Taiwan High Speed Rail

Taiwan

Project outline

Appointed by the Joint Venture of Bilfinger+Berger and Continental Engineering Corporation to carry out the design and detailing of seismic resistant viaducts to carry the high speed railway.

Contract value

$980m

Key features

• Value engineering in design
• Fast track design and build
• Seismic-resistant design and detailing
• Multi-modal and time history analysis
• Track structure interaction analysis
• Soil liquefaction and amplified ground motion

Skills utilised

• Structures and Bridges
• Rail Planning and Engineering
• Earthquake Engineering
• Geotechnical

Project detail

Faber Maunsell has a long history of working on technically demanding fast track Design and Construct Projects. The design commission recently completed for the Taiwan High Speed Railway Project is no exception - an economic design for an extreme seismic performance criteria in difficult ground conditions with demanding programme and construction constraints. It required the production of over 12,700 drawings and several volumes of design reports for the project located some 11,000km from the design office.

The project, one of the largest transport infrastructure initiatives to date, will enable 300,000 people a day to travel at speeds of up to 300km/h along the newly constructed 345km of high-speed line between Taipei and Kaohsiung. Faber Maunsell was commissioned to carry out the construction design for Contract C270 - a varied and tecnically complex stretch along this route, where 38km of the railway is carried on high level viaducts.

The specification for the project is stringent, particularly for the seismic performance, as Taiwan sits on an active tectonic region with seismic activity among the highest in the world. The viaducts are required to satisfy three key requirements: strict ride performance under normal operating conditions; safe operation at maximum design speed during a significant seismic event; remain repairable after an extreme earthquake.

In Contract C270,  the railway passes through several wide river plains of weak soils, where the bedrock is over 100m below ground level. The basic peak ground acceleration of 0.34g increases to 0.66g close to a known fault zone. The high seismic acceleration gives rise to soil liquefaction and amplified ground motion in weak layers, particularly in the river areas. The Choshue River, the largest in Taiwan, is one of four rivers situated within Contract C270. The railway crosses the river at 28m above the foundation level, but the allowance for scouring lowers the design bed level a further 11m. The river piers are subject to forces resulting from hydrodynamic effects during a seismic event and subsequent mud slides.

The structural form, layout and dimensions were developed through a value engineering exercise. Multi-modal response spectrum analysis was used to determine seismic demand. The adoption of Capacity Protected Design principles together with the non-linear soil-pile interaction for foundation analysis and non-linear time history analysis for track-structure interaction produced cost effective, but realistic solutions. In general, the foundations comprise 2.0m diameter bored cast in-situ concrete piles between 30m and 65m long; the foundation configuration and column types being selected to suit the standard, near-fault and river scour regions. The superstructure comprises post-tensioned concrete box girders, 3.25m deep, up to 35m long and weighing up to 780 tonnes

Faber Maunsell also developed the design to suit the Full Span Launching Method which was chosen for deck erection on this contract due to the variable terrain and restricted site access. In this method, a launcher and a dedicated girder transporter makes use of the substructure and deck sections already completed to advance the deck erection.

The civil works contract, completed two months ahead of schedule, awaits the completion of the trackwork contract. There is no doubt that the commissioning of this high-speed railway will bring great benefit to Taiwan, where the existing road and rail network are showing signs overcrowding and deterioration.