Why can't the design of curtain wall opening window apply the existing requirements of modern curtain wall design? This is because the opening window is a special kind of curtain wall component: in the curtain wall system, it is the only moving component, while the others are all stationary components. The moving parts include at least two static working states and one moving working state, while the opening window also covers the largest number of functional requirements and the most complex man-machine relationship requirements, which is the root cause of its special.
When the opening window is in the open and closed working state, the difference between the bearing condition and the working demand is relatively large, which should be treated separately in theory. However, I have checked a lot of information and found that the analysis content of the opening state of curtain wall window is almost blank:
First of all, the mechanical model of the window changes in the open state (failure of the lock point). In the working condition of the combination of negative wind pressure, even the bearing state of the curtain wall frame is very different from its designed bearing state. For example, the sliding support is connected to the fixed window sash. In the open state, the sliding support is only equivalent to the fulcrum of a sliding dumpling. When the window sash is opened to the maximum limit Angle, the sliding brace and the brace act together to form a mechanical model of the four-point support plate with overhanging section. Contrary to our common sense, the brace becomes the most stressed hardware in this new mechanical model. In fact, in the selection of accessories, the main concern is the bearing capacity of the slide brace. For the brace, it is always regarded as the auxiliary positioning accessories for opening and passing through the curtain glass window, not to mention the structural check calculation. So a lot of window sash in the open state blown down by the wind, are from the support damage began.
Secondly, the contents and standards that need to be checked when the opening fan in the open state also need to be analyzed, especially how to value the safety factor? Because the opening fan of structural glass curtain wall is a moving part, its connection structure bears alternating impact loads. The failure modes are probably not simple bending failure or shear failure, but more complex failure modes such as loosening, instability and fatigue.
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Post time: Oct-25-2021
