# Preventing Overturning of Mobile Cranes Using an Electrical Resistivity Measurement System
## 1 Introduction  
Mobile cranes are widely used in construction for moving heavy materials to elevated positions. Their demand has increased with the growth of large-scale urbanization and the rapid construction of skyscrapers. Unlike fixed cranes, mobile cranes offer the advantage of moving relatively freely within narrow urban areas or construction sites [1, 2]. They also reduce construction time by efficiently transporting heavy materials and objects that are beyond human capability. However, with the increasing scale of construction projects, there is a growing demand for the development of larger and higher-specification mobile cranes. Concurrently, rising concerns over safety incidents involving mobile cranes have highlighted the need for technological advancements to ensure safe and efficient operations, thereby preventing human casualties and property loss. Crane accidents can be categorized into several types, including overloading, side pull, outrigger failure, host limitations, and upset/overturn, among others [3]. Mobile cranes are particularly at risk of accidents due to their reliance on outrigger-based installation, limited workspace, and operation on potentially unstable ground, unlike tower cranes,gantry cranes, and overhead cranes, which are installed on stable concrete pads and operate on solid gantry structures. The following literature consistently points to a high risk of overturning accidents involving mobile cranes. [PERSON] (2017) analyzed global crane accidents from 2011 to 2015 and categorized them by crane type [4]. According to the literature, there were a total of 937 crane accidents during this period, with the distribution of accidents by crane type as follows: mobile cranes accounted for 71.82%, tower cranes 21.88%, barge cranes 2.45%, gantry/overhead cranes 0.85%, and other lifts/platforms 2.99%. Notably, the number of mobile crane accidents was more than 3.6 times higher than that of tower crane accidents, highlighting the necessity for preventive measures specific to mobile cranes. Furthermore, 45% of mobile crane accidents were due to overturning, indicating that addressing technical solutions to prevent overturning is a critical challenge. Mobile crane overturning was identified as the predominant cause of these accidents, attributed to outrigger structural defects, operator errors, overloading, and ground instability. [PERSON] (2019) analyzed 44 crane accident cases, and 24 of them involved mobile cranes, which were associated with a higher mortality rate than other types of cranes. Importantly, overturning accidents accounted for 39% of all crane-related accidents [5]. Similarly, [PERSON] (2022) analyzed 56 mobile crane accidents in Korea from 2015 to 2019, which resulted in 59 fatalities, 13 of which were caused by crane operators. The analysis revealed that the primary cause of these fatalities was falling accidents linked to outrigger installation defects. Although the overturning accident rate of mobile cranes was 10.7%, which is lower than that of falls (46.4%), collisions (28.6%), and mechanical failures (12.5%), the mortality rate was relatively high at 22% [6]. As a means to prevent such crane accidents, safety regulations are being strengthened in several countries [7; 8]. Considering the high overturning accident rate of mobile cranes and the significant risk of fatalities when such accidents occur, developing technologies to enhance safety is essential. Mobile crane overturning accidents can be classified into two categories: mechanical accidents, such as those caused by outrigger installation issues, overloading, and operator errors, and environmental accidents, such as ground subsidence due to sinkholes, groundwater, or other subsurface conditions. Various studies have been conducted to effectively prevent mechanical accidents and improve mobile crane safety.