The project is an office building located in Songshan District, Taipei City, featuring four 19 levels towers and 7 underground levels. It is constructed with a steel superstructure and reinforced concrete for the basement levels. This is a reconstruction project; the original building was a shopping center called "Core Pacific City." Due to the client's business strategy adjustment, the original shopping center was demolished, and four new office towers are being erected.
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Project Details
Location: Taipei, Taiwan Gross Building Area: 254,527 m^2 Scope of Service: Schematic design through construction administration Client: Core Pacific Development Corporation Architect: C.Y.LEE & Partners architects / Planner (Taipei, Taiwan) Structural engineer: King-Le Chang & Associates |
The design concept of this project is to make the most use of the existing building structure when constructing the new building. The old structure consists of reinforced concrete flat slab from B4 and below, and steel from B4 and above. It has an extensive pile foundation system because the "Core Pacific Plaza" structure system was designed to incorporate pile/soil interaction for the seismic motion to go through the pile/soil system then into the building structure. The design is to retain only the reinforced concrete structure below B3 while replacing the steel structure above it, the below B3 reinforced concrete member are reinforced and retrofitted. However, since the positions of the new steel columns in the new towers do not align with the existing concrete columns, a reinforced concrete (RC) transfer slab, with a depth ranging from 1 to 2.5 meters, is used to evenly distribute the load from the steel columns to the nearby concrete columns. This approach is feasible because the existing pile foundations are strong enough to support the weight of the new structure. The basement retaining walls, foundations, piles, and mat foundations are all existing.
The new superstructure utilizes a special moment-resisting frame in both the X and Y axes, along with buckling-restrained braces (BRBs) in the X direction. To ensure the public areas remain unobstructed by the BRBs, most of these braces are positioned in the service areas. However, this arrangement introduces eccentric stiffness to the structure, which can lead to torsional behavior. To address this issue, the four towers are interconnected at level 2, 3, 5, 7, 9, 19, and R1F with connector frames in order to make the four towers behave as one under seismic loading.
The demolition of the existing building in this project is divided into three phases.
The first phase involves demolishing the steel structure above the first floor. In the second phase, the structure from B3F to the first floor was demolished, while retaining the outer perimeter framing, which served as support for the slurry wall. Some sections of the outer perimeter frame was reinforced to adequately support the slurry wall. The third phase focuses on retrofitting the structure from B4F to B7F, which includes column enlargements and slurry wall retrofitting. Following this, construction will proceed on the reinforced concrete transfer slab at B3F, and finally, the steel structure will be erected above B3F.
The first phase involves demolishing the steel structure above the first floor. In the second phase, the structure from B3F to the first floor was demolished, while retaining the outer perimeter framing, which served as support for the slurry wall. Some sections of the outer perimeter frame was reinforced to adequately support the slurry wall. The third phase focuses on retrofitting the structure from B4F to B7F, which includes column enlargements and slurry wall retrofitting. Following this, construction will proceed on the reinforced concrete transfer slab at B3F, and finally, the steel structure will be erected above B3F.