Search results for "0201 civil engineering"
showing 10 items of 242 documents
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…
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…
Interaction between Longitudinal Shear and Transverse Bending in Prestressed Concrete Box Girders
2017
In box girder bridges, the quantity and distribution of reinforcement to be put in concrete elements of sections can be evaluated only by considering the deformation of the cross section in addition to the longitudinal analysis of the static scheme, establishing the entire state of stress of box sections. This leads to a need to evaluate the interaction between internal forces obtained by the global analysis and the ones obtained by the local analysis of the cross sections. The frame effect implies the elastic deformation of slabs and webs, whereas eccentrically applied loads lead to cross-section distortion with the loss of the box shape. Hence, the reinforcement is strongly influenced by …
Reconstruction of the Rib Vaults of the Hypostyle Hall in the Maniace Castle of Siracusa After the 1693 Earthquake
2016
ABSTRACTBuilt in the first half of the 13th century on behalf of the Emperor Frederick II, the Maniace Castle of Siracusa focuses its enigma in the hypostyle hall (which was composed of 25 quadripartite rib vaults) and the design criteria adopted for its implementation. Recent research and a careful rereading of the documentary “restoration project” after the earthquake of 1693 have offered new tools to understand the construction techniques and building procedures for the entire organism. It has been possible to demonstrate that the different material (white limestone and volcanic stone) used for the vaults is, in fact, a product of reconstruction. The constructive node, which historiograp…
Numerical prediction of the shear response of semi-prefabricated steel-concrete trussed beams
2016
Abstract In this study, the shear behavior of hybrid steel-trussed-concrete beams (HSTCBs) realized with prefabricated steel trusses embedded into a concrete core cast in situ, is investigated by means of Finite Element (FE) numerical simulations. HSTCBs do not behave as classical RC elements nor composite beams. Up to now, there are not specific design criteria in the building codes and the calculation of this type of beams is conducted by means of design-by-testing procedures. The knowledge of the material behavior as well as the understanding of the interaction between materials in contact is the first requirement for the definition of proper design procedures and calculation methods for…
Formwork application optimization by using augmented reality
2016
By using the PLM (Product Lifecycle Management) principle on the formwork case study, after determining the functions and the technical solutions, the application must be made as optimum as possible in order to assure productivity and provide the necessary information as quick as possible. The concept is to create a complex management for the formwork based on augmented reality. By taking into account the development rate of the information, augmented reality is tending to be one of the widest (in term of domain) visualization instrument. Also used in the construction domain, augmented reality can be applied also for the case of formwork design and management. The application of the solutio…
Theoretical approaches for modelling buckling effects in rebars of RC members
2017
Buckling of longitudinal bars in reinforced concrete (RC) members is definitely a critical issue in framed structures subjected to seismic loads. Second order effects can affect the compressive stressâstrain law of steel bars, influencing ductility calculations of RC structures. Moreover, literature studies show that buckling can occur over a length wider than stirrupsâ pitch (global buckling mode), involving more stirrups and inducing large deflections in the bar. If the critical length is not carefully estimated, stirrupsâ failure can occur, causing also the sudden loss of confining effects in concrete. This paper presents the results of different approaches for calculating the crit…
Effects of corrosion on a steel bowstring bridge in marine environment: A case-study of assessment and retrofit
2021
The case-study of a steel bowstring bridge set in a marine environment and highly damaged by corrosion is presented. The bridge was built in 2004 and was repainted for corrosion protection in 2010. Despite the recent construction and the maintenance interventions, many structural elements like hangers are highly damaged by corrosion with decreasing performance in terms of serviceability and ultimate limit states. A deep investigation was carried out in order to assess the bridge and to establish the necessary retrofit actions to be carried out in the near future. In-situ tests reveal the reduced performance of the original steel in terms of strength and corrosion protection, together with t…
An extension of the fractional model for construction of asphalt binder master curve
2015
Knowledge and prediction of viscoelastic behaviour of asphalt binder is of great interest in order to design asphalt mixtures for civil construction of road and airports with good performances. The capability of a fractional model – requiring a very limited number of parameters – to describe and predict the linear viscoelastic behaviour of asphalt binder subjected to sinusoidal oscillations is investigated. Experimental data of complex modulus, |G*|, and phase angle, δ, are used to validate the proposed constitutive model. Based on the proposed extension of a fractional model, complex modulus isotherms for a range of frequencies can be created simply starting from isochronals at frequency v…
Comparative Analysis of Four New Alternative Types of Roundabouts: “Turbo”, “Flower”, “Target” and “Four-Flyover” Roundabou
2016
Analysis of literature shows that “modern roundabouts” nowadays exist in all European countries, as well as in more than 60 countries elsewhere in the world. Nowadays, a growing number of studies, presented in scientific and professional literature, point out a poor traffic safety characteristics of “standard” two-lane roundabouts and lower capacity then was expected. These problems are resolved in more ways in different countries; however the solution, whereby the number of conflict spots is diminished has proven to be the most successful. Lower number of conflict spots is one of characteristics of the alternative types of roundabouts. The alternative types of roundabouts are usually more …