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Steel Structures 6 (2006) 237-246 www.kssc.or.kr
A Study on the Effective Lateral Drift Control of
Super-tall Buildings in Korea
Young-Hak Kim1,* and Sung-Woo Shin2
1Senior Researcher, Research & Development Institute, Lotte Engineering & Construction Co., Ltd., Korea2Professor, Department of Architectural Engineering, Hanyang University and
Chairman, KSTBF (Korea Super-Tall Building Forum), Korea
Abstract
High-rise residential buildings, especially multi-use residential and commercial buildings, have been prospering in Koreasince the late 1990s. Although six of the 200 tallest buildings in the world are in Seoul, no building over 100 stories tall hasyet been constructed. The characteristics of Korean high-rise buildings are as follows: they are located in Seoul City, Sung-nam City, Kyung-gi province, and Busan City; they are 100-300 m tall; and they are multi-use residential and commercialbuildings. The purpose of this study is to determine special features of super-tall buildings in Korea through the value of theirdisplacement contribution factor, calculated using the principle of virtual work. Ultimately, the most effective methods forcontrolling lateral drift are controlled analysis of real structural models using computer programs. Effects of lateral load-resisting systems are evaluated and compared in this study. Consequently, the most effective members for controlling lateraldrift are presented in this study through an analysis using computer programs on a real structural model.
Keywords: Super-tall building, lateral drift control, principle of virtual work, displacement contribution factor
1. Introduction
1.1. Social background
Six Korea high-rise buildings are ranked among the
world’s tallest buildings. In the last decade, Korean
construction companies have built high-rise buildings such
as the KLCC and Telecom builiding, overseas buildings,
and so many domestic high-rise buildings 100-300 m
high (Fig. 1).
As a result, Korea now has more than 70 over-100-m-
high buildings mostly in Seoul City and Busan City. In
addition, over-100-story building projects have been
announced one after another, and so many tall buildings
are still under construction (Fig. 2).
1.2. Research objective and background
A survey carried out during the 1st KSTBF International
Symposium (2002) showed that the necessity of super-tall
buildings is acknowledged by 70.6% of.experts and the
public in Korea.
Current circumstances such as demand for ESSD
(Environmentally Sound and Sustainable Development)
and the search for a solution to population explosion are
leading to expectations that tall buildings will be continually
constructed. Hence, technologies for constructing super-
tall buildings in Korea have shifted from those in the
initial phase to more advanced technologies.
Tall buildings are uniquely characterized by the prime
necessity for lateral loads to be considered in their design.
Two types of loads normally associated with lateral loads
are wind and earthquake loads.
This study first analyzes emerging issues with respect
to Korean super-tall buildings (STBs), then selects
existing or proposed structural systems of tall buildings,
analyzes these structural systems using a computer
program, calculates the displacement contribution factor
*Corresponding authorTel: +82-2-718-4688, Fax: +82-2-702-0959E-mail: [email protected]
Technical Article
Figure 1. Chart of height of buildings in Korea.
238 Young-Hak Kim and Sung-Woo Shin
of the structural components such as the beam, column,
shearwall, and outrigger using the principle of virtual
work, and evaluates the results.
Therefore, this study aims to present data for effective
structural control of lateral drift.
1.3. Research method
In this study, after analyzing a structural model similar
to a real structural model using a computer program
(MIDAS Genw. 5.8.1) and values calculated as one
member force of each structural component under the
ultimate loading condition and the member force of each
structural component under the unit load (P = 1), the
displacement of each structural component is calculated,
and then the value is divided by the volume of each
component. Finally, the impact on the relative size and
locations of various structural elements is evaluated.
2. Emerging Status of Structural Systems of STBs in Korea
Korean super-tall buildings are mainly located in Seoul
City, Kyung-gi province, Sung-nam City, and Busan City;
are 100-200 m tall; and are mostly multi-use residential
and commercial buildings.
In selecting the structural systems, economic considerations
demand that the economics of the structural system be
considered the most important factor in Korea. The
possible structural systems for the defined high-rise buildings
are: a reinforced concrete shearwall + a moment-resisting
frame (MRF), a reinforced concrete shearwall + an outrigger
system, a tubular system, a multi-tubular system, and a
mega-structure system. Among these, the structural system
composed of a shearwall with high-strength concrete in
its core, a moment-resisting system, and an outrigger is
the more popular structural system in Korea (Table 2).
The quest for more efficient structural systems has led
to a new generation of hybrid mixed steel and concrete
building structures.
The displacement contribution factor of each component
is calculated by applying it to the lateral resisting system
of Korean super-tall buildings that consist of a reinforced
concrete corewall, a moment resisting frame, and an
outrigger and beltwall system. The purpose of this study
is to find the most essential element in controlling lateral
drift and to suggest the most effective method of lateral
drift control.
3. Importance of the Core Position in the Building Plan
The higher the building is, the more important it is to
solve the vertical flow. For an effective structural system,
it is important to determine the shape of the building plan
and to determine the position of the core in the plan.
Lotte world II (555 m) Lotte world II (510 m)
Figure 2. Korea super-tall building projects being planned.
IBC130 Project (570 m) Songdo tower (510 m)
Figure 3. Super-tall buildings in Seoul.
A Study on the Effective Lateral Drift Control of Super-tall Buildings in Korea 239
3.1. Classification of STBs in Korea according to plan
type
Table 3 presents the types of plans of Korean super-tall
buildings, which are generally classified into 8 groups.
3.2. Study on the efficiency of building plans
according to the building’s core position
To design super-tall buildings effectively and economically,
the position of the core in the plan should be carefully
determined. This study demonstrates a simple example
using a 60-story building structural analysis model that
has the same size plan under the same loading condition.
The design variable is the position of the core in the plan;
the central reinforced concrete corewall, the eccentric
Table 1. List of Korea’s Super-tall Buildings
Rank NameNo. ofstories
Height(m)
Type of plan Structural system
1 Tower Place 69 261 YRC Core + RC Belt Wall (16, 55 F) +
SRC Column
2Hyperion (Mok dong)
A 동69 256 X RC Core + MRF + Outrigger Truss (9, 32, 50 F)
3 KLI 63 building 60 249 Rectangular MRF + Interior Brace
4 Tower Place I 66 234 BoxRC Core + Steel Outrigger with Belt Truss +
SRC Column
5 Trade Tower 54 228 Box RC Core + MRF
6 Star Tower 45 206 RectangularRC Core + MRF + Outrigger/Belt Truss/Cap
Truss
7 Tower Palace 55 195 Box+BoxRC Core + Steel Outrigger
With Belt Truss + SRC Column
8 Techno Mark (Kang Byun) 39 189 - -
8 ASEM Tower 41 170 - Tube + Brace + Moment Frame
10 Lotte World (Busan) 41 167 - -
Table 2. Lateral force resisting system in Korea
Table 3. Types of plans of Korean super-tall buildings
Rectangular Boxed Triangular Box + Box
Y T X Free
Figure 4. Analytical models.
Figure 5. Diagram of test results.
240 Young-Hak Kim and Sung-Woo Shin
Table 4. Analytical model (Real structural model in Korea)
Group NameLateral force resisting system
Shearwall MRF Outrigger Belt Truss Number(s) Outrigger position
A
H-239-A O O O O 4 9, 30, 50, 69 F
C-175-A O O O O 1 19 F
S-145-AA O O O O 1 15 F
D-133-A O O O O 2 23, 43 F
H-106-A O O O O 1 10 F
B
H-156-C O O × × - -
D-129-AA O O × × - -
HW-109-Y O O × × - -
C
S-81-B O O × × - -
S-79-B O O × × - -
S-56-B O O × × - -
H - 239 - A
A: Type of plan
239: Overall height
H: Construction company
Table 5. Lateral force resisting system with outrigger
Lateral force resisting system with outrigger
H-239-A C-175-A S-145-AA
D-133-A H-106-A
Table 6. Lateral force resisting system without an outrigger
Lateral force resisting system without an outrigger
H-156-C D-129-AA HW-109-Y
Table 7. General structural buildings
Approximately 20-story structural buildings
S-81-B S-79-B S-56-B
A Study on the Effective Lateral Drift Control of Super-tall Buildings in Korea 241
reinforced concrete corewall, and the exterior reinforced
concrete corewall (Fig. 4).
The results show that the most effective case is the
application of the central core, the second eccentric core,
and the third exterior core. If the application of the
exterior corewall will be used, however, a reinforced
concrete brace should be used. This is very unreasonable,
though.
Figure 5 graphically shows the difference according to
the application of concrete compressive strength.
Table 8. H-239-A diagrams
Displacement contribution factor of H-239-A
Beam
Column
Outrigger
Truss
Wall
Table 9. C-175-A diagrams
Displacement contribution factor of C-175-A
Beam
Column
Outrigger&
Belt Truss
Wall
242 Young-Hak Kim and Sung-Woo Shin
4. Analysis of the Displacement Contribution Factor
Once the structural layout of a tall building is defined,
the main effort is to size the structural elements to satisfy
the lateral serviceability performance criteria.
Generally, under wind or seismic loading conditions,
the lateral top deflection is limited to H/500 and the inter-
story drift is limited to 0.015 h, where H is the overall
height of the building above the pile cap level and h is the
story height in Korea.
Using the principle of virtual work, explicit serviceability
stiffness constraints can be expressed in terms of the
cross-sectional properties of the structural elements.
4.1. Analytical method of determining the
displacement contribution factor
4.1.1. Principle of virtual work
The exterior virtual work (∆ext) done by a unit load (P
= 1) in a linearly elastic structure is the verified work
done by a unit load while accruing virtual deformation, as
shown in Eq. (1).
Wext = 1 · ∆ (1)
Deformation occurs by unit load (P = 1). The interior
virtual work is shown in Eq. (2).
Wext = (2)
The deformation is presented in Eq. (3) based on the
virtual work.
∆ = (3)
Using the unit loading method, the maximum lateral
drift of the building is calculated. Adding this to the unit
load (P = 1) at the top position of the building in the same
NN
EA-------- xd
0
l
∫MM
EI---------- xd
0
l
∫feVV
GA----------- xd
0
l
∫TT
GI------ xd
0
l
∫+ + +
NN
EA-------- xd
0
l
∫MM
EI---------- xd
0
l
∫feVV
GA----------- xd
0
l
∫TT
GI------ xd
0
l
∫+ + +
Table 10. S-145-AA diagrams
Displacement contribution factor of S-145-AA
Beam&
Outrigger
Column
Wall
Table 11. D-133-A diagrams
Displacement Contribution Factor of D-133-A
Beam&
Outrigger
Column
Wall
A Study on the Effective Lateral Drift Control of Super-tall Buildings in Korea 243
direction, the sum of the values of the components is the
lateral drift of the building.
4.2. Analysis of the displacement contribution factor
in a real structural model
4.2.1. Analytical structural model
Table 4 presents 11 analytical models. The structural
systems are classified into three groups. One group
consists of five models with outrigger systems, another
group consists of three models without outrigger systems,
and the third group consists of three 20-story or so
models. The variables are the structural height and the
outrigger system.
4.3. Analysis of the displacement contribution factor
of structural components
4.3.1. Displacement contribution factor of H-239-A
The outriggers are located at the 9th, 30th, 50th and
69th floors. Thus, stiffness is more significant on these
floors than on other floors.
The displacement contribution factor of the truss and
the beam is distributed uniformly. In the upper floors, the
outrigger affects the column more than the wall, so that
the what? of the column is larger than that of the upper
floors.
The outrigger on the upper floors contributes more than
the outrigger on the lower floors.
4.3.2. Displacement contribution factor of C-175-A
The rigidity of the upper and lower floors and the
outrigger is larger than that of the other floors.
The displacement contribution factors reach their
maximum value on the 19th floor.
4.3.3. Displacement contribution factor of S-145-AA
The residential and commercial building, S-145-AA,
has a marked stiffness at its podium.
The displacement contribution factor of the beams is
influenced by the outrigger on the middle floor. That of
the columns and walls on the lower floors is relatively
large.
The outrigger on the 15th floor has maximum value.
4.3.4. Displacement Contribution Factor of D-133-A
The stiffness of the lower floors is large. The rigidity of
the wall on the 41st floor is larger than of the beam on the
23rd floor.
Table 12. H-106-A diagrams
Displacement contribution factor of H-106-A
Column
Wall
Table 13. H-156-C diagrams
Displacement contribution factor of H-156-C
Beam
Column
Wall
244 Young-Hak Kim and Sung-Woo Shin
4.3.5. Displacement contribution factor of H-106-A
The stiffness of the lower and upper floors is large. The
rigidity of the beam on the 10th floor is larger than on the
other floors.
4.3.6. Displacement contribution factor of H-156-C
The structural system consists of a flat slab and a
reinforced concrete shearwall that affect the displacement
contribution factor of the beams.
The value is especially large at the beams on the middle
floor.
4.3.7. Displacement contribution factor of D-129-AA
The structural system is similar to that of H-156-C.
Also, the results were similar to those shown in Table
13.
The value is especially large at the beams on the middle
floor.
4.3.8. Displacement contribution factor of HW-109-Y
This structural model has a transfer layer on the 2nd
floor.
Table 14. D-129-AA diagrams
Displacement contribution factor of D-129-AA
Beam
Column
Wall
Table 15. HW-109-Y diagrams
Displacement contribution factor of HW-109-Y
Beam
Column
TransferGirder
Wall
A Study on the Effective Lateral Drift Control of Super-tall Buildings in Korea 245
The displacement contribution factor of the beam is
distributed equally on all floors.
4.3.9. Displacement contribution factor of S-81/79/
56-B
These buildings were selected to evaluate the behavior
of super-tall buildings in Korea.
The displacement contribution factor of the beams is
distributed equally on all the floors.
5. Conclusions
In this paper, the lateral resisting system was analyzed
and the most effective method of lateral drift control was
suggested.
The results of the study are as follows.
a. To control the lateral drift effectively, the structural
system consisting of a reinforced concrete corewall,
a moment-resisting system, outriggers, and a belt
wall is popular in Korea.
b. In the case of the usage of an exterior corewall in the
plan, a concrete brace should be used in the
reinforced concrete building.
c. The structural system consisting of a reinforced
concrete corewall, a moment-resisting frame, and an
oOutrigger is common in Korea.
d. To determine the structural system of a super-tall
building, a Korean construction company reviewed
the structural system at the point of economic
efficiency.
e. It is important to determine the position of the core
in the plan close to the center to promote the
efficiency of the structural system.
f. The value of the displacement contribution factor is
as follows:
- In the structural system with an outrigger:
Wall > Beam > Column
- In the structural system without an outrigger:
Wall > Column > Beam
g. The curve of the displacement contribution factor is
similar to the curve of the stiffness ratio of the
building.
h. In using a structural member such as an outrigger,
the stiffness of which is higher than of others, the
displacement contribution factor also has a higher
factor. Moreover, in using an outrigger system, the
position of the outrigger must be considered carefully.
i. The stiffness curve of the structural models, the
lateral drift curve, and the displacement contribution
factor curve have a similar behavior.
j. Generally, stiffness is inversely proportional to stiffness;
but the concentration of the stress makes the drift is
larger.
Acknowledgments
The authors would like to thank MIDAS IT and
STRESS (advanced STructure RESearch Station) at
Hanyang University for their technical support.
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246 Young-Hak Kim and Sung-Woo Shin
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