Structural System of North-East Asia Trade Tower in Korea.pdf

Structural System of North-East Asia Trade Tower in Korea

Kwang Ryang Chung 1 , David Scott 2 , Do Hyun Kim 3 , In Ho Ha 4 and Ki Dong Park 5

1 President, DongYang Structural Engineers Co., Ltd, Rm 301, O-chang B/D, #208-2, Nonhyun-Dong, Gangnam-Gu, Seoul, Korea

Tel: +82 2 549 3744, Fax: +82 2 549 3745 Email: krchung@dysec.co.kr

2 Principal, Ove Arup & Partners New York Ltd

3 Senior Researcher, DongYang Structural Engineers Co., Ltd

4 General Manager, Daewoo E&C Co., Ltd

5 Senior Researcher, Daewoo Institute of Construction Technology

krchung@dysec.co.kr

David.Scott@arup.com

Kwang Ryang Chung

Dr. Chung has had experience in the structural design and analysis of many major commercial and residential projects in

Korea.

His particular expertise is in the design and analysis of tall building. He has also developed techniques to optimize the

size and weight of structural steel and reinforced concrete.

David Scott

David Scott is a Principal at Arup, the international engineering design irm. He is a leader of the Arup New York ofice

responsible for the Building Engineering Business. In February 2006 David was elected as Chairman of the Council on Tall

Buildings and Urban Habitat. David graduated with a irst class BSc in Engineering from Edinburgh University and joined

the London ofice of Arup in 1977 as a structural engineer.

During his career David has been based in Europe, Africa, Asia and the United States. He spent 15 years based in South

East Asia, working on Arup’s irst major building projects in China, Korea, Indonesia, Philippines and Taiwan. While based

in Hong Kong he has worked on many award winning and innovative projects, such as the Hongkong Bank Headquarters,

the Biological Sciences Building at HKU, the International Airport Terminal Building in Hong Kong and the 300m Cheung

Kong Center for Hong Kong’s largest developer.

David moved to New York in 1998 to take up a key role in the Arup Buildings Business in the United States. From New

York he has worked with leading architects on a wide range of tall buildings, major infrastructure projects and long span

structures. These projects included the redevelopment of New York’s Penn Station, Second Avenue Subway project which

has 16 stations and 8 miles of track as well several commercial tall building projects.

In 2001 David was one of the team leaders working with the contractors on the search, recovery and clean-up of the World

Trade Center site after 9-11. This was part of the SEoNY led effort that was coordinated by Thornton Thomasetti. He was

extensively involved in the industry review of building design and standards; presenting a paper on Fire Induced Progres-

sive Collapse at the NIST Chicago conference, and being involved with the review of GSA’s new design requirements to

mitigate progressive collapse, that were issues in 2002. David has written papers on Seismic Design in Areas of Low to

Moderate Seismicity, ire and structures, composite structures and the design of long-span roofs.

CTBUH 8th World Congress 2008

Structural System of North-East Asia Trade Tower in Korea

Kwang Ryang Chung 1 , David Scott 2 , Do Hyun Kim 3 , In Ho Ha 4 and Ki Dong Park 5

1 President, DongYang Structural Engineers Co., Ltd, Rm 301, O-chang B/D, #208-2, Nonhyun-Dong, Gangnam-Gu, Seoul, Korea

Tel: +82 2 549 3744, Fax: +82 2 549 3745 Email: krchung@dysec.co.kr

2 Principal, Ove Arup & Partners New York Ltd

3 Senior Researcher, DongYang Structural Engineers Co., Ltd

4 General Manager, Daewoo E&C Co., Ltd

5 Senior Researcher, Daewoo Institute of Construction Technology

Abstract

This paper introduces the structural system and new outrigger connection of Northeast Asia Trade Tower (NEATT).

NEATT comprises 68 stories with a level to the top of the roof +305m and is currently under construction in Song-do,

South Korea. NEATT is designated as a landmark of Song-do International Free Trade city. The structural system of

NEATT is composed of the perimeter column, corner mega column, core wall, outrigger and belt truss system. This

tower can be characterized by its highly irregular shape and two outrigger floors such that the structural members

including perimeter columns and belt trusses are out of plumb and several steel members meet at one joint of outrigger

truss. The proposed outrigger connection in this paper was conceived to overcome the difficulty of keeping small gaps

at the conventional outrigger connections. The new outrigger connection is applied at outrigger truss to acquire

structural stability and construction efficiency. The large scale laboratory test showed that the proposed Oil Jack

Outrigger Joint System was proved to handle the differential column shortening during the construction. It also

efficiently resists the dynamic lateral loads.

Keywords : Tall buildings, Structural System, Adjustment Joint, Outrigger System

Introduction

North-East Asia Trade Tower (NEATT), currently

being built in Song-do Free International City, is a

68-story high-rise building. This building has been

planned to serve as a landmark that symbolizes Song-do

City as an advanced International Free Trade city.

NEATT’s 2nd through the 33rd floors are offered

to domestic and foreign companies as 24-hour open

business spaces, whereas its 35th through 64th floors are

to be used for the highest-grade business hotel. The

following is the design summary of NEATT.

x Location: Yeonsu-gu, Incheon

x Total floor space: 138,316 m2

x Usage: Offices and a hotel

x Size: 68 stories above ground level and 3 stories

x underground

x Floor Height: 4.3 m (office), 3.7 m (hotel)

x Structural system: RC Core, Mega columns,

x Outrigger & Belt truss

x Foundation: RCD pile foundation

x Design by Heerim Architects & Planners, KPF

x Structural design by Dongyang Structural

Engineers Co., Ltd. and Ove Arup & Partners

New York Ltd.

x Construction by DAEWOO E&C Co.

unique exterior, visually

differentiating its stylish

facade from other

buildings while providing

NEATT a significantly

superior structural status

as shown in Figure 1.

As shown in the

ground floor plan of

NEATT (Figure 2), the

first floor has trapezoidal

shape (lower right corner

of Figure 2) that

gradually transforms into

the triangular shape

(upper left corner of

Figure 2) toward the roof

floor. The dynamic

exterior elevation created

by such a change in the

shape of the planes

considerably reduces the

wind’s impact on the

building and ensures a more economical structural design

than a box-shaped building could offer. The structural

design of NEATT has been worked by DongYang

Structural Engineers Co., Ltd and Ove Arup & Partners.

Reflecting the latest trends in modern architecture

characterized by free and dynamic forms, NEATT has a

CTBUH 8th World Congress 2008

Figure 1. NEATT (source: KPF)

load dominates the lateral resistance system.

Table 2. Calculation conditions for wind load

Basic wind speed

30 m/s

Exposure

Importance factor

1.0

Topographic factor

1.0

External pressure coefficients/

Internal pressure coefficients

0.8, -0.2q-0.5

Table 3. Calculation conditions for earthquake load

Zone factor

0.11

Figure 2. Change in the shape of the plans (source: KPF)

Importance factor

1.2

General Information on Structural Design

The followings are basic information about the

structural design of NEATT, such as material, design

criteria, design load, and wind tunnel test results.

Site class

Response modification factor

4.5

Seismic design category

Material

The core walls and columns of NEATT, an SRC

structural building, were designed with high-strength

reinforced concrete (50 MPa), and SD40 reinforcing bars.

The detailed list of reinforcing steels for NEATT is

shown in Table 1.

Table 1. Steel Strength

Steel Member

Type of steel

Corner mega column

SM570TMC

Perimeter column

SM490TMC

Interior column

SM490 / SM490TMC

Floor/cross beam

SM490

Figure 3. Overturning Moment Comparison

Outrigger truss

SM490TMC

Belt truss

SM490TMC

Wind tunnel test

Design criteria

The structural design followed the “Korean

Building Code 2005 / Architectural Institute of Korea,”

as the basic design code. To ensure the building’s

stability and serviceability, the design observed the

following design limitations.

↟ Criteria on roof displacement: H/500

(Wind Load : return period = 100 years)

↟ Criteria on story drift: 0.015hx

(Earthquake Load)

Design load

The wind load and earthquake load applied to the

design of NEATT are as follows:

Shown in Figure 3 is a graph comparison of the

overturning moments by wind loads and earthquake

loads in strength design standards. It shows that wind

Figure 4. Wind Tunnel Test (source: RWDI)

The three-dimensional shape of NEATT is not the

usual hexagonal shape, and therefore, as shown in Figure

4, it is essential that the building be subjected to a wind

CTBUH 8th World Congress 2008

tunnel test. The wind load and acceleration data acquired

from the wind tunnel test were applied to the strength

and serviceability design.

satisfying the design criteria of H/500. Figure 10 shows

the ratio of the story drift to story height for the case of

earthquake. It shows that every floor satisfies the criteria

for story drift of 0.015h.

The comparison of each floor level moments by

the wind load according to KBC 2005 and the wind load

calculated from the wind tunnel test is shown in Figure 5.

As was previously discussed, it was confirmed that

NEATT’s wind response shows a drastic reduction

compared with the code value due to its upward tapered

shape.

The acceleration was evaluated through the wind

tunnel tests with two different cases: one with the impact

of a typhoon and the other without the impact of a

typhoon. As shown in Figure 6, both cases satisfied

ISO’s acceleration criteria with respect to the return

period of one year, five years and ten years.

Figure 7. Structural System of NEATT(source:Arup)

Figure 5. Comparison of the Code Wind Load and the Wind

Load acquired from the Wind Tunnel Test

(a) 1 st Mode (b) 2 nd Mode (c) 3 rd Mode

Figure 8. Mode Shapes

Figure 6. Acceleration based on the Wind Tunnel Test

Structural System

NEATT’s main frame system consists of 27

perimeter columns, six corner mega columns, core wall,

and outrigger/belt truss, all of which are systemically

integrated (Figure 7). The result of the 3-dimentional

analysis showed that the natural periods of NEATT are

5.8 sec in the first mode, and 5.5 sec in the second and

third modes. Fig. 8 shows three significant mode shapes.

The ratio of roof displacement to building height

with respect to different wind direction is shown in

Figure 9. The maximum roof drifts are H/775 and H/988

in the direction of X and Y-axis, respectively, which is

Figure 9. Ratio of the lateral displacement to building height

depending on the wind load

CTBUH 8th World Congress 2008

Figure 10. Ratio of story drift to earthquake load

Figure 13.

The outrigger systems are installed on the 34th and

65th floors of NEATT. The outrigger and belt system

takes 30% of overturning moment (Figure 14), and the

structural design was performed in such a way that the

axial load developed in columns due to the outrigger’s

share of the overturning moment could also be resisted

safely. As members meet obliquely and three or four

members are joined in one joint connection of the

outrigger, gusset plates were applied to the joints to

provide manufacturing and construction efficiency

(Figure 14).

As with other high-rise buildings, NEATT’s core

wall functions as a major structural element that resists

gravity and lateral load. As shown in Figure 11,

NEATT’s core wall thickness and shape change along the

building height to optimize the core wall. Figure 12

shows the core wall’s distribution ratio of gravity load.

The core wall takes about 65% of the total gravity load

and 70% of the total overturning moment due to wind

load (Figure 12).

Figure 13. Structural Frames at the 34 th /65 th Outrigger Floors

Figure 11. Shape and Thickness of NEATT’s Core Wall along the

Building Height (source: Arup)

Figure 14. Effect of the Outrigger’s Sharing of Overturning Moment

Figure 12. Core wall’s distribution ratio of gravity load

To resist lateral load, NEATT uses core walls with

the outrigger and belt system. The 3-D frame and

elevation of the outrigger and belt truss are shown in

Figure 15. Joint Connections of the Outrigger System

(source: Arup)

CTBUH 8th World Congress 2008

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: