How to calculate the force of frame column

1. Do you want to know the horizontal concentrated force on the column or the axial force on the column? If the axial force is natural, according to the sum of the constant live load transmitted by the beam and slab that the column bears, that is, all the loads within the loading area of the column, including all floors from top to bottom, the live load can be reced according to the number of floors, referring to the load specification.

2.

The bearing capacity of reinforced concrete is mainly borne by the concrete, that is to say, the concrete grade determines the bearing capacity of the column. Therefore, when the concrete grade is C20, it means that the concrete standard test block 150 * 150 * 150 is 20n / mm2 ring the pressure test. If it is converted into square meter, it is 20000 kn / m2

By analogy, C25 concrete is 25000kN / m2, C35 is 35000kN / m2. Where 1kg = 10N. C20 concrete can bear 2000 tons per square meter. Of course, it needs to be slightly lower than this number. After all, the algorithm is somewhat expanded

what grade of concrete can be configured can make the column bear much weight

According to the apparent density, concrete can be divided into heavy concrete, ordinary concrete and light concrete. The difference between these three kinds of concrete is the difference of aggregate

heavy concrete is made of aggregate with apparent density greater than 2500 kg / m3, which is especially dense and heavy. For example, Barite Concrete and steel chip concrete have the properties of X-ray impermeability and high temperature resistance γ The properties of X-ray; It is usually made of barite and iron ore

ordinary concrete is the concrete commonly used in construction, with apparent density of 1950-2500kg / m3, mainly made of sand and stone as the main aggregate, which is the most commonly used concrete in civil engineering

lightweight concrete is the concrete with apparent density less than 1950 kg / m3. It can be divided into three categories:

1. The apparent density of lightweight aggregate concrete is 800-1950 kg / m3. Lightweight aggregate includes pumice, volcanic slag, ceramsite, expanded perlite, expanded slag, slag, etc

2. concrete (foam concrete and aerated concrete) is 300~1000 kg / cubic meter. Foam concrete is made of cement slurry or cement mortar and stable foam. Aerated concrete is made of cement, water and air generating agent

There is no fine aggregate in the composition of macroporous concrete (ordinary macroporous concrete, lightweight aggregate macroporous concrete). The apparent density of ordinary macroporous concrete ranges from 1500 kg / m3 to 1900 kg / m3. It is prepared with crushed stone, soft stone and heavy ore slag as aggregates. The apparent density of lightweight aggregate macroporous concrete is 500-1500 kg / m3, which is made up of ceramsite, pumice, broken brick and slag

The selection of cement grade should adapt to the design strength grade of concrete. In principle, high strength concrete should be prepared and high grade cement should be selected; The concrete with low strength grade shall be prepared with low grade cement

If high-grade cement must be used to prepare low-strength concrete, the amount of cement will be less and the workability and compactness will be affected, so a certain amount of mixed materials should be added. If it is necessary to use low-grade cement to prepare high-strength concrete, the amount of cement will be too much and uneconomical, and other technical properties of concrete will be affected

High strength concrete: at present, the average strength of concrete used in western developed countries has exceeded 30MPa. In China, high strength concrete refers to concrete with strength grade of C60 or above.

2. Light weight concrete

light weight aggregate concrete: light weight concrete composed of light coarse aggregate, light fine aggregate (or ordinary sand), cement and water, The application of lightweight aggregate concrete is referred to as P92 5-16.

porous concrete. It is a kind of concrete with evenly distributed small pores and no aggregate. It is divided into two kinds: aerated concrete and foam concrete. Aerated concrete is generally used for roofing materials and wall materials. Foamed concrete is mainly used for roofing insulation material.

large hole concrete: coarse aggregate with similar particle size. It is mainly suitable for wall materials.

3. Impermeable concrete

impermeable concrete refers to the concrete whose impermeability grade is equal to or greater than p6.

4. Polymer concrete:

polymer concrete is made of organic polymer, Polymer concrete embodies the advantages of organic polymer and inorganic cementitious materials, Polymer concrete can be divided into three types: polymer cement concrete, polymer impregnated concrete and polymer cemented concrete

6. Pumping concrete:

pumping concrete refers to the concrete whose slump is not less than 100 mm and is pumped for construction. In addition to the strength required by the project, pumping concrete also needs to meet the requirements of fluidity, non segregation and less bleeding, The pozzolanic cement is not suitable for slag cement and fly ash cement.

7. Mass concrete

the minimum size of concrete structure is equal to or greater than 1m, or the concrete is expected to cause cracks e to the excessive temperature difference between the inside and outside of the concrete caused by the heat of cement hydration.

8, The purpose of adding fiber is to improve the tensile strength of concrete and rece its brittleness. The commonly used fiber materials are: glass fiber, mineral wool, steel fiber, carbon fiber and various organic fibers. At present, fiber concrete has been graally used in aircraft runway, bridge deck, light structure with thin end face and pressure pipeline

3. It's a bit of a hole, 8@200
look up the table to calculate the reinforcement area! AS‘
Nu=0.9
φ( FCA + as'
FY ')
this is the formula! Lo=2.8*1.0=2.8
L/ B = 2800 / 300 = 9.3
look up the table according to class B section
coefficient of determination
φ
refer to Appendix C of code for steel structures (GB 50017-2003)
fcdesign grade of concrete strength
page 20 of code for design of concrete structures
A = 300mm
column section size 300 * 300
so a = 300mm
= 0.3m
fy'reinforcement design grade
refer to page 20 of code for design of concrete structures
bring in the above values< br />Nu
Even if it comes out! These tables are not around. Check them yourself! Just bring in the numbers!

4. The stress of frame column is a group of forces, namely shear, pressure and bending moment. There is a connection between them
when two forces are known, the other can be calculated according to the material
in the case of M, we can calculate the pressure, i.e. n
generally, several groups of forces to be borne by the column are analyzed according to the method of structural mechanics, and then the reinforcement is arranged according to the unfavorable group of forces
so
if you want to calculate back, there are many groups of bearing capacity. So many groups of bearing capacity can not solve the problem. I think
is that ok?

5. 1. According to the requirements of "code for design of concrete structures", all the formulas are in it
2. The foundation will deform under the action of load. With the increase of the load, the deformation of the foundation increases graally, and the stress in the foundation soil is in an elastic equilibrium state at the initial stage, which has a safe bearing capacity. When the load increases to a certain point in the foundation or when the shear stress of each point in a small area reaches the shear strength of the soil in a certain direction plane, the point or each point in a small area will be in the limit equilibrium state and the stress in the soil will redistribute. This small shear failure zone is called plastic zone. The limit equilibrium state of the foundation in a small range can be restored to the elastic equilibrium state, and the foundation can still tend to be stable with safe bearing capacity. But at this time, the foundation deformation is slightly larger, so the calculated value of deformation must be checked, and it is not allowed to exceed the allowable value. When the load continues to increase and a large range of plastic zone appears in the foundation, it will show that the bearing capacity of the foundation is insufficient and lose stability. At this time, the ultimate bearing capacity of the foundation is reached.

6. The ring beam and structural column are not the load-bearing components of the building structure, but the anti-seismic structural measures, which should be equipped with grade, section and reinforcement at least without calculation; Frame column calculation, not read a few books on the line! We have to go through professional study and training. We only know some basic knowledge when we read a few books. Even students who can do homework in school only have theory, not practice.

7. As a load-bearing member, the role of concrete is compressive, and the role of steel is tensile, so the tensile capacity of the column mainly depends on the amount of reinforcement and the size of the concrete section, which can be calculated by the structure specialty.

8. When the section size of a column is roughly estimated by hand, the vertical load accumulation within the area of a column is determined by drawing blocks according to the longitudinal and transverse dimensions of the column in the plan

When entering into the formal calculation, the bearing shear force of the beam is calculated by using the load of the limit equilibrium four side support calculation plate on the beam (the same as the triangular or trapezoidal distributed load drawn in the title picture), so as to accumulate the axial force acting on the column

Manual calculation is approximate calculation, so it is impossible to calculate the most unfavorable live load combination of slab and beam. In the frame analysis of beam and column bending moment, multi span frame beam can do the most unfavorable combination of live load, get the maximum bending moment of column joint support with the axial force of column under the load, and the bending moment of column joint under the load when the axial force of column is maximum, and calculate the section of column with two groups of internal forces

at least two groups of internal forces at the top section and the base section of each column should be calculated, and the most unfavorable result should be selected

It is very troublesome to calculate by hand, which can only be calculated by computer, and space effect, settlement effect of column base and even temperature effect can also be considered by computer; Some software can also consider the second-order effect of high-rise columns after compression deformation and bending deformation

The column is the most important vertical component of high-rise building structure, and its design calculation is the most important thing< br />

9. Under pressure and torsion

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