Reinforcement Calculation of Normal Section of Tensile Members
10.7.1 When external fiber composite materials are used to strengthen ring or other closed reinforced concrete tension members, the fiber fabric shall be pasted on the concrete surface at the corresponding position according to the arrangement of the longitudinal tension reinforcement of the original member, and the fiber direction shall be It should be consistent with the tensile direction of the component, and the problems of overlapping and anchoring of the surrounding parts should be handled well.
10.7.2 For the reinforcement of axial tension members, the bearing capacity of the normal section shall be determined by the following formula:
 
In the formula: N——design value of axial tensile force;
ƒf——The design value of the tensile strength of the fiber composite material shall be adopted according to the specifications in Table 4.3.4-1, Table 4.3.4-2 and Table 4.3.4-3 of this code according to its type.
10.7.3 For the reinforcement of rectangular section with large eccentric tension members, the bearing capacity of its normal section shall comply with the following formula:
 
In the formula: N——Design value of axial tensile force after strengthening (kN);
e——the distance from the point of action of axial tension to the resultant point of longitudinal tensile reinforcement (mm);
ƒf——The design value of tensile strength of fiber composite materials (N/mm²), which should be adopted according to Table 4.3.4-1, Table 4.3.4-2 and Table 4.3.4-3 of this code according to its variety.
10.8 Reinforcement calculations to improve column ductility
10.8.1 When reinforced concrete columns are subjected to seismic reinforcement due to insufficient ductility, the circumferential enclosure composed of circumferentially bonded fiber composite materials may be used as additional stirrups.
10.8.2 When the hoop enclosure is used as the additional stirrup, the volume reinforcement ratio ρv of the stirrup after reinforcement in the densified area of the column stirrup shall be calculated according to the following formula, and shall meet the current national standard "Code for Design of Concrete Structures" GB 50010 Stated requirements:
 
In the formula: ρv, e——the volume reinforcement ratio of the original stirrup of the reinforced column; when it needs to be re-checked, it should be calculated according to the core section within the range of the stirrup;
ρv,f—increment of the hoop volume reinforcement ratio calculated as the hoop enclosure as additional hoop;
ρf—circumferential enclosure volume ratio, to be calculated according to Article 10.4.4 of this code;
kc——the effective confinement coefficient of circumferential enclosure, circular section, kc=0.90; square section, kc=0.66; rectangular section kc=0.42;
bf——the width of the circumferential bundle fiber strip (mm);
sf—the center-to-center distance of the hoop-bound fiber strips (mm);
ƒf——design value of tensile strength (N/mm²) of circumferentially bound fiber composite materials, which shall be in accordance with Table 4.3.4-1, Table 4.3.4-2 and Table 4.3.4- 3 adopt;
ƒyv0——Design value of tensile strength of original stirrup (N/mm²).