Floor Of Building Research Articles

WiFi round-trip time (RTT) fingerprinting: an analysis of the properties and the performance in non-line-of-sight environments

ABSTRACT Indoor positioning systems based on WiFi round-trip time (RTT) measurement were reported to deliver sub-metre-level accuracy using trilateration, under ideal indoor conditions. However, the performance of WiFi RTT positioning in complex, non-line-of-sight environment remains an open research question. To this end, this article investigates the properties of WiFi RTT in several real-world indoor environments on heterogeneous smartphones. We present three datasets collected on a large-scale building floor, an office room and an apartment. The datasets contain both RTT and received signal strength (RSS) signal measures with correct ground-truth labels for further research. Our results indicated that in a complex indoor environment, RTT fingerprinting system delivered an accuracy of 0.6 m which was 107% better than traditional RSS fingerprinting and 6 m better than RTT trilateration which failed to deliver sub-metre accuracy as claimed.

Housing Adaptations to Climate: Vernacular Settlements on the Kahayan Riverbank at Palangka Raya, Indonesia

Producing buildings that can adapt to climatic conditions is one of the notable abilities of people who improve the quality of their houses. Lake Tundai is a residential area in Palangka Raya, Indonesia, occupied by a fishing community, isolated and only accessible through the Kahayan River. People prefer wood materials for house construction, and with a largely impoverished population, they remain in those houses they have inherited from the past. However, it is an example of a village resistant to the effects of global climate change, because their houses are climate-friendly, although natural breeze is the only thermal comfort enjoyed by the inhabitants of Lake Tundai. Using thermal performance simulation on the Tundai Lake houses, this research presents four types applied to four variable elements through the Ecotect analysis program to ascertain how the houses deal with the climate. Based on the climatic conditions in Lake Tundai. Type 2 with stilts, light roof, light walls, single ventilation, and ceiling is the most suitable model condition in Tundai Lake. The research concluded in 2023 that the influence of the building floor height from the ground may affect the thermal comfort in the room. If the floor height over the water level is below 1.2 meters. This study proposes an example of housing adaptation using wood materials nearby the water.

MIGRATIONS AND CULTURAL EVOLUTION IN THE LIGHT OF RADIOCARBON DATING OF BRONZE AGE SITES IN THE SOUTHERN URALS

ABSTRACT This research aims to contribute to our knowledge of the chronology of the main cultural entities of the Bronze Age in the Southern Urals. The objectives of this work include the verification of earlier conclusions regarding individual sites, expanding the date series for the key cultures with reliable dates, and creating reference series for the Bayesian modeling of key archaeological sites. Thirty-two samples were selected from reliable contexts. They reflect seven different cultural traditions of the 2nd millennium calBC (Sintashta, Srubnaya, Alakul, Fedorovka, Cherkaskul, Final Bronze Age1, Transition to Early Iron Age2). Collagen (human and domestic animal bones), charcoal, and wood samples were used for radiocarbon dating. Pairs of different-type samples (human bone – animal bone, animal bone – charcoal) were obtained for the same undisturbed burial and the building floor at the time of its abandonment. The data and the composition of δ15N and δ13C isotopes allow the new dates to be considered reliable. Furthermore, the new results do not conflict with the previously obtained accelerator mass spectrometry (AMS) dates. Determining boundary intervals for the main cultures of the Andronovo cultural community (Alakul and Fedorovka) resulted in statistically reliable conclusions on their relationship. The Alakul culture appeared earlier than the Fedorovka culture. The latter has a migratory origin in the Southern Urals. The two traditions have a long history of interaction, but the Alakul culture ending earlier. The series of dates for the Final Bronze Age, divided into two sub-periods, has been significantly expanded. Bayesian modeling of the chronology of the stratified settlement Sintashta II (Levoberezhnoe) made it possible to determine the intervals of the main phases of its history: 2004–1852 calBC (Sintashta culture) and 1410–1170 calBC (Final Bronze Age). Intermediate Cherkaskul phase is represented by a single date (1731–1541 cal BC).

Train-Induced Vibration Prediction and Control of a Metro Depot and Over-Track Buildings

To predict and control the train-induced vibration in depot buildings, a case study of the depot of Tianjin Metro, Line 5, was conducted. The platform of the depot has been constructed and is in use, and the construction of over-track buildings has not been completed. Firstly, an in situ measurement was performed to obtain the train loads and validate the numerical model. Secondly, a finite element model of the track–soil–depot structure was established. The train was simplified as a series of two spring-mass models and the train load was simulated using the measured rail acceleration. The calculated results were validated by the measurement data. To predict the vibration responses of the over-track building to be built, a sub-system of the over-track building was added to the numerical model. Finally, the vibration control effect of vibration isolation bearings was discussed. The results indicate that vibrations exceeded guideline limits without mitigation measures in some rooms of the over-track building. The dominant frequency of the building floors is 31.5 Hz. Vibration isolation bearings effectively mitigated the vibrations, and the IL reached approximately 7–15 dB at about 31.5 Hz.

The Effects of Rhythm on Building Openings and Fenestrations on Airflow Pattern in Tropical Low-Rise Residential Buildings

Effective passive airflow in low-rise residential buildings in hot-humid environment is crucial to maintaining good indoor thermal comfort for occupants. However, investigation of effects of the rhythm of window openings on achieving a passive airflow pattern in such buildings in the tropical climate of sub-Saharan Nigeria have been rarely studied. Therefore, this research aimed to evaluate the effects of the rhythm of window openings on passive airflow patterns for indoor thermal comfort in low-rise residential buildings in the hot-humid environment of Obosi, Nigeria. It involved experimental research using the Anemometer TA465 instrument for measuring wind velocity, relative humidity, and temperature of the purposively designated buildings in the three layouts of the study area for both wet and dry seasons. Employing the Yamane statistical formula, a sample size of 433 was obtained, and questionnaires were administered to occupants of the studied buildings and analyzed using categorical Regression Analysis (CATREG). The regression analysis showed that p=0.000, i.e. p<0.05 indicating that there was a significant relationship between the type and sizes of windows (elements used in measuring rhythm) and the intensity or force of breeze (a measure of passive airflow pattern). Further analysis of the data involved the use of Autodesk CFD 2018 (Computational Fluid Dynamics) for building wind flow simulations. The result showed variations in temperature levels (indications of differences in indoor thermal comfort) of various indoor spaces of the investigated designated floors and buildings, especially ground floors and the top-most floors of the buildings. The study underscored the need to use architectural rhythm design strategies to create a positive impact on airflow patterns in low-rise buildings, especially in densely built-up urban areas. The results of this study are instructive in noting that in order to attain passive airflow in buildings in the face of challenge of land restrictions, vertical stacking of building floors could be used once an adequate rhythm of window openings is adopted. Doi: 10.28991/CEJ-2023-09-08-016 Full Text: PDF

Visualisation and dissemination of 3D valuation units and groups – An LADM valuation information compliant prototype

The timely and effective dissemination of property values is an essential part of a transparent and efficient property valuation system. Over the last decade, web-based data-sharing systems have been increasingly used for the dissemination of assessed property values. 3D valuation units (e.g., condominium) and groups (aggregation of valuation units, e.g., a building floor in a multi-occupied building, a multi-occupied building, street, district or valuation zone) may be required to better communicate with users and to support a more effective and efficient dissemination. However, none of these systems share valuation information associated with 3D representation of the valuation units and groups. In this paper, a prototype of a web-based system is developed utilising the proposed Valuation Information part of the Edition II of the ISO 19152 Land Administration Domain Model compliant dataset for not only disseminating the spatial, physical, thematic and temporal characteristics of 3D valuation units, but also for sharing the valuation statistics at each designated level and with level-specific attributes. It is expected that the outcomes of this work may contribute to the development of local or national valuation systems and systems for geo-based data visualisation for effective and efficient sharing of valuation information. As such, it is anticipated that the study's outcomes will not only increase the level of communication with the public, but also support politicians and planners in their decision-making processes and help them to better analyse and understand the property market. With the proposed system, confidence in valuation results can be further increased due to the high level of transparency.

Study on Sound Transmission across a Floating Floor in a Residential Building by Using SEA

For the purpose of reducing the impact noise transmission across floating floors in residential buildings, two main sound transmission paths in the floating floor structure are considered: the stud path and the cavity path. The sound transmission of each path is analysed separately: the sound transmission through the cavity and the stud are predicted by statistical energy analysis (SEA). Then, the sound insulation prediction model of the floating floor is established. There is reasonable agreement between the theoretical prediction and measurement, and the results show that a resilient layer with low stiffness can attenuate the sound bridge effect, resulting in higher impact noise insulation. Then, the influences of the floor covering, the resilient layer and the floor plate on the impact sound insulation are investigated to achieve the optimised structure of the floating floor based on the sound insulation.

Construction Projects’ Waste Prevention and Expected Minimization of Cost and Environmental Impacts through Adopting a Comprehensive System for Document Management

Waste originating from construction projects is the major source of pollution amongst all industrial sectors in the European Union (EU) as well as globally. It is estimated that more than 35% of all disposed waste in the EU has been a by-product of building activity. This significant loss of materials hinders project profitability, reduces competitiveness of companies involved in such projects and causes considerable environmental burden. An acceptable level of waste is inevitable; however, there are possibilities to minimize the waste through amendments of reducing problematic executive procedures. One of the most important reported factors that increase waste is ineffective document management that may lead to inadequate communication throughout the construction project. As such, the present paper focuses on estimating the possible environmental and economic benefits if a proper document management system is applied on construction projects. The research steps include the approximate calculation of the operational project cost, the volume of material waste related to inadequate information systems based on statistical data and the calculation of benefits from the establishment of adequate information systems using measurable indices. The findings suggest that significant waste reductions are feasible and that the volume of solid construction debris that usually ends up in landfills can be greatly reduced. The actual debris in every skip bin could be reduced to approximately two-thirds of the currently produced volume, for every 100 square meters (m2) of an industrial building floor area. Besides, the debris volume in a skip bin could be reduced to more than half of the currently produced volume for every 100 m2 of public and commercial retail building floor area.

Study on Installation of the Vertical Axis Wind Turbines on the Upper Floors of High-Rise Buildings

Introduction. Nowadays the sector of high-rise and super high-rise buildings construction is rapidly developing. The deficiency of non-renewable energy sources and the deterioration of the environment are two major problems faced by every country. Therefore, the wind power engineering is intensely developing and is able not only to stop the rapid deterioration of environmental situation but also to improve accessibility of energy supply and considerably reduce the deficit of energy. It is rational to use the wind power to source the clean renewable energy for the high-rise buildings by installing the vertical axis wind turbines on the upper floors of the buildings. The aim of the work is to confirm that the vertical axis wind turbines are the best appropriate for installation on the upper floors of high-rise buildings in the cities due to unique advantages thereof (simple design, easy maintenance, adaptability to complicated and changeable wind environment, long operation life), which ensure the supply of the cities with the safe and clean green energy.Materials and Methods. A small-size vertical axis wind turbine was taken for the study. The operation efficiency of various wind turbines was measured by changing the wind strength and direction under the same environmental conditions to determine whether a vertical axis wind turbine could operate safely, sustainably and efficiently in the complicated and changing wind environment of the city. Alongside it was proved that for ensuring the supply of the cities with the safe and clean energy the installation of the vertical axis wind turbines on the upper floors of high-rise buildings is more appropriate compared to the installation of horizontal ones.Results. By changing the wind strength and direction, it was found that the vertical axis wind turbines have good and stable operation efficiency and can provide a constant source of clean energy for urban development in a safer and more stable way.Discussion and Conclusions. The vertical axis wind turbines are ideally adapted to the complicated and changing wind conditions of the upper floors of high-rise buildings and can be safely and efficiently operated, making positive contribution to reducing the energy load and improving the state of environment.

Evaluation of the cost of residential buildings with environ-mentally friendly concepts

The initial stages of construction implementation begin with planning, implementation, and operation. From each stage of the project must be with a green or environmentally friendly concept. Eco-friendly planning in residential buildings starts from the use of building materials, energy-efficient design concepts, and economical development costs. In addition, the construction of houses must also pay attention to health, such as ventilation, garbage disposal, and the provision of green environments for plants. The costs analyzed in this study refer to environmentally friendly concepts that can be applied to the construction of residential houses. Residential buildings in urban areas generally have narrow land, so that the 1st floor building built is with an area of 36 m2, 45 m2, or 60 m2. The object of research in this case is building housing built by developers in general. As for the results of field observations, that environmentally friendly concepts that can be used are land arrangement, energy saving, healthy homes, and the use of environmentally friendly materials. Design modifications from existing conditions are the addition of loster, glassblock, the use of red brick, mild steel, and modification of water taps.

Hybrid Vibration Control of Hospital Buildings against Earthquake Excitations Using Unbonded Fiber-Reinforced Elastomeric Isolator and Tuned Mass Damper

Lifeline structures such as hospital buildings need to be specifically designed such that they experience reduced vibrations when subjected to earthquake excitations because it will be difficult to vacate hospital buildings under the event of any earthquake. Therefore, to ensure operational condition under earthquake excitations in an existing hospital building, the present study utilizes flexible unbonded fiber-reinforced elastomeric isolators (UFREIs) for its seismic isolation. The UFREI-based isolation system is designed to restrict the structural acceleration within the tolerable limits for the building inhabitants even during earthquake hazards. However, the use of such flexible isolators results in excessively large bearing displacements, which either may not be practical and/or pose several serviceability issues. Therefore, tuned mass damper (TMD) is attached to the base floor of the UFREI-isolated hospital building to reduce the large isolator displacements. Properties of the hybrid vibration control system are designed according to the site-specific scenario in New Delhi, India. Further, nonlinear time-history analyses of the UFREI-isolated hospital building with the TMD are carried out, and responses are compared with its uncontrolled response. Results show that the peak bearing displacement response of the UFREI-isolated hospital building is reduced by 9% to 27%, due to the addition of the TMD. Importantly, the required design displacement of the UFREI-based isolation system is decreased by 27%, without compromising the effectiveness of base isolation. In fact, the performance of the hybrid vibration control system is superior to the base isolation system alone.

Analysis of the out-of-plane buckling collapse of a masonry wall: A case study

This paper presents the methodologies followed and the analyses performed to interpret the out-of-plane collapse of a masonry wall located on the fourth floor of a historical building in Palermo (Italy). The collapse mechanism was related to the slenderness of the wall and the presence of ineffective tie rods, unable to restrain the wall. Moreover, the collapse involved the wooden slabs, loaded under the impact of the wall. The case is analysed by examining the crack pattern, the constructive features and the kinematic of the collapse. Finally, a theoretical interpretation of the buckling mechanism is made through non-linear Finite Element (FE) analyses combined with simplified models provided in the literature, showing as reliable considerations can be made by combining two levels of analysis.

A Procedure for Taking a Remotely Controlled Elevator with an Autonomous Mobile Robot Based on 2D LIDAR

Navigating between the different floors of a multistory building is a task that requires walking up or down stairs or taking an elevator or lift. This work proposes a procedure to take a remotely controlled elevator with an autonomous mobile robot based on 2D LIDAR. The application of the procedure requires ICP matching for mobile robot self-localization, a building with remotely controlled elevators, and a 2D map of the floors of the building detailing the position of the elevators. The results show that the application of the procedure enables an autonomous mobile robot to take a remotely controlled elevator and to navigate between floors based on 2D LIDAR information.

Ten Years Behavior of Carbonaceous Ultrafine Particulate Matter (PM0.1) in Phnom Penh, Cambodia

The long-term behavior of mass concentration of ambient ultrafine particulate matter was discussed on samples collected at a site located in Phnom Penh City, Cambodia, between 2011-2020. A cascade air sampler that can collect PM0.1 (<0.1 μm) has been used at a site located on a roof floor of a 5-story building on the campus of the Institute of Technology of Cambodia (ITC) located near the central part of Phnom Penh City. The main goal was to investigate PM0.1 and carbon compositions, including elemental carbon (EC) and organic carbon (OC). As a result, PM0.1 increased by about 2.3 times, and PM0.1 remarkably increased in the past ten years. EC and soot-EC, which are considered to be road traffic sources, also increase PM0.1 mass concentration. Soot-EC and the number of vehicles per year are correlated. Biomass burning indicators such as OC, char-EC, and hot spots number increase at the same time. Consequently, it is considered that the dry season (January to March) is greatly affected by open fires in Cambodia and neighboring countries.

Influence of the hot water mass flow rate on heating of radiant floors of green buildings

The objective of the research is to improve space heating of green buildings by examining experimentally the influence of the heating medium mass flow rate on thermal performance. A green building was built in Cairo, Egypt, that consists of two similar rooms: one is the heated room and the other is a reference for comparison. A photovoltaic thermal (PV/T) collector is used to heat up water in a storage tank, and the hot water in the tank is circulated in the radiant floor of the examined green building. The hot water mass flow rate was varied between 0.04 and 0.08 kg/s. It was found that decreasing the water mass flow rate improves the heating of the radiant floor. The percentage improvement in floor temperature due to heating over the reference room, reaches about 17% and 6% at mass flow rates of 0.04 and 0.08 kg/s, respectively. Engineering Equation Solver (EES) was used to solve the equations for the heat transfer process between the heating water and the floor. It was found that decreasing the mass flow rate increases the residence time of the heating water in the radiant floor, consequently, increases the heat energy transfer and the floor temperature. Increasing the heating fluid mass flow rate in green buildings could have a negative effect on the heat transfer, such that the appropriate heating fluid mass flow rate should be calculated based on the green building massive material as well as the operating conditions, for example, ambient temperature and wind speed.

Generalized Damped Outrigger Systems for Suppressing Multimode Vibrations of Tall Buildings

Damped outrigger is a viable means for reducing dynamic responses of tall buildings. This study focuses on generalized damped outrigger (GDO) systems. A GDO is composed of a damper for energy dissipation, a negative stiffness device and an inerter for damping enhancement. The GDO system incorporates GDOs at different floors of the tall building optimized to varied structural modes. Frequency equation of a tall building simplified as a cantilever beam with multiple GDOs is first derived by complex modal analysis. A finite different model of such a system is used for verification. Parametric analyses are then performed to compare damping effects of different GDO systems. It is found that a negative stiffness damped outrigger (NSDO) or inerter damped outrigger (IDO) needs to be optimized for maximizing damping of a specific mode. GDOs, respectively, tuned to different modes can largely improve the multimode damping effects. The optimal parameters of the GDOs are slightly different from those in the case when they are installed separately. With both negative stiffness and nonzero inertance, a GDO still needs to be tuned to a specific mode because multimode damping is sensitive to the damper coefficient. The combination of an NSDO optimized to the first mode and an IDO tuned to a higher mode seems the best solution. The IDO additionally improves the first mode damping provided by the NSDO and the two-mode damping is not sensitive to the damper coefficient of the NSDO. The findings are confirmed through seismic response analyses of a tall building with different GDO systems.

The effectiveness of the Iranian building code in mitigating climate change in Bandar Abbas

Climate change has a varying impact on building energy demand. In Bandar Abbas, a city on the southern coast of Iran, global warming is expected to exacerbate an already harsh climate. Although the Iranian building code has an energy efficiency ranking with specific design requirements, its effectiveness in mitigating climate change is still to be fully understood. Furthermore, Iran's energy mix based on fossil fuels makes filling this gap even more urgent. This study assesses the magnitude of the impact of global warming on a real-case multi-apartment building in this region and evaluates the effectiveness of the different energy efficiency levels designated in the building code in reducing energy consumption under present and future climate conditions. Depending on the projected shared socioeconomic pathways scenarios, the annual electricity consumption may increase by 14 % to 21 % and 21 % to 40 % in 2050 and 2080 timeframes, respectively. When implementing Iranian building code requirements for the envelope's higher levels of energy efficiency, energy consumption reduces substantially, thus contributing to mitigating the impact of global warming. By applying these regulations, energy savings of 5 % to 19 % and HVAC electricity reductions of 9 % to 26 % can be achieved for units on different building floors. In order for Iran to meet the carbon neutrality targets, we recommend making the highest energy efficiency level of the building code mandatory immediately and pushing forward new and more stringent legislation.

Estimation of scattered radiation influence on neutron beams at a calibration laboratory using Monte Carlo simulation of a long counter

At the Neutron Calibration Laboratory (LCN) of IPEN/CNEN, a 241AmBe source was used to test and calibrate neutron detectors. The neutrons emitted by the source reach the detector as intended, but they also scatter undesirably from the building's floor, ceiling, and walls, leading to indirect detection. A Long Counter (LC) detector was modeled using the MCNPX Monte Carlo code. The objective of this study was to measure the contribution of scattered radiation at the LCN / IPEN, and to determine the fluence rate, at different points in the calibration room at source-to-detector distances of 100 cm and 150 cm; subsequently, the results were compared with those of the Brazilian Laboratory of Metrology of Ionizing Radiation (LNMRI). The results show that the fluence rates of LCN / IPEN are comparable to those of this neutron laboratory for the 100 and 150 cm source-to-detector distances using a 241AmBe source (37 GBq). The results show that the calibration of neutron detectors should be performed at distances less than 100 cm, where the contribution of scattered radiation is within the 40% limit recommended by ISO 8529-1.

Full scale testing of timber-concrete composite floors in an overhanging configuration

The behavior of timber-concrete composite floors in an overhanging configuration has been analysed. The floor consisted of a prefabricated T-shape piece formed by a glulam flange glued to a plywood rib and connected to an upper concrete slab poured in situ. The connection between both materials is achieved by penetrating the concrete into the holes made in the rib.Three-point bending tests were performed with a total of 8 specimens with depth of 25, 30 and 35 cm and overhanging length of 1.50, 1.80 and 2.10 m, respectively. That means a length-to-depth ratio equal to 6 in all cases.The experimental results showed that the lowest ultimate load value obtained was 8.03 and 5.55 times higher than the estimated service load for a building with residential use (5 kN/m2) and public use (9 kN/m2), respectively.Two types of failure were observed after a marked cracking process in the concrete as the ultimate load value was approached: tensile failure affecting the plywood rib and shear failure at the glulam flange-plywood rib connection.The maximum deflection for the total load was between 1/358 and 1/523 of the overhanging span for the estimated loads for a residential use building (5 kN/m2), and between 1/266 and 1/390 for public use buildings (9 kN/m2).Regarding to vibrations, floors in an overhanging configuration with a length-to-depth ratio equal to 6 and a simply supported portion equal to four times the length of the overhanging portion, with total loads up to 9.0 kN/m2, both in multi-storey buildings for residential and office use, present a high comfort level.Consequently, the proposed timber-concrete composite (TCC) overhanging floor solution has demonstrated high stiffness and strength that make it a suitable alternative for the construction of high-performance lightweight floors in multi-storey buildings.

Localization and imaging of internal hidden defects in concrete slabs based on deep learning of vibration signals

Internal hidden defects such as delamination and voids are common distress of concrete slabs and the localization of these defects is important for structural safety. This paper develops a damage inspection method that is feasible for locating and imaging internal defects of concrete slabs based on deep learning of impact-caused vibration signals. To alleviate the problem of low efficiency of manual signal collection, a prototype of mobile detection system is developed for the automatic generation and acquisition of vibration signals. Two optimized deep learning models in the framework convolutional neural network (CNN) are proposed for 1D time series signal and 2D time-frequency spectrogram to address the problems of low recognition accuracy and long training time of the traditional network, where the principal component analysis (PCA) and squeeze and excitation (SE) modules are incorporated respectively for a better feature learning and extraction of vibration signals of internal defects. The softmax layer is added in the networks to calculate the state probability value for the completion of damage contour maps. The network proposed in this paper is used to systematically compare the training and recognition effects of the data collected by contact senor (accelerometer) and air coupled sensor (microphone). The experiments show that the detection accuracy of the one-dimensional (1D) and two-dimensional (2D) network based on the accelerometer-acquired data reaches 90.4% and 93.4%, respectively. The generalizability of trained models is also validated based on the independent dataset from other research and actual concrete floor of a multistorey building. In the future, the prototype of the hardware system can be further improved by embedding GPS information to realize the real-time automatic localization of hidden defects of engineering structures.