Office building in Shanghai (T2 Tower)

Tongji University – China

Office building in Shanghai (T2 Tower)

Building use

Office building

Country/Region

All Regions

Overview

C80 SRC columns were adopted to reduce component size and improve bearing capacity.

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

Construction date: 2023
Number of stories: 70
Gross floor area: 240,575m2
Adopted design code: –
Engineer(s): Arup
Contractor(s): Shanghai Construction Group

Issue and/or innovation

The tower is equipped with viscous dampers as energy dissipation and vibration reduction measures. At the same time, due to the adoption of the viscous damper scheme, the overall ductility performance of the tower’s vertical components during large earthquake elastic-plastic analysis is ensured. The tower’s frame columns are further equipped with C80 high-strength concrete to reduce the vertical dimension and steel content.

Reason for composite solution

To reduce component size and improve bearing capacity.

Specific solution/technical details

In order to achieve the rationality, economy, and safety of the structural design of the T2 Tower, after several project consultations and demonstrations, the T2 Tower has finally decided to adopt energy dissipation and vibration reduction technology to achieve a ductile design. For energy dissipation and damping schemes, in the early stage, we analyzed and compared three energy dissipation and damping schemes using buckling constrained support, coupling beam damper, and viscous damper. The buckling constrained support scheme is to replace the waist truss diagonal bar with buckling constrained support, while the coupling beam damper scheme is to replace the coupling beam with a shear type energy dissipation damper along the full height of the tower, and the viscous damper scheme is to arrange viscous dampers in the refuge floor. The results of scheme comparison and analysis indicate that the buckling constrained brace and coupling beam damper schemes have poor seismic mitigation effects, so the viscous damper scheme was ultimately adopted. The specific seismic mitigation goal is to add a damping ratio of 1% to 2% for frequent earthquakes, and the damper output is controlled at 1000 KN. At the same time, through the installation of dampers, the overall performance of the tower under rare earthquakes has been improved. Except for a small number of columns at the top that are partially plastic, the rest of the frame columns are elastic, The number of outer frame beams entering the IO stage decreased from 42 to 36, and the proportion of coupling beams entering the IO stage decreased from 70% to 58%. The coupling beams basically did not enter the CP stage.

Impact or effectiveness

The damper adds a damping ratio of 2% to the tower under frequent earthquakes, with a damping force of about 50% under frequent earthquakes and a damping force of about 100%~110% under large earthquakes. The base shear force and displacement angle of frequent earthquakes are reduced by 10%, reducing the damage ratio of components under large earthquakes, and ensuring the ductility of the tower, making the application of high-strength concrete maximize its advantages. Based on the reduction of seismic response and the use of high-strength concrete, the section of the vertical components of the tower can be reduced by about 18%, and the steel content in the vertical components can also be reduced accordingly, improving the occupancy rate and economy of the tower. By adopt composite components, utilize high strength of the steel, the member size can be outstandling reduced. Also SRC column is friendly in connection with steel beam, and no fire coating concern since SRC has nature fire-proof character.

References / Technical Papers Content

Ke, X. G. 2020. “Analysis and Reinforcement of Core Tube Structure of Xujiahui Center T2 Tower Under out of Plane Horizontal Load” J. Proceedings of the Twenty-sixth East China Six Provinces Civil Engineering and Construction Engineering and Technology Exchange Conference. 946-949. 10.26914/c.cnkihy.2020.021368