Glass Curtain Wall Research Articles

Seismic behavior of a fully tempered insulating glass curtain wall system under various loading protocols

AbstractThis paper investigates the seismic behavior of a glass curtain wall system under various loading scenarios. Experimental set‐ups and approaches were developed to test full‐scale fully tempered (FT) insulating glass curtain wall systems subjected to three loading protocols: quasi‐static in‐plane loading, dynamic in‐plane loading, and dynamic coupled in‐plane and out‐of‐plane loading. A refined finite element (FE) model was developed to understand the behavior of the system. The average drift associated with glass cracking and fallout was found to be nearly identical for quasi‐static and dynamic in‐plane loading, indicating that in‐plane floor accelerations exerted marginal influence on the failure of the glass curtain walls. Bi‐directional loading led to an approximately 30% decrease in the glass fallout drift compared with in‐plane loading. This is because the out‐of‐plane drift placed an increased stress demand on the glass panel, as indicated by the FE analysis. Both the experimental tests and FE analysis revealed that the ASCE 7–16 formula, which is used to calculate the drift of contact between the glass and frame, is nonconservative as it does not consider the deformation of the surrounding frame and the friction between the gasket and the glass. The failure mechanism of the glass panel was caused by the stress concentrations at the diagonal corners due to glass‐to‐frame contact. The FE analysis indicated that the interactional effect among different glass units was negligible, and the glass panels exhibited a similar stress state regardless of their positions.

The Influence of Aeroelastic Effects on Wind Load and Wind-Induced Response of a Super-Tall Building: An Experimental Study

To investigate the wind-induced response and equivalent wind load of a super-tall building, an aeroelastic model of the building was designed to measure aerodynamic interference in wind tunnel tests. Experiments on pressure and vibration measurements were conducted in both uniform and turbulent wind fields, and the displacement response and surface wind pressure at different locations of the model were recorded. The displacement time-history response spectrum and aerodynamic spectrum in both fields were compared and analyzed. The research showed that the mean displacement responses of the model in the across-wind and along-wind directions gradually increased with velocity under different wind attack angles. The mean displacement response of torsion moment in a uniform wind field changed very little, and the mean and fluctuating wind pressures in each layer were significantly stratified, making it is easy to generate a coupled vortex-induced resonance. On the other hand, the mean displacement response of torsion moment in a turbulent field increased with wind velocity. Strong turbulence made the fluctuating wind pressure at the top and bottom of the model slightly more significant than in a uniform field. The resistance of super-tall buildings came from turbulence excitation in the along-wind direction and the self-excited resistance generated by the across-wind direction. The test methods and main research conclusions may provide a reference for glass curtain walls and the structural wind-resistant design of super-tall buildings.

Reference-free infrared thermography detection with subsurface heating for deep cavity in adhesive of hidden frame glass curtain wall

Since the current infrared thermography (IRT) is not effective in detecting deep and invisible cavities in the silicone structural adhesive of hidden frame glass curtain walls (HFGCW), a reference-free IRT with subsurface heating for the deep cavity is proposed. A near-infrared linear laser with high energy density and high transmission is chosen as the subsurface heating source to directly heat the silicone structural adhesive through the glass. Temporal sequence reconstruction and image enhancement based on reference-free calibration are proposed to reduce thermal inhomogenety and thermal noise and ensure comparable results for damage detection under different environments. The effects of traditional surface heating and subsurface heating are compared and analyzed through numerical simulations. And an evaluated feature, which is the maximal temperature difference feature, derived from temperature difference is used to quantitatively analyze the thermal effect caused by different cavities. The subsurface heating simulation results showed that the highest temperature difference between the region with cavity and defect-free region is up to 88% higher than that of traditional surface heating. The experiments revealed that the deep cavities of different lengths, located at 7 mm, 9 mm, and 11 mm below the glass surface, can be successfully detected using subsurface heating and reference-free calibration. A quadratic linear model is proposed to reflect the relationship between the depths and lengths of cavities and the evaluated feature. In conclusion, the proposed method can protect the HFGCW from deep and invisible cavities which can reduce its adhesion and strength.

Measurement and Curb of Light Pollution Risk Levels

Nowadays, light pollution has become a serious environmental problem. However, there are no clear indicators to assess the level of light pollution risk in a certain area. Firstly, we took 31 provinces and cities in China as the research object, and collected the data of seven indicators that affect the risk level of light pollution, then weighted them using Analytic Hierarchy Process (AHP). Secondly, we used the Topsis method for quantitative calculation, and classified the light pollution risk level into five levels: heavy light pollution (score>0.05), high light pollution (0.04<score<0.05), moderate light pollution (0.03<score<0.04), mild light pollution (0.02<score<0.03), and no light pollution (score<0.02). Thirdly, we linked the light pollution risk level to the Comprehensive Development Level Index (CDCI) of each province and city, and divided the cities into four categories according to the CDCI. Then we used analogy analysis to measure the risk level of light pollution in four land types: protected land(score<0.02), rural area (0.02<score<0.03), suburban area (0.03<score<0.04) and urban area (score>0.04). Fourthly, we propose three intervention strategies to combat light pollution: strengthen urban planning and management, better the ecological design of nightscape lighting and improve the material of glass curtain wall. Finally, we test its rationality and feasibility. Our model can analyze the light pollution risk level of other countries or even continents. This is conducive to the government's future planning and resource control of the region.

Experimental and numerical study on indoor thermal environment of solar Trombe walls with different air-channel thicknesses in plateau

Trombe wall is an effective method for passively absorbing solar energy and providing heat to buildings. This paper conducts a comparative experiment between Trombe wall buildings and glass curtain wall buildings during the winter season in Songpan County, western Sichuan. The climate characteristics of the western Sichuan plateau are analyzed, and the potential applications of these two building types in the region are investigated. To further understand the heat transfer mechanism of Trombe wall buildings, numerical simulations are carried out to analyze the indoor thermal environment of buildings with varying air channel thicknesses. The results show that Trombe wall buildings are more effective at delaying heat loss compared to glass curtain wall buildings, due to the thermal storage of the Trombe wall providing heat at night. This makes Trombe wall buildings well-suited for regions with strong solar radiation and large temperature differences between day and night, such as the alpine region. However, excessively small air channel thickness can lead to excessive air flow speed during the day, causing more heat loss and weaker insulation at night. Conversely, excessively large air channel thickness reduces air flow temperature difference and diminishes the heat brought into the room. Among different air channels, a thickness of 100 mm performs best with a temperature difference between the inlet and outlet of about 45 °C. At 13:00 o ‘clock, the maximum airflow rate of approximately 5.8 L/s is achieved for a thickness of 100 mm, whereas for thicknesses of 150 mm and 50 mm, the corresponding values are 4.9 L/s and 4.1 L/s, respectively. It is important to note that blindly increasing air channel thickness to raise indoor temperature is not a practical or reasonable engineering solution. The measured and numerical results can provide valuable reference value for the improvement and development of Trombe wall buildings in the future.

Glass Recognition and Map Optimization Method for Mobile Robot Based on Boundary Guidance

Current research on autonomous mobile robots focuses primarily on perceptual accuracy and autonomous performance. In commercial and domestic constructions, concrete, wood, and glass are typically used. Laser and visual mapping or planning algorithms are highly accurate in mapping wood panels and concrete walls. However, indoor and outdoor glass curtain walls may fail to perceive these transparent materials. In this study, a novel indoor glass recognition and map optimization method based on boundary guidance is proposed. First, the status of glass recognition techniques is analyzed comprehensively. Next, a glass image segmentation network based on boundary data guidance and the optimization of a planning map based on depth repair are proposed. Finally, map optimization and path-planning tests are conducted and compared using different algorithms. The results confirm the favorable adaptability of the proposed method to indoor transparent plates and glass curtain walls. Using the proposed method, the recognition accuracy of a public test set increases to 94.1%. After adding the planning map, incorrect coverage redundancies for two test scenes reduce by 59.84% and 55.7%. Herein, a glass recognition and map optimization method is proposed that offers sufficient capacity in perceiving indoor glass materials and recognizing indoor no-entry regions.

Adaptive reuse of vernacular built heritage: learnings from Alcino Cardoso House (1971–1991) by Álvaro Siza

The Alcino Cardoso House (first phase: 1971–1973; second phase: 1988–1991), located in northern Portugal, was one of the first interventions in pre-existing buildings undertaken by the Pritzker Prize-winner architect Álvaro Siza (1933) to receive national and international acclaim. The design consisted of the conservation of vernacular farm buildings and their transformation into a holiday home and tourist accommodation. This intervention echoes the concerns of the critical revision of modern architecture in the Portuguese context (the so-called ‘third way’ as coined by Fernando Távora) marked by an innovative reinterpretation of tradition: modern principles such as spatial fluidity, curtain wall glass façade, architectural promenade are introduced while respecting the pre-existence landscape and character by integrating vernacular design principles and construction techniques. This early Álvaro Siza intervention in a rural context has become a reference case-study for the School of Porto architects and provides us with lessons on contemporary reuse of built heritage.

Detailed Design Analysis of Curved Glass Curtain Wall—Taking the Design of a Headquarters Building in Wuxi as an Example

Taking the design of a headquarters building in Wuxi as an example, from the perspective of architecture, this paper extracts many key points of the detailed design of curved glass curtain wall, combines actual cases and work experience, specifically analyzes the challenges and problems faced by glass curtain wall in the practice of detailed design, and expounds the basic ideas and technical strategies of this case in the selection of curtain wall system scheme and the related structural design of curtain wall.

Construction defect identification for structural sealant by statistical driving-point accelerance

Accidental defects occur often during the construction of the structural sealant in a glass curtain wall structure. However, there are tens of thousands of glass panel units in a building, and the baseline models of different panel units are different from each other. In this paper, a two-stage construction defect identification method is proposed to identify a few units with structural sealant defect from a large number of units. In the first stage, the average driving-point accelerance (DA) was used as statistical baseline DA to calculate the accumulative difference of driving-point accelerance (ADDA). Then, the abnormal panel units are identified by the quantile estimation method. In the second stage, structural sealant construction defects are detected further by comparing the peak frequency difference between the statistical baseline DA and the abnormal DA. Several numerical examples and on-site experiments indicated that the probability density function of ADDA is agreement with the Weibull distribution, and the proposed method can effectively detect the structural sealant construction defects from many units without baseline model.

Recommendations for Improvement of the Thermal Performance of an Office Building Based on Retrofitting the Glazed Curtain Wall

Glazed curtain wall systems have become indispensable particularly in office buildings due to their light weight, aesthetic appearance, easy installation, and resistance to climate conditions. Curtain walls, however, also have problems in terms of thermal efficiency because of their wide, glazed windows and metal frames that have high thermal conductivity. The aim of this study is to offer proposals for improving the thermal performance of an office building with a glass curtain wall system built in a hot-humid climate zone. An office building constructed in Antalya, Turkey was modelled with the help of DesignBuilder energy simulation software, and various modifications were made to the model in order to improve the thermal performance of the building. With the improvements proposed in the study, it is possible to decrease the annual thermal loads of the whole building by 6.6%, and the annual thermal loads of the space with the curtain wall by 33.2%. The study revealed that applying an additional skin is more effective than lowering the U-value of the glass of the curtain wall in terms of thermal performance improvement.

Occupant’s thermal responses to asymmetric radiant thermal environment with warm wall and cool ceiling, Part A: Overall thermal responses

A radiant ceiling cooling (CC) system integrated with a mechanical ventilation system, which can improve human thermal comfort and reduce HVAC system energy consumption simultaneously, has been extensively applied in the modern office building with glass curtain walls. In a ceiling cooling room with a glass curtain wall, the horizontal and vertical asymmetric radiation caused by the warm wall and cool ceiling may result in different thermal responses of human body. Therefore in this paper, occupant’s thermal responses in a simulated ceiling cooling office room with mixing ventilation (MV) or underfloor air distribution (UFAD) were investigated by a combination of subjective and objective experiments. Indoor operative temperature was increased from 23.0 °C to 30.0 °C as the surface temperatures of warm wall and cool ceiling were from 30.0 °C to 40.0 °C and from 14.0 °C to 27.0 °C. The results showed that the indoor thermal environment with CC + MV or CC + UFAD was comfortable and acceptable as the indoor operative temperature was from 25.0 °C to 27.0 °C. The thermal neutral operative temperature in the room was 25.6 °C with CC + MV and 26.4 °C with CC + UFAD, and the corresponding thermal neutral skin temperatures was 33.4 °C and 33.7 °C, respectively. Moreover, the thermal comfort stability of indoor operative temperature was close to 0.30 °C−1 with CC + MV or CC + UFAD, and the corresponding thermal comfort stability of mean skin temperature was 0.90 °C−1–0.94 °C−1. There were clearly linear relationships between thermal sensation or thermal preference and indoor operative temperature or mean skin temperature, and these relationships may be beneficial for the intelligent control of a radiant ceiling cooling system combined with a mechanical ventilation system.

Three-Dimensional Flight Trajectories and Impact Damage Prediction Model for Wind-Borne Debris

The risk of damage of glass curtain walls in residential areas caused by impact of wind-borne debris has been given increasing importance. In this paper, by incorporating the numerical analysis of three-dimensional (3D) flight trajectories of wind-borne debris and computational fluid dynamics (CFD) simulation of the local wind environment in the context of buildings group, a novel impact damage prediction model for the glass curtain wall of urban buildings is proposed. To this end, the 3D flight trajectories and characteristics of plate-type debris are first studied by solving the 3D equation of motion of debris, of which the aerodynamic coefficients of plate-type debris is obtained by CFD numerical simulation. The flight characteristics of debris with different initial parameters are analyzed, showing that the properties of debris and initial conditions have significant effect on the flight trajectories and impact position of plate-type debris. Further, an impact damage prediction model for the glass curtain wall of an urban building is proposed. In the proposed model, the flight trajectory analysis of the wind-borne debris is embedded in the context of the local wind environment in a residential area obtained by CFD simulation. The damage caused by the impact of debris on the glass curtain wall of the buildings is then analyzed and illustrated by an example. The proposed model is of great significance for the wind damage analysis of urban building glass curtain walls considering local wind environment and real trajectories of debris.

A Full-Coverage Path-Planning Algorithm for a Glass-Curtain-Wall-Cleaning Robot Driven by Ropes

Rope-driven robots are increasingly being applied for the efficiently cleaning of glass curtain walls. However, increasingly complex wall surfaces and the various shapes of obstacles may block the robot and reduce coverage. In this study, three-DOF rope-driven cleaning robots and a full-coverage path-planning algorithm were developed to achieve global operation. The robot adopts a five-rope parallel configuration, and four winches are mounted on the wall and one on the ground to produce 3D motion performance. We used a grid method to build the wall model to mark obstacles, and then we decomposed it according to the wall curvature to better access cleaning subareas. To further increase the cleaning coverage rate, a full-coverage path-planning algorithm based on an improved priority heuristic was designed, which does not ignore the inset area of U-shaped obstacles. By introducing two sets of priority criteria to judge the forward direction, the robot can switch directions to cover a whole area when encountering U-shaped obstacles. Furthermore, by planning a return route requiring the least amount of time when entering a dead zone, an escape strategy was developed to prevent the robot from being unable to choose a direction. The experimental results show that the robot, after applying the proposed path-planning algorithm, could complete the global cleaning of complex glass walls with various obstacles.

Numerical study of the geometrical dimensions for glass curtain wall with an enclosed rectangular cavity

ABSTRACT To gain further insight into the thermal performance of a glass curtain wall with an enclosed rectangular cavity, a 2D mathematical model was established to analyze the characteristics of radiation and convective heat transfer in the glass curtain wall with an enclosed rectangular cavity, as well as to evaluate the effect of the glass curtain wall structure on thermal performance. The results showed that the total heat flux of the glass curtain wall with an enclosed rectangular cavity decreased at a decreasing rate with the increase in emissivity of glass. The total heat flux of the glass curtain wall with an enclosed rectangular cavity decreased with the increasing height of the enclosed rectangular cavity. At 15 mm thickness of the glass curtain wall, the total heat flux reached its minimum value and then increased with further thickeness of the enclosed rectangular cavity. In addition, the least square method was used to obtain the Nu correlation of argon with a relative deviation of less than 12% for better predicting the flow and heat transfer characteristics of argon in the glass curtain wall.

“Rhapsody in blue”—the blue color in architecture and the built environment: traditions and contemporary applications

AbstractThe main goal of this article is to summarize and present the most important facts concerning the use of the blue color in the built environment, considering its symbolic, functional, and decorative aspects. This monograph of color is aimed to contribute to a better understanding and clarify the place and meaning of the blue color in the architectural space and allow architects to use this color with greater awareness of its characteristic features in the historical context. The results of the detailed analysis of more than 200 blue buildings, collected by the author since 2006, are grouped into seven main thematic sections, which express different ways of applying blue in the architectural space: as a symbol/idea, the color of the sky, as traditional, contrast, and material color, as a visual attribute and brand color, and last but not least as the color of the light. The main conclusion is that, although the rationales for using blue color in architecture were diverse, symbolic and aesthetic considerations prevailed. As the dominating color of the sky and water, blue is considered the most intangible of all hues in architecture. Also, as a worldwide attribute of divinity, connected with Heaven as the domicile of deities and gods, it has received a considerable spiritual load. The universality of this symbolism, combined with the high cost of pigments, has given the blue color its unique and exclusive value. Even nowadays, despite the greater availability of blue materials and colorants, blue has not become a prevalent color in architecture. On the contrary, its visual impact, both in glass curtain walls and in night illuminations, still emphasizes its immateriality and reference to spiritual symbolism.

Wind Resistance Performance of Large-Scale Glass Curtain Walls Supported by a High-Rise Building

A large-scale glass curtain wall (LGCW) attached to a high-rise building is analyzed using the finite element method to investigate the wind resistance performance of the LGCW with and without the high-rise building. The results show that without the high-rise building, the peak wind-induced response occurs in the center of each glass panel of the LGCW, and it gradually decreases away from the center towards the edges of each glass panel. When the high-rise building is included in the finite element model, the additional wind-induced response on the LGCW caused by the deformation of the high-rise building is large at the upper and lower glass panel edges, and gradually decreases toward the panel center. The high-rise building produces great effects on the displacements of the LGCW but weak effects on the stresses, where the peak displacement of the whole LGCW is increased by 40.5%. The influences of key structural parameters, including the lateral stiffness of the high-rise building and the connection stiffness between the large glass curtain wall and the high-rise building, on the wind resistance performance of the LGCW are further investigated. The results demonstrate that the smaller the lateral stiffness of the high-rise building is, the greater the additional responses caused by the deformation of the high-rise building on the LGCW are, and the greater the total load responses of the LGCW are. The smaller the connection stiffness between the LGCW and the high-rise building is, the greater the responses of the independent LGCW are, while the additional responses induced by the deformation of the high-rise building on the LGCW are not significant.

A simplified analytical approach for assessing non-linear in plane seismic response of stick-built glass curtain walls

In the last decades, glass facades are increasingly used for building skin, especially for their pleasant aesthetic look. During recent earthquakes, such systems have often shown significant damages. Sometimes this made the whole building inoperable, even in the case of no structural damage, so causing extensive direct and indirect losses (e.g. due to the downtime). Herein, the author starts from the experience they gained performing laboratory tests and non-linear finite-element models of stick-built glazing systems to give a contribution in the direction of a simplified modeling of the seismic behavior for such components. An approximate analytical method is herein proposed for an expeditious estimate of the non-linear seismic capacity of a glass-aluminum façade system. This tool can be of great use to the professional dealing with the design and preliminary verification of the seismic performance of such a façade, avoiding or, at least, limiting the use of demanding laboratory tests. Some suggestions are also given about its possible use in the framework of code-based applications. Input data are geometry and mechanical parameters of involved materials. The output is a non-linear static pushover curve representing the lateral response of the façade. The step-by-step procedure is first introduced and explained in terms of assumptions and methodological approach, then applied to a commercial case-study façade, previously tested through a 1:1 sample at the ITC-CNR laboratory (Milan, Italy). The simplified model provides a very fine match to the experimental data, so demonstrating its effectiveness.

Relevance of natural light design in glass curtain wall of high-rise office building

Relevance of natural light design in glass curtain wall of high-rise office building

A Parametric Design Method for the Lighting Environment of a Library Building Based on Building Performance Evaluation

The lighting conditions of a library directly affect the users’ spatial experience, with glass curtain walls being widely used in the design of library skins. Although glass curtain walls have been extensively adopted, they increase indoor sun exposure and glare. Considering sunlight duration and radiation as the design basis, this study employs the Rhino and Grasshopper parametric platforms to parametrically design a library with a dynamic shading skin. Specifically, our design utilizes modular shading components that can change depending on the simulated sunlight data at different times. Additionally, a new optimal design strategy has been developed to enhance the environmental lighting performance of the library. The simulation results highlight that the indoor environmental lighting performance, under dynamic epidermal shading and based on sunlight duration data, is better for east–west, north–south, and east–west orientations on the summer solstice and the winter solstice. Meanwhile, the indoor environmental lighting performance, under dynamic epidermal shading based on daylight radiation data, is better for north–south orientation on the winter solstice. Overall, this study uses parameterization to integrate building simulation and architectural design to improve a building’s lighting performance.

Construction technology on dismantlement and reconstruction of point supported glass curtain wall for airport terminal building

Based on the corridor channel curtain wall reconstruction project at Wuhan Tianhe airport T2-T3 terminal building, the structural system of point supported glass curtain wall with cable structure 18 years ago was analyzed, the technical difficulties of curtain wall glass panel removal and bearing cable removal were studied, and technical measures for the dismantlement and reconstruction of point supported glass curtain wall with cable structure were reasonably proposed. During the construction process of the dismantlement and reconstruction, the curtain wall structure was dynamically monitored, the deformation of the monitoring points were small, and the construction process was in a safe state. Due to the success in the dismantlement and reconstruction control technology of the point supported glass curtain wall with cable structure in this project, it not only ensured the construction safety, but also improved the construction quality, which could provide a reference for other similar projects.