Structural Design of Mongol and Yuan Culture Museum
Major Designers: Zhang Huaiyong, Wang Qi, Zhu Bingyin, Wang Shule, Liu Wei, He Xiangyu, Lin Tao, Xi Zhigang, Cao Qing
The Project is the world’s largest building block of Mongol and Yuan culture museum. It is located in the central area of new district of Xilinhaote City, connects with the railway station and airport on its west, neighbors the city proper on its east, adjoins the flat grassland on its south and is opposite to the new district on its north. The building block of Mongol and Yuan Culture Museum has gross floor area of 48,880 ㎡, consisting of three functions blocks: museum, folk custom hall and folk custom culture theatre. Its functions include museum, folk custom hall, culture theatre, meeting center, dining hall, hotel, office, etc.
In the museum locally, there is a basement of one floor, mainly serves as cultural relics storage and various equipment rooms. On the ground, it is roughly divided into three floors, mainly functioning for office and exhibition. Its building height is 23.400m, and floor area 21,153 ㎡. In the folk custom culture theatre locally, there is a basement of one floor, mainly serves as make-up room, prop room, office and various equipment rooms. On the ground, it is roughly divided into four floors, mainly functioning for theatre, food & beverage, coffee bar and hotel. Its building height is 20.250m, and floor area 16,093㎡. The folk custom hall is semi-circle one-floor building block, on which there are mainly folk custom exhibition hall and conference center. On its top is sightseeing stand. Its floor area is 5,642㎡. The building block is 450m long on the whole.
Model of structural design and major structural members
Structural type and seismic-resistance grade:
The museum is of framework – seismic-resistance wall structure. Its seismic-resistance grade is: Grade II for framework and Grade II for seismic-resistance wall. The culture theatre is framework – seismic-resistance wall structure. Its seismic-resistance grade is: Grade III for framework and Grade II for seismic-resistance wall. The folk custom hall is framework structure, and its seismic-resistance grade is Grade III.
The ground structural layout of the culture theatre is indicated in Fig.3. It can be seen from the figure that, difficulty rests with how to deal with the stand and box seats on the second floor. The stand has a transverse span of 27m. In the design, 600x1700 bonded prestressed beam is employed, and upper end is made to extend within the two end spans as far as possible. For box seats, cantilever beam is mainly used. Typical fabrication of cantilever beam is illustrated in Fig.3.
The layout of the museum’s underground structure is shown in Fig.4. Its planer size is 100x100m. In the #-shaped beam on the four corners, the largest span is 26m, the section is 600x1500. In the plane of inner circle, the cantilever length of the beam is 7.2m, and section of cantilever beam is 300x900. In the design, post-tensioned prestress is adopted for large span beam and cantilever beam, so as to control its deflection and crack within the requirements of criteria. The section of the Project is demonstrated in Fig.5. For the three inclined components, their angles of inclination are 150 and 200 respectively. Since it is not allowed to make columns protrude from walls in the building, concrete wall 400mm thick is used for the three inclined components in view of larger additional bending moment outside the plane and larger section of planar beam.
Measures to deal with super-long exposed structure in extreme cold area
1) Six seismic-resistance joints are made in the plane, of which locations are shown in Fig.2; 2) One post-poured strip is added for every 30~50m; 3) Additives with good performance is selected; 4) Floor slab reinforcement is properly added, and upper iron is connected, no smaller than Ф12@200 in two floors and two ways; 5) Fibre concrete is used: for too protruded and exposed floor slab, propylene fibre is mixed in the concrete; 6) Prestress is applied on some floor slabs: three bundles of 1Φs15 non-bonded prestressed tendons of Grade 1860 are placed each meter, with stretch-draw stress controlled at 0.75fptk; 7) Thermal insulation measures are required from architecture profession.
Durability requirements for Class I environmental concrete for buildings with designed service life of 100 years:
1) Maximum chloride ion content in concrete is 0.06%; 2) When alkali-active aggregate is used, maximum alkali content in concrete is 3.0kg/m3; 3) Thickness of protective layer of concrete is increased by 40% beyond normal requirements.
Durability requirements for Class IIb environmental concrete for buildings with designed service life of 100 years:
1) All four requirements shall be met; 2) Grade of concrete strength is increased, with C40 to be used for foundation and the upper; 3) Maximum ratio between water and cement in concrete is 0.50; 3) Liquid anti-rust agent is added in concrete.
According to the survey report offered by Architectural Survey Planning and Design Institute of Xilingol League, the Project adopts column-beneath independent foundation and wall-beneath stripe foundation. For the portion with basement, independent column foundation, wall-beneath stripe foundation plus waterproof board are used, and load-bearing stratum is ③1 layer (fine sand).
Anti-floating water level of the Project is ±0.00. Loads on the upper can not resist floating force of water in the portion with basement, so in the design, borehole poured pole at a diameter of 400mm and at a length of 12m serves as tension pole to resist floating force. According to the data contained in the survey report, standard value of limit side resistance of pole is 50Kpa for medium and fine sand.