Qianhai Shimao Financial Center Project is planned by Gensler and the construction drawing is designed by Shenzhen Zhubo. FORCITIS is the facade consultant of the whole process, and the facade is contracted by Jiangho.

There are two plans in conceptual design of architecture. The owner chose a harmonious & conceptual design with a rotation angle of 60°. Externally, the two volumes are independent but closely intertwined, symbolizing the interaction, cooperation and harmony between Hong Kong and the mainland. In the later stage, FORCITIS cooperated with the owner to deepen the study on the scheme from more perspectives. Finally, the owner considered many factors such as architectural effect, structural system and realization effect to determine the optimal scheme with a rotation of angle of 45°. In addition, as the project is a super high-rise building, it is impossible to avoid the problem of aviation height limit, and the final height is reduced from 330m to 295m.

During the design, the architect wants to achieve a smooth and glossy skin effect. Thus, the project team studied the facade partition with division and fixed distance, and issued relevant reports. In addition, by studying the skin profile of the project, that is, to achieve a rotation of about 0.6136° per layer, a total twist of 45°, and an equal rotation angle per meter at height. Through comparison and selection of circular arc parts, the scheme of breaking line fitting is adopted. After comprehensive consideration, the principle of grid division is finally determined, as shown in the following figure:

Curved surface analysis and construction verification

During the study of skin division, we try to set out the facade system. If the keel is interfered with, it is necessary to analyze the curved surface and find the law. After curved surface analysis, it is found that the maximum warpage value of four points is about 22mm, and most of them are within 18mm. After the analysis, the stress is mostly distributed in the corner of cold-formed glass, and the size is less than 2MPa.

Comparison of system solutions:：

Finite element simulation analysis:

Regardless of any method is adopted, the glass needs to be cold-bent, which will also have a certain impact on the profile. According to the most unfavorable situations, the team carried out a large number of finite element analyses, considering the internal stress, strain and displacement analysis of glass and profiles caused by warping cold bending, and found that the stress of cold bending has little influence, which is theoretically feasible.

After theoretical analysis, the team also benchmarked the project with similar cases. The actual data of a project is shown in the figure below.

After theoretical demonstration and project benchmarking, the laboratory demonstration was carried out in the follow-up. At the beginning of 2015, the unit was cold-drawn in the test room with the cooperation of Yuanda. It is proved that when the unit is bent by cold-drawing, the ordinary unit is normal, and the waterproof function is not affected. However, after cold bending, the horizontally pivoted window cannot be opened normally, and after opening, it cannot be closed normally.

According to the integrated study and judgment of the project team, the warpage value of cold-formed glass is within L/60, which is basically the same with that of flat glass.

Analysis of structure and joint design

△Partial joint construction

△Joint at arc

△Joint of opened window

BMU design and implementation

BMU design is also one of the huge problems faced by the project: Architects disagree with the installation of BMU on the roof, and think that it will affect the effect; Due to large torsion angle of building, if BMU is set in the middle position, how to deal with the cramped refuge floor; How does the BMU suspended working platform work on the twisted facade and how does the suspended working platform walk? Is there any special design for the windproof pin? All these are a series of difficulties encountered in the project.

In the early stage, a lot of study and analysis were carried out to persuade architects to accept the installation of BMU on the roof, but to ensure that the BMU track does not protrude from the inclined plane of the roof. Subsequently, we persuaded the owner to accept the installation of BMU on the refuge floor. As shown in the figure below, with the countless times of coordination with electromechanical discipline, the space of the refuge floor is almost used to the extreme extent.

Two sets of BMUs with folding arms are set on the 33rd floor of refuge floor, eight BMUs with outriggers are set on the 11th, 22nd, 44th and 55th floors, and two oblique climbing track BMUs are set on the roof, which are adjusted from the original connecting track to the run-through track, greatly improving the safety and finally solving all related problems.