At 1:00 a.m. on October 10, with the completion of pouring for the mid-span closure segment of the right carriageway of the Baishaxi Bridge on the Guizhou Jianli Expressway, the concrete continuous rigid-frame bridge of the Baishaxi Bridge officially achieved closure of both carriageways.

It is reported that the Baishaxi Bridge is invested in by China Railway Construction Kunlun Group and constructed by China Railway Construction Bridge Engineering Bureau Group Co., Ltd. Pier No. 3 of the main bridge is 106 meters high. The superstructure is designed as an 81+150+81 m prestressed concrete continuous rigid frame, adopting a variable cross-section single-box single-cell section, with a box top width of 12.3 m and a bottom width of 6.5 m. The top surface of the box girder has a one-way 2.0% cross slope. The girder height of Segment No. 0 is 9.2 m, and the girder heights of the cast-in-place segment and the closure segment are both 3.4 m.

In advancing the construction of high piers and long spans, the project team adopted mature processes such as integral hydraulic climbing formwork and symmetrical pouring construction methods, achieving millimeter-level high-precision closure with "zero deviation."

"The construction process of simultaneously releasing water to unload weight and 'reduce load' as pouring progresses is an important means of maintaining the overall balance of the bridge and ensuring construction quality. The reason for choosing nighttime pouring is the thermal expansion and contraction characteristics of concrete. Construction during low-temperature and constant-temperature periods at night is an important factor in ensuring that the bridge has a better stress state," introduced Shi Hongtao, project manager of TJ-2 section of the Jianli Expressway.

According to his introduction, because the bridge is located in the slope zone transitioning from the hilly plateau and mountainous area of central Guizhou to the hills of Hunan, the ground elevation in the site area ranges from 466 m to 728 m, with a relative height difference of about 262 m. There is no road access to the bridge site, and traffic conditions are poor. Therefore, it has the characteristics of comprehensive construction difficulty and high technical precision requirements typical of high-pier long-span bridges in mountainous areas.

To this end, over the past more than two years, in the face of unfavorable factors such as the steep terrain and complex geological structure on both banks of the Baishaxi River, the pile foundations and pile caps being located on the cliffs beside the Baishaxi River, the generally monoclinal occurrence of the rock strata, and the severe and complex terrain, the project department established a Party member vanguard team. Through multiple on-site production scheduling arrangements and discussions of construction plans with expert groups from various parties, they resolved on-site production and construction problems. They successively adopted mechanical cold excavation along the mountainside for branch access roads, and used 3,500 cubic meters of rubble concrete embedded in the mountain body for the pile foundation excavation platforms and pile cap foundations, promptly completing the construction of pile foundations, pile caps, and pier shafts.