1,692,438 research outputs found
Monitoring Bridge Dynamic Behaviour Using an Instrumented Two Axle Vehicle
No full textBridge & Infrastructure Research in Ireland 2010 (BRI 10), Cork, 2-3 September 2010Highway structures such as bridges are subject to continuous degradation primarily
due to ageing, loading and environmental factors. A rational transport policy must
monitor and provide adequate maintenance to this infrastructure to guarantee the
required levels of transport service and safety. Increasingly in recent years, bridges are
being instrumented and monitored on an ongoing basis due to the implementation of
Bridge Management Systems. This is very effective and provides a high level of
protection to the public and early warning if the bridge becomes unsafe. However, the
process can be expensive and time consuming, requiring the installation of sensors
and data acquisition electronics on the bridge. This paper investigates the use of an
instrumented 2-axle vehicle fitted with accelerometers to monitor the dynamic
behaviour of a bridge network in a simple and cost-effective manner. A simplified
half car-beam interaction model is used to simulate the passage of a vehicle over a
bridge. This investigation involves the frequency domain analysis of the axle
accelerations as the vehicle crosses the bridge. The spectrum of the acceleration
record contains noise, vehicle, bridge and road frequency components. Therefore, the
bridge dynamic behaviour is monitored in simulations for both smooth and rough road
surfaces. The vehicle mass and axle spacing are varied in simulations along with
bridge structural damping in order to analyse the sensitivity of the vehicle
accelerations to a change in bridge properties. These vehicle accelerations can be
obtained for different periods of time and serve as a useful tool to monitor the
variation of bridge frequency and damping with time.Deposited by bulk importRB 20/02/1
Sereno Bridge Civil War letters
No full textThis collection contains ten letters written at Helena, Ark., by Sereno Bridge while he was serving with Company G of the 15th Illinois Cavalry, as well as a transcription of each letter
Individual Wellbeing and Bridge: An Empirical Analysis
No full textThere is a growing interest in the Sociology of bridge. This research is part of a wider examination of bridge from a sociological and medical perspective, and is conducted with the intention of providing some of the groundwork for a larger study of the social and cognitive benefits of playing bridge, in particular its role in delaying the onset and reducing the severity of dementia (Ashworth et al., 2016; Graham & Punch, 2016). At the top level, bridge can be a professional card game played full-time by experts who are sponsored to play in teams. It is a mind sport that, even at amateur level, requires much work in terms of developing bridge partnerships and strategies. The dynamics of bridge can be understood in relation to a range of sociological areas such as gender, class, age and generation, identity. In this paper we address another key sociological topic: individual wellbeing. This exploratory study contributes to the evidence base on the benefits of playing bridge by answering the following research questions: 1. What are the characteristics of bridge players and their playing habits? 2. Is there an association between playing bridge and measures of individual wellbeing? Related dataset available at: http://hdl.handle.net/11667/8
Wind loads analysis at the anchorages of the Talavera de la Reina cable stayed bridge
No full textThis paper describes wind tunnel tests performed on wind tunnel models of the Talavera de la Reina cable stayed bridge. The work describes the aeroelastic model construction and it is focused on the evaluation and analysis of the mean and peak wind loads at the tower foundation and the cable anchorages since these data can be very useful by the bridge manufacturer as a support for the bridge design. The work is part of a complete wind tunnel study carried out to analyze the aeroelastic stability of the bridge
Bridge and Dementia Study
No full textThe dataset contains a cross section of over 7000 individuals completing a survey exploring the link between the card game Bridge and quality of life. The responses were collected over a three-month period in 2016 through four online questionnaires; these were disseminated via the Bridge community in the UK and further abroad. The survey captures demographic, social, subjective wellbeing, and bridge playing characteristics of individuals.bridge_allsurveys_20160930.dta Stata dataset of over 7000 responses to a 2016 survey exploring the link between playing bridge and individual wellbeing. Data file is from Data Analysis and Statistical Software (STATA) version 13
Bridge Load Testing: State-of-The-Practice
No full textBridge load testing can answer a variety of questions about bridge behavior that cannot be answered otherwise. The current governing codes and guidelines for bridge load testing in the United States are the 1998 NCHRP Manual for Bridge Rating through Load Testing and Chapter 8 of the AASHTO Manual for Bridge Evaluation. Over the last two decades, the practice of load testing has evolved, and its intersections with other fields have expanded. The outcomes of load tests have been used to keep bridges open cost-effectively without unnecessarily restricting legal loads, when theoretical analyses cannot yield insights representative of in-service performance. Load testing data can be further used to develop field-verified finite-element models of tested bridges to understand these structures better. In addition, structural reliability concepts can be used to estimate the probability of failure based on the results of load tests, and noncontact measurement techniques capturing large surfaces of bridges allow for better monitoring of structural responses. Given these developments, a new Transportation Research Board (TRB) Circular, Primer on Bridge Load Testing, has been developed. This document contains new proposals for interpreting the results of diagnostic load tests, loading protocols, and the determination of bridge load ratings based on the results of proof load tests. In addition, included provisions provide an estimation of the resulting reliability index and the remaining service life of a bridge based on load testing results. The benefit of load testing is illustrated based on a cost-benefit analysis. The current state-of-The-practice has demonstrated that load testing is an effective means for answering many important questions regarding bridge behavior that are critical to decisions on bridge maintenance or replacement. Load testing has evolved over its history, and the newly developed TRB Circular reflects this evolution in a practical way. Accepted Author ManuscriptConcrete Structure
Traffic data collection using a bridge-weigh-in-motion system in a cable-stayed bridge
No full textReliable live traffic data collection is crucial for effective pavement life prediction, fatigue estimation, vibration control, maintenance, and condition assessment of the bridge structures. Bridge weigh-in-motion (BWIM) is a technology utilising a series of conventional strain gauges to characterise the traffic data including speed, number of axles, axles spacing, and gross and axle weight of the passing vehicles. A short-span cable-stayed bridge over the Great Western Highway in the state of New South Wales in Australia is considered as a case study to test and validate the performance of the BWIM axle detection schemes. The bridge is supported by four longitudinal girders sitting on the cross beams which are connected to the bridge cables. The bridge structure including the cables, the girders and the deck have been instrumented with several uni-axial and shear strain gauges to measure the axial, the bending and the shear strains at various locations along the bridge. Data are collected using an HBM Quantum-X data acquisition system and are transferred into a server through 4G connection for signal processing. The purpose of this work is then to identify the sensor arrangement through which the closely-space axles can reliably be detected regardless of the vehicle’s speed, travelling direction and lateral location on the bridge. It is demonstrated that the axial strains on the cables and bending strains under the girders are unable to identify closely-spaced axles. On the contrary, it is revealed that the longitudinal strains under the deck can identify the closely-spaced axles, provided they are accurately positioned under the wheel path. Finally, it is illustrated that the shear rosettes at the end of the span are well capable of producing accurate results for closely-spaced axles irrespective of the location of the vehicle on the bridge
Sustainability of bridge maintenance
No full textBridge maintenance activities are important to consider within sustainable development due to the cost and environmental impact associated with various maintenance activities. Comparisons have been made between different bridge structural forms, based on materials, components and construction method, but less information is available on bridge maintenance activities to help decide a sustainable structural form. Typical maintenance aspects of the predominant forms of bridge structure (i.e. concrete, steel and masonry bridges) were considered in this study to reveal their sustainability in terms of materials, energy, transportation, human health and ecosystems. The results indicate that concrete and steel bridge maintenance activities have an average impact of 42% and 46% compared with 12% for masonry bridge maintenance activities. It is concluded that the component parts of concrete and steel bridges should be revised as they play an integral role in the selection of maintenance options
The Effect of Lane Changing on Long-Span Highway Bridge Traffic Loading
No full textBridge Maintenance, Safety, Management, Resilience & Sustainability, Sixth International IABMAS Conference, Stresa, Lake Maggiore, Italy, 8-12 July 2012Maximum loading on long-span bridges typically occurs in congested traffic conditions. As
traffic becomes congested car drivers may change lane, increasing the tendency for trucks to travel in platoons.
For long-span bridges this phenomenon may increase the regularity and severity of bridge repair programs,
with potential significant associated costs. This research investigates the effect of lane changing by car
drivers on bridge loading. A Monte Carlo simulation model in which individual car drivers probabilistically
decide, based on a lane-changing bias probability, whether or not to change lane has been developed. The
sensitivity of bridge loading to this factor is investigated for different bridge lengths and traffic compositions.
This research concludes that the lane-changing behavior of car drivers has an effect on bridge loading for
long-span bridges, and the magnitude of this effect is quite sensitive to the percentage of trucks in the traffic.Deposited by bulk impor
Evaluation of the Buena Vista IBRD Bridge: A Furthering of Accelerated Bridge Construction in Iowa;TR-605, February 2012
No full textThe need to construct bridges that last longer, are less expensive, and take less time to build has increased. The importance of accelerated bridge construction (ABC) technologies has been realized by the Federal Highway Administration (FHWA) and the Iowa Department of Transportation (DOT) Office of Bridges and Structures. This project is another in a series of ABC bridge projects undertaken by the Iowa DOT.
Buena Vista County, Iowa, with the assistance of the Iowa Department of Transportation (DOT) and the Bridge Engineering Center (BEC) at Iowa State University, constructed a two-lane single-span precast box girder bridge, using rapid construction techniques. The design involved the use of precast, pretensioned components for the bridge superstructure, substructure, and backwalls.
This application and demonstration represents an important step in the development and advancement of these techniques in Iowa as well as nationwide. Prior funding for the design and construction of this bridge (including materials) was obtained through the FHWA Innovative Bridge Research and Deployment (IBRD) Program. The Iowa Highway Research Board (IHRB) provided additional funding to test and evaluate the bridge.
This project directly addresses the IBRD goal of demonstrating (and documenting) the effectiveness of innovative materials and construction techniques for the construction of new bridge structures. Evaluation of performance was formulated through comparisons with design assumptions and recognized codes and standards including American Association of State Highway and Transportation Officials (AASHTO) specifications
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