1 General Provisions
1.0.1 This Specification is prepared to apply and develop the steel reinforced concrete composite structure in construction engineering appropriately, by using advanced technology, making the structure safe and reliable, economic and rational and finally realizing a guaranteed quality.
1.0.2 This Specification applies to the design and construction of steel reinforced concrete composite structure for multi-storey building and high-rise buildings and general structure at nonseismic region and those with No.6~No.9 seismic precautionary intensity. The steel reinforced concrete composite structure member shall consist of concrete, profile steel, longitudinal rebar and stirrup.
1.0.3 The design and construction of steel reinforced concrete composite structure shall not only meet this Specification but the national current mandatory standards.
2 Terms and Symbols
2.1.1 Steel Reinforced Concrete Composite Structures
Structures which allocate (rolling or welding forming) profile steel and rebar in the concrete.
2.2.1 Material performance
Ec——Elastic modulus of concrete;
Es——Elastic modulus of rebar;
Ea——Elastic modulus of profile steel;
fck, fc——Normal value and design value of compressive strength of concrete axis;
fy, fy——Design values for the tensile and compressive strength of rebar;
fyv——Design values for the tensile strength of stirrup;
fyk, ——Normal values for tensile and compressive strength of rebar;
fa, ——Design values for tensile and compressive strength of profile steel;
fak, ——Normal values for tensile and compressive strength of profile steel.
2.2.2 Action and effect
N——Design value for axial force;
M——Design value of bending moment;
V——Design value of shear force;
σs, σs'——Tensile and compressive stresses of longitudinal rebar in normal section bearing capacity calculation;
σa, ——Tensile and compressive stresses of profile steel flange in normal section bearing capacity calculation;
ωmax——Maximum fracture width of steel reinforced concrete frame beam.
2.2.3 Geometric parameters
αs, ——Distance of resultant points on longitudinal tensile rebars and longitudinal compressive bars each to the proximal edge of concrete section;
αa, αa'——Distance of section gravity center on profile steel tensile flange and profile steel compressive flange each to the proximal edge of concrete section;
b——Concrete section width;
h——Concrete section height;
h0——Distance of resultant points on profile steel tensile flange and longitudinal tensile rebar to the proximal edge of concrete section;
h0s, h0f——Distance of section gravity center on longitudinal tensile rebar tensile flange and profile steel tensile flange each to the compressive edge of concrete section;
ha——Profile steel section height;
bf——Profile steel flange width;
tf——Profile steel flange thickness;
hw——Profile steel web height;
tw——Profile steel web thickness;
e——Distance between action point at axial force and tensile flange resultant point of longitudinal tensile rebar and profile steel;
e0——Eccentricity of axial force against section gravity center, e0=M/N;
x——Height of the compressive area of concrete;
c——Thickness of concrete protective cover;
Ac, Aa, As, , , , ——Areas of total section for concrete, profile steel, tensile rebar, compressive rebar, profile steel tensile flange, profile steel compressive flange and profile steel web section;
Bs——Short-term rigidity on steel reinforced concrete frame beam section;
Bl——Long-term rigidity on steel reinforced concrete frame beam section;
Ic——Inertia moment of concrete section;
Ia——Inertia moment of profile steel section.
2.2.4 Calculation coefficient and others
η——Amplification coefficient for axial force eccentricity when deflection influence is considered in eccentric compressive member;
ξ——Height of relative compressive area of concrete, ξ=x/h0;
ρs, ——The reinforcement ratios of longitudinal tensile rebar and longitudinal compressive rebar each.
3.1 Profile Steel
3.1.1 Profile steel materials of steel reinforced concrete member should adopt Q235-B, C, D carbon structural steels and Q345 -B, C, D, E low alloy high tensile structural steels. The quality standard thereof shall be in accordance with the requirements of the current national standards "Carbon Structural Steels" (GB 700) and "High Strength Low Alloy Structural Steels" (GB/T 1591).