#1 and #2 Research & Development Building of CS & S Sci-Tech Park in Changping
Location of the site: In CS & S Changping Sci-Tech Park, Huazhuang Village, on the southeast of Changping District, Beijing
Time of design: February 2003
Date of completion: December 2004
Major Designers: Bi Lei Zhang Haibo Liu Songhua You Tianzhi
Architectural function: office
Gross floor area is 30,000㎡
Number of floors: one underground floor and six floors on the ground
Building height: 24m
Designed seismic-resistance intensity: Richter scale 8
Scheme of foundation base: natural foundation base, cast-in-place concrete flat-slab raft foundation
Structural type selection and design points:
1)With complicated architectural layout, the building is irregular horizontally and vertically. Two seismic-resistant joints above the ground divide the principal structure into #1 building, #2 building and connecting corridor between the two buildings, which are lateral force-resistance structural units of which architectural plane is relatively regular, so as to improve the seismic-resistance performance of the structure and reduce adverse effect caused by irregularity of the buildings. Cast-in-place reinforced concrete frame structure is adopted to bear vertical load and resistant planar force.
2)For floor cover structure, cast-in-place reinforced concrete beam and slab structure is used.
3)Sand cushion layer is laid on the foundation bottom, which serves to properly increase the thickness of foundation baseplate and reinforcement ratio. On the juncture of principal structure and pure underground structure, construction post-poured stripe is installed, located on the underground structure, which serves to adjust uneven settlement of the two, and meanwhile properly reinforce structural integrity. After the structure top is covered and settlement of foundation is substantially stabilized, the post-poured stripe is supplemented by slightly expanded concrete the strength of which is one grade above that of the concrete used on corresponding structural position.
Adoption of new material, technology and process:
The architectural plane of the Project is of considerably large dimension, so the following measures are taken to diminish the adverse effect on the structure by concrete shrinkage and temperature stress caused by super-long building.
1)Thermal insulation measures are emphasized on the exterior of the building, the roof in particular, so as to minimize severe change of temperature and structural temperature stress. Constructional reinforcement ratio of each floor slab is properly increased (controlled at 0.3% or so). On key positions (e.g., roof), dual-layer and two-way through reinforcement is used to resist the influence of temperature stress.
2)For raw material of concrete, cement of low shrinkage and low heat of hydration is used so as to improve the quality of aggregate and diminish concrete shrinkage and heat of hydration of cement. In the concrete used in foundation baseplate and exterior wall of basement, proper quantity of waterproof agent is mixed, in the meantime, the variety, quality and dosage of concrete additive are put in strict control.
3)Construction post-poured stripe is placed so as to partially eliminate the adverse effect on the structure caused by concrete shrinkage and temperature stress. Two months after the pouring of the concrete of structural components on its two sides, the post-poured stripe is supplemented by slightly expanded concrete the strength of which is one grade above that of the concrete used on corresponding structural position. In the construction of concrete, it is vibrated twice in an effort to control pouring time and temperature, decrease final-setting temperature, and enhance concrete curing, especially high-humidity curing to be adopted in the early period.