D. Design Capacity of Columns
Concrete column design through the userspecified component type, seismic parameters such as standardized test grades, the program selected by the user load combinations and design parameters for the design and reinforcement, testing results and design process will be output to the report.
Column Capacity Under Axial Load
Axial compression component capacity
Axially loaded reinforced concrete structures, when the configuration of the stirrup meet GB500102002 the provisions of section 10.3, which is crosssection compression capacity should meet the following requirements:
N ≤ 0.9ф(f_{c}A + f_{y} ^{’}A_{s} ^{’})  (7.2.15) 
When the vertical steel reinforcement ratio greater than 3%, the formula (7.2.15) in A Should use (AA'_{s}) in its place.
Axially loaded reinforced concrete structures, when the configuration of the screw or welded steel ring indirectly found GB500102002 the provisions of section 10.3, which is crosssection compression capacity should meet the following requirements:
N ≤ 0.9(f_{c}A_{cor} + f_{y} ^{’}A_{s} ^{’}+2αf_{y}A_{ss0})  (7.3.21) 
Eccentric compression component capacity
Eccentric rectangular cross section compression member compression capacity should meet the following requirements:
N≤α_{1} f_{c}bx + + f_{y} ^{’}A_{s} ^{’} – σ_{s}A_{s}  (7.3.41) 
Ne≤α_{1} f_{c}bx(h_{0} – x/2) + f_{y} ^{’}A_{s} ^{’}(h_{0} – a_{s}’)  (7.3.42) 
Uniform configuration along the peripheral ring of longitudinal reinforcement section eccentric compression, which is crosssection compression capacity should meet the following requirements:
$N\le \alpha {\alpha}_{1}{f}_{c}A(1\frac{\mathrm{sin}2\pi \alpha}{2\pi \alpha})+(\alpha {\alpha}_{1}){f}_{y}{A}_{s}$  (7.3.7  1) 
$N\eta {e}_{i}\le \frac{2}{3}{\alpha}_{1}{f}_{c}Ar\frac{{\mathrm{sin}}^{3}\pi \alpha}{\pi}+{f}_{y}{A}_{s}{r}_{s}\frac{\mathrm{sin}\pi \alpha +\mathrm{sin}\pi {\alpha}_{1}}{\pi}$  (7.3.7  2) 
Calculation of Oblique Section
Eccentric compression
Rectangular reinforced concrete eccentric compression, the Shear Capacity meet the following requirements:
$V\le \frac{1.75}{\lambda +1}{f}_{1}b{h}_{o}+{f}_{yv}\frac{{A}_{sv}}{s}{h}_{o}+0.07N$  (7.5.12) 
Shear span ratio calculation section the following provisions shall be drawn:
 Columns on the kinds of structures, should take λ = M / (Vh_{o} ); on the frame structure of the frame column, when the inflection point in the story context, the desirability of λ = H_{n} / (2h_{0} ); when λ < 1, take λ = 1; when λ> 3, the take λ = 3; here, M for the calculation of the cross section and the shear design value V corresponding moment design value, H_{n} clear height for the column.
 On the other eccentric compression, when the bear uniformly distributed load, take λ = 1.5; when the bear meet GB500102002 section 7.3.4 provides a concentrated loads, taking λ = a/h0, when λ <1.5, the taking λ = 1.5; when λ> 3, the take λ = 3; here, α for the concentrated load to the bearing or distance from the edge node.
Seismic design of concrete columns
Longitudinal reinforcement force
Columns and pillars of steel frame configuration, should meet the following requirements
Box columns and pillars all vertical steel reinforcement percentage of the force should not be less than the values specified table 11.4.121 the same time, each side of the reinforcement ratio of not less than 0.2;
Box columns and pillars of strength in all the longitudinal reinforcement ratio should not exceed 5%. Column longitudinal steel should symmetric configuration. Column section size greater than 400mm, vertical spacing of reinforcement should not be greater than 200mm. When the level of design by an earthquake, and the column shear span ratio λ ≤ 2, the columns on each side of longitudinal steel reinforcement ratio should be less than 1.2%.
Column Type  Seismic Level  

1  2  3  4  
Framework of columns, edge columns 
1.0 
0.8 
0.7 
0.6 
Framework of the corner column, pillar box 
1.2 
1.0 
0.9 
0.8 
Stirrups
Box columns and pillars of the upper and lower ends of stirrups should be encrypted, encrypted area of the stirrups and the stirrups minimum diameter maximum spacing should be consistent with the provisions of the table 11.4.122;
Seismic Level  Maximum Stirrup Spacing (mm)  Stirrup minimum diameter (mm) 

1 
6 times the longitudinal bar diameter and 100 of the smaller value 
10 
2 
8 times the longitudinal bar diameter and 100 of the smaller value 
8 
3 
8 times the diameter of longitudinal reinforcement and 150 (column root of 100) of the small value 
8 
4 
8 times the diameter of longitudinal reinforcement and 150 (column root of 100) of the small value 
6 (column root 8) 
Pillar box and the shear span ratio λ ≤ 2 the framework of the column should be encrypted column within the whole stirrup high, and the spacing should not exceed 100mm;
Two level columns earthquake, when the stirrup diameter is not less than 10mm, less than 200mm from the limb, in addition to the root column, the stirrup spacing should be allowed to use 150mm; three seismic level frame column section size not greater than 400mm, the stirrups should be allowed to use the minimum diameter 6mm; 4 seismic rating columns span ratio less than 2, the stirrup diameter is not less than 8mm.
Columns of the stirrup length encryption area, take the long side of column section size (or cross section diameter), column clear height of 1 / 6 and 500mm in maximum. Secondary level prism earthquake along the whole column stirrups high encryption.
Encrypted column stirrup limbs from the region: a seismic level not greater than 200mm; two, three seismic levels should be less than 250mm in diameter and 20 times larger value of hoop; 4 seismic rating not greater than 300mm. In addition, every one vertical bar in both directions should have stirrups or stretching constraints.
One, two, three levels of various types of seismic structure of the frame column and pillar boxes, the axial load ratio N / (fcA) is not greater than the limits specified Table 11.4.16.
Structural System  Seismic Level  

1  2  3  
Frame 
0.7 
0.8 
0.9 
Frame  shear wall, tubular structures 
0.75 
0.85 
0.95 
Part of the framesupported shear wall structure 
0.6 
0.7 
 
 An axial load ratio N / (fcA) that consider the combination of earthquake and the box frame column pillar design value of axial pressure on the whole sectional area of N and column A and the design value of concrete compressive strength fc ratio of the product; of the nonseismic the role of the structure calculation, to take no seismic design values combined axial force;
 When the concrete strength grade of C65C70, the axial compression ratio should decrease according to values in the table 0.05; concrete strength grade of C75C80, the axial compression ratio values in the table should decrease by 0.10;
 shear span ratio λ ≤ 2 columns, the axial compression ratio should be values in the table decreases 0.05;
Column encryption area stirrup reinforcement ratio of the volume of stirrups meet the following requirements:

column volume of stirrups stirrup reinforcement encrypted area ratio, shall meet the following requirements:
whereρ_{v} ≥ λ_{v}f_{c}/f_{yv} (11.4.17)  ρ_{v}
=  column encryption area the size of stirrup reinforcement ratio, according to GB500102002 section 7.8.3 of the Ordinance calculated, should be less overlap in the stirrups volume
 f_{c}
=  design value of concrete compressive strength; when the intensity level of less than C35, the values according to C35;
 f_{yv}
=  stirrups and reinforcement design value of tensile strength;
 λ_{v}
=  Minimum stirrup values used in Table 11.4.17.
Table 4. Column encryption area stirrup minimum value λv Table 11.4.17 Seismic Level Stirrup Type Axial Compression Ratio ≤0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.05 1
General hoop, composite hoop
0.10
0.11
0.13
0.15
0.17
0.20
0.23


Spiral hoop, composite or continuous composite rectangular spiral hoop
0.08
0.09
0.11
0.13
0.15
0.18
0.21


2
General hoop, composite hoop
0.08
0.09
0.11
0.13
0.15
0.17
0.19
0.22
0.24
Spiral hoop, composite or continuous composite rectangular spiral hoop
0.06
0.07
0.09
0.11
0.13
0.15
0.17
0.20
0.22
3
General hoop, composite hoop
0.06
0.07
0.09
0.11
0.13
0.15
0.17
0.20
0.22
Spiral hoop, composite or continuous composite rectangular spiral hoop
0.05
0.06
0.07
0.09
0.11
0.13
0.15
0.18
0.20
Notes: A general refers to a single rectangular hoop or single circular hoop; spiral hoop that a single spiral reinforcement; composite hoop means rectangular, polygonal, circular or reinforcement consisting of stirrups stirrup; compound spiral hoop means spiral hoop and rectangular, polygonal, circular or reinforcement consisting of stirrups stirrup; continuous composite rectangular spiral refers to all the spiral hoop to hoop with a steel processed into the stirrups;
 in the calculation of the volume of composite spiral hoop reinforcement ratio, one of the spiral reinforcement of the volume of nonconversion factor should be multiplied by 0.8;
 on 1, 2, 3, 4 seismic rating column, the encrypted area of stirrups stirrup reinforcement ratio of the volume should not be less than 0.8%, respectively, 0.6%, 0.4% and 0.4%;
 concrete strength higher than C60, the stirrup should the composite hoop, composite or continuous composite rectangular spiral hoop; when the axial compression ratio is not greater than 0.6, the encryption region the value of the minimum stirrup according to values in the table should increase 0.02; when the axial compression ratio greater than 0.6, the appropriate values in the table increased by 0.03.

box pillar should adopt the compound spiral hoop or crosswise composite hoop, the minimum transverse reinforcement characteristic values should be the value in Table 11.4.17 0.02 increase access to, and the volume reinforcement ratio of not less than 1.5%;

When the shear span ratio λ ≤ 2, the one, two, three seismic level of composite column should spiral hoop or crosswise composite hoop, the hoop reinforcement ratio of volume of not less than 1.2%; 9, when the degree of fortification should not be less than 1.5%.