Membrane Structure and Its Application
1.Classification of Membrane Structure
Membrane structure can be divided into inflatable membrane structure, Tension/Suspension membrane structure, Frame membrane strcture, Cable dome membrane structure and Compound membrane structure.
The inflatable membrane structure can be divided into air-supported membrane structure and inflatable membrane structure. Air-supported membrane structure inflates into the building through pressure control system, which keeps a certain pressure difference between indoor and outdoor. The membrane body is subject to buoyancy and produces a certain pre-tension to ensure the stiffness of the system. Indoor air pressure automatic regulation system is set up to continuously adjust the indoor air pressure to adapt to the change of external load. The inflatable membrane structure inflates into a single membrane member to maintain sufficient internal pressure. Multiple membrane members are combined to form a certain shape of a whole force system. This structure requires high air tightness of the membrane itself, or needs to continuously inflate into the membrane structural member.
Tensioned membrane structure is an important part of modern membrane structure architecture. The membrane surface is generally negative Gauss surface. Therefore, it is rich in shape, natural and smooth, and has a soft surface, which is favored by architects. However, the structural system is complicated in force analysis and requires high construction accuracy. Therefore, it is difficult to design, calculate, manufacture and construct.
The skeletal membrane structure is a closed and stable framework system (generally steel truss system, grid structure, cable-net structure or tensegrity system) and the membrane material together constitute a structural stress system. The construction of this system is similar to that of conventional structures (except cable net or tensegrity system), which is easy to be understood and accepted by engineering circles. However, in order to make the membrane rigid, the supporting system provided by the skeleton system should have a certain curvature, and the prestressing mechanism should be set up to apply the prestressing force to the membrane.
Composite membrane structure is usually divided into several units on its own stable truss system. Tension membrane structure units are arranged on each unit. Membrane units are basically independent of each other in force. It can be considered as a physical combination of several simple tension membrane structure monomers. The stress complexity is between tension membrane structure and skeleton membrane structure. This system is also widely used in the current membrane structure stadium canopy.