Bridge bottom surface crack detection mechanism

The utility model discloses a bridge bottom crack detection mechanism which comprises a first supporting rod, a second supporting rod is vertically arranged at the end of the first supporting rod, a bearing frame is movably connected to the second supporting rod, a third supporting rod is vertically arranged at the bottom of the second supporting rod, and a bearing rod penetrating through the bearing frame is arranged on the third supporting rod. A transverse moving assembly for driving the third supporting rod to move in a reciprocating mode in the direction parallel to the first supporting rod is arranged in the bearing frame, a fourth supporting rod is movably connected to the third supporting rod, a sliding base is movably connected to the fourth supporting rod, and a camera is arranged on the sliding base. According to the detection mechanism, a combined supporting rod structure is adopted, accurate and flexible camera shooting detection processing can be carried out on the diameters of cracks at differe