Search results for "Civil Engineering"
showing 10 items of 1216 documents
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…
Environmentally appraising different pavement and construction scenarios: A comparative analysis for a typical local road
2015
Abstract The aim of this work is to carry out a comparative analysis of environmental impacts for different scenarios of a typical local road. Life Cycle Assessment (LCA) is the modeling tool used to quantify and characterize comparative environmental impacts. In carrying out this specific application of the LCA, different road construction techniques were considered with regards to the whole structure and compared in order to identify the best alternative in terms of environmental sustainability. So far, in fact, typical LCA frameworks of roads have focused on recycled materials for pavement layers only, thus neglecting study of the materials used in the embankment or in the subgrade. In t…
Medición del efecto látigo en redes de suministro
2016
La variabilidad de la demanda que se origina de un agente a otro en la cadena de suministro, aumenta o amplifica a medida que la señal se aleja del punto de origen; estas distorsiones se denominan Efecto Látigo. En este artículo se aborda una red de suministros multieslabón, que estima los intervalos de medición de la distorsión de la demanda de la red, de acuerdo a comportamientos extremos en el sistema que permiten diagnosticar su desempeño en términos de la amplificación de demanda. Para la investigación se aplican mediciones estáticas locales y globales del efecto látigo, en cada nivel de la red de suministros del juego de la cerveza de cuatro eta-pas; cada etapa o eslabón tiene múltipl…
The experimental research strategy of the endmilled aluminum alloys
2017
In this paper, the most important aspects of the research methodology of the resulted surface quality by aluminum alloys endmilling, are presented. The first part of the paper includes a short presentation of the cutting processes aluminum alloys evolution. In the second part, the research problem was defined by setting a fundamental objective and identifying the specific objectives which contribute to achieve the fundamental objective. In this context an experimental study, was performed, starting with the organization and conducting the endmilling process, in which the cutting regime were established, then the characteristic measured parameters were determined, so that the research factor…
Flower Roundabouts And Double-Lane Roundabouts: A Comparative Performance Analysis
2014
AbstractIn the paper, a choice criterion between flower roundabouts and double-lane roundabouts is proposed, focusing on operational benefits that can derive from one scheme over the other, and outlining a general framework for benefit-cost analysis. In order to assess operational benefits of innovative roundabouts over modern roundabouts, a comparative analysis was made. Capacity was estimated using gap-acceptance models. In detail, assuming the dichotomic shifted negative exponential distribution to model headways in circulating streams, the Hagring formula was adjusted to obtain entry capacity estimations at roundabout approaches where entering vehicles face one or two conflicting flows.…
Studies on wheel mounting options on shafts
2019
The paper presents a general description of chains and chain transmissions, their advantages and disadvantages. A triple chain wheel is then projected into the CATIA V5 program. A static analysis of some wheel mounting variants on a camshaft with the Generative Structural Analysis module in the CATIA V5 program is then made. The orientation-fastening variants with a wedge, two feathers or three screws positioned equidistant at 120 degrees on a diameter are analysed. As a result of the finite element analysis, the conclusion is that the three-screw variant is the most appropriate. Material stresses and deformations are smaller, simpler processability, fewer types of components are present ov…
New solutions for prefabricated secondary substations in the view of sustainability
2016
The secondary substations will assume an important role as “smart nodes” of the smart grid. So in few years there will be a widespread dissemination on the territory of this apparatus. Consequently, great care have to be taken not only on safety issues, but also on the constructive methodology, in order to determine low environmental impact and decommissioning cost. This paper focuses on innovative solutions for the realization of prefabricated secondary substations, in the direction of sustainability. Innovative layout and enclosure topologies have been here taken into account. In particular, by considering that the substation concrete box is, at the same time, uneconomical and with strong…
Occupational emerging risks affecting international virtual project Team Results
2017
The expansion of internet access, high-speed connection services, collaborative work platforms and tools, allowed employees to interact virtually offering companies the possibility to develop projects around the world, reducing operational costs and gain competitive advantage. Realizing the advantages and disadvantages of developing a project team in an international virtual work environment, requires adopting specific strategies to construct an effective team and ensure the project success. One of the most important disadvantages that we identified is that the new work environment brings new risks for both team members and managers. So, it becomes mandatory to identify and analyze the occu…
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 …