9762 papers found
Bridge testing and especially monitoring are very important for evaluating the structure state. Using modern technologies (ICT) it is possible to achieve on-line permanent monitoring and therefore we are trying to design such measurement system based on industrial communication network with PROFIBUS protocol.
As one of the important works in the pre-stressed concrete structure design, magnitude of the pre-stress loss has not been measured conveniently until now. A suitable measuring technique for pre-stress loss is the studying goal of researcher in a long time. In the present work, the fiber-optic measuring technique has been introduced to measure the pre-stress loss, and all of the measuring works were conducted on the model of a wastewater tank. Result of the measurement shows that optical fiber sensor can be used to measure the pre-stress loss in engineering, and the short-term pre-stress...
Two concrete bridges of the new Lehrter Bahnhof in Berlin have to be monitored with regard to their deformation performance during construction and later over several years. For this purpose sensors with excellent long-term stability are needed. The paper describes a new system for the measurement of settlements and elevations by means of laser-based optics and hydrostatic levelling, the application of fibre-optic strain sensors and conventional strain gauges, inclinometers and temperature sensors as well as model tests on pre-stressed concrete beams inside and outside the laboratory.
In a German slab track system (“Feste Fahrbahn” FF, system Bögl) for speeds up to 300 km/h and more different fibre optic sensors have been embedded in several levels and locations of the track system. The track system consists of prestressed precast panels of steel fibre concrete which are supported by a cast-in-situ concrete or asphalt base course. The sensors are to measure the bond behaviour or the stress transfer in the track system. For that, tiny fibre-optic sensors - fibre Fabry-Pérot and Bragg grating sensors - have been embedded very near to the interface of the layers....
The increasing traffic density and increasing axle loads on highways requires an efficient road maintenance. Within a long-term project over 10 years load and pavement deformations on a heavily travelled expressway are measured. A newly developed sensor based on the magnetostrictive principle measures the vertical deformations within the pavement layers in parallel to existing inductive sensors. Short-term data of the two different systems and longterm data of the new sensor over a one year period are presented and further improvements discussed.
This paper presents a smart elastomeric bearing using PVDF polymer film, which is very sensitive to dynamic loading condition. The PVDF polymer film is inserted into the elastomeric bearing to monitor the normal load, which is applied to the bridge structure. Therefore, the prototype of the smart elastomeric bearing is finally fabricated with the electric circuit for signal of the PVDF polymer film subjected to vertical loading. The evaluation system for smart elastomeric bearing is manufactured with shake, accelerometer and plate. The bearing was tested under sinusoidal loading condition....
This contribution deals with the development of a new sensor for measuring stress in massive concrete structures. It starts with a technical overview regarding the apparatus and its theory of operation. At least some application examples from building sites ard results will be shown.
The monitoring of bridge constructions can be performed by optimised eddy-current sensors to recognise damages earlier and to reduce rehabilitation expenses. The aim is to measure the coil impedance of an eddy-current sensor positioned close to a pre-stressing cable and to conclude the change of stress in steel of reinforced concrete elements. For this purpose, measurements were taken with specified specimen to investigate the influence from the air gap variation and hysteresis curve.
This paper describes a successful approach of integration of Marie Curie Chairs (EXC) project based course on "Smart Sensors Systems Design" into the current curricula in "Sensors and Signal Conditioning" at Technical University of Catalonia (UPC-Barcelona, Electronic Engineering Department) for graduate and postgraduate students. It is strongly connected with new research results obtained during the SMARTSES project in this emerging field. The course main objectives, contents, teaching methodology, laboratory activities and qualification criteria are discussed.
Three typical examples with great relevance to practice are demonstrating that as well mathematics as physics must be used to solve problems and especially to gain closed solutions as necessary for application in practice. Therefore both methods have to be teached in measurement education also to-day.