Kansai International Airport (Phase-I) Foundation Case Study By Rajul Teredesai CE 5333-Foundation Engineering Spring 2005

Overview Kansai International Airport (KIA)

Key Features Located on a biggest man-made island in Osaka Bay, Japan Constructed cost over $14 billion The island of 4 X 1 km, constructed in around 18m of water, entirely from landfill Project Started in 1986 Opened for flights in 1996 The ASCE named KIA the #2 civil engineering project of the 20th century, second only to the Panama Canal

Kansai Airport Aerial View

Construction of Airport Stage Activity Time I Subsurface Investigation 1 year II Sea Wall Construction 2 years III Landfilling 4 years IV Terminal Construction

Bore Hole Locations

Subsurface of the Kansai Airport Foundation

Seawall Construction Up to 40 ft. above sea level Tripod blocks on seaward side for dissipation of wave energy

Seawall After Completion Seawall Construction

Mechanism of Sand Drains

Advantage of Sand Drains The weight of the piled sand forces the water in the clay to move outward along the sand piles.

Application of One Million Sand Drain at KIA

Reclamation Three distinct grades of sand, gravel and rock from nearby mountains Four years and 750 million cubic feet of fill Transportation on Ground: Conveyor Water: Barges

KIA Terminal Building Architect: Renzo Piano

Settlement Predictions Lack of experience with construction on deep deposit of diluvial clay Expected settlement = 19 to 25 ft Actual settlement = 27 ft (by the end of island construction in 1990) It continued at the rate of 2 in/month

Settlement Calculations Consolidation Settlement: Time Rate of Consolidation (Terzaghi 1925):

What Went Wrong in Predictions? Un-conservative estimation of consolidation settlement Wrong estimate of the time required for completion of consolidation settlement Ineffectiveness of the sand drains in achieving the required success 100%

Incomplete Consolidation

Underestimation of Excess Pore Water Pressure Airport Started Settlement Continued

Coping With The Problem of Continued Settlement Basement of the terminal was lined with a quarter of a million tons of iron ore. Result: Island sank faster than the building it is trying to hold Installation of hydraulic jacks under the colums Result: No differential settlement between the columns of entire building

Learning From Mistakes Using data actual settlement data obtained from 1st phase of project Analysis of 400-m-deep boring exploration State-of-the-art soil test methods Expected Settlement = 18 m http://www.kald.co.jp/eindexframe.html

References A report by Justin Phalen, UC-Davis, 2002 The official website of KIA http://www.kald.co.jp/eindexframe.html

Questions?