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Povzetek: When creating a simulation model to assess the performance of buildings, there is usually a lack of feedback information. Only in the case of measurements of a real building is a direct comparison of the measured values and simulated results possible. Parameter data related to users’ behavior or other events can also be obtained. Their evaluated frequency, magnitude and duration, along with boundary conditions, are crucial for the results. It is clear that none of them can be predicted very accurately. Most of them, however, are needed for computer modeling. In this paper we analyzed the well-defined TRNSYS simulation model of offices equipped with radiant ceiling panels for heating and cooling. The model was based on real case offices and was validated based on measurements for 1 year. The analysis included simulations in order to define what effect the parameters related mainly to users have on the energy use and the indoor air temperatures. The study confirmed that specific human activities influence the annual energy use to a relatively small degree and that their effects often counteract. It also confirmed the even more important fact that although small, these activities can influence the thermal comfort of users. It is believed that despite the fact that this research was based on an analysis of offices equipped with radiant ceiling panels, most of the results could be applied generally.
Ključne besede: measurements, modeling, simulation, validation, analysis, energy use, temperature
Objavljeno v DiRROS: 15.09.2023; Ogledov: 328; Prenosov: 153
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Povzetek: As far as the utilization of the value-added potential of hardwood assortments is concerned, we have considerable reserves in Slovenia. These could be exploited mainly by increasing the economic use of roundwood in Slovenia and by developing more technologically advanced processing methods for roundwood. The aim of this paper is to assess the untapped potential of the forest-wood chain in Slovenia using input-output models, focusing on the use of hardwood. For the whole forest-wood chain, we assessed the existing situation and tested five scenarios for the improvement of the forest-wood chain in Slovenia. We developed a national input-output model to evaluate possible scenarios for the future development of the wood-based bioeconomy. The results of scenario analysis of the input-output model show that the Slovenian wood-based bioeconomy can achieve up to 20% higher production value, a 24% increase in employment and 19% increase in household income in the future through restructuring of economic activities. In the paper, we discuss how upgrading the forestry and wood-processing industry (according to the defined scenarios) could be achieved by increasing the processing capacity of hardwoods and provide recommendations for decision makers.
Ključne besede: forest- and wood-based bioeconomy, hardwoods utilization, input-output models, wood processing industry, scenario analysis, mobilization of hardwoods
Objavljeno v DiRROS: 03.08.2023; Ogledov: 343; Prenosov: 181
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Povzetek: The dynamic component of bridge traffic loading is commonly taken into account with a Dynamic Amplification Factor (DAF)—the ratio between the dynamic and static load effects on a bridge. In the design codes, this factor is generally more conservative than in reality. Recently a new method of cal- culation of this factor had been developed. Data from 15 different bridges have been analysed since then and this paper presents the results of the analyses. The background for Bridge Weigh-in-Motion is given, and the most recent method for DAF calculation is described. The sites from which the data originated are presented, and the selection of data discussed. The results of the analyses are presented and discussed and some examples of DAF calculations are shown. Data from the considered sites have invariably demonstrated a DAF decrease with increasing axle load. This is a significant result, especially for assessment of existing structures, since it is beneficial to use measured structural param- eters to optimise structural analysis.
Ključne besede: bridge loads, bridge weigh-in-motion, dynamic amplication factor, dynamic analysis, measurement, traffic loading
Objavljeno v DiRROS: 14.07.2023; Ogledov: 324; Prenosov: 172
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Povzetek: This paper investigates the effectiveness of a specific crystalline waterproofing admixture (CWA) in concrete as a function of a water–binder ratio. Four concrete mixes with and without CWA were prepared; two of them with a water–binder ratio of 0.45 and two of them with a water– binder ratio of 0.55. Water permeability and compressive strength were tested on hardened concrete specimens and self-healing of cracks over time was observed. Cement paste and CWA paste were prepared to clarify the results obtained on the concrete specimens. SEM and EDS and XRD and FTIR were performed on the hardened pastes to explain the mechanism of CWA working. The results show that the addition of CWA had no significant effect on the compressive strength of the concrete, but reduced the water penetration depth in the concrete, and the reduction was more effective for mixes with lower water–binder ratio. Regarding the self-healing effect, it can be concluded that the addition of CWA improves the crack healing in concrete, but the efficiency of self-healing is highly dependent on the initial crack width. The mechanisms involved in the reduction of water penetration depth and crack healing in concrete can be explained by different mechanisms; one is creation of the CSH gel from unreacted clinker grains, then formation carbonate, and additional mechanism is gel formation (highly expansive Mg-rich hydro-carbonate) from magnesium based additives. The presence of sodium silicate, which would transform into carbonate/bicarbonate, also cannot be excluded.
Ključne besede: slag, self healing concrete, crystal admixture, microstructural analysis
Objavljeno v DiRROS: 03.07.2023; Ogledov: 289; Prenosov: 207
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Povzetek: In this study, a large arch-gravity Moste Dam was analyzed, where an automated system for the measurements of horizontal displacements of the upper part of the dam was established. Two-dimensional (2D) and three-dimensional (3D) analyses of dam behavior, taking into account the earth pressures and the hydrostatic load, using the finite element method (FEM)-based computer program DIANA, were performed. The influence of lowering the water level of the reservoir by 6.2 m, on the horizontal displacements of the upper part of the dam, at stationary temperature conditions, was investigated. It was found that the results of the performed 2D and 3D FEM analyses fitted in very well with the result of experimentally determined measurement of horizontal displacements (which was 0.48 mm in the upstream direction) that was obtained using a hanging pendulum. An additional comparison of the results of 3D calculations showed that the finite element mesh density had a small effect on the calculated horizontal displacements.
Ključne besede: concrete dam, finite element method, material properties, structure behavior, measuring instruments, monitoring, ime series analysis, horizontal displacements, hydrostatic pressure
Objavljeno v DiRROS: 21.06.2023; Ogledov: 363; Prenosov: 205
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