constructing outdoor industrial pavements. (ABSTRACT IN FRENCH: Le present code de bonne pratique traite des revetements industriels exterieurs en beton à distinguer clairement des sols industriels interieurs, principalement en raison des influences meteorologiques. De nombreuses publications, directives et recommandations existent deja pour les sols industriels interieurs. Le present ouvrage vise a combler la lacune dans le domaine des revetements industriels exterieurs. Le premier chapitre traite du domaine d’application et de la terminologie relatifs aux revetements exterieurs en beton, tandis que le deuxieme aborde le dimensionnement et les facteurs qui l’influencent. Le troisieme chapitre se penche en detail sur la conception et l’execution proprement dite, notamment la composition du beton, les armatures, les joints, les methodes de mise en oeuvre, la finition de surface et la cure du beton frais. Il prete aussi attention aux conditions meteorologiques a la mise en oeuvre. Le chapitre 4 est consacre a quelques applications particulieres comme les grandes dalles en beton armé, les toppings, le béton à faible retrait, etc. Le chapitre 5 donne des informations sur le controle et l’evaluation, tandis que le chapitre 6 aborde les degradations, l’entretien et les reparations. Le document se termine sur quelques aspects de construction durable.]]></description>
      <pubDate>Mon, 01 Jul 2013 12:03:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/1254108</guid>
    </item>
    <item>
      <title>Einfluss einer nachtraeglichen externen Vorspannung in Laengsrichtung auf die Querkrafttragfaehigkeit bestehender Spannbetonbruecken / Impact of subsequent, external prestressing in a longitudinal direction on the shear resistance of existing prestressed-concrete bridges</title>
      <link>https://trid.trb.org/View/1246830</link>
      <description><![CDATA[Bei der Nachrechnung von aelteren Spannbetonbruecken entsprechend den Regelungen der DIN-Fachberichte (DIN-FB) 101 und 102 werden oft Defizite bei der Querkrafttragfaehigkeit des Laengstragsystems festgestellt. Diese Bruecken haben zu wenig Querkraftbewehrung, gelten also nach den Regelungen des DIN-FB 102 als nicht ausreichend tragfaehig. Die ersten Regelungen des Spannbetonbrueckenbaus legten eine so genannte "Bemessungsnachweisgrenze" fuer die schiefen Hauptzugspannungen fest. Somit war eine Schubbewehrung rechnerisch nicht erforderlich, wenn diese Grenze nicht ueberschritten wurde. Eindeutige Regelungen fuer den Einbau von Mindestbewehrung gab es zunaechst nicht, sodass vielfach Bruecken mit geringer Querkraftbewehrung gebaut wurden. Ursachen fuer das Defizit bei der Querkrafttragfaehigkeit nach den heutigen Regelungen sind die groesseren charakteristischen Einwirkungen, insbesondere bei den Verkehrslasten, aber auch Einwirkungen, beispielsweise Temperaturunterschiede, die bei der Statik aelterer Bruecken haeufig nicht ausreichend beruecksichtigt wurden. Das Defizit wird aber auch wesentlich durch die gestiegenen Anforderungen des DIN FB 102 bei der Querkraftbemessung und den Konstruktionsregeln fuer die Mindestbewehrung beeinflusst. Zur Erhoehung der Tragfaehigkeit von aelteren Spannbetonbruecken in Laengsrichtung erfolgt haeufig eine Verstaerkung mit externer Vorspannung. Die zusaetzlich erzeugten Laengsdruckspannungen im Beton fuehren dabei vermutlich auch zu einer Verminderung der Hauptzugspannungen. Im Zustand II koennte die externe Vorspannung durch die Steigerung der Druckbogentragfaehigkeit einen wertvollen Tragfaehigkeitsgewinn liefern. Diese guenstigen Einfluesse einer externen Vorspannung auf die Querkrafttragfaehigkeit sollen im Rahmen des Projekts erfasst und in die Nachweise zur Querkrafttragfaehigkeit von Spannbetonbruecken integriert werden. Werden die positiven Einfluesse der externen Vorspannung auf das Querkrafttragverhalten bestaetigt und ein Nachweisformat aufgezeigt, koennte vielfach auf konstruktive Querkraftverstaerkungen von aelteren Spannbetonbruecken, die sehr kostenaufwendig und mit gravierenden Eingriffen in das Tragwerk verbunden sind, verzichtet werden. ABSTRACT IN ENGLISH: Recalculation of older, prestressed concrete bridges according to the regulations of DIN Technical Reports (DIN-FB) 1001 and 1002 often shows deficits in the shear resistance of the longitudinal force carrying system. These bridges have too little shear reinforcement and therefore do not have sufficient carrying capacity according to DIN-FB 102. The first regulations for prestressed concrete bridge constructions defined an "assessment threshold" for the diagonal main shear tensions. Shear reinforcement was therefore not required when the calculations showed that this shear force was not exceeded. At first, there were no clear regulations concerning the installation of minimum reinforcements, so many bridges were built with little shear reinforcement. Reasons for the lack of shear force resistance according to current regulations are larger characteristic impacts, in particular traffic loads, but also factors such as temperature differences that were not sufficiently taken into account in the static calculations for older bridges. Further important reasons for the shortfall are the increased requirements of DIN FB 102 regarding shear force dimensioning and the design rules for minimum reinforcement. The carrying capacity of older, prestressed concrete bridges is frequently increased by reinforcement with external prestressing. The additionally created, compressive stress in a longitudinal direction in the concrete is expected to lead to a reduction of the main shear forces. In state II, external prestressing forces could provide a valuable increase in carrying capacity by increasing the pressure arch carrying capacity. The beneficial effects of external prestressing force on the shear force resistance are to be determined in this project and integrated into proofs of the shear force capability of prestressed concrete bridges. When the positive effects of external prestressing on the shear force resistance are confirmed and can be proven, structural shear reinforcements of older prestressed concrete bridges, which are often very costly and involve massive interference with the carrying structure, might be avoidable.]]></description>
      <pubDate>Tue, 02 Apr 2013 09:11:55 GMT</pubDate>
      <guid>https://trid.trb.org/View/1246830</guid>
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