1 General Provisions
1.0.1 This standard was formulated to implement the guideline on prevention first in seismic operation, lighten the seismic destructiveness of the prestressed concrete building structures after the seismic protection, avoid the casualties and reduce the economic loss.
1.0.2 This standard is applicable to the seismic design of such building structures as the cast-in-situ post-tensioned prestressed concrete frame and slab-column in the areas with seismic protection intensity of 6~8 magnitude; however, the seismic design of the prestressed concrete structures in the areas with seismic protection intensity of 9 magnitude shall be with full references and adopted with reliable measures.
1.0.3 The seismic design of the prestressed concrete building structure shall not only comply with this standard, but also shall comply with those specified in the current relevant national compulsory standards.
2 Terms and Symbols
2.1 Terms
2.1.1 Damping ratio
It is the ratio of the actual resistance of damped vibration and the resistance required for generating the critical damping.
2.1.2 It is the ratio of axial compressive force to axial compressive ultimate capacity of section under combination of earthquake action
It is the ratio between the design value of the axial pressure of concrete column under the combination of the earthquake action and the arithmetic product of the bulk cross-section area of column with the design value of concrete compressive strength; as for the prestressed concrete column, it shall be taken as the design axial force value of the combination in which the prestress action participates.
2.1.3 Post-tensioned bonded prestressed concrete structure
It is the bonded concrete structure by stretching and anchoring the prestressed reinforcements to establish prestress after the concrete has been hardened, and then grouting in the pipe, for instance, prestressed concrete frame and portal.
2.1.4 Unbonded prestressed concrete structure
It is the post-stressed concrete structure that is allocated with such prestressed reinforcements with paint coat and cladding but does not bond with concrete.
2.2 Symbols
2.2.1 Material properties
fc——the design value of concrete compressive strength;
f1——the design value of the axial tensile strength of concrete;
fy, ——the design values of the tensile and compressive strength of regular reinforcement;
fpy——the design value of the tensile strength of prestressed reinforcement;
fyv——the design value of the tensile strength of hooped reinforcement.
2.2.2 Actions and effects
N——the design value of the axial pressure of column under the combination of earthquake action;
V——the design value of the shear force under the combination of earthquake action;
Npe——the total effective pre-applied force of the prestressed reinforcements.
2.2.3 Geometric parameters
Aa, ——the cross-sectional area of nonprestressed reinforcements in tensile region and compressive region;
Ap——the cross-sectional area of prestressed reinforcements in tensile region;
Asvj——the total cross-sectional area of the hooped reinforcements in one same sectional recalculation direction within the effective recalculation width of the core area;
b——the width of rectangular section, and the width of the web plate of T-shape and I-shape sections.
h——the height of the section;
ho——the effective height of the section;
hp——the effective distance from the point of force concurrence of the longitudinal tensioned prestressed reinforcements to the compression flange of the section of girder;
hδ——the effective distance from the point of force concurrence of the longitudinal tensioned nonprestressed reinforcements to the compression flange of the section of girder;
bc, hc——the width and height of column section;
bj, hj——the effective recalculating width and height of the section in the core area of node;
bd——the effective width of flat backing plate;
lo——the theoretical span;
x——the height of the compressive region of concrete;
laE——the minimum anchorage length of longitudinal tension reinforcement with the consideration of antiseismic requirement;
s——the space between hooped reinforcements;
2.2.4 Calculation factors and others
α——the value of the horizontal seismic influence factor;
αmax——the maximum value of the horizontal seismic influence factor;
γp——the partial safety factor of prestress;
γRE——the antiseismic adjustment factor of the bearing capacity;
εapu——the total strain of prestressed reinforcement-anchorage assembly parts when they reach the actual ultimate tension.
ηa——the efficiency factor of anchorage device measured in the static test of prestressed reinforcement-anchorage assembly parts;
λ——the strength ratio of prestress;
βc——the influence factor of concrete strength;
ρ——the reinforcement ratio of longitudinal tension reinforcements;
ηj——the restraining influence factor of perpendicular girders;
λNp——the axial compression ratio of the prestressed concrete column.
T——the natural vibration period of structure;
Tg——the eigenperiod of the site.
3 General Provisions of Seismic Design
3.1 Earthquake Action and Structural Seismic Checking
3.1.1 The seismic influence factor of the building structures shall be determined according to the intensity, site category, design earthquake classification and the natural vibration period of structure as well as the damping ratio. And the maximum value of the horizontal seismic influence factor shall be adopted in accordance with those specified in Table 3.1.1-1; the eigenperiod shall be adopted accord
1 General Provisions
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 General Provisions of Seismic Design
3.1 Earthquake Action and Structural Seismic Checking
3.2 General Provisions of Design
3.3 Materials and Anchorage Devices
4 Prestressed Concrete Frame and Portal
4.1 General Provisions
4.2 Prestressed Concrete Frame-beam
4.3 Prestressed Concrete Frame Frame-column
4.4 Joint of Prestressed Concrete Frame
4.5 Prestressed Concrete Portal Structure
5 Prestressed Concrete Slab-column Structure
5.1 General Provisions of Design
5.2 Calculation Requirements
Explanation of Wording in this Standard
