Problems of perceived quality of the environment find its reason especially when monitoring performance and productivity of work. Thus, verification of the degree of environmental quality impact on ...employee performance comes into consideration. The results of two independent studies involving 50 subjects, and using similar procedures and blind exposures have shown that increasing the air quality (by decreasing the pollution load or by increasing the ventilation rate, with otherwise constant indoor climate conditions) can improve the performance of simulated office work (text typing, addition and proof-reading). Performance testing was performed in the open space office of an office building at three air exchange intensities: n1 = 0.5 h−1, n2 = 1.5 h−1 and n3 = 2.5 h−1. Other physical environmental parameters that could have affected the assessors' performance were maintained in the range: indoor air temperature θai = 22 - 24 °C, relative air humidity φai = 40 - 60%, air velocity vai ≤ 0.25 m.s−1, noise level load L = 40 - 50 dB (A), daylight - diffuse radiation component. The present results document the productivity benefits of providing good indoor air quality and indicate that providing indoor air of a higher ventilation level will increase productivity.
The current knowledge shows that the interior microclimate of residential buildings that were constructed between 1950 and 1990 using panel construction, not only in the Czech Republic but also in ...Europe, and were renovated in accordance with applicable legislation related to thermal comfort and energy is significantly affected by gaseous pollutants. At increased concentrations and exposure times, these pollutants negatively affect the interior microclimate and at the same time have a negative effect on the health of users. After the implementation of remediation measures, which are mainly focused on improving the thermal technical parameters of the building envelope, the concentration of CO2 in the indoor environment increases. Carbon dioxide is one of the most important active factors and in terms of the quality of the interior microclimate, it is considered a reliable indicator of whether the interior microclimate can be considered a healthy and favorable environment. It is thus clear that the set and de facto systematized measures in the renovation of the housing stock from the second half of the 20th century has led to energy savings on the one hand, but on the other hand, this has contributed to the hygienic damage of housing units and an unhealthy interior microclimate. The paper aims to define the interaction of interdisciplinary contexts that have led to an increase in the indoor air quality (IAQ) of renovated residential panel buildings.
Abstract
In general, steel beams are stressed by bending and shear. Due to the loading a normal stresses σ and shear stresses τ arise in individual cross-sections of steel beams. But they are usually ...stressed mainly by bending. This follows both from several theoretical analyzes and especially from the corresponding experiments. Therefore, current standards for the design of steel structures allow the impact of shear to be neglected to a certain level of shear stress of the most stressed - decisive cross-sections of beams (EN 1993-1-1, respectively CSN EN 1993-1-1 and others). However, in the case of shorter beams, especially in places of support and in places of application of concentrated forces, the shear effects of the load can also be significant. In the case of more significant shear effects of the load, the plastic flexural strength of the decisive cross-sections and also the overall load-bearing capacity of the steel beams must be adequately reduced. However, the degree of flexural strength reduction with a significant effect of shear in the case of I cross-sections is still unambiguous. It is therefore important to experimentally investigate steel beams in the area of significant shear effects. The presented article contains selected results of experimental investigation of the significant effect of shear on the flexural strength of steel beams I cross-sections.
Abstract
The paper presents basic information on determining of strength and resistance of structural steels and materials based on test results. The actual European standard EN 1990:2002 and related ...national standards CSN EN 1990:2004, and other are respected within the paper. The practical application of standard procedures is applied in determining the characteristic and design values of strength and resistance of structural steel S235 used for the production of welded test bars of the previous author’s experimental researches. Experimental data on the actual geometric dimensions and material properties of the individual test bars enabled their detailed statistical evaluation. Subsequently, the characteristic and design values of strength and resistance of structural steels used for the production of test bars were determined. The characteristic and design values of strength and resistance determined in this way are compared with the standard ones, which for S235 steel contain valid standards for the design of steel structures.
Abstract
Construction is a reflection of the current state of society. The construction is created as a result of a creative process including preparation, all stages of design and implementation. ...Current trends of modern building structures with a large span are characterized by the introduction of new types of load-bearing structural systems with excellent ecological, economic and aesthetic properties. The paper aim is to introduce the interaction and context in design and create a reliable economic and environmental friendly structure that will serve the required purposes.
Abstract
The paper aims are to assess and evaluate the hygiene and quality of the indoor environment in selected indoor areas of the kindergarten, to analyse the construction, technical and ...technological solutions of the building in accordance with the concept of designing healthy buildings and their environment. The paper will propose the operation of the building in terms of hygiene and perceived air quality. The paper assumes in-situ monitoring of the indoor environment of the nursery school using a multifunctional measuring instrument for analysing the quality of the indoor environment and comfort (Testo 480 + accessories). The research goal is to update and expand information on the quality of the indoor environment of kindergartens during the heating season. The aim is to design a concept for improving the quality of the environment in nursery schools and to prepare documents for relevant recommendations, including recommendations concerning, for example, construction or utility materials for nursery schools and the mode of their operation.
The efficiency of plasticity for the design of steel frame structures is analysed in the paper. Technical theory of plasticity and standard assumptions and requirements for numerical study are ...applied. Two types of simple frames (double-sided pinned supporting and fixing) with different loading, geometrical dimensions of the frames and cross-sections of their columns and beams are considered. Some results of the numerical study and conclusions are also presented.
The technical plastic theory is applied for steel structures design in actual standards. This theory and standard calculate procedures assumed the plastic redistribution of internal forces by arising ...and development of plastic hinges and plastic mechanism failure of the structure. The plastic redistribution of internal forces enables the loading of structure to increase. The plastic redistribution and increasing of the loading cause also changes in the support reactions that are generally needed to consider as the actions on the structural supports. The redistribution of internal forces and the changes of support reactions depend on the elastic-plastic properties of constructive steels that are variable. Therefore, plastic redistribution of internal forces may not be absolute, or may not arise at all. In the paper, the effect of elastic-plastic redistribution of internal forces on the load-carrying capacity and the changes of support reactions for selected continuous beams are analyzed.
This paper is focused on the quality of the indoor environment in terms of Total Volatile Organic Compounds (TVOC) in the office buildings. Working in the office is one of the most common occupations ...in developed countries of the world. Employees spend up to 25% of their time in the workplace each year. Obviously, the internal environment affects not only the health of workers but also their performance and productivity. Observe the long-term level of Total Volatile Organic Compounds in the context of Indoor Air Quality (IAQ) in a single cellular office is subjected within the presented study. IA-Quest (Indoor Air Quality Emission Simulation Tool) developed by the National Research Council is used for emission of VOCs from building surface materials and furnishings in time. The simulation and monitoring of TVOC concentration are carried out in two phases. In the first phase, only building materials such as walls, doors, floor, ceiling, window, etc. are considered. In the second phase, the basic furniture including the office table and chair, coffee table, 2 chairs and wardrobe are included in the calculation. TVOC concentration values in a furniture room are 10 - 15% higher than in a room without furniture.
This paper presents results to thermal comfort and environment quality questions in 21 school building rooms. Results show that about 80% of the occupants expressed satisfaction with their thermal ...comfort in only 11% of the buildings surveyed. Air quality scores were somewhat higher, with 26% of buildings having 80% or occupant satisfaction. With respect to thermal comfort and air quality performance goals set out by standards, most buildings appear to be falling far short. Occupant surveys offer a means to systematically measure this performance, and also to provide diagnostic information for building designers and operators. The odours from building materials as well as human odours were studied by field measurement. The odour intensity and indoor air acceptability were assessed by a sensory panel. The concentrations of total volatile organic compounds and carbon dioxide were measured. The odours from occupancy and building materials were studied under different air change rate. The case study of indoor air acceptability concerning to indoor odours and its effect on perceived air quality are also presented in this paper.
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