Office building in Shenzhen (China Merchants Taiziwan Building)

default

Tongji University – China

Office building in Shenzhen (China Merchants Taiziwan Building)

Building use

Office building

Country/Region

China

Overview

The tower adopts a frame-core tube structure system. Combined with the functional requirements, 8 mega columns are set in the outer frame of the office area, and 16 pillars are set in the outer frame of the hotel area. Combined with the equipment layer, set up 3 ring trusses to strengthen the lateral stiffness of the structure.

Basic information (construction date, number of stories, gross floor area, adopted design code, engineer(s), Contractor(s), etc.)

Construction date: 2022
Number of stories: 60
Gross floor area: 132,000m2
Adopted design code: GB 50009-2012; GB 50011-2010 (2016 Edition); GB 50017-2017; JGJ 138 -2016; JGJ 99 -2015; GB 51249-2017
Engineer(s): East China Architectural Design and Research Institute Co., Ltd.
Contractor(s): Southern China Office of China Construction Second Engineering Bureau Co., Ltd

Issue and/or innovation

This project employs the mega frame-core tube structure system. As an important part of the mega frame, the mega column has the characteristics of large cross section and high bearing capacity. According to the current structural design code, it is recommended that the solid-web steel is used in the internal steel of SRC mega columns, but the measure has the following shortcomings:
1. A high steel ratio of the cross section;
2. Web-opening stirrups weaken the steel section, and the construction is difficult ;
3. Steel sizes in transportations and the weight as lifting are limited, so steel segmentations are required;
4. The on-site welding splicing amount is large, welding deformation and welding stress is not easy to control ;
5. A low construction efficiency, quality problems and the long construction period ;
6. In an irregular plane layout, the joint structure of mega column connecting outrigger, ring truss, diagonal bracing and other mega components is complex.
7. There is no clear calculation formula for the arrangement of studs, and the situation is not rare;
8. The size of a single internal steel is large, and the steel column plate separates the concrete in the column section, which affects the quality of concrete pouring ;
9. The position of beam-column joints needs a horizontal partition, and the range covered by the partition is large. The partition needs to open pouring holes, air holes or flowing holes, etc., which weakens the joints greatly and still has a certain impact on the quality of concrete pouring.
The above problems can be effectively solved or alleviated by using separated steel in the mega column.

Reason for composite solution

China Merchants Taiziwan Building is located in Shenzhen, Guangdong Province, China. The project consists of a 380-meter-tall tower and commercial podium. Among them, the tower is 60 floors above the ground and 5 floors below the ground. The building provides offices (below floor 34) and hotel rooms (above floor 34). The tower adopts a frame-core tube structure system. Combined with the functional requirements, 8 mega columns are set in the outer frame of the office area, and 16 pillars are set in the outer frame of the hotel area. Combined with the equipment layer, set up 3 ring trusses to strengthen the lateral stiffness of the structure. The ring truss between the office area and the hotel area is also a conversion truss. The above-ground part of the tower building weighs about 250,000 ton, which is fairly heavy; Shenzhen is in a high wind pressure area, the basic wind pressure of 50-year return period is 0.75 kN/㎡, and the project is at the seaside, which has a large wind load, that is, the base shear under the wind load is close to 2 times that of minor earthquake state. In order to meet the requirements of bearing capacity and lateral stiffness of the structure under vertical and horizontal loads, and to reduce the weight of the structure and improve the utilization rate of the building area, steel is embedded in the vertical components such as 8 mega columns, 16 outer pillars and core tube shear walls, which are steel reinforced concrete (SRC) composite members. The floor structure outside the core tube adopts steel-concrete composite floor structure, and the floor slab is steel truss floor slab.

Specific solution/technical details

According to the accumulation of scientific research results of the design team in the composite structure and the stress characteristics of mega columns in this project, mega columns are proposed to adopt the separated steel, which solves the problems of the solid-web steel SRC column alongside ensuring the reasonable stress of the building structure. This project will be the first super high-rise building in China to adopt separated steel SRC mega columns. The size of the bottom member is 2.4mx2.6m, and two separated steel ribs are buried. Through the scale test and finite element theoretical analysis of the separated steel SRC mega column, the mechanical performance of the component is verified. The purpose of the scale test is to verify the stress state and failure mode of the separated steel reinforced mega column. The bearing capacity of the separated steel reinforced mega column under cyclic loading is studied, including the plastic development and stress redistribution of the joint under cyclic loading, and the deformation of the joint domain. The test results are compared with the finite element analysis of the specimen to verify the results of the finite element model, and the parametric analysis is carried out based on the finite element model. The beam-column joints of typical positions were selected in the scale test. The cross section of columns were divided into single steel-reinforced columns, two separated steel-reinforced columns and three separated steel-reinforced columns according to the same steel ratio. The performance of separated steel-reinforced columns and ordinary steel-reinforced columns was compared by comparing the joint tests of three different types of column sections. The test adopts the quasi-static test method, and the reciprocating load is applied step by step on both sides of the beam. In the force loading stage, the vertical force is applied on the beam until the beam section yields under the axial force condition of the service condition. Finally, the vertical load of the column is continued to be applied until the specimen is destroyed.

Impact or effectiveness

The results show that the ultimate bearing capacity and ductility index of the separated steel reinforced concrete column are not significantly different from those of the solid steel reinforced concrete column, but the ultimate lateral deformation capacity of the separated steel reinforced concrete column is weaker than that of the solid steel reinforced concrete column. The ultimate bearing capacity and deformation capacity of the separated steel reinforced concrete column can meet the bearing capacity and deformation requirements of the practical engineering mega column under the action of major earthquakes. The steel ratio has an effect on the ultimate bearing capacity and deformation capacity of the mega column, but the effect is not significant. Larger axial compression ratio will significantly control the bearing capacity and deformation capacity of mega columns. High strength concrete can improve not only the ultimate bearing capacity of separated steel reinforced concrete columns, but also their lateral deformation capacity. The selection of concrete compressive strength and steel strength should be matched, so that the two can play their rightful material properties ; the construction of shear studs should guarantee the collaborative work of steel and concrete. The design methods of bearing capacity and structure of separated steel can refer to solid-web steel mega columns, and can meet the requirements of engineering design and construction. The use of separated mega columns reduces the amount of on-site welding and construction period, while achieving structural functions and making joint construction uncomplicated.