Calculation of longitudinal compression reinforcement of axial compression members

For a long time, there was a saying in the circle of friends that the world was in a panic, but the picture broke several taels of silver; But it is these two pieces of silver that can avoid famine, ensure health and relieve the melancholy of the world…

1、 Member No.: ZH-1 II.

Basis specification: Code for Design of Concrete Structures (GB50010-2010) III.

Calculation parameters 1.

Geometric parameters: section shape: rectangular section width: b=400mm section height: h=400mm effective length of member: lo=5000mm 2.

Material information: concrete strength grade: C30 fc=14.3N/mm2 reinforcement type: HRB335 fy ‘=300N/mm2 3.

Design parameters: structural importance coefficient: γ O=1.0 minimum reinforcement ratio of longitudinal reinforcement: ρ Min=0.600% 4.

Load information: design value of axial force: N=2000.000kN IV.

Calculation process 1.

Determination of stability coefficient Φ: Lo/b=5000/400=12.500, according to Table 6.2.15 of Code for Design of Concrete Structures (GB50010-2010), Φ= 0.9432.

Calculate the area of longitudinal reinforcement A’s: sectional area A=bh=400 * 400=160000 mm2 A’s=（ γ o*N/0.9 Φ- Fc * A)/fy ‘=(1.0 * 2000.000 * 1000/(0.9 * 0.943) – 14.3 * 160000)/300=228mm2 longitudinal reinforcement ratio ρ= A’s/A=(228/160000)%=0.143% ≤ 3%, the results meet the standard.

3.

Check and calculate the longitudinal reinforcement ratio: ρ= A’s/A=(228/160000)%=0.143% ρ min=0.600% ρ＜ρ Min The longitudinal reinforcement ratio does not meet the requirements, so the minimum reinforcement area A’s=A* ρ min=160000*0.600=960mm2。
.