# Performance and Measurement Devices for Membrane Buildings in Civil Engineering: A Review
## 4 Development of Measurement Devices
### Structural Monitoring Systems  
Structural health monitoring (SHM) enhances structural performance and reduces upkeep costs by monitoring the structural response and detecting probable damage, which extends the service life of the structure [135]. Benefiting from the development of sensing technology, computers, and structural control methods, SHM has been more broadly adopted in recent years [136]. Nevertheless, there is still a lack of application of SHM in membrane structures, especially for large-span membrane structures.  
[PERSON] et al. [32] designed an SHM system and applied it to the cable-membrane structure of an airport terminal building. Monitoring system components included a sensor system, data acquisition and transmission system, data management system, and early warning system. The choice of measuring point position was directly tied to the degree of influence each building component had on structural safety due to the restrictions of economy and practicality. The structural response data collected by the monitoring system included: (1) the cable force of the back-cables connecting the mast to the ground anchor; (2) the inclination and the top acceleration of masts, which were the only compressed structure members; (3) the vertical acceleration of the steel truss; (4) the strain of the nodes, ear plates, and lower truss chords in the steel structure; (5) the wind speed and direction; and (6) the temperature of the structure and the environment. The framework of the SHM system is shown in Figure 23. As there were different kinds of sensors in the sensor system, achieving the simultaneous processing of multiple signals was the key to realizing the early warning of structural anomalies. Two approaches were adopted to determine the presence of anomalies in the structure. The first was to compare the magnitude of the monitored data with the upper limit of the prescribed values, and the other was to acquire the structural modalities and the correlation between the variables through the data.  
A similar practice was adopted for an air-supported membrane structure by [PERSON] et al. [19]. As above, the SHM system also consisted of four parts: a sensor subsystem, data  
Figure 23: The framework of the SHM system for the cable–membrane structure of Yueyang Airport, China [32].  
acquisition and processing subsystem, data storage subsystem, and alarm and analysis subsystem. Wind pressure, wind speed and direction, ambient temperature, humidity, solar radiation, and rainfall were measured using a wind pressure sensor and a weather station. The acceleration and deformation of the membrane surface were monitored by using triaxial accelerometers and Global Navigation Satellite System (GNSS) rovers. The monitoring data acquired also included the pressure inside the structure and the strain of the steel cables. Since it was hard to repair the sensors on the surface of the air-supported membrane structure in working conditions, the sensors and data receivers were transmitted through a multi-core shielded cable for data transmission, which also supplied power to the sensors. Figure 24 shows the framework of the SHM system.