Abstracts:Abstract In suspension bridges commonly used for ultralong spans, the weight of steel cables gradually becomes a significant proportion of the total load as the span diameter increases, sometimes exceeding half of the weight. However, carbon fiber–reinforced polymer (CFRP) cables, which are known for their lightweight and high-strength properties, can greatly enhance the maximum length achievable for suspension bridges. This study introduces a novel concept—the CFRP partial suspension cable-stayed bridge—by comparing the designs for a 3,300 m span bridge. A comprehensive comparison of eight steel or CFRP cable suspension bridges, cable-stayed suspension bridges, and partial suspension cable-stayed bridges was conducted. The results show that the new CFRP partial suspension cable-stayed bridge has advantages in terms of cost, vibration frequency, critical flutter wind speed, and carbon emissions despite its low stiffness. Compared to conventional suspension bridges, the new bridge offers several advantages, including a reduction in the main cable force, resulting in fewer difficulties in cable anchorage and construction. Additionally, there are no concerns regarding inadequate shear-bearing capacity at the suspension points. To streamline the process of optimizing the cable force in the new CFRP partial suspension cable-stayed bridge, a cable force estimation technique that considers the nonlinear effects was developed. Furthermore, useful recommendations are provided on critical aspects, such as construction methods and cable layout.