The biggest feature of subway top head urban complex is the seamless connection of businesses with the subway, and there are two main types of the connection mode of businesses and the subway: overall construction type and embedded connection type. The overall construction type is the synchronous design and simultaneous construction of the subway and Urban Complex; and the embedded connection type is mainly used in the subway station that has already been built, through the underground passage to combine the subway with the commercial complex perfectly.
In the design of subway top head urban complex, Shanghai Zhongfang Construction Co., Ltd. has always been at the leading place of the industry, with many years of practical experiences in architectural design, it led the design and construction of the first subway top head mega urban complex - Shanghai ASE Center, which has become the most influential subway top head landmark in down town area. Currently in Shanghai Yangpu district, CIFI commercial plaza project which is under construction, is located in Anshan Xincun station of subway line eight, with the subway cutting through the base, the project design has fully considered the relationship between the already completed subway station and architectural space form, so as to achieve the maximization of construction quality and the commercial value.
1 China´s first domestic built mega subway top head urban complex
2 The first complex with overall seamless connection of high-rise buildings and subway in Shanghai region and even the soft soil area.
3 Synchronous design and simultaneous construction of the subway and commercial complex
The project is located at the interchange of Xujiahui Road and No. 2 Ruijin Road, with subway line 9 cutting through the base, Dapuqiao station hall and platform are located in the property. The total construction area is 315,618 square meters: a super high-rise office building with the area of 45,965 square meters, two high-rise SOHOs with the area of 19, 560 and 19,154 square meters respectively, commercial annex 95,739 square meters, underground construction 135,200 square meters, super high-rise office building 145 meters high, SOHO 99.5 meters high, commercial annex 24 meters high, and underground 26.27 meters deep.
People flow organization - as a mega urban complex integrated with the subway, people flow organization is one of the difficulties, while the people flow of the project includes commercial flow, office flow, SOHO flow and subway traffic flow. Therefore, three-dimensional traffic has also become an important feature of this project.
Vehicle flow organization - in order to maximize the commercial value of the project, there is no parking area or waiting area on the ground, all taxies are parked in the designated area of B1, passengers can get off the car and enter the mall directly; general vehicles are parked in B3, people can take the elevator to reach the mall or office building directly; in addition, considering the downtown traffic situation, a specific loading area was also set in B1 for trucks to park temporarily.
Fire safety – the underground construction area of the project has reached 135,200 square meters, which make fire safety a real difficulty for such huge volume of underground commercial buildings. The project has fire compartment through underground commercial street and sunken square, which not only achieved interconnection but also met the fire code requirements. And the subway and the commercial are also separated by firewall, fire shutter and sunken square, to ensure not only the subway safety and independent evacuation system, but also the greatest degree of accessibility to the subway station hall and the commercial.
The project is also the first in Shanghai with full integration of subway and civil buildings, and there come many new problems in the fire protection and utilization safety. Preliminary design study and argumentation had lasted for six months, and was not approved until the Shanghai Fire Bureau made "Provisions of Shanghai Public Building Fire Compartment Fire Protection Design (Provisional)" based on this project, among which relevant chapters of building fire code were also set accordingly.
Uneven settlement - taking into account that the project is the first high-rise top head building complex in Shanghai region and even the soft soil area that has overall seamless connection of the high-rise and the subway, large volume of uneven settlement will seriously affect the safe operation of the subway line, therefore in the design of the pile foundation, pile bearing stratum with smaller settlement was chosen, and post-grouting technology was applied to improve the quality of the pile body, which effectively controlled the absolute settlement of the pile foundation of the super high-rise, and successfully solved the settlement influence on the metro section.
Noise and vibration – also due to the seamless design of the project and the subway station, the subway running will generate vibration and noise that directly influences the commercial value of the project. Therefore, we firstly applied the principles of mechanics, to adjust the mass ratio of subway cars and station, which effectively controlled the vibration and noise influence of the subway operation to the top head buildings; thus no vibration and noise generated by the subway operation, shall be felt in the buildings of underground floor two and above. In addition, rubber shock absorbers were set at both ends of the subway station to further reduce the transmission of noise.
Leakage – the project has a lot of underground space, and how to reduce the impact of leakage on the subway and commercial facilities effectively is indeed a difficulty in the project design. Therefore, we consider not to set permanent settlement joint between the subway station and property basement, which achieved the overall seamless connection of the subway with the property basement, and effectively reduced the probability of leakage, so that the anti-leakage performance of the project was improved several times compared with the regulatory requirements; in addition, we applied waterproof blanket technology of rock wool with expansive soil, and improved the waterproof blanket design nodes, which permanently solved the waterproof problem.
Construction progress – With the large quantities, tight development schedule and numerous coordinating departments of the project, there were only 4 years from the design to the completion of the project. Therefore, some unconventional technical means had to be applied, through the coordination and communication with the construction unit, the project applied a deep foundation excavation construction, through structural partitions, set post-cast strip and construction joint, with block construction, successfully solved the technical difficulty of the synchronous design and simultaneous construction of the subway and the top head buildings.
Economical efficiency - the economical efficiency is not only a key concern of developers, but also our core competencies as a design unit. For the super high-rise building C in this project, we applied steel frame column, compared with ordinary concrete column, steel column has reduced cross-sectional dimensions, increased the effective usable area, and enhanced the spatial effect of the building; with the utilization of new joints for steel reinforced concrete beam column, and spot-cast reinforced concrete floor slab, safety and economic efficiency was effectively ensured.