Search Results (6)

In this study, a thermal analysis of the building envelope of Atatürk University Faculty of Architecture and Design, located in Erzurum in the cold climate zone, was conducted. It is aimed to analyze the thermal efficiency of the educational building on the façade. Firstly, situation analyses were conducted using infrared thermography in the interior spaces and on the exterior. Secondly, a thermal analysis simulation was performed on façade designs used in the faculty. The configurations of indoor and outdoor spaces were obtained with the instantaneous field of view (IFOV) calculator using the Testo 872 thermal camera. Convection thermal loads were applied with the SolidWorks 2022 to simulate the designs. According to the analysis, optimum values were shown in classroom D-306 on glass surfaces, studio D-202 on external walls, studio E-301 on interior walls, studio E-201 on floors, and classroom E-301 on ceilings. According to the surface temperatures on façade sections, the D-202 studio has a 4.1% advantage over the closest performing D-305 and a 33.4% advantage over the farthest performing D-101. According to the simulation results, the glass surfaces used in the autoclaved aerated concrete (AAC) wall had a 39.6% advantage in terms of U-value compared to the glass surfaces in the curtain wall. Full article

Building materials, such as brick and concrete, are known indoor radon (²²²Rn) and thoron (²²⁰Rn) sources. Most radon and thoron exhalation studies are based on the laboratory testing of pieces and blocks of such materials. To discuss if laboratory findings can be applied to a real-world environment, we conducted intensive in situ exhalation tests on two solid concrete interior walls of an apartment in Japan for over a year. Exhalation rates of radon (J_Rn) and thoron (J_Tn) were measured using an accumulation chamber and dedicated monitors, alongside monitoring indoor air temperature (T) and absolute humidity (AH_in). There were weak correlations between J_Rn or J_Tn and T or AH_in at one tested wall, and moderate correlations of J_Rn and strong correlations of J_Tn with T or AH_in at the other wall, meaning more or less seasonal variations. The findings aligned with previous laboratory experiments on J_Rn but lacked corresponding data for J_Tn. Additionally, a moderate or strong correlation between J_Rn and J_Tn was observed for both tested walls. Comparison with theoretical calculations revealed a new issue regarding the impact of each process of emanation and migration within concrete pores on radon and thoron exhalation. Overall, this study provides insight into parameterizing radon and thoron source inputs in modeling the spatiotemporal dynamics of indoor radon and thoron. Full article

During bridge deck construction, the deck finishing machine and the fresh concrete often produce large vertical loads and torsional moments acting on the bridge girder system. In some cases, these loads can cause excessive vertical deflection and transverse rotation in the bridge girders, leading to many maintenance and safety problems, such as changes in deck thickness and local and global instabilities during construction. To minimize the potential problems caused by deck construction, the AASHOTO LRFD Bridge Design Specification requires consideration of these torsional moments during the design procedure, and a detailed three-dimensional finite element analysis may be conducted. However, for bridge girders with open-section thin-walled sections, only the solid or shell element can be used to recognize the warping of the girder since the torsional warping effect is not included in the classical beam element. In this research, a warping degree of freedom was added to a beam element, and a three-dimensional beam element with seven degrees of freedom (7-DOF) at each node was derived as an alternative method for analyzing girder bridges during deck construction. A computer program based on the 7-DOF beam element was also developed in MATLAB. To assess the 7-DOF beam element, one bridge was selected to measure the transverse rotation, vertical deflection, and stress of the exterior girder and the first interior girder during deck construction. Also, three full-scale numerical models using solid elements, classical three-dimensional beam elements, and 7-DOF beam elements were created based on the geometries and loads of the experimental bridge. A comparative study was conducted by comparing the results from the numerical models and experimental monitoring data to evaluate the 7-DOF beam element. The results showed that the 7-DOF beam element had excellent behavior in analyzing the girder bridges under construction load, especially in the torsional analysis of bridge girders. Also, unlike the solid element model, which also provided reasonable results, the 7-DOF beam element model can compute the internal forces of the cross-sections along the bridge, which allows the 7-DOF beam element to be an alternative approach for design and research requiring less modeling effort and computational complexity. Full article

This article explores several aspects of the three-dimensional concrete printing (3DCP) industry. More specifically, it begins with a literature review discussing the background of this technology. This literature review also explores several of the challenges that the industry is currently facing. In this way, a knowledge gap is identified. More specifically, there are few studies that have explored the structural and thermal performance of typical walls printed in this industry. Therefore, we used the simulation tool in SolidWorks to examine the structural behavior of several different wall types when pressure was applied to the exterior face. In addition to this, the thermal performance of different wall types was also studied in SolidWorks by applying a temperature difference between the exterior and interior faces of each wall. For example, one wall shape in this study had minimum factor of safety of approximately 100 due when a load was applied, and the same wall lost approximately 212 W due to the temperature difference applied in this study. Finally, SolidWorks was used to calculate the moment of inertia of the cross sections of several of these walls, which helped to provide a better understanding of each wall’s structural rigidity. Full article

The retrofitting of cultural heritage buildings for energy efficiency often requires the internal thermal insulation of external walls. Most of the in situ studies of capillary active interior insulation were performed in mild oceanic climate regions, and they showed an excellent performance. However, as a large part of Central–Eastern Europe belongs to a continental climate with cold winters and long periods of temperatures below the freezing temperature, the applicability of the capillary active interior insulation in cold climate was studied. The hydrothermal behaviour of the three walls was determined—each consists of one of three different interior insulations—and the original wall is made of historic regular solid bricks. Two interior thermal insulations were capillary active (aerated cellular concrete, calcium silicate) and one vapour-tight (glass foam). A hot box–cold box experiment and a steady-state model were used to demonstrate an increase in the original wall mass due to the water condensation only when the capillary active interior insulation is used. The combination of the water condensation and the low sub-zero temperature may lead to a risk of freeze–thaw damage to the original wall. The numerical simulation of the water vapour condensation for the considered walls for the Slovenian town Bled with sub-zero average winter temperatures was performed to obtain the whole temperature and moisture profile. It showed good agreement between an experimentally and numerically obtained amount of water condensation. The capillary active interior insulation proved to be unsuitable for improving the thermal insulation of buildings in cold continental climate, and only a vapour-tight system can be recommended. Full article

Supported by thousands of years of history, traditional Huizhou buildings have played a vital role, both functionally and culturally, as residential buildings in China. Masonry walls are one of the key building components of a Huizhou building; however, the traditional Huizhou masonry wall structure, predominantly a hollow brick structure, cannot meet the local building energy code requirements, and thus needs to be improved. Within this context, the present research measures the actual thermal performance of traditional Huizhou masonry walls for historical buildings and new-built buildings, which results in mean thermal transmittances of 1.892 W/m²·K and 2.821 W/m²·K, respectively, while the local building energy code requires a minimum thermal transmittance of 1.500 W/m²·K. In order to improve the thermal performance of traditional Huizhou masonry walls, four design scenarios for wall insulation are proposed and tested in a climate chamber: (1) hollow brick wall with inorganic interior insulation mortar, (2) solid brick wall with inorganic interior insulation mortar, (3) hollow brick wall with foamed concrete, and (4) hollow brick wall with foamed concrete plus inorganic interior insulation mortar. The experiment results indicate that, among the four proposed design scenarios, only scenario 4 can significantly improve the thermal performance of Huizhou masonry walls and meet the building energy code requirements, with a mean thermal transmittance of 1.175 W/m²·K. This research lays the foundation for improving the thermal performance of Huizhou masonry walls with new insulation and construction technology, thereby helping to improve the quality of life of Huizhou residents while respecting the cultural significance of the traditional Huizhou building. Full article