State of the Art of High Performance Steel in Supertall Building in Korea 

11th Pacific Structural Steel Conference, Shanghai, China, October 26-28, 2016

Authors: 김종호 ･ 김상섭 ･ 김경태 ･ 김윤기

Abstract:

Lotte World Tower located in Sincheon-Dong, Seoul is a part of the Second Lotte World complex. It has 123 stories above the ground and 6 stories underground and its square footage is about 330,000 m2. It consists of shopping stores, offices, hotel and a sky lounge. At the uppermost of the Lantern, the height is about 555m. It is the tallest building in Korea among many others that are currently being built. From 2nd to 86th stories, consisting of stores, offices and hotel, floors have steel beams and deck slabs. From 87th to 102nd floor has 225~285mm thick concrete flat slab. Underground and the 1st floor, are built by reinforced concrete. Geology surveys show foundation bed is made of both soft and hard rock. Allowable soil pressure is 3000 kPa which can sufficiently support the tower weight. Reinforcing pile was provided because the soil bed is near fault zones that may cause sagging. Concrete strength for core wall and mega column is between 40 and 80 MPa. Yield strength of rebar is 400 MPa, and 600 MPa high strength rebar is applied where diameter is greater than 25mm. For the most of steel beams, SM490 and SM490TMC, SHN490 were applied. For Belt Truss, peripheral steel columns, and some part of outriggers, high strength steel HSA800 was used which yield strength is about 650MPa. For the Lantern, STKN490B was used. Lateral load is resisted by RC core, two steel outriggers (39~44th and 72nd~76th stories), eight RC mega columns and two steel belt trusses (72nd~76th and 104~107th stories). When constructing outriggers, delay joints are used and outriggers are connected after frame completion. This is because extra forces can be developed to the outriggers when shrinkage between the core wall and mega columns occur unevenly. Lantern is exposed diagrid structure. For wind test, HFFB test was performed at the SD50% stage. At DD100% stage, aeroelastic model wind tunnel study was performed. Spandrel girders and belt trusses surrounding the mega columns are welded to the side instead of penetrating the center of the columns.

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