1. It creates a more uniform bending moment distribution in the girder
2. It allows for an increased span length with the same structural depth
3. It reduces the required height of the king posts while maintaining similar girder depth
4. All of the above

Explanation

Explanation: A symmetrical double king post system with a continuous cable path offers several advantages over a single central king post system. By placing the king posts at the third points of the span, the system creates multiple upward reaction forces, reducing peak bending moments and creating a more uniform moment distribution along the girder—improving structural efficiency. This reduction in bending moments allows the bridge to achieve a longer span while maintaining the same structural depth, making it an efficient choice for medium-span applications. Additionally, the load distribution between two king posts enables them to be shorter than in a single king post system while maintaining the same support effect, which benefits fabrication, aesthetics, and clearance requirements. The continuous cable system also ensures efficient load transfer, with king posts acting in compression and cables in tension, minimizing deflections and improving redundancy during localized stress redistribution

1. Both king posts experience 1,635 kN of compression
2. Both king posts experience 1,890 kN of compression
3. The first king post experiences 1,890 kN and the second king post experiences 1,380 kN
4. The first king post experiences 1,380 kN and the second king post experiences 1,890 kN

Explanation

Solution: 

1. Calculate factored loads and support reactions:
• Factored dead load = 1.25 × 30 kN/m = 37.5 kN/m
• Factored point live load = 1.7 × 600 kN = 1,020 kN
• Left support reaction = 1,125 kN (dead) + 765 kN (live) = 1,890 kN
• Right support reaction = 1,125 kN (dead) + 255 kN (live) = 1,380 kN
2. In this continuous cable system with horizontal middle segment, the compression in each king post directly equals the corresponding support reaction:
• First king post (left) = 1,890 kN
• Second king post (right) = 1,380 kN

Explanation: In this continuous cable path system, the compression forces in the king posts are directly related to the support reactions due to vertical equilibrium requirements. Since the middle cable segment is horizontal, it cannot transfer vertical forces between posts, meaning each post independently balances the vertical component from its adjacent cable. For the asymmetrically loaded bridge, the point load positioned closer to the left support creates unequal reactions (1,890 kN left, 1,380 kN right). These reactions directly translate to the compression forces in the respective king posts, as each post must provide upward force equal to its adjacent support reaction. This direct relationship between support reactions and king post compression forces demonstrates how asymmetric loading affects the structural behavior of the system, requiring engineers to design each post for different compression capacities based on potential live load positions. The continuous cable system remains effective under asymmetric loading, though the force distribution becomes proportionally uneven based on the loading pattern.