what is launcher bridge crane

Launcher bridge crane, also known as bridge erecting machine, is a special - purpose construction machinery for lifting and installing pre - cast reinforced concrete (or prestressed concrete) girders on bridge bearings (piers). The relevant introduction is as follows:
Historical Evolution: China's first cantilever beam - erecting 65 - 53 type bridge erecting machine was accepted and delivered from Shanhaiguan Bridge Factory in 1953. In 1994, the JQ130 bridge erecting machine was born, which realized "air - borne beam movement, one - time in - place" in China for the first time, and the T - beam erection efficiency was increased by 25%. In 2022, the world's first pile - beam integrated bridge erecting machine "Gonggong" was successfully developed, realizing the fully pre - fabricated construction of bridges.
Working Principle: It uses the lower guide beam as the beam - transporting channel. The main girder generally adopts a double - track triangular steel frame structure, and its length is usually twice the maximum span. During the beam - erecting operation, the beam is transported to the rear of the bridge erecting machine by the beam - transporting vehicle, and then lifted by the lifting trolley, dragged to take the beam, and the position of the box girder is finely adjusted in the air and placed in place. The bridge erecting machine is driven by hydraulics, and moves forward in a step - by - step manner.
Basic Structure: It mainly includes a main structure, a trolley system, a hole - passing system, and a power system. The main structure is used to install the trolley system, power system, cab, and related electromechanical equipment. The trolley lifting system is composed of two lifting trolleys, which realize the uniform load function through "four - point lifting, three - point balance". The hole - passing system is responsible for moving the bridge erecting machine to the next position. The power system includes a diesel generator set, various electric motors, and an electrical control system.
Basic Classification: According to the purpose, it can be divided into 900t double - line box girder bridge erecting machines, 450t, 550t, 60t single - line box girder bridge erecting machines, etc. According to the presence or absence of the guide beam and its purpose, it can be divided into guide - beam type and non - guide - beam type.
Features: It has the advantages of light weight, large load - bearing capacity, and strong wind resistance. It can be used not only in plain construction, but also to meet the construction requirements of mountain highway slopes, small - radius curved bridges, skew bridges, and tunnel - exit bridges.