During use, the installation is positioned on the superstructure of the bridges, supporting it by means of folding or telescopic outriggers. The structure of the arm has the shape of a lattice girder or beams with closed section (caisson) regardless of the type of construction there is at least one telescopable section. The equipment is similar in design to mobile crane installations – crane lorries, with the rotating part in the form of a boom at the end of which is the work platform for personnel and tools. The inspection process shall be carried out by visual means using special equipment called bridge inspector.

The inspection of bridges is an essential activity to maintain the viability and safe operation of these structures. It can provide accurate information on whether the lifting load process is safe or overloaded. Meanwhile, to find the SWL value, the comparison scanning method can provide the SWL value according to the lifting load chart of the mobile crane. The test results show that the sensors used to measure boom length, boom angle, and actual load each have a maximum relative error of 0.92%, 8%, and 4%, respectively. The nearest value search algorithm follows the rules of how to read the mobile crane lifting load chart. The programming algorithm is still manual, namely by equating and comparing boom crane conditions such as boom length, boom angle, and radius contained in the lifting load chart with the results of measuring boom crane conditions by sensors. The method used is an algorithm to find the closest value from the lifting load chart of a crane car.

In this paper, a prototype LMI has been made on a mobile crane based on a microcontroller that can provide value. Mobile cranes have a high accident potential when compared to tower cranes, and this is because mobile cranes have high mobility.

This tool has a very important role because it provides accessible information to the operator about the safe working load (SWL) that the crane can lift. A load moment indicator (LMI) is an electronic device on heavy equipment cranes that can provide information and a warning system to operators in the event of an overload during the lifting load process.

Mobile crane lifting chart