The project is the construction of a high-speed railway connecting Pyeongtaek and Osong with a total length of 46.95 kilometers to relieve bottlenecks in the common section of the high-speed line, and is divided into a total five construction packages. CP-1, which BANDI participated in, is a section of about 10-kilometer connecting Paengseong-eup, Pyeongtaek-si, Gyeonggi-do, and Eungbong-myeon, Asan-si, Chungcheongnam-do, with a total length of 4.49 kilometers and four bridges. 

BANDI provided the consulting services for the tender and detailed design of the bridges in CP-1. 

In particular, this project is the first in Korea to introduce a 400km/h next-generation high-speed train (HEMU-430X), while at the same time building new up and down lines on both sides of the existing Gyeongbu high-speed rail line, so securing safety for large-scale adjacent construction was of utmost importance.

The bridge type adopted for most sections of this project is the PSC box girder bridge, which has been widely used in existing high-speed railway projects because it has the appropriate sectional stiffness for high-speed railway loads. In the section plan, the bridge width was planned to be 6.4 meters with maintenance ways and derailment prevention walls on both sides, and the bridge span was planned to be 40 meters as a single-span bridge, which is the optimal span length for ensuring train running safety and eliminating resonance. In addition, the height of the PSC box girder was proposed to be 3.0 meters, and the strand pretensioning method was applied.

Due to the proximity to the existing railway bridge, precast span method (PSM) was used to construct the PSC box girders. Fabricated in a precast yard, the PSC box girders were planned to be transported and erected using straddle carrier type PSM equipment to shorten the construction period. No impact to the existing railway tracks was planned.

Since the project involves the construction of a new railway on both sides of the existing Gyeongbu high-speed railway line, it was important to ensure the safety of the existing high-speed railway line due to the close construction. To this end, a single cast-in-place concrete pile foundation method was applied to maximize the separation distance from the existing bridge foundation. While PHC pile foundations, which are commonly used for railway bridges, require a separation distance of only 1.7 meters from the existing tracks due to temporary facilities, single cast-in-place piles do not require temporary facilities and can secure a separation distance of more than 5.5 meters from the existing tracks.

On the other hand, as a large-scale fault fracture zone was found in a area of about 400 meters of the Sin-hue Bridge passing through the reservoir, a PHC pile foundation was planned for this area, and instead, the existing and new line piers were staggered to maximize the separation distance between the new and existing lines. In particular, a return period of 2,400 years was applied for seismic design to ensure constructability and seismic safety.

The piers have a circular cross-section like cast-in-place piles, and precast copings were applied to the piers to shorten the construction period and minimize field work due to close-up construction.

The abutment was separated from the existing abutment (Gyeongbu Highspeed Railway) by up to 20 meters to increase construction safety due to close proximity work, and a U-shaped retaining wall was installed at the back of the abutment to prevent soil from flowing over the existing tracks. In addition, to prevent differential settlement, a soil pressure separation type connection was applied to ensure the safety of high-speed train running of the bridge and earthwork connection.