A contribution to the study of some greek marbles

The use of marble in Architecture began on the 7th century B.C. and continued to be used without stop untill today. Greece and especially the East Macedonia region is an extremely privileged area on marble deposits both in quantities and qualities and colours. In the present work the main physical and engineering properties of some varieties of greek marbles are given and a comparison with the international standards is made. The experimental material (marbles) was from East Macedonia, Argolida-Arcadia and Magnessia, three of the biggest marble deposit areas in Greece. From the results obtained, it is concluded that the marbles examined satisfy all the international standard codes and thus they can be used as building stones and decoration materials.     

Stress-Strain State of Weak Saturated Clay Beds of Embankments

Results are presented for laboratory and field tests of weak saturated soils serving as beds for embankments in Ho Chi Min City and various regions of the Mekong River Delta (Vietnam). A method is outlined for quantitative evaluation of the stress-strain state (SSS) of the weak saturated clayey beds (plane problem). A method is described for quantitative evaluation of the deformation and stability of weak beds in the initial, intermediate, and stabilized stages of the formation and transformation of the SSS. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 2–6, September–October, 2005.     

Lead contamination in tap water of households with children in Lower Saxony, Germany

Lead has numerous acute and chronic adverse effects on human beings. This is especially true for infants and children. The main path of lead ingestion in children can be different according to housing and living situation. The intake of lead through drinking water is commonly due to metal corrosion. The users plumbing can be an important factor. In recent years, many lead pipes in Germany have been replaced by pipes made of an alternative material. The aim of this study is to assess the present state of drinking water contamination and the resulting exposure of infants to lead. For this purpose mothers of new-born babies were offered a free examination of their drinking water. After a written declaration of consent had been obtained and after the infant in question had reached an age of 3 months, a stagnation sample of cold tap-water after overnight stagnation together with a random daytime sample was obtained from the family. The collected samples were analysed by atomic absorption spectrometry for their lead concentration. In total, 1485 samples from households were collected. Of the 1434 stagnation samples, 3.1% had lead concentrations greater than 0.01 mg/l (recommended limit of the WHO) and 0.6% had concentrations above the limit of the German drinking water regulation (0.04 mg/l). The values for the 1474 random daytime samples were 2.1% above 0.01 mg/l and 0.2% greater than 0.04 mg/l, respectively. By region, the areas Bovenden, Friedland, Duderstadt, Northeim and Rosdorf were particularly affected. The highest measured concentrations of lead in the stagnation samples were 0.11 mg/l and 0.15 mg/l in the random daytime samples, respectively.     

Energy and environmental comparison of three variants of a family house during its whole life span

The aim of this study is to analyse and compare three variants of a family house in order to evaluate the total environmental impacts produced during the whole building life cycle. The first variant corresponds to the standard in force in Switzerland, the second alternative to the requirements of a quality control label for houses with low energy consumption and the third case is a very low energy consumption building. The three variants have the same architectural aspect but different insulation thicknesses and types, different energy production systems and the use of different renewable energies. The calculation of the environmental impacts is carried out by means of a life cycle analysis, which includes not only the impact related to the energy consumption during the occupancy stage, but also the materials manufacture, transport, replacement and elimination at the end of the building lifetime. The results are expressed with the Swiss and the UCTE (Union for the Co-ordination of Transmission of Electricity) electricity mix to analyse how they influence the building impact.     

An experimental behaviour of concrete-filled steel tubular columns

In this paper results of tests conducted on 27 concrete-filled steel tubular columns are reported. The test parameters were the column slenderness, the load eccentricity covering axially and eccentrically loaded columns with single or double curvature bending and the compressive strength of the concrete core. The test results demonstrate the influence of these parameters on the strength and behaviour of concrete-filled steel tubular columns. A comparison of experimental failure loads with the predicted failure loads in accordance with the method described in Eurocode 4 Part 1.1 showed good agreement for axially and eccentrically loaded columns with single curvature bending whereas for columns with double curvature bending the Eurocode loads were higher and on the unsafe side. More tests are needed for the case of double curvature bending.     

Stability analysis of simply-supported rectangular plates under non-uniform uniaxial compression using rigorous and approximate plane stress solutions

The non-classical problem of buckling of a simply-supported rectangular plate due to various types of non-uniform compressive edge loads is analysed here. For each case, the elasticity solution for the internal in-plane stress field is obtained rigorously using a superposition of Airy's stress functions and also approximately using extended Kantorovich method. Subsequently, the convergent buckling loads are obtained using Galerkin's method. Results are presented to highlight the dependence of the total buckling load and the corresponding buckled shape on the edge load distribution, as well as to illustrate the applicability of the approximate plane stress solutions.     

Field measurement of the air flow characteristics of big mechanically ventilated spaces

Air speeds induced by mechanical ventilation systems in the occupied zone are studied experimentally in seven railway stations in Hong Kong. Values of air speed at different positions are measured. From these values, air speed contours and turbulence intensities are calculated. Macroscopic numbers describing airflow in a space including the Reynolds number and the jet momentum number are estimated and their potential uses are discussed.     

Profiles of mean wind speeds and vertical turbulence intensities measured at seashore and two inland sites using Doppler sodars

The authors’ group has been conducting full-scale measurements of wind velocities with Doppler sodars. It is very important to accurately assess the profiles of mean wind speeds and turbulence intensities in relation to terrain roughness. In this study, the profiles were evaluated for all data measured over a long period at a seashore and two inland sites. It is confirmed that for strong winds the profiles can be approximated by a single power law at altitudes between 50 and 340 m. The power law exponents of the mean wind speed profiles are approximately 0.1 for wind from the sea and 0.2-0.3 for wind blown over land. Those of the turbulence intensity profiles are approximately 0 and −0.2 to 0.4, respectively.