Search results for "Structural engineering"
showing 10 items of 1998 documents
Design, manufacturing and testing of a fast disconnecting system for the European target assembly concept of IFMIF
2013
The International Fusion Materials Irradiation Facility (IFMIF) will be equipped with a lithium target assembly to produce the required neutron flux for the irradiation of candidate fusion materials up to a damage rate of 100 dpa (cumulated damage in five years). The present European target assembly design is based on the so called replaceable backplate bayonet concept that was developed with the objective to simplify the maintenance operations for its refurbishment/replacement and to reduce the material for disposal as well. To this purpose it was also conceived to be attached to the lithium pipes and to the beam line by means of remotely operated connections based on clamped flanges with …
Combining TMD and TLCD: analytical and experimental studies
2017
Abstract In these years several research efforts have been focused on developing efficient and reliable control devices for mitigating the structural response of tall and lightly damped buildings in case of strong dynamic excitations, such as wind and earthquake ones. In this context, Tuned Mass Dampers (TMDs) represent probably the most common control device due to their high control performances. On the other hand, Tuned Liquid Column Dampers (TLCDs) are increasingly becoming more popular because of some of their attractive features, cost-effectiveness among the others, even though they yield slightly less control performance compared to the classical TMDs. Aiming at combining the benefic…
Effect of climate change on asphalt binder selection for road construction in Italy
2015
This work explores the influence of climate changes on the proper selection of asphalt binder for pavement construction purposes, according to the Performance Grade (PG) defined in the SUPERPAVE specifications. Based on temperature data at national level, it is possible to obtain thematic maps for the whole Italian territory, which is extremely useful for technicians and pavement engineers for selection of asphalt binder for road construction purposes. Furthermore, the statistical significant temperature trends’ knowledge enables deriving thematic maps which allows to include the effects of climate change in the asphalt binder design. It is argued that, due to climate change, the binders to…
Off-line path correction of robotic face milling using static tool force and robot stiffness
2015
In this paper the developed method for off-line compensation of tool deflections when milling aluminum with an industrial robot is presented. The efficiency of this approach is verified with high precision measurements of deflections using a laser tracker. The compensation method includes both the static milling process model which can predict the mean value components of the tool forces and a new combined local/global approach for estimating the combined stiffnesses of joints. With a process model such as the one presented in this paper and estimates of the robot's joint stiffness values, the tool path can be adjusted to counteract deflections of the tool during milling operations. The mod…
Fatigue methodology for life predictions for the wheel-rail contact area in large offshore turret bearings
2016
The present report presents a fatigue life prediction method for large roller bearings applied in the turret turn table for large loading buoy units. The contact points between wheel and rail in these bearings are subjected to a multi-axial fluctuating stress situation and both surface wear and fatigue cracking may occur. A methodology based on the Dang Van fatigue criterion is adopted. The criterion is based on an equivalent stress defined as a combination of the fluctuation of the shear stress from its mean value at a critical plane and the associated hydrostatic stress at the given time. The present work is supporting the theoretical model by extensive laboratory testing. Both full scale…
Exploring the Potential and the Boundaries of the Rolling Horizon Technique for the Management of Reservoir Systems with over-Year Behaviour
2016
The paper presents a set of experiments on the Rolling Horizon Technique (RHT), applied to the management of a multi-reservoir, multipurpose water resources system with over-year behaviour. In the RHT, decisions on releases from reservoirs are taken for a number of time steps ahead (the Forecasting Horizon – FH) through an optimization model, based on the present water availability in reservoirs and on some forecasts of future inflows over the FH. Only the decision concerning the first time step (the current month) is then implemented, as new information on reservoir levels and forecasts becomes available so that the process can start again with updated information. The paper investigates h…
Life cycle assessment of large scale timber bridges: A case study from the world’s longest timber bridge design in Norway
2018
Abstract This paper seeks to use life cycle assessment to investigate the comparative environmental impacts of two proposed bridge designs for the new Mjosa Bridge over Lake Mjosa in Norway. The Norwegian Public Roads Administration has designed one timber and one concrete alternative for the 1650 m 4-lane highway bridge. If the timber bridge design is chosen, it will be the longest timber bridge in the world once constructed. The main motivation for building the timber bridge is to utilize local industry and to reduce environmental impacts in road infrastructure. This study aims to determine the expected emissions from both construction designs by using life cycle assessment. Life cycle as…
Structural behavior of the old masonry bridge in the Gulf of Castellammare
2016
Abstract Masonry arch bridges represent a very significant part of the heritage of road and railway artworks all over the word and especially in the Mediterranean area, both in terms of: numbers; reduced environmental impact; and static efficiency. In these cases, the cost of maintenance is often limited to the content and channeling of surface water and control of vegetation, which can eventually take root on the joints of the masonry at the shoulders. In masonry bridges, there are no expansion joints or hinges with support equipment or trolleys, as in metal bridges and reinforced concrete ones, or paint, or resin surface protection, all items that affect the cost of maintenance. The perma…
Serviceability of segmental concrete arch-frame bridges built by cantilevering
2013
The evaluation of the safety degree in service life for a segmental prestressed concrete bridge built by the cantilever method presents different aspects related to strength, deformability, durability and to effects of time-dependent phenomena as creep and shrinkage. The case-study of a prestressed concrete frame bridge with inclined piers is presented, built by cantilevering, with precast segments. By considering the fundamental items of design and construction stages, the implications due to the arch effect in this static scheme are investigated, with respect to an equivalent bridge with a final scheme of continuous girder on vertical piers. The birth of a significant value of axial force…
A criterion for the assessment of the reliability of ASHRAE conduction transfer function coefficients
2010
This paper presents a new mathematical approach, which, when applied to conduction transfer functions (CTFs) of a multi-layered wall, is able to predict the reliability of building simulations. This new procedure can be used to identify the best set of CTF coefficients, which are a critical point at the core of the ASHRAE calculation methodology founded on the transfer function method. To evaluate the performance of different CTF coefficient sets, the authors performed a large number of thermal simulations on the multi-layered walls included in the ASHRAE Handbook, volume fundamentals, and on other walls typical of Mediterranean building heritage. Those data were employed to test an algorit…