247,085 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
Report on proposed Mackinac Straits bridge /
No full textAt head of title: State of Michigan, Mackinac Bridge Authority.Pier foundations for a proposed bridge across the Straits of Mackinac : an engineering geologic report / Charles P. Berkey and Sidney Paige.Mode of access: Internet
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
Durability of FRP strengthened reinforced concrete flexural members for bridge structures
No full textThe use of externally bonded Fibre Reinforced Polymer (FRP) composites has become a popular means to strengthen and repair bridge and building infrastructure in recent years. The use of FRP composites as an alternative to steel plates presents a more sustainable option for structures such as concrete, steel or timber bridges subjected to aggressive environments. However, the long-term service life and durability of FRP strengthened structures is of importance and in Australia alone it is estimated that 70% of concrete bridge infrastructure are in need of repair or strengthening due to material degradation over time and increased traffic loading. This paper presents work done to date by the authors on the long-term durability of the critical bond between the FRP and concrete considering environmental conditions and material durability.R.J. Gravina, H. Aydin, S.A. Hadigheh & P. Visinti
Detection of Bridge Dynamic Parameters Using an Instrumented Vehicle
No full text5th World Conference on Structural Control and Monitoring, 12th-14th July, Tokyo, JapanHighway structures such as bridges are subject to continuous degradation primarily due to ageing and environmental factors. A rational transport policy requires the monitoring of this transport infrastructure to provide adequate maintenance and guarantee the required levels of transport service and safety. In Europe, this is now a legal requirement - a European Directive requires all member states of the European Union to implement a Bridge Management System. However, the process is expensive, requiring the installation of sensing equipment and data acquisition electronics on the bridge. This paper investigates the use of an instrumented vehicle fitted with accelerometers on its axles to monitor the dynamic behaviour of bridges as an indicator of its structural condition. This approach eliminates the need for any on-site installation of measurement equipment. A simplified half-car vehicle-bridge interaction model is used in theoretical simulations to test the possibility of extracting the dynamic parameters of the bridge from the spectra of vehicle accelerations. The effect of vehicle speed, vehicle mass and bridge span length on the detection of the bridge dynamic parameters are investigated. The algorithm is highly sensitive to the condition of the road profile and simulations are carried out for both smooth and rough profiles.Proceedings for the conference are available online as a .zip file from http://www.bridge.t.u-tokyo.ac.jp/WCSCM5/5WCSCM_Paper.zipDeposited by bulk importRB 19/02/1
Experimental Investigation of the Detection of Bridge Dynamic Parameters Using a Moiving Vehicle
No full text23rd KKCNN Symposium on Civil Engineering, Taipei, November 13-15, 2010This paper investigates the feasibility of using an instrumented vehicle to detect bridge dynamic parameters,
such as natural frequency and structural damping, in a scaled laboratory experiment. In the experiment, a scaled
vehicle model crosses a steel girder which has been adopted as the bridge model. The bridge model also includes
a scaled road surface profile. The effects of varying vehicle model mass and speed are investigated. The damping
of the girder is also varied. The bridge frequency and changes in damping are detected in the vehicle acceleration
response in the presence of a rough road surface profile.Deposited by bulk impor
Evaluation of Bridge Replacement Alternatives for the County Bridge System, HR-365 August 1994
No full textRecent reports have indicated that 23.5 percent of the nation's highway bridges are
structurally deficient and 17.7 percent are functionally obsolete. A significant number of these bridges are on the Iowa county road system. The objective of the investigation described in this report was to identify, review and evaluate replacement bridges currently being used by various counties in Iowa and surrounding states. Iowa county engineers, county engineers in neighboring states as well as private manufacturers of bridge components, and regional precad prestressed concrete manufacturers were contacted to determine the most common replacement bridge types being used. Depending upon the findings of the review, possible improvements and/or new replacement bridge systems were
to be proposed. A questionnaire was developed and sent to county engineers in Iowa and several counties in surrounding states. The results of the questionnaire showed that the most common replacement bridges in Iowa are the continuous concrete slab and prestressed concrete bridges. The primary reason these types are used is because of the availability of standard designs and because of their ease of maintenance. Counties seldom construct these types of bridges using their own labor forces, but instead contract the work. However, county forces are used to construct steel stringer, precast reinforced concrete and timber bridges. In general, 69 percent of the counties indicate an ability and
willingness to use their own forces to design and construct relatively short span bridges (i.e., 40 A or less) provided the construction procedures are relatively simple.
Several unique replacement bridge types used in Iowa that are constructed by county forces
are documented and presented in this report. Sufficient details are provided to allow county engineers to determine if some of these bridges could be used to resolve some of their own replacement bridge problems. Where possible, cost information has also been provided. Each of these bridge types were evaluated for various criteria (e.g., cost effectiveness, conformance to AASI-ITO standards, range of sizes, etc.) by a panel of four Iowa county engineers; a summary of this critique is included. After evaluating the questionnaire responses from the counties and evaluating the various bridge replacement concepts currently in use, one new bridge replacement concept and one modification of a current Iowa county bridge replacement concept were developed. Both of these concepts would utilize county labor forces
The Politics of Bridge Building: The Long Wait for the Tees (Newport) Bridge
No full textThe Tees (Newport) Bridge officially opened in February 1934 to much fanfare and public celebration, the event receiving extensive local, regional and national media attention. The bridge provided a crucial link across the River Tees to the emerging industrial works on the north bank of the river and beyond, and similarly provided access to the industrial, commercial and retail businesses on the Middlesbrough side of the river. However, delays in the project meant approximately fourteen years had elapsed from initial discussions of a crossing to its fruition in the form of the world’s largest vertical-lift bridge
Evaluation of the Performance of A709 Grade 65 QST Bridge Steel
No full textThe primary goal for this project was to evaluate the efficacy of A709 Grade QST 65 steel for use in Iowa bridge projects. The objectives of the project were as follows: Identify the current state of use of A709 Grade QST 65 steel in bridge projects; Identify the ductility and strength characteristics of A709 Grade QST 65 steel through full-scale laboratory testing; Identify the fatigue characteristics of A709 Grade QST 65 steel through cyclic fatigue testing; Observe and compare bridge construction similarities and differences to conventional steel construction using a new bridge planned over Sand Creek in Buchanan County, Iowa; Compare relative costs of using A709 Grade QST 65 steel versus conventional steel; and, Measure the live load response at various points in time on the Sand Creek Bridge, which was constructed using A709 Grade QST 65 steel. The ductility and strength of the steel was observed through the various laboratory tests completed for this project as well as the testing performed by others. Minimum requirements for this steel grade have been established, and the results of this study indicate that the requirements were met and surpassed. The modified design of this first-in-the-nation bridge using Grade QST 65 steel over Sand Creek allowed for a reduction in beam size for this relatively short-span, low-traveled bridge due to the increased strength of the steel beams. The total steel cost for these beams resulted in a 20% material cost savings. The results should give confidence to engineers considering use of this steel grade on bridge construction projects with longer spans and higher traffic counts
CRC Bridge Review Panel final report
No full textThis archived document is maintained by the Oregon State Library as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Title from PDF caption (viewed on Feb. 15, 2011)"February 3, 2011.""... by the Independent Review Panel (IRP) report submitted to Governors Gregoire and Kulongoski in July 2010. Consequently, a Bridge Review Panel (BRP) was formed by the executives of the repective state DOTs. This 16 member panel was comprised of national and international bridge experts, plus key representatives from federal, state and local partner transportation agencies"--P. 11Mode of access: Internet from the Oregon Government Publications Collection
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