rss_2.0Modelling in Civil Environmental Engineering FeedSciendo RSS Feed for Modelling in Civil Environmental Engineering in Civil Environmental Engineering Feed SEISMIC BEHAVIOUR OF CURTAIN WALLS: AN ANALYSIS BASED ON NUMERICAL MODELLING<abstract><title style='display:none'>Abstract</title><p>The paper proposes a numerical model to estimate the structural behaviour of a stickbuilt glazed curtain wall system subjected to an imposed displacement of the supports in the plane of the wall. We discuss the role of the parameters that influence on the maximum inter-storey drift corresponding to the service limit state of the wall. The considered parameters are the dimensions of the glazed panel, the gap between the panel and the aluminium frame and the gap between the supports and the mullions. We discuss the problem of remnant deformation of glazed panels, and of misalignment as serviceability criteria. Comparisons are made to laboratory testing results.</p></abstract>ARTICLEtrue ASPECTS IN SEISMIC DESIGN OF TALL REINFORCED CONCRETE BUILDINGS<abstract><title style='display:none'>Abstract</title><p>Tall buildings present some specific aspects influencing the modeling and response to seismic loads. Therefore, the design rules recommended in codes, calibrated for low and medium rise buildings, are not appropriate for design of tall buildings. Other rules are needed, and performance based design represents a viable alternative for tall buildings. In this paper a methodology for the design of tall structures is proposed and it is illustrated trough a case study for a structure with perimeter tube and interior core walls, which aims to identify the particularities regarding the design, behavior and the parameters that define the post elastic behavior at the global and local level, for this structures.</p></abstract>ARTICLEtrue METHODS FOR SOIL-STRUCTURE INTERACTION APPLIED IN WIND TURBINE FOUNDATION DESIGN<abstract><title style='display:none'>Abstract</title><p>The article presents a case study on soil-structure interaction modelling for Wind turbines. After a brief presentation on the history of wind turbines and their potential in Romania, the authors take on the task of modelling the soil-structure interaction for the raft and piles. Three models are chosen: in the first model the piles are fixed at foundation depth; in the second, elastic supports are modelled on the raft and the piles and in the third model both elastic supports and fixed supports are modelled. Several comparisons are made between the three cases referring to displacements, efforts and necessary reinforcement. Based on these comparisons, the most important conclusion drawn is that the modelling of the soil-structure interaction has an important effect on the final reinforcement of the raft and the piles, considering that the difference between the models reaches almost 18%, which in the case of really large foundations can draw the line between economic and non-economic design.</p></abstract>ARTICLEtrue ON RELATION BETWEEN INELASTIC AND ELASTIC DISPLACEMENT FOR VRANCEA EARTHQUAKES<abstract><title style='display:none'>Abstract</title><p>At present, Romanian code for seismic design P100 is in a process of assimilation of the requirements from the equivalent European code, EN-1998-1. However, the unique characteristics of the Vrancea earthquakes require additional adjustment for some relations. One of these relations regards the simplified calculation of inelastic displacements and represents the main objective of this article. The paper uses dynamic nonlinear analysis performed on single degree of freedom systems as the main investigation tool. For all the analyses, two hysteretic models are used: Takeda and kinematic hardening. In the beginning, the paper presents the influence of overstrength on inelastic displacements for several behaviour factors. Next, the overstrength-period diagram is proposed based on a case study. Finally, the spectrum of c, the ratio between inelastic and elastic displacement is calculated. The main result of the study is the simplified equations proposed for c factor, relations that can be successfully used in current design.</p></abstract>ARTICLEtrue RESULTS FOR LOTKA-VOLTERRA MODEL USING APPROXIMATE INERTIAL MANIFOLDS<abstract><title style='display:none'>Abstract</title><p>A numerical study on the classical Lotka-Volterra model is performed, using approximate inertial manifolds. An analytical study consisting in the inertial form of the system is made. The construction of the approximate inertial manifolds is based on the identification of the absorbing domains using the graphical representations of the phase portraits. The hypotheses of the Jolly-Rosa-Temam algorithm are verified for certain values of parameters and the approximate inertial manifolds are constructed. Errors of approximation are computed.</p></abstract>ARTICLEtrue ANALISYS OF CONCRETE PRE-STRESSED RESERVOIRS FOR SLUDGE FERMENTATION – WASTE WATER TREATMENT PLANT BUCHAREST – GLINA.<abstract><title style='display:none'>Abstract</title><p>The paper refers to a structural finite element analysis on the reservoirs for sludge fermentation at Glina Waste Water Treatment Plant. The purpose was to assess the dynamic response of the structure, the stress and deformation states due to the design earthquake. A linearelastic analysis was performed, according to the Romanian actual codes, in order to verify the design provisions and to emphasize the sensitivities, for a structure which was designed by analytical procedures. The results obtained on the numerical models highlight the importance of the soil-structure interaction, in peculiar the one influenced by the soil mass deformability, on the overall structural response. Based on the results of the analysis, an in-situ measurement campaign for structural dynamic characteristics was initiated, taking advantage of the ongoing repair works with subsequent exhaustion and re-filling of reservoir No. 4.</p></abstract>ARTICLEtrue Plane Cyclic Behavior of Masonry Walls Jacketed with Fiber Reinforced Mortar and Fiber Grids<abstract><title style='display:none'>Abstract</title><p>Masonry buildings represent the most vulnerable part of the building stock to seismic action in Romania. The main goal of this experimental research program is to investigate the efficiency of several retrofitting solutions using fiber reinforced polymers. Research focused on the lateral strength and displacement capacity of the retrofitted specimens. The masonry walls were built using solid bricks. Glass or carbon fiber reinforced polymers (GFRP or CFRP) embedded in a fiber reinforced mortar layer were used for jacketing. Seven specimens having essentially 25cm width, 1,75m height and 2,10m length were tested in the experimental research program. These specimens were subjected to a constant vertical compressive stress of 1,2MPa. A quasi-static load protocol was considered for the horizontal loading. This paper presents the layout of the experimental research program and some preliminary results.</p></abstract>ARTICLEtrue Aspects Concerning Nonlinear Dynamic Analysis of Cable Structures<abstract><title style='display:none'>Abstract</title><p>The paper is about some aspects concerning the nonlinear dynamic analysis of prestressed cable structures. A method for the assessment of the tangent stiffness matrix and of the nonlinear parameters is proposed. The methodology is similar to the one described by P. Krishna. The Newmark method is used to integrate the motion equation. In the final section of the paper a comparison between the output supplied by the software of the presented method is made, with constant stiffness matrix(linear) and with the non-linear matrix updated step by step (geometric non-linear). The elements used for comparison are the displacement and velocity response of a given pretensioned cable structure.</p></abstract>ARTICLEtrue Direct Seismic Losses Assessment Using Gis. Case Study for Iaşi Municipality<abstract><title style='display:none'>Abstract</title><p>Expected direct seismic losses assessment is performed on probabilistic basis using world-wide accepted methodologies for two study areas located in Iasi Municipality. The probabilistic assessment refers to the following issues: site-dependent seismic hazard, expected seismic response of buildings, seismic fragility of structures, expected seismic damage. The analysis of the spatial distribution of the existing building stock as well as the presentation of the results on expected direct seismic losses are performed using geographic information systems (GIS)</p></abstract>ARTICLEtrue of the Statistical Distribution Used in Hydrology Using Kernel Functions<abstract><title style='display:none'>Abstract</title><p>In this paper we will study the statistical distributions for the extreme discharges of the Danube River using kernel functions. We will also compare the results with those obtained using classical cumulative distribution functions (Pareto, Weibull, etc). </p></abstract>ARTICLEtrue of Granulometric Cement Characteristics on the Uniformity Degree<abstract><title style='display:none'>Abstract</title><p>In industrial practice, the dimensional characterization of the polygranular materials can be done, experimentally and/or by calculation, on the basis of various types of granulometric distribution laws, of the different types of diameters, of the specific surface and of some indicators related to the granulometric uniformity. This paper aims at introducing a new indicator, called granulometric uniformity degree, defined on the basis of some informational statistics elements, and calculated in a unique way, different from any particular type of granulometric distribution. At the same time, a series of correlations between the granulometric uniformity degree and different characteristic diameters is pointed out, i.e. the specific surface of cements, characterized by the Rosin-Rammler-Sperling ganulometric distribution.</p></abstract>ARTICLEtrue Analysis for Prognosis of a Photochemical Smog Episode<abstract><title style='display:none'>Abstract</title><p>In this paper we describe the evaluation of various climatic parameters in establishing their prognostic value in a photochemical smog episode. Our application was validated using real data from the “Cercul Militar National” and “Sos. Mihai Bravu nr. 47-49”, from April 2008 to May 2008. The study was performed on hour averages of pollutant concentrations and meteorological parameters and the statistical analysis was based on multiple regressions. We concluded by using mathematical and statistical methods, [1], that an accurate Global Solar Radiation is one of the most important and essential information in the pollution report.</p></abstract>ARTICLEtrue Performance Analysis of Insulating Windows<abstract><title style='display:none'>Abstract</title><p>The present paper thematically fits in the current concern for reducing energy consumption to ensure normal thermal comfort in residential and tertiary building heated spaces. Windows are an important area of the building envelope through which heat dissipates from the interior space to the exterior. As it is known the new insulating window types significantly reduce energy dissipation by both transmission and infiltration. This paper aims to establish the theoretical correlations that exist between different constructive functional parameters of insulating windows, such as gas or gases located between two or three window sheets and low-ε films to be applied on interior faces of the transparent elements. The theoretical work procedures as well as the tabulated and graphical results regarding the thermal resistances for various insulated window structures are presented. The results are analyzed in comparison with the values contained in the C107 regulation for building heat calculations.</p></abstract>ARTICLEtrue of Pressure Drop in Horizontal Pipes for Air – Water Two Phase Flow<abstract><title style='display:none'>Abstract</title><p>The gas-liquid two-phase flow is characterized by continuous and local change of surface separation of phases and by their mutual interactions. Due to the instability of the flow, heat transfer and mass, a precise analytical approach is difficult to achieve. Despite these difficulties, efforts are underway to progress from the more frequent empirical studies to reliable analytical models. This requires an accurate research of the processes involved in the two phase flow and how they interact with one another. This paper aims to determine the pressure drop for a two-phase flow in a horizontal pipe of a heating plant. The author compares the results obtained by numerical simulation with existing results in the domain. The mixture is air-water, at an environmental temperature of 25°C.</p></abstract>ARTICLEtrue analisys of concrete pre-stressed reservoirs for sludge fermentation – water waste treatment plant bucharest – glina. numerical fem assessment of the structural response for static in-duty loads<abstract><title style='display:none'>Abstract</title><p>The paper refers to a structural finite element analysis on the reservoirs for sludge fermentation subjected to static in-duty loads, at Glina Water Waste Treatment Plant. The purpose was to assess the stress and deformation states in subsequent erection and service conditions, to verify the design provisions and to emphasize the sensitivities, for a structure which was designed in the ‘80s based on analytical procedures. The results obtained on the numerical models highlight the importance of the soil-structure interaction, in peculiar the one influenced by the soil mass deformability, on the overall structural response. Based on the calculated stresses, all structural components were verified according to the actual design codes at the ultimate limit state and the service limit state (water tightness/crack emergence).</p></abstract>ARTICLEtrue Study on Temporal Domain Discretizing for Hydrogeological Modeling Practices<abstract><title style='display:none'>Abstract</title><p>One of the key operations in the construction of hydrogeological models is the transformation of continuous physical systems into discrete models while conserving the aimed model performance level and optimizing the available resources. Such operation is called discretization, and it has to be applied to both spatial and temporal domains in hydrogeology. The present paper deals with the temporal domain discretization. A literature review is given first, and then a parametric study (using 1D flow modeling) is conducted to assess the effects induced by boundary conditions (specified head or specified recharge rate), data temporal resolution and model simulation time step on hydrogeological flow model performances. It was found that the effect induced by the dynamic comportment of a recharge rate boundary condition type is more important than that due to a specified head. For the recharge rate, the time step must be smaller or equal to the data resolution when using Modflow. As for a specified head boundary condition type, it was recommended to take a time step satisfying Δt<sub/>∞1/(K × Δh).</p></abstract>ARTICLEtrue Signification Tests in Linear Regression and Economic Applications<abstract><title style='display:none'>Abstract</title><p>In this paper we will use the statistical inference, in particular the Bayes tests for the signification of the parameters of linear regression. We will consider the cases of known variance, and unknown variance respectively. Because we replace the Student tests by the Z tests in practice if the involved number of degrees of freedom is at least 30 , we can replace the case of unknown variance with that of known variance in our paper, if the above number of degrees of freedom is at least 30 . Because in economics we generally know the signs of the involved parameters, in practice the one-sided parametric tests are used. However, in this paper we will refer also to the two-sided Bayes test.</p></abstract>ARTICLEtrue Study of Codes for Seismic Design of Structures<abstract><title style='display:none'>Abstract</title><p>This paper presents a comparative evaluation among some international, European and American, seismic design standards. The study considers the criteria for the analysis of conventional (residential and commercial) buildings. The study is focused on some critical topics: definition of the recurrence periods for establishing the seismic input; definition of the seismic zonation and shape of the design response spectra; consideration of local soil conditions; definition of the seismic force-resisting systems and respective response modification coefficients; definition of the allowable procedures for the seismic analysis. A model for a standard reinforced concrete building (“Model Building”) has been developed to permit the comparison among codes. This building has been modelled with two different computer programs, SAP2000 and SOFiSTiK and subjected to seismic input according to the several seismic codes. The obtained results compared are leading to some important conclusions.</p></abstract>ARTICLEtrue numerical simulation of seismic failure of concrete gravity dams considering base sliding<abstract> <title style='display:none'>Abstract</title> <p>The sliding of dam base along dam-foundation rock interface during earthquake excitation can decrease the earthquake response of the dam. The present study reveals a numerical simulation of the seismic failure response for Oued Fodda concrete gravity dam, located in northwest of Algeria, considering base sliding. Nonlinear finite element analyses are performed for Oued Fodda damfoundation rock system. The Smeared crack approach is used to present cracking of dam concrete under the 1980 El Asnam earthquake (M7) using Willam and Warnke failure criterion. The hydrodynamic pressure of the reservoir water is modeled as added mass using the Westergaard approach. The sliding behavior of contractions joints is modeled by surface-surface contact elements that provide the friction contact at dam-foundation interface. Drucker-Prager model is considered for dam concrete in nonlinear analysis. According to numerical analyses, several cracks may appear due to tension particularly at middle upper parts located along the symmetry central axis of the dam in both upstream and downstream faces. Although the dam sliding on its foundation reduces the magnitude of principal tensile stresses in dam body; however, the reduction magnitude is generally not large enough to preclude the cracks propagation in dam body.</p> </abstract>ARTICLEtrue of the geotechnical map of ain temouchent-city (Algeria)<abstract> <title style='display:none'>Abstract</title> <p>The region of Ain-Témouchent is a seismic zone; its land is predominately agricultural and shows complex structures, with many problems linked to the development of urbanized areas; these problems are directly or indirectly related to the geotechnical conditions of soil.</p> <p>The purpose of the present research is to build a database from the different measurements carried out in the region, and to conduct tests in places where information is not available in order to consider the entire perimeter of the study area.</p> <p>Once the database is completed, an analysis of all the data will be carried out using a numerical tool in order to establish the geotechnical map of the city. This map will certainly allow all decision-makers and designers to have clear and precise information when proposing or designing new structures.</p> <p>The geotechnical mapping of Ain-Temouchent soils based on 178 observations divided these soils into ten groups. Eight of them according to the Unified Soil Classification System (USCS): CH (High plasticity clay), CL (Low plasticity clay), MH (High plasticity silt), ML (Low plasticity silt), SC (clayey sand), SM (Silty sand), GM (Silty gravel with sand), OH (organic soil of high plasticity). The other two groups are rocky soils: basalts (hard volcanic rock with high resistance), and limestone turf (sedimentary rock).</p> </abstract>ARTICLEtrue