Mimosa pass viaduct completed at Da Lat's landslide gateway

The Xuan Huong viaduct, built over the landslide site on Mimosa pass, is largely complete and set to open to traffic before 30/4, significantly improving a vital route to Da Lat.

From an aerial perspective, a significant rupture remains visible at the landslide site on the mountainside. The Xuan Huong viaduct now spans this area, its design following the natural terrain, and has connected traffic across Mimosa pass on National Route 20 as of 15/4.

Mimosa pass, stretching over 10 km, serves as a key southern gateway to Da Lat, alongside Prenn and Sacom passes (which restrict trucks). Last November, a landslide over 70 m long and around 40 m deep obliterated the roadbed and surface. To restore connectivity, authorities established a temporary route along the cliff while simultaneously initiating construction of a viaduct over the landslide, a project costing over 33 billion VND.

The viaduct measures 133 m in length, with its main span extending 108 m and a width of 9 m. The deck has been asphalted and successfully undergone heavy truck testing.

According to Pham Van Thai, the project manager, despite its length of just over 100 m, the viaduct was a critical emergency project to address the landslide on this vital route. At peak times, the construction team deployed over 70 engineers and workers, operating in shifts and simultaneously advancing multiple tasks around the clock to ensure the viaduct opened on schedule.

The viaduct's underside reveals its robust structure: 6 main beams, each approximately 1,4 m high, cast from prestressed reinforced concrete. Its U-shaped abutments and solid piers are each supported by 5 bored piles, 1,2 m in diameter, which penetrate the gravel layer and anchor into the hard rhyolite bedrock beneath.

Workers are currently finalizing the guardrail painting and the viaduct's drainage system.

Workers are casting concrete panels to construct the 'cone' sections along the viaduct's edges. Below the landslide's negative slope, trucks are clearing debris.

The project manager noted that following the technical opening in late March, the final asphalt layers were applied, and vehicle tests were conducted early last week. The viaduct was then temporarily closed for final cleaning, aesthetic improvements, and traffic safety installations, with full public access anticipated late this month.

The viaduct spans the landslide area on Mimosa pass, as seen from the lower slope.

Replacing the landslide-affected road segment with a viaduct significantly reduces subsidence risks in this geologically unstable area, providing a direct route instead of a winding path along the pass. This construction also ensures stable traffic connectivity for Da Lat's gateway, particularly crucial with the impending rainy season.