Investor Presentaiton
KUALA LUMPUR
SHANGHAI
HONG KONG
ΤΑΙΡΕΙ
PETRONAS TOWER
452 M
JIN MAO TOWER
420.5 M
'WO INTERNATIONAL
FINANCE CENTER
413 M
TAIPEI 101
508 M
SHANGHAI
SHANGHAI
WORLD FINANCIAL CENTER
492 M
1997
1998
2003
2004
2008
500 M
400 M
300 M
2:00 M
100 M
OM
Figure 2. Shanghai World Financial Center in comparison with some
of the world's current tallest buildings.
Following the completion of conceptual structural
designs by Ove Arup & Partners, New York, all design
work, but for Architecture, then moved to Tokyo...to be
completed by Shimizu Corporation.
By 1995, the piling had been tendered and installed,
and the structural package had been completed. In
preparation for tendering of structural steel, Leslie E.
Robertson Associates R.L.L.P. (LERA) was approached
by Nippon Steel Corp. with the goal of providing a
lower-cost, faster-to-construct structural system.
Structural designs were completed by LERA in sufficient
detail for tendering; however the project then went on
hold.
In 1999, with KPF remaining as Design Architect,
and with the foundation piling in place, the height of the
building had been increased from 460meters (1,509 feet)
to 492meters (1,614feet) and the base dimension had
been increased from 55.8meters (183 feet) to 58.0meters
(190feet). The exterior appearance of the proposed
building remained essentially unchanged.
Making use of reusable followers, about two
hundred concrete-filled steel pipe friction piles at
minimum spacing (under the tower to a length of
78meters), had been driven from the ground surface.
Pile cut-off was at the anticipated bottom elevation of the
mat [-17.5meters (-58 feet)]. To be used later for top-down
construction, providing temporary vertical support for the
below-grade concrete floors, steel H-piles extended from
some of the piling to the ground surface.
With the re-birth of the project, Mori Building
Company approached LERA seeking an alternative
design to that contained in the original construction
documents. In part because the pile cut-off was well
below grade and in part due to non-engineering
considerations, the cost of reinforcing the existing piling
was high. LERA determined that the installed pile
foundation could accept a larger building, but only by
decreasing by more than 10% the weight of the original
building and by re-distributing the loads to the piling so
as to accept the increased lateral loads from wind and
earthquake.
The New Structural System
In order to decrease the weight of the building, the
majority of that decrease had to be found in a reduction of
the thickness of the concrete shear walls of the services
core. This reduction was achieved by decreasing the wind
and earthquake-induced lateral forces resisted by those
walls. That decrease was found by significantly
increasing the stiffness of the lateral force resisting
system of the perimeter wall and by decreasing the
stiffness of the concrete walls of the services core.
Accordingly, abandoning the Developer's original
design for the perimeter framing (that of a Vierendeel
moment-resisting space frame), LERA proposed the
resurrection of its 1995 design: a diagonal-braced frame
with added outrigger trusses. KPF, LERA, and Mori
Building Company worked closely together to
incorporate this new structural system into the existing
architectural form. The change enabled a decrease in the
thickness of the services core shear walls as well as a
decrease in the weight of structural steel in the perimeter
walls. Further, by making use of outrigger trusses coupled
to the columns of the mega-structure, a further reduction
was realized.
The Mega-Structure
The Mega-Structure concept is shown in Figures 3
and 4 (both Figures omit intermediate floors). To resist
the forces from typhoon (hurricane) winds and
earthquakes, three parallel and interacting structural
systems were introduced:
1. The mega-structure, consisting of the major
structural columns, the diagonals, and the belt
trusses.
2. The concrete shear walls of the services core.
3. As created by the outrigger trusses, the
interaction between these concrete walls and
the mega-columns (see Figure 5.).
Figures 3 & 4. Model showing the building's mega-structure system
of mega-columns, diagonals and belt trusses along with concrete core
walls and outrigger trusses.
CTBUH 8th World Congress 2008
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