Abstract：A new suspension bridge called internally anchored suspension bridge, which is mainly composed of main cable, sling, cable tower, horizontal bar, girder and auxiliary pier, was developed. The horizontal bar as a part of the approach bridge perpendicularly intersects the main tower. The main cable passes by tower top, horizontal bar, and tower bottom in turn, and eventually, it is anchored on the horizontal bar. Based on the mechanical principles, the calculation formulas of internal force in structure and foundation reaction force were established, and the concepts of reasonable eccentric line and reasonable breadth line were presented. The first concept allows the main tower to be momentless, while the second concept ensure to make full use of material. The research shows that under the premise of guaranteeing the span of traditional ground anchored suspension bridge, the large-volume anchorage can be removed from the internally anchored suspension bridge. The horizontal tensions in main cables can still be balanced by the foundation reaction, but the force on the foundation is inclined downward. Based on appropriate structural arrangement and adoption of open-cut foundation, the foundation of main tower and the pier foundation can be incorporated into one. Consequently, more reasonable internal forces can be achieved in the internally anchored suspension bridge compared to the traditional ground anchored suspension bridge, and in addition, force and beauty can be readily unified in the internally anchored suspension bridge under the premise of ensuring the safety, economy and durability of structures.
