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Applying a two degree of freedom model for drive-by identification
Bayer, Jan
A new concept of drive-by identification is examined applying the analogy with a Two Degree Of Freedom (DOF) system where the bridge is considered the ground-supported spring-mass and the moving spring-mass the second DOF. The response of the moving spring-mass is simulated on a bridge model using different road profiles and compared to parameters of the corresponding two DOF system. The focus is the spectral shift that can be observed on the moving spring-mass during its passage along the bridge and could possibly be applied for drive-by identification. The accuracy mainly depends on the relation of the moving spring-mass to the bridge mass and the relation between the natural frequency of the spring-mass and those of the bridge. The simulations showed that road profile can significantly reduce the accuracy of identified results, which imposes limits on practical applications.
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Continuous Welded Rail Track on Tramway Bridges
Křečková, Magdalena
The issues related to the continuous welded rail remain a debated topic, especially in connection with bridge structures. The issues are relevant not only to railway tracks where bridge structures with long expansion lengths are becoming more and more common but also to tramway tracks. This article presents the continuous welded rail theory on tramway bridges, including an example of a structure on which the monitoring of expansion displacements in rail expansion joints has been initiated.
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Examining the Impact of Demand-Side Management Through Dynamic Simulation: Integrating Smart-Grid-Ready Control of Residential Heat Pumps
Horváth, Miklós ; Takács, Zoltán ; Gergely, László Zsolt
This paper investigates the suitability of air-to-water heat pumps for smart grids, with a particular focus on load shifting. The research uses dynamic building energy simulations to show that the utilisation of these features effectively addresses the energy consumption challenges of heat pumps while ensuring that heating and domestic hot water demands are met. The implemented control system successfully shifts the morning and evening peaks to the daytime period, resulting in a modest 2% increase in total energy demand.
These results not only demonstrate the balancing of heat pump energy consumption, but also provide insights for the development of objective functions. Such functions can play a key role in supporting the smooth integration of renewables into the wider energy framework.
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Comparison of Green Façade Systems Based on Experimental Basis Weight Measurements
Vystrčil, Jan ; Chomová, Štěpánka ; Nespěšný, Ondřej ; Šuhajda, Karel ; Bečkovský, David
Green facade systems are gaining attention due to their potential for the urban environment, building aesthetics, and energy efficiency. This study compares different green facade systems and their surface weight, which is one of the critical parameters for performance and longevity. The research evaluates construction, installation, water consumption, and sustainable operation. Experimental measurements of surface weight examine changes depending on water consumption and performance.
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Extension of Discrete Model for Simulations of Ballistic Experiments
Fleischerová, Beáta ; Eliáš, Jan
During the ballistic experiments, fiber-reinforced concrete panels are loaded by a high-velocity projectile. The meso-scale discrete model built in programming language C++ is used to simulate these tests. The mechanical behavior of short fibers crossing a single crack is derived and implemented. The explicit time integration scheme is under development to replace the current implicit solver utilizing the generalized-alpha method. The paper presents some partial results.
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Assessing Adaptation Measures in a Selected 4th Order Watershed
Plevková, Miroslava ; Dumbrovský, Miroslav
The aim of this study is to propose and evaluate adaptation measures within the selected 4th order watershed (4-15-03-104). The primary goal of these proposed measures is to stabilize the water regime in the landscape and manage extreme hydrological phenomena, as well as to mitigate erosion risks in the territory. This approach aims to create a harmonious landscape aligning with the fundamental principles of sustainable development. Prior to the proposal, the territory underwent a detailed analysis based on available data and field reconnaissance. The research compares two variants with the current state of the landscape. Variant 1 utilizes historical maps as a foundation, while variant 2 incorporates measures designed to optimize the landscape in response to ongoing climate change.
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Sustainable Asphalt Recyclate Base Course
Spies, Karel ; Tanečková, Pavlína
In the construction industry nowadays, it is the concepts such as sustainability, recycling, emission and energy reduction which are coming to the fore. This article follows the same path, looking at the design of new, recycled road subbase layers. These layers are almost 100% composed of recovered reclaimed asphalt, crushed to the appropriate fraction. This reclaimed asphalt is either mixed with a suitable binder, heated to a low temperature, or a combination of both effects occurs. The research described in this paper is partially related to the newly developed standard ČSN 73 6147 Cold recycling of pavement structural layers [1]. The aim of this research is to economically and environmentally reuse reclaimed asphalts of lower quality, specifically in the subbase layer of pavements. Otherwise, this precious material is mainly used for the backfilling of roadsides.
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Room Modes in Rectangular Rooms with Complex Impedance Boundaries
Jun, David ; Plasek, Josef ; Rychtarikova, Monika ; Glorieux, Christ
In many calculation approaches in room acoustics, one models the reflection of surfaces via a positive, real absorption coefficient, neglecting the fact that the reflection coefficient can have a non-zero phase. For some sound-absorbing structures such as resonators, this simplification leads to erroneous results, e.g. when room modes are of interest.
This contribution presents an approach for the calculation of room mode frequencies in a rectangular room with complex and frequency-dependent acoustic impedance wall boundary conditions. The results are to be used for auralizations of different scenarios in which the modal behaviour of a room is modified, and for evaluation by listening tests.
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Analysis of the Development of Prices of Construction Projects and Materials in the Territory of the Slovak Republic
Hopocký, Adam ; Ďubek, Silvia
In recent years, the global economy has developed unpredictably. This unpredictable and unstable development has also affected the construction industry, not only in the territory of the Slovak Republic, but all over the world. This unexpected development of the market, which has caused an increase in the prices of building materials and construction work, has also caused complications, and the slowing down and subsequent extension of construction time. The relevant authorities have tried to compensate for the impact by implementing certain remedial measures.
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