How to judge whether the column reinforcement is reasonable

The reinforcement, cross-sectional dimensions, and location elevations of all different columns and walls in the diagram are listed in **. For example, the first row in the column reinforcement table shows the frame column.

kz1, the elevation of its location is, the cross-sectional size is 450mmx450mm, and the corner bars.

4 HRB335 grade steel bars with a diameter of 25mm; The middle ribs on the B side and the H side are 4 HRB335 grade steel bars with a diameter of 25mm; Stirrups.

Using the type stirrups in the figure, the spacing of the infill area is 100mm, the spacing of the non-infill area is 200mm, and the rebar with a diameter of 8mm of HPB235 grade is used.

The location, number, thickness, elevation and reinforcement of different walls are indicated. For example, Q1 shows wall 1, the wall thickness is 250mm, located between the elevations, and the ribs are distributed vertically.

The inner and outer sides are HRB335 grade steel bars with a diameter of 12mm and a spacing of 200mm; The inner horizontal distribution ribs are HRB335 grade steel bars with a diameter of 12mm and a spacing of 200mm; The outer horizontal distribution bar is HRB335 grade steel bar with a diameter of 12mm and a spacing of 100mm; The wall tie bar is HPB235 grade steel bar with a diameter of 16mm and a spacing of 600mm.

First of all, it is necessary to determine whether it is a large eccentric compression or a small eccentric compression. Then it is necessary to ask how to reinforce, symmetrical or asymmetrical, if the load is very large, and the column section cannot be expanded, it may be necessary to consider the use of spiral stirrups for reinforcement.

In the case of asymmetrical reinforcement, it should also be noted that the area of one side of the reinforcement is known (if so, it will tell you how many reinforcements are equipped and how many diameters) or it is unknown.

1. If it is not known, first identify e(i) >the subscript in parentheses).

Secondly, let x= (b)h, and then use the equations of moment balance and force balance to remove the area of the two reinforcements. Finally, the reinforcement ratio is verified.

Second, if one of them is known, you can use the above two equations to solve x, and then determine the range of x, whether to rearrange the reinforcement according to a single reinforcement or re-reinforcement.

Look at the gluten content. The first two are a professional from the force aspect, I am the cost aspect, so our regular practice is to look at the weight of the steel bar contained in each cubic meter of concrete to judge, that is, the reinforcement ratio to judge whether the final calculated steel bar index is reasonable, I don't know if you ask the cost or the force, so for the time being.

The in-plane and out-of-plane stability is checked, from which the area of the steel is derived. Whether the comparability is reasonable.

Formula for calculating the total reinforcement ratio of the column:

a（s）/a。Here the brackets are actually corner marks, the same below. where: a(s) is the cross-sectional area of the longitudinal reinforcement in the tension or compression zone;

The reinforcement ratio is a parameter that affects the stress characteristics of the component, and the control of the reinforcement ratio can control the failure mode of the structural component, and the over-reinforcement failure and the less-reinforcement failure do not occur, and the reinforcement ratio is the main index reflecting the economic effect. Controlling the minimum reinforcement ratio is to prevent the failure of the component with less reinforcement, and the failure of less reinforcement is brittle failure, which should be avoided during design.

The reasons why the shear span is worse than the short column and the measures that should be taken in the design:

1) The column end of the frame generally has a bending moment m and a shear force v at the same time, and the column is determined to be a long column, a short column and a very short column according to the shear-span ratio of the column = m vh o and the effective height of the column section parallel to the bending moment m. >2 (when the column reverse bending point is in the middle of the column height h o, i.e., h o h o >4) is called a long column; < 2 is called a stub column; This is called a very short column.

2) In the frame structure of high-rise buildings, frame shear wall structure, core tube structure in the outer frame, etc., due to the reasons such as setting up the height of the equipment layer and the large column section, the short column is difficult to avoid in some projects.

Do you say hand count or pkpm?

Hand arithmetic university textbook concrete design has, judging the large eccentricity or small eccentricity, there is a corresponding formula calculation, the general side columns are eccentric compression in order to meet the needs of the building, and there may be axial compression in the middle, depending on the specific situation. The load is the transfer of dead and live loads from the plate to the beam, from the beam to the column, and that's it.

In the case of PKPM, there are single bias calculations and double bias calculations for column calculations, and double bias is generally used for review, and there are also plots with double bias. As for how to calculate single bias and double bias in PKPM, it is like this: single eccentricity calculation:

1. Symmetrical reinforcement. 2. Calculate the reinforcement of the two pairs of sides separately. ASX is calculated from n,mx, without considering ASY role; ASY is calculated by n,my, and ASX role is not taken into account.

Double eccentricity calculation: 1. Arrange the reinforcement according to the minimum area and the maximum spacing. 2. Check the bearing capacity of N, MX and MY for all combinations; 3. If one group is not satisfied, increase the area of a single root according to the corner bar, MX side and MY side; 4. The area of a single root is not enough, and the number of steel bars is increased.

Knowing the above principle, then there are the following conclusions:

If the bending distance is large and the eccentricity is large in both directions (the axial force is small and the bending distance is large), the two-way reinforcement result is large. If there is a bending distance in two directions at the same time, one large and one small and small eccentricity, the unidirectional reinforcement result is large.

Finally, it is explained that, because the two-way eccentric reinforcement is automatically arranged by the program first the corner reinforcement, and then the X-direction, and finally the internal arrangement of the Y-direction reinforcement sequence, will cause the Y-direction bending distance to be larger, often because the X-direction reinforcement is completed, the bearing capacity has met the requirements, and the Y-direction is no longer arranged, so that the reinforcement arrangement is unreasonable, and the result is large, so the manual adjustment of the reinforcement is checked again. ”

It depends on the specific situation, and the situation is different under the requirements of engineering accuracy.

The reinforcement of the column is symmetrical, that is to say, the left and right symmetry and the top and bottom symmetry, so only the whole side is used.

The area should be matched to 110mm2, and the stirrups of the finger column should meet the structural reinforcement of the column stirrups in the concrete specification.

Column: axial compression ratio, shear stirrups in the core area0, one side of the longitudinal bar is 11, the other side does not show do not know, the corner reinforcement, increase the stirrups in the simple and dense area of the car.

Beam: top surface left end reinforcement 8, middle and right end 0; Reinforcement 8 at the left end of the bottom, 6 in the middleRight end 7,; Both the encrypted and non-encrypted areas are equipped with stirrups.

Column reinforcement: according to, select angle reinforcement 16;

The area of the middle reinforcement of the B side is 8 2 2 (the area of the real matching angle reinforcement is cut) 4, with 2 16;

The area of the middle reinforcement of the H side is 12 2 2 (the area of the real matching corner reinforcement) 8, which can be equipped with 4 16, 2 20 1 16 (when the diameter is greater than the corner bar, the corner bar 16 and the middle 20 are exchanged, that is, the corner bar is 20 at this time, and the middle part of the H side is 3 16).