The paper is specially addressed to the seismic device manufacturer, designers and end users of these products, to explicitness the provisions of EN 15129:2009 regarding the tests shall be performed for the displacement depended devices used for bridges and viaducts. Are presented some of examples of dynamic tests carried out under the supervision of the certification body ICECON CERT SRL for the assessment and verification of constancy of performance, based on the evaluation of conformity procedures indicated in the reference document and the regulation EU no (305)/2011
Lucrarea abordează comportarea unui model de solid-rigid cu anumite simetrii structurale. Aceste simetrii permit simplificarea calculelor (ecuaţii de mişcare) şi, deci, a modelelor matematice. Dacă solidul rigid este conectat la structură prin patru legături elastice, modelul rămâne încă simplu şi uşor de rezolvat, vibraţiile putând fi decuplate în patru subsisteme de mişcare.
În final, se prezintă un studiu de caz pentru analiza modală a unui viaduct, modelat precum un corp solid-rigid, rezemat elastic, de pe autostrada Transilvania (km 29+602.75 m).
The article presents the successful restoration of a railway viaduct in Zielona Góra. The carried out reconstruction, in the scope of increasing the clearance gauge under the bridge, made it possible to increase operational safety while maintaining the existing structure of the object. The described case serves as an example of actions facilitating the further historic use of transportation infrastructure structures while limiting financial outlays for adapting them to current expectations.
Ghindea Cristian Lucian, Răcănel Ionuţ Radu and Cruciat Radu Iuliu
. STAS 12504-86: “Railway bridges, viaducts and walkways. Testing of superstructures with test actions” , IRS, Bucharest, 1986.
. “ Static and dynamic tests at bridges – between 71 +035.82-71 + 715.82 (object 3) and km 73+040.32 - 73+285.32 (object 5), at the Orăștie – Sibiu highway, batch 4“, UTCB Contract no. 205/ 2013.
. ISO 5348:1998: “ Mechanical mounting of accelerometers ”, International Organization for Standardization, Geneva, 1998 .
. A. K. CHOPRA: “ Dynamics of Structures “, third ed., Prentice Hall
The in service safety and reliability assurance of bridges and viaducts is determined by the choice of materials and products suitable for the design bearing solution of that construction structure. The paper proposes an operational solution for the performance characteristics assessment and verification of elastomeric bearings, which will be the basis for the consistent and coherent application of the requirements established by technical and legal regulations in the construction domain.
Artur Juszczyk, Marek Dankowski and Adam Wysokowski
At the turn of the 19th and 20th century, on the areas of today northern and western Poland, the railway infrastructure was developing rapidly. In the late 80’s of the previous century many of the railway lines, together with the whole infrastructure including bridges, were being closed down. The example of such practices can be the brick bridge located near Nojewo, Voivodeship wielkopolskie. This article presents the technical parameters of these bridges and their damages as well as ideas for the future development of the railway facilities.
Aldo Giordano, Ionuţ Radu Răcănel and Giovanni Voiro
This paper is intended to show the design of two composite bridges along the Orastie- Sibiu motorway, from the basic concepts, applied without the need for a clause-by- clause checking of codes and standards, to the construction methods.
The bridges are seismically isolated in the longitudinal direction, while transversally the seismic action is distributed among the piers.
Calculations have been carried out through state of the art procedures, taking into account form effect of the cross section. For this reason, different FE models have been set up to study different aspects of the behavior, with increasing degrees of approximation. For example, “beam” elements have been utilised to investigate global effects both in the linear and non linear range, while more accuate 2D and 3D elements have been used for refined cases such as stress checks and local buckling analyses.
The present paper goes into detail in particular for what concerns some of the most interesting parts of the design process for the specific case. Namely, time dependent properties of the materials have been considered, and extensive “staged construction” analyses have been carried out to ensure safety in each phase of the complex life of the bridges, while at the same time guaranteeing significant cost savings.
The Author reports the results of a survey about a breeding extra-alpine Peregrine Falcon population in Cuneo Province, NW Italy. The first reproduction was recorded in 2000, and from that year, the monitoring work localized 16 occupied territories in an area of 1,900 km2 covering the hills and nearby lowland areas. The average distance between breeding territories was of 7.6 km with a density 0.7 pairs/100 km2. During the eighteen years, 89 successful breeding attempts were recorded, 81 of them led to fledging of 206 young. Average breeding success was 2.5 juv/reproducing pairs. The nests are located on bridges (motorway viaducts and rail way bridges) and clay/sandstone cliffs. Preliminary prey analyses showed that pigeons and doves represent the 75% of their diet.
Recently, we observe the rapid development of the Global Navigational Satellite Systems (GNSS), including autonomous positioning techniques, such as Precise Point Positioning (PPP). The GNSS have different conceptions, different spacecraft and use different types of orbits which is why the quality of real-time orbit and clock products is inconsistent, thus, the appropriate approach of the multi-GNSS observation processing is needed to optimize the solution quality. In this paper, the kinematic field experiment is conducted in order to examine multi-GNSS real-time Standard Point Positioning (SPP) and PPP performance. The test was performed on the 26 km-long car route through villages, forests, the city of Wrocław, crossing under viaducts and a high tension line. For the first time, the solution is based on GPS + GLONASS + Galileo + BeiDou observations using streamed corrections for orbits and clocks with two different weighting scenarios. Thanks to the usage of the multi-GNSS constellation the number of positioning epochs possible to determine increases by 10%. The results show also that the appropriate weighting approach can improve the root mean square error in the SPP solution by about 13% and 42% for the horizontal and vertical coordinate components, respectively. In the case of PPP, the maximum quality improvement equals 70% for the horizontal component and the results for the vertical component are comparable with those obtained for the GPS-only solution.
On concrete bridge and viaduct decks, traditional bituminous pavements are often subject to rapid degradation, particularly due to precipitation, traffic loadings and chemical attack. Pavement failure can also be due to underlying cracks related to steel reinforcement corrosion. For this reason waterproofing plays an important role in durability of the structure. Waterproofing can be done by means of polymeric binders and aggregates, mixed or applied together in the surface course.
The paper summarizes the main results of a study aimed at mechanically characterizing resin-aggregate mixtures (premixed and multi-layers) for bridge waterproofing and paving: two types of resins and several types of natural and artificial/industrial aggregate (EAF slag, C&D aggregate, limestone and quartz sand) were used. Permanent deformation resistance and adhesion tests were conducted, as well as trials to define the surface characteristics of the product (skid resistance, permeability, macro-texture). The comparison demonstrates that polymeric slurries present better resistance than polymeric multi-layers and bituminous mixtures to permanent deformation at higher temperatures (40 to 60 °C), but show some deficiencies in adhesion properties. However, the surface characteristics of polymeric multi-layers are preferable to those of slurries and traditional bituminous mixtures.