Integrated Platform for the Analysis and Design of Tall Buildings for Wind Loads

The Romanian, as well as other wind design codes for building structures, provides with limited degree of accuracy, the aerodynamic loads distribution on buildings up to 200 meters tall in an equivalent static approach (ESWL). For tall wind-sensitive building structures, especially for those with irregular shapes, most of the codes or standards recommend for design to use pressure data recorded in the wind tunnel. The ESWL approach is however used as reference estimation and structural first phase design. Advances on experimental and computational capabilities, led in the past decade to a significant development of time-domain analysis framework, both for seismic and wind loads. While the major outcome for earthquake engineering practitioners is to select appropriate design input ground motions at a particular site, the wind engineering practitioners are facing numerical difficulties to handle large wind loading durations, especially dealing with nonlinear-induced effects. The paper presents a real-time integrated framework for the analysis and design of tall buildings to wind loads, based on the time-domain analysis tool, as a prerequisite for higher level modules as vulnerability, risk and loss estimation, and optimization analyses.

Modelling the Unsteady Flow of Water into a Partly Saturated Soil

Flows in unsaturated medium are frequent in the field of civil engineering and more particularly in geotechnics. The study undertaken here tries to solve the unsaturated transient flow equation in porous media using the finite element method. Numerical solution of a finite element discretization is used along with an implicit integration scheme of the time stepping. A functional one that makes it possible to find the distribution of the hydraulic load has been proposed and a calculation program has been developed. The results obtained by this program called TFAP (Transient Flow Analysis Program) are compared to other previous work in the subject. The authors show the importance of this study through two real examples. Liakopoulos conducted several experiments on the water drainage through a vertical column filled with Del Monte sand. One of these experiments was chosen to perform a simulation by the model. The results of the calculation are compared with the experimental data as well.

The Potential Wind Power Resource in Central-South of the Constanta County

Usually, wind turbine generator’s structures or radio masts are located in wind exposed sites. The paper aims to investigate the wind conditions in the nearby area of Cobadin Commune, Constanta County, Romania at heights of 150-200m above the surface using global reanalysis data sets CFSR, ERA 5, ERA I and MERRA 2. Using the extreme value theory and the physical models of the datasets, the research focuses on the assessment of the maximum values that are expected for the wind speeds, but the wind statistics created can be used for a further wind or energy yield calculation. Without reaching the survival wind speed for wind turbine generators, with mean wind speed values higher than 7 m/s and considering the cut-in and cut-out wind speeds of 3 m/s, respectively 25 m/s, the site can be exploited in more than 90% of the time to generate electricity, thus, the paper is addressed to the investors in the energy of renewable sources. At the same time, the insights of the wind characteristics and the knowledge of the extreme values of the wind speed can be useful, not just for the designers, in the rational assessment of the structural safety of wind turbines, but also those evaluating the insured losses.

Wind Load Design of Photovoltaic Power Plants by Comparison of Design Codes and Wind Tunnel Tests

Wind load design of the ground-mounted photovoltaic (PV) power plants requires interpretation of the design code considering the particularities of these structures. The PV power plants consist on systems of several solar panels. Wind load pressure coefficient evaluation, by design code, for a single solar panel considered as a canopy roof, neglect the group effect and the air permeability of the system. On the other hand, the canopy roofs are structures with medium serviceability, but the PV power plants are structures with low serviceability. This paper discuss the difficulties of the wind load design for the PV power plants ground mounted in Romania and compares the Romanian, German, European and American wind design code specifications with the parameters provided by the wind tunnel test, for this type of structures. For Romanian wind load design an evolution of the 1990, 2004 and 2012 editions of the design codes specifications is also studied. Evaluation of the internal resultants for the structural elements of the PV panel, considering the pressure coefficients and the force coefficients, conducts to different results. Further code explanations and design specifications are required for wind design of the PV power plants.

Probabilistic Analysis for Estimation of the Initiation Time of Corrosion

In this paper, a probabilistic study on durability concrete was carried out. In such a design, initiation time of corrosion must be expressed as a mathematical model using Fick’s second law and the statistical distributions properties of theirs parameters was included in this model. The scatter both in the environmental exposure conditions and structural properties was considered as random fields in the mathematical model with a probabilistic design. The main objective of this study is predicted initiation time of corrosion of concrete structures in chloride containing environments. This probabilistic study is developed using Monte Carlo simulation to determine the contribution of each input parameters and the statistical parameters of the random variables on the probability distribution functions of the initiation time of corrosion. Also, a comparison study was carried out to analyze the impact of the probability distribution on the response (the initiation time of corrosion).

Benefit of Wind Tunnels with Large Test Sections for Wind Engineering Applications

Atmospheric Boundary layer wind tunnels (ABLWT) dedicated to building safety and comfort have been operated by CSTB in Nantes since 1971. Because ABLWT only deal with reduced scale models of real structures, the necessity of a larger wind tunnel, the Jules Verne Climatic wind tunnel (CWT), able to reproduce extreme wind loads on real scale structures arose in the years 80. Hence, it became a major European facility operating for improvement of the safety, quality and environmental impact of buildings and civil engineering works as well as products from industrial fields (transportation, energy…) with respect to strong winds and other climatic hazards. Both wind tunnel types, the ABLWT and the CWT are complementary and used for studying the effect of wind on the same structures at two different scales, when the effect of wind scaling is important. During the 2018 year, several modifications were made to the CWT facility. The atmospheric test section of the existing facility was elongated preserving the initial advantages, very large test section (approximately 120 m2) with wind velocity performance compatible with many applications (up to 90 km/h). This new test section makes it possible to simulate turbulent wind and driving rain testing. The sand winds capabilities have been maintained in the new design, despite the closed loop configuration, by fitting a filtering. The modifications of the wind tunnel geometry now offer a long test section upstream the turning vanes where a whole set of new tests can be carried out, as windmill field, natural ventilation of urban environments, slender structures (large bridges, pylons, cable transport systems,)

On the Use of the Cubic Translation to Model Bimodal Wind Pressures

The cubic translation model is a well know tool in wind engineering, which provides a mathematical description of a non-Gaussian pressure as a cubic transformation of a Gaussian process. This simple model is widely used in practice since it offers a direct evaluation of the peak factors as a function of the statistics of the wind pressure data. This transformation is rather versatile but limited to processes which are said to be in the monotonic region. For processes falling outside this domain, this paper describes an alternative which is based on the physics of the wind flow. First, it is shown, with a classical example of a flow involving corner vortices on a flat roof, that the pressure data which does not meet the monotonic criterion is in fact associated with a bimodal distribution. Then, the proposed approach is to decompose this data into the two governing modes (slow background turbulence and fast corner vortices) and apply the usual translation model to each of them.

Identifying the Reference Time for Determining the Compressive Strength of Concrete Containing Different Types of Cements

The compressive strength of the concrete measured at 28 days is the criterion for assessing the concrete class, and these values will be acceptable precise indications for other physical and mechanical characteristics of the concrete. In addition to the factors the compressive strength of concrete varies on (such as: the characteristics and proportion of constituents, the placement conditions and subsequent treatment and testing conditions), the concrete class should also depend on the type of cement contained and the concrete strength evolution over time. Due to the fact that concretes with composite cements have a slower evolution of compressive strength and a significant strength increase after 28 days, concretes with different types of cements and mineral admixtures were tested for compression after 28 days in order to determine the reference time for such tests – and thus the concrete’s class.

Determine the Required Log Reductions of Human Intestinal Helminth Eggs by Waste Stabilization Pond: A Simulation for Wastewater Recycling in Agriculture

This paper investigates the determined the required log reductions for human intestinal helminth eggs by waste stabilization ponds as simulation as assessing of mitigating health risk to satisfy practice WHO, 2006 guidelines for the safe use of wastewater in agriculture (≤ 0.1 helminth egg/L) to protect the health of children under 15 years was the development of MATLAB, a computer program based waste stabilization ponds design based on parameter uncertainty and 10,000-trial Monte Carlo simulations were developed for a series of anaerobic, facultative and maturation ponds based on 95%-ile of effluent (≤ 0.1 helminth egg/L) which the result in a health-based target. Whereas the influent of the helminth eggs (Nematode) was (932.500 eggs/L). While the treatment provided (100 % reduction/removal) for the overall treatment process with total hydraulic retention time in climatic conditions of Libya it took 36.207 days in the anaerobic pond, facultative pond, first maturation pond and one of the subsequent maturation pond.

Experimental Investigation of the Relationship Between Noise Level and Thermal Power Inside the Boiler Plant – Study Case

The acoustic comfort of a building or house is typically given little or no attention during project planning and design. This study is aimed at quantifying noise pollution from a building technical room. To attain the research specified result, simultaneous measurements were recorded for the gas flow and noise level in the boiler room. The noise levels were recorded for different operation statuses of the boilers (different thermal loads). It was observed that noise level depends on the thermal load: the increase of thermal load is directly proportional to the noise level inside the plant room). Further, the measured values of the noise level were compared with literature predicted values and the maximum limit values from the Romanian norm. These research findings are useful for mechanical design engineers and architects in order to assure the noise protection and fulfill the residents’ expectations.