Search results for "technical"
showing 10 items of 955 documents
Evaluation of the laboratory prediction of surface properties of bituminous mixtures
2009
Abstract An experimental and analytical investigation was carried out both in laboratory and in situ on wearing courses. The approach presented in this paper aims to predict the in situ density and surface properties of bituminous layers, during the phase of mix design in laboratory. Therefore, the main attempt of this study is to identify, amongst the commonly available laboratory equipments, the most adequate for producing specimens that, used for carrying out simple and reliable laboratory test, allow the prediction of the surface characteristics of the mixture as laid on site. This is done by comparing the data collected from an experimental site with those calculated from laboratory sp…
Stress separation in the photoelastic study of centrifugal stresses
1972
This technical note refers to the problem of stress separation in the photoelastic analysis of plane models under centrifugal stresses. Two methods are described in order to determine the sum of principal stresses. These methods, which are based on the compatibility equation, reduce the determination of the sum of principal stresses to the solution of a Laplace's or Poisson's equations. As an example of application, the separation of stresses in a rotating disk with two eccentric holes is shown and comparison with the stresses obtained by using the shear-difference method is made.
Legal Liability of Professional Engineers: The Case of a Fire at a Shopping Center
2019
In this paper, the authors discuss the legal liabilities of the professional engineer as both the engineer of record of a project and the construction site manager. In particular, this paper analyzes the case of a fire at an end-user MV/LV substation of a shopping center in Italy, occurred a few years after maintenance works on the electrical installation. The professional engineer who had designed and overseen the construction of the substation was accused of criminal negligence. The authors through the examination of applicable technical standards, as well as of safety regulations, demonstrate that the professional engineer had acted diligently and that there was no ground for the neglige…
Long term energy efficiency study on different wall envelopes in Latvian climate conditions
2017
Abstract Five test stands have been built in Riga, Latvia equipped with sensors (temperature, solar radiation, humidity, etc.) to measure energy efficiency and thermal comfort conditions. Roof and floor constructions are made the same. For the walls building envelopes differ and typical materials used in Latvia (aerated concrete, ceramic building blocks, wooden log and plywood frame with rock wool insulation) are compared. Only rock wool is used for insulation to provide moisture transport through the construction. For study to be comparative thermal transmittance of all five test stands have been calculated equal (U=0.15…0.16 W/(m 2 ∙K)). The aim of research is to compare the integral calc…
Incremental dynamic based fragility assessment of reinforced concrete structures: Stationary vs. non-stationary artificial ground motions
2017
Abstract Artificial and natural records are commonly employed by researches and practitioners to perform refined seismic assessments of structures. The techniques for the generation of artificial records and their effectiveness in producing signals which are significantly representative of real earthquakes are still debated as well as results of the consequent seismic assessment to expect from their application. The paper presents an in-depth comparative study highlighting the effect of employing different typologies of artificial ground motion records on seismic assessment results, especially addressing seismic fragility curves. Three sets of 50 stationary, nonstationary evenly modulated a…
Battery storage systems for peak load shaving applications: Part 2: Economic feasibility and sensitivity analysis
2016
This paper is the second of a two-part series, aiming to evaluate the economic feasibility of electrochemical storage systems in peak load shaving applications. The battery energy storage system (BESS) is considered to be added to a private facility, with the aim of reducing the customer electricity bill. The BESS is charged during the night, when the electricity prices are the lowest and discharged during the daily hours, when the prices are the highest, contemporary achieving a leveling of the daily usage pattern. The economical evaluations are carried out considering four different electrochemical technologies: lithium-ion (li-ion), advanced lead-acid, sodium-sulphur (NaS) and flow batte…
New Theoretical Solution of the Stage-Discharge Relationship for Sharp-Crested and Broad Weirs
2012
In this paper, the outflow process of a sharp-crested and broad weir is studied using the dimensional analysis and the incomplete self-similarity theory. The new stage discharge is theoretically deduced and its testing is carried out using measurements both available in literature and obtained by laboratory runs carried out in this investigation.
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…
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…
Modeling Round Robin Test: An Uncoupled Approach
2014
Abstract The solution of the modeling test presented in the paper is based on an uncoupled hydro-mechanical approach. Firstly, the controlled infiltration process is modeled by a finite element transient groundwater seepage software. Afterwards, calculated pore water pressures at successive instants are used for the slope stability analysis. Time evolution of the slope stability is analysed by using the infinite slope model, according to the classical limit equilibrium method.