Beam string structure

The invention relates to a string beam, which comprises a rigid beam, a bracing cable and a plurality of bracing bars, the upper ends of the bracing bars are hinged with the rigid beam, the lower ends of the bracing bars are fixedly connected with the bracing cable through rope clamping devices, the both ends of the bracing cable after being stretched are respectively and fixedly connected with the both ends of the rigid beam, the bracing cable is formed into broken lines in an axle symmetrical way, the adjacent two broken lines form a broken line angle, the various turning points of the broken lines are positioned on the identical parabola, each bracing bar is respectively positioned on the angle bisector of the broken line angle. The string beam of the invention can avoid the loose bracing cable generated by the slipping of a pre-stressed rope at the position of the rope clamping device when being used, and the potential safety hazard is eliminated.