| As a common exterior structure, hidden frame curtain wall has been widely usedin city buildings of China. However, the quality of hidden frame curtain wall was notimproved along with its widely application. In recent years, hidden frame curtain wallproblems such as glass spontaneous breakage, drop and structural sealant ageingcaused number of personal injuries and property loss and caused extensive concern ofgovernment and community.In hidden frame curtain wall, there are three important parts: panel material,structural sealant and aluminum alloy sections. The panel material mainly includesstone panel and glass panel. Due to best transparency and decoration, glass is widelyused as panel material in hidden frame curtain wall. As the key part of hidden framecurtain wall, the structural sealant connects panel material with aluminum alloysections. It is the most important load transmitting node in the whole hidden framecurtain wall system. Accordingly, in the past research on the hidden frame curtain wall,many researchers focus on the ageing problems of structural sealant through outdoorexposure tests and artificial weathering tests. Besides the ageing research, Vallabhanpointed out the size and material properties of the silicone sealants affected theefficiency of the structural glazing system.Hidden frame curtain wall carries various loads from external environment. Thewind load, temperature load and seismic load are the three most important parts. Aswind load to the safety and reliability of hidden frame curtain wall, its importantmeaning is far exceeding the temperature load and seismic load. Therefore themechanical behavior study of hidden frame curtain wall has great significance.This paper considered the hidden frame curtain wall as the main research subject,looking wind load and structural sealant dimension as the two main controlling factors,systematically researched the mechanical behavior of the glass panel in the hiddenframe curtain wall under uniform wind load.Research result indicated that the mechanical behavior of glass panel has markeddifference with simply supported plate. The main reason resulting in the difference ismaybe the different supporting style between glass panel and simply supported plate.Besides, glass panel has negative deflection when it was loaded positive wind load.The exiting of negative deflection is probably real reason of structural sealant ageing in hidden frame curtain wall.According to the design requirement of standard, five different geometrydimensions of structural sealant were designed in this paper. The mechanical behaviorof glass panel in hidden frame curtain wall was studied respectively with differentstructural sealant glazing dimension under uniform wind loading. Through this partstudy, we found the mechanical behavior of glass panel and even the quality of thewhole hidden frame curtain wall system are directly affected by the dimensionchanging of structural sealant. Accordingly, the geometry dimension should be strictlycontrolled in the curtain wall engineering designing and construction process.This paper used two wind load loading modes: positive wind loading andnegative wind loading. Through the mechanical behavior comparing under the twoloading modes, we could find that the wind load loading mode could influence themechanical behavior of glass panel deeply. The reason causing this difference isconsidered the elastic modulus has tensile modulus and compression modulus.Relative research indicated the compression modulus of sealant is always greater thanthe tensile modulus. When the hidden frame curtain wall under positive wind load,most of the structural sealant was compressed and the compression modulus plays asignificant role. However, the tensile modulus of structural sealant plays a great roleunder negative wind load. Therefore, comparing with the positive wind loading, theglass panel in the hidden frame curtain wall beared smaller boundary constrain undernegative wind load. The deflection and stress of the glass panel are bigger than whenunder positive wind load.This paper attempted to model the glass panel and structural sealant by integratedbuilding method using finite element software-ANSYS. Through the modeling, wefound the important role of structural sealant in hidden frame curtain wall could notbe modeled really when we only use the tensile stress-elongation curve of structuralsealant. Subsequently, if we want to accurately model the whole system of hiddenframe curtain wall by integrated building method, we should know not only themechanical behavior of structural sealant in tension, but also we should know itsmechanical behavior in compression, shear, and other stressing situation. |
