# UAV Application for Typhoon Damage Assessment in Construction Sites
## 2 Construction Sites and Natural Disasters  
Natural disasters include disasters related to meteorological, geological, ecological, and environmental phenomena and disasters caused by biological agents. Each type of disaster can be further divided into several sub-disaster series [24]. For example, meteorological disasters can be divided into a rainstorm, typhoons, snow, ice, and other disasters. Each type of natural disaster may act as a disaster-causing factor in a construction area at the same time and produce a co-occurrence disaster chain [25]. The generation of typhoons may be accompanied by a rainstorm [26]. The simultaneous occurrence of these two leads to a sharp increase in the destructive power of disasters, forming an amplified effect. Meteorological disasters and geological disasters are the main culprits of severe property losses in construction sites. In disaster science, the formation of a construction site disaster mainly consists of three parts: disaster-forming environment, disaster factors, and disaster-affected body [27]. The three parts are interconnected and interact with each other leading to the final losses. Relevant studies in disaster science indicate that a disaster is usually the result of the coupling of multiple factors [28]. The complex construction site is the central part of the disaster environment. The factors causing damage are relatively complex, divided into internal factors such as human factors in the construction site and external factors such as typhoons as the force majeure factors. Moreover, the vulnerability of disaster-affected bodies, the risk of disaster-causing factors, and the exposure of disaster-affected bodies are widely used as indicators to quantify the theoretical model of disaster science [29]. Disaster prevention and reduction indicators are established and applied in relevant fields [30; 31], and a theoretical model of the natural disaster is in Equation (1). The current study further optimized the applicable model based on construction site parameters as in Equation (2). \[\text{Risk of Typhoon = (Danger \times Vulnerability \times Exposedness)/}\] (1) (Disaster-prevention Capability \[\times\] Disaster-mitigation Capability)  
Damaged Degree to Construction Sites from Typhoon = (Danger of Typhoon \(\times\)  
Exposure to Construction Site \(\times\) Fragility of Construction)/(Disaster-prevention Capability  
of Management Personnel \(\times\) Disaster-mitigation Capability of Management Personnel)The establishment of the theoretical model of the construction site under typhoons in Equation (2) enabled the analytic hierarchy process (AHP) for quantitative analysis in this study. In order to make better use of the theoretical model, various parameters from related kinds of literature were analyzed in the disaster chain to ensure the systematic, typical, scientific, and quantifiable rationality of the indicator selection [32]. After a comprehensive content analysis, the parameters in construction sites under natural disasters were classified into five groups, namely risk, exposure, vulnerability, the capability of disaster prevention, and the capability of disaster mitigation. For determining the detailed impact indicators of the five groups, 35 specific indicators were categorized in Table 1.  
As the ecological environment is being destroyed, the risk of global natural disasters rises sharply. Natural disasters include earthquakes, forest fires, typhoons and rainstorms, mud-rock flows, blizzards, landslides, etc. The prevention and mitigation of natural disasters have attracted the attention of scientific researchers in various fields such as tourism [33], campus security [29], fire department [34], energy [23], and municipal councils [22,27], who reviewed power system risk identification combined with typhoon scenario. They provided a new research idea about using appropriate data analysis methods to identify risks and faults, simulate fault propagation, and develop disaster prevention