Mao Jin Tower
Shanghai, China
Eric Bert Kory Krieser Eddie Gebauer Jaime Kurten Mark Ray 12/01/04
The Jin Mao Tower is located in the finance and trade center of Shanghai, China known as Pudong. Situated at the mouth of the Yan'an Dong Lu Tunnel and adjacent to Century Avenue, the tower is easily accessible by tunnel bus, subway line, or personal vehicles (Jin Mao Building). The lack of zoning laws in Shanghai made it easy for developers to get authorization to construct such a large high rise building in the Pudong district. However, zoning laws currently under consideration prevent high-rises from being built side-by-side and limit the ratio of a building's land area to total floor space ratio. The goal of the new restrictions is to prevent further land subsidence and adverse living conditions caused by high construction density (Shanghai). The developer of the Jin Mao Tower was China Jin Mao Group Co. Ltd. The Jin Mao ("much gold" in Chinese) Group, formerly China Shanghai Foreign Trading Center Co. Ltd, is a joint-equity enterprise that was established in 1993. The Jin Mao Group focuses on building and facilities management, hotel management, and tourist and recreational product development (China Jin Mao Group). The tower is a multi-use facility that includes a block of office space, a hotel, restaurants, and an observation deck. Above the lobby is a block of office space that occupies the 3rd through the 50th floors. The column-free office floors have attracted twenty-one fortune 500 companies. The 51st and 52nd floors contain mechanical equipment, followed by the Grand Hyatt Shanghai hotel on the 53rd through 87th floors. The Grand Hyatt Shanghai contains 555 guestrooms, 12 restaurants, a fitness center and extensive conference facilities. On the 88th floor is an observation deck which offers visitors views of Shanghai, as well as the 27 meter wide atrium that rises 152 meters through the center of the hotel. Additionally, there is a 6-story skirt annex to the tower
that houses a theatre, an exhibition hall, a banquet area, and a retail mall (China Jin Mao Group). 1World renowned architectural and structural engineering firm Skidmore, Owings, & Merrill LLP (SOM) based out of Chicago and New York designed the Jin Mao Tower. The Jin Mao Tower was just one of the many tall buildings that SOM has completed over the last 65 years. Since SOM was founded in 1936, they have completed over 10,000 engineering, architectural, and planning projects in more than fifty countries. SOM has established a reputation for building some of the largest buildings in the world, including the tallest building in the United States, the Sears Tower. SOM continues being recognized internationally with the design of the Jin Mao Tower in Shanghai (SOM). The Jin Mao Tower is the centerpiece of the Shanghai skyline. Since it was finished in 1999 it has claimed the title of the "China's tallest building." While China Figure 1. Chinese Pagoda Style Architecture
Figure 2. Vertical columns with Outcropping
continues to move forward in a wave of modernism, the Jin Mao Tower maintains the traditional Chinese pagoda style architecture as seen in Figure 1. The traditional upward sloping roofs and telescoping tiers were included in the design of the Jin Mao. The tower contains rigid vertical columns broken up by the pagoda-like outcropping (Figure 2). Other exterior architectural features include stainless steel mullions that were used mainly as a structural component but placed throughout the building to provide a visual continuity that was aesthetically pleasing to the common eye (Figure 3). Figure 3. Stainless steel mullions provide visual continuity for the building
Figure 4. Canopy lighting system At the entrance pavilion, steel planes are used to counterpoint the glass mullions as well as provide shade to the glass surfaces of the building. Steel and glass were two of the most prominent materials considered during the design of the Jin Mao Tower. One example of the blending of the materials throughout the building is the canopy lighting system that was created using geometric elements of steel and glass (Figure 4). Structural rods support the weight
Figure 5. Double helix staircase in the atrium
of the large glass and steel canopy that is displayed at the entrance of the Visitor's Center (Figure 6) (Londt). The interior of the Jin Mao is as magnificent as the glass and steel used on the exterior. Upon entering the five-story Visitor's Center, a double helix staircase with structural glass treads awaits the visitors as a main focal point in the entry way (Figure 5). The interior contains one of the tallest atriums in the world, extending 34 floors (Emporis). Skidmore, Owings & Merrill also served as the structural engineering firmed that designed the Jin Mao Tower. SOM is based out of Chicago and New York but is a major international company with other offices around the world. Because of the Jin Mao Tower's geographic location, it had to be designed to withstand the strongest level typhoon as well as an earthquake with a rating of six on the Richter scale. Figure 6. Structural rods supporting the glass and steel canopy
The structural system of the Jin Mao Tower is comprised of a high-strength reinforced concrete core surrounded by eight composite perimeter mega columns that are up to 5 feet by 16 feet in dimension. The mega columns are used to frame the entrances to the tower at the lobby level. The core webs were removed to open up the interior of the building and permit the open atrium to extend from the 53rd floor to the 87th floor. The mega
Figure 7. The hotel pool on the 57th floor also serves as a critical dampener
columns and core webs are linked by two-story deep steel outrigger trusses at three levels, acting in composite with horizontal diaphragm slabs. Lateral loads are distributed between the core and the exterior mega columns by a steel cap truss located at the top of the tower. The pool on the 57th floor (Figure 7) also absorbs lateral loads by acting as a critical dampener. The gravity loads are carried by the eight built-up steel mega-columns along the perimeter. The building is designed around the Chinese lucky number eight, which is considered to be lucky because it corresponds to the age of Deng Xiaoping, a legendary Chinese leader, when he died. In addition to being eighty-eight stories tall, the building was dedicated on August 28, 1998. The core is shaped like an octagon and the piles are capped with a 13-foot thick reinforced concrete mat that is shaped like an octagon. There are eight perimeter composite mega columns and also eight built-up steel perimeter columns. This structural system is linked by eight outrigger trusses. The first elevation is 16 stories (sixteen being a multiple of eight) and the elevation of each subsequent setback level is another eighth shorter than this first elevation. The members that frame the floor system are even based on multiples of eight. The general contractor on the Jin Mao building was the Shanghai Jian Gong Group. Construction began in June of 1994 and was opened in March of 1999 for a total cost of around $540 USD. Throughout the project the construction team was faced with difficult problems involving extremely deep foundations, erection of the steel and concrete structures at large heights as well as site coordination and management. The Jian Gong Group was able to overcome these problems and successfully completed the world's 4th largest skyscraper.
The Jin Mao Tower site had poor upper-strata soil conditions that caused a massive foundation to be constructed by combining high-capacity piles supporting a reinforced concrete mat. On the 23,000 square meter site 429 high capacity stele piles, 914 millimeters in diameter, were driven 83 meters deep. The foundation area was 19,600 square meters with a tower block of 19.65 meters and an annex block of 15.5 meters constructed in this space. Almost 320,000 cubic meters of soil was excavated from the site. In order to control and stabilize the construction process a 40-meters-deep slurry wall was constructed to act as an excavation retention system. The foundation plate that sat on the deep foundations was constructed of 13,600 cubic meters of C50 grade concrete poured four meters thick. Tests and statistical analyses were completed on the concrete to make sure the pour was high quality so that cracks would be prevented from forming in the foundation plate. In order to construct the framework tube structure, the core tube in the center was made of octagonal reinforced concrete. Reducing the weight of the building was also a challenge; cruciform-shaped cores with hollow centers were used below the 53rd floor. The formwork was separated from the concrete, moved up to the next section, and reused. This construction method allowed for high speed construction of up to thirteen stories of reinforced concrete core tube completed each month. The 1,000 to 1,600 ton extended frame girders were set between the pillars and core tube on levels 24 to 26, 51 to 53 and 85 to 87. girders The had to be installed piece by piece due to their weight and because they supported the reinforced concrete core tube while it cured. Various theories and advanced technologies were used to meet the design requirements for the project.
Maintaining the time schedule was accomplished bye speeding up construction to complete the last 3.2 meters of reinforced core tube in two days. The Jin Mao Building main tower and annex block contain 18,000 tons of structural steel. The heaviest single piece of equipment weighed in at twenty tons. Construction of the Jin Mao Building required almost 10,000 cubic meters of concrete to be poured above 300 meters, usually the C50 grade concrete can only be carried up to 260 meters. Through intense observation and quality control methods the C40 grade concrete was lifted up 382.5 meters resulting in a mainland China construction method record. Site management was a crucial issue in completing the building on time. Due to its complicated structure the Jin Mao Building has a very technical electrical system. The large atrium required the inside and outside decoration had to be completed simultaneously because the inside ornament could not be installed after the building envelop was closed up. This requirement drastically limited the time and space of construction. Pre-construction design planning and cooperative planning management was required by the conditions of the contract to resolve any coordination problems between contractors. The binding conditions of the contract made teamwork compulsory and allowed for a smooth construction process with a high level of quality control. CECELEC was the electrical engineering firm that provided expertise on the systems in the Jin Mao building. The Jin Mao building is the only major tall building that CECELEC has worked on ("CECELEC France", Emporis). The lighting contractor was Thorn Light and similar to CECELEC, the Jin Mao building is their only major tall building project ("Thorn Light", Emporis). Thorn Light was started in 1928 by Jules
Thorn and in 1948 it was the first company in Europe to mass produce fluorescent tubes (Thorn Light). Transportation systems in the Jin Mao building was developed by Edgett Williams Consulting Group, Inc ("Edgett Williams Consulting Group, Inc", Emporis). Edgett Williams Consulting Group, Inc., founded 1986, has a lot of expertise in all types of building transportation systems with experience on over 700 projects throughout the world ("About Us", Edgett Williams Consulting Group, Inc.). Mitsubishi Elevator and Escalator installed the elevators and escalators. Mitsubishi Elevator and Escalator has done work in 69 high rise buildings throughout the world. Manntech Fassadenbefahrsysteme GmbH provided the facade maintenance system that is used to clean and repair the outside of the building. They have done work on 86 buildings world wide and have systems for buildings up to 450 meters tall ("Manntech Fassadenbefahrsysteme GmbH", Emporis). Facade maintenance is critical on the Jin Mao building because the owners strive to keep energy costs as low as possible. To do this the building must be kept as tight as possible so as not to loose any conditioned air to the outside. Moving people in the Jin Mao building is done using sixty elevators and eighteen escaladers. Two high speed elevators transport visitors to the sightseeing level on the 88th floor. These elevators only take 45 seconds to move 35 people from the 1st floor to the 88th floor. The building's high speed elevators move at 540 meters per minute (9.1 meters per second) and have a capacity of 2,500kg (Mitsubishi-Elevator). Since the city of Shanghai has over 3,500 buildings that are more than eight stories tall and 1,500 buildings that are over twenty stories tall, high rise fire safety is a
major concern. The challenge in pumping water up to a fire in a high rise building makes rescue efforts very difficult. The only way to successfully manage a fire, in a short amount of time, on a high floor is to make sure that the fire-fighting equipment existing in the building is of good quality and durability. According to building code, high rise buildings must contain safety exits as well as sprinkler systems. Shanghai fire squadrons are trained so that they can reach higher floors in a limited amount of time. To prepare firefighters for the possibility of a fire in the Jin Mao Tower, the building has three drills a month in which the "fire" is scheduled on an upper level floor. The firefighters are required to be able to reach the 20th floor in 80 seconds carrying a weight of 10 kilograms. These training sessions allows the firefighters to fulfill their training requirement for speed and also practice maneuvering to put out a fire on an upper level floor. The fire squadrons are not the only ones responsible for fire safety in high rise buildings. The building occupants are responsible for preventing fires by using basic safety precautions as well as knowing how to use fire extinguishers and evacuate the building if the need arises. Buildings in China are designed with more of a focus on people getting out by themselves during an emergency than being rescued by emergency personal. To aid in evacuation, the Grand Hyatt Hotel has twinkling lights in the hallway to lead occupants to exits and refuge areas with better ventilation. The exits go straight to the ground fl...