The Maju Perdana project, now under construction in Kuala Lumpur, Malaysia, is composed to two towers and a mid-rise podium. Tower 1, being constructed of steel, is 50 stories tall, including three basement levels, the ground floor, and lift motor rooms. The total area of the building is 50,000 square meters. Steel erection, begun in March 2000 will be completed by November 2000. Tower 2 and the podium, both being construction of concrete are 35 floors and 13 floors and 35,000 square meters and 120,000 square meters respectively.
Tower 1 had originally been conceived as a concrete building. In 1997, when the Malaysian steel industry was privatized, and the building owners decided that Tower 1 should be constructed of steel, a world-wide search was conducted to select a firm with expertise in steel design. In February of 1998, Structural Affiliates International, Inc. formed a new company in Malaysia, Perwaja Structures International to promote steel design in that area of the world and to redesign Maju Perdana Tower 1 out of steel.
Since Tower 1 had originally been conceived as a concrete building, the structural systems and architectural details had to be reconsidered. These included plan layout, exterior wall and cladding details, stair and lift opening details, floor deck construction, stairs, and fire protection. While these items were initially considered constraints, Perwaja Structures International was able to turn them into advantages for a successful building design.
The design objectives of the project included maximizing the use of Malaysian steel sections, maximizing the net leasable area by minimizing the size of columns as compared to concrete, minimizing the cost while maximizing the speed of construction.
PSI considered three alternatives for the Lateral Load Resisting System - an all-steel system, composite columns and composite shear walls, and composite columns and concrete shear walls. The advantages and disadvantages of all three systems were compared and PSI found that the contribution of the perimeter frames was low and the construction of the perimeter beams was moderate, but at a high cost due to the welded connections that would have been required. So the final result utilized the shear elements and outrigger trusses at the 21st floor which mobilized the stiffness of the exterior columns and reduced the tendency for overturning. In the end, the 50-story building was designed with no element being in tension under wind and gravity load combinations.
For the column design, PSI utilized composite sections made from the heaviest beam and column sections produced by Perwaja Steel arranged in a cruciform format and filled with concrete and reinforcing between the flanges. This type of column arrangement has been shown by fire research in Europe to achieve two-hour fire rating without the need for additional fire protection on the flanges.
The floor system was also carefully considered. Once the comparative cost of metal decking vs. forming was understood, an alternative was investigated that utilized a forming system supported form the steel structure so that is does not require any propping from the floors below. This allowed work to progress underneath it. With this system, the determinant for beam spacing became the strength of the finished concrete slab rather than the strength of the metal deck as a form. Therefore, beams could be spaced out up to 4.2 m as opposed to a maximum of 3 m. dictated by metal decking. This saved a total of 300 tones of steel on the project.
Because the steel fabrication and erection was anticipated to be considerably faster than the casting of concrete on the beams, the sheer walls, and the floors, the total structural system was conceived so that the steel structure erection could proceed well ahead of the concrete construction. As a result, in this intermediate construction phase, the steel structure was able carry the loads, so it could be constructed by itself, without any help from the composite action with the concrete. The cruciform Perwaja steel section columns can carry up to 10 floors of steel framing above, including up to five floors of concrete slab. The steel braced core systems is also designed to withstand the wind loads and to stabilize up to 10 stores of construction above it. Eventually, the composite concrete column that utilizes both the steel section and the concrete carries the total load for the structure. The same is true for the core walls. The concrete that encases and totally encompasses the steel-braced core system now works in conjunction with the steel to carry the lateral loads and stabilize the building.
