GEOMATICS IN BRIDGE STRUCTURAL HEALTH MONITORING, INTEGRATING TERRESTRIAL LASER SCANNING TECHNIQUES AND GEOTECHNICAL INSPECTIONS ON A HIGH VALUE CULTURAL HERITAGE

Abstract. The paper presents preliminary findings from a research study designed to assess the health status of a medieval bridge built on 1500 under the Medici dynasty over the river Sieve, close to Florence. The structure, a two span stone bridge with a main central pillar, experienced some restructuring interventions from 1555 to the present. The left span has been closed for some decades, and for many years the water has been allowed to float under it in case of severe flood only. At the beginning of year 2000 the left span has been opened to the regular flux of water. After opening, a maelstrom has been noticed as permanently present at the main pier's basis highlighting the presence of a fracture in the concrete base around the central pile of the bridge. In order to investigate structural health and to assess bridge's stability structural inspections and hydraulic surveys have been carried out. This manuscript reports Terrestrial Laser Scanning (TLS) survey results. Surface comparisons to identify anomalies and defromations have been carried out by exploiting Two TLS campaigns that were performed within a 6 years time span.</p

Bessel beam propagation: Energy localization and velocity

The propagation of a Bessel beam (or Bessel-X wave) is analyzed on the basis of a vectorial treatment. The electric and magnetic fields are obtained by considering a realistic situation able to generate that kind of scalar field. Specifically, we analyze the field due to a ring-shaped aperture over a metallic screen on which a linearly polarized plane wave impinges. On this basis, and in the far field approximation, we can obtain information about the propagation of energy flux and the velocity of the energy.Comment: 6 pages, 4 figure

High Accuracy Field Mappings with a Laser Monitored Travelling Mole

The LEP Spectrometer is an alternative method adopted to predict the LEP beam Energy. A bending magnet is flanked on either side by tgree beam position monitors /BPM) used to determine thedeflection angle of the beam. In order to reach the desired accuracy on the beam energy a relative precision of a few 10-5 on the magnetic field intefral is necessary. The magnet is a full-iron core dipole, 5.75 m long, of the MBI type used in the LEP injection region. It has been specially designed in order to have high field uniformity

Energy calibration at LEP using Nuclear Magnetic Resonance probes

The accurate Standard Model investigations carried out at LEP require knowledge of the beam energies of the order of a few 10-5. The resonant depolarisation method, used for absolute calibration in de dicated experiments, cannot be used to monitor continuously the beam energy during the physics runs. Moreover appreciable polarisation of the beams has not been measured above energies of 55 GeV. A me thod for continuous energy monitoring based on Nuclear Magnetic Resonance (NMR) probes mounted in tunnel magnets has been in use at LEP since 1995. The average field of the dipole magnets is sampled v ia 24 NMR probes mounted in the gap of the C-shaped yokes on top of the vacuum chamber. The probes are distributed over the 27 km of the accelerator. The probes are used for the continuous monitoring of the field during LEP operation and to determine the absolute field value

Outcomes of the 9th EGU Plinius Conference on Mediterranean Storms (2007)

No abstract available

GNSS control network supporting large historical building architectural survey

The paper points the attention to some hidden parts of metric surveys, that usually are not enough documented in scientific papers but in technical reposts. Reporting encountered challenges and discussing identified technical solutions and methodologies to overcome bottlenecks and operative issues, highlights the novelty of the presented experience from a technical viewpoint. The overall approach has been reported taking care of describing technical details and present case study’s implementation of the applied techniques. Integrating GNSS control Networks and topographic tools to design, implement and perform a rigorous topographic survey methodology in describing built heritage, which is one of the modern geomatics’ advancements, has been depicted. An ad hoc datum has been designed to guarantee a clear compliance both to cartographic standards and architectural representations in 1:50 to 1:100 graphical output scale

Model of Dipole Field Variations in the LEP Bending Magnets

The determination of the Z mass at LEP requires a knowledge of the relative beam energy in the order of 10 ppm, therefore it is essential to understand the dipole field variations to the same level of accuracy. In LEP the bending magnet field shows a relative increase of the order of 100 ppm over 10 hours, which was found to be caused by leakage currents from railways flowing along the vacuum cham ber and temperature variations. A LEP dipole test bench was set up for systematic investigations. Field variations were monitored with NMR probes while the cooling water temperature of both coil and vacuum chamber was kept under control. The results lead to a parametrisation of the magnetic field variation as a function of the vacuum chamber current and temperature