# Performance and Measurement Devices for Membrane Buildings in Civil Engineering: A Review
## 2 Membrane Structure  
The properties of membrane materials are the most distinct evidence of the uniqueness of membrane structures. The fabrics and composites adopted in membrane buildings are depicted in Figure 1. The most widely adopted membrane materials include polytetrafluoroethylene (PTFE), polyvinylchloride (PVC), polyvinylidene fluoride (PVDF), and ethylene tetrafluoroethylene (ETFE) [1; 20]. Different types of membranes are designed by incorporating materials in different ways. However, 90% of the membranes employed in building structures have been categorized into a few limited production methods [21]. As shown in Figure 2, the type of membrane material chosen is governed by the purpose of the building. In engineering practices, membrane structures are classified as tensioned, skeleton, cable-membranes, or inflatable based on architectural shape and support circumstances [23]. Membrane roofs, membrane ceilings, and hybrid membranes are included in addition to these basic varieties, depending on service requirements [5, 24, 25, 26]. In a tensioned membrane system, steel construction components akin to cables serve as the boundary. To reach the final shape and bear load, the pretension of the membrane is performed by tensioning the boundary or a jacking structure [27]. The main components of the structure are a spatial hyperbolic tensile membrane, supporting mast system, supporting cable, and edge cable. Tensioned membrane structures are generally employed in large public buildings due to their distinctive structural form, which allows for a wide range of design options [28]. The skeleton membrane structure is supported by a spatial grid structure. The membrane, as a subsidiary component in the structure, primarily provides a shielding effect [29]. The prime load-bearing frame of the cable-membrane structure is the space cable system, which differs from the skeleton membrane structure in that the membrane materials are deposited and fastened to the cable system according  
Figure 1: Membranes applied in architecture [21]. Figure 2: Distribution of membrane materials utilized in various buildings [22]. to functionality [23]. Unlike other types of membrane structures, stable configuration and load-bearing capacity are achieved in inflatable membrane structures by forming pressure differences between the inside and outside of the membrane. It can be divided into four categories according to the different forming methods of the enclosed space: air-supported membrane structure, air-inflated membrane structure, air cushion membrane structure, and airbag membrane structure [7]. These four major membrane structures are shown in sequence in Figure 3.  
Membrane roofs offer a competitive alternative to traditional roofing systems due to their durability, low cost, and limited environmental impact. They have been employed extensively in low-slope commercial and industrial structures [33]. Membrane ceilings have gained much interest in recent years due to building energy efficiency standards, making them one of the tactics for achieving low energy consumption because of their ability to expand or retract on demand. The hybrid membrane structure comprises two types of membrane structures or structures combined with other components to meet specific needs. For example, inflatable beams (air beams) have a low bending stiffness and tend to fold or buckle when loaded [34]. The stiffness of a structure is increased by raising the internal pressure. Nonetheless, the safety of the structure is compromised by high internal pressures. The main components of the construction, according to the concept of tensairity, are air beams, struts, and cables [35]. In this system, the compressive loads in the structure are carried by the struts, while the cables bear tensile loads. The purpose of the air beam is to keep the entire structure stable so that just a tiny amount of pressure is required. [PERSON] et al. [26] presented a fairly large movable laboratory. The air-supported membrane structure was the main structure of the laboratory.