What are the composition of steel columns?

Steel column is an industrial product and is a pillar made of steel. Most of the pillars of large and medium -sized industrial plants, large span public buildings, high -rise houses, light -type activity houses, work platforms, trestle bridges and brackets are mostly steel columns.

Steel columns can be divided into real abdominal columns and grid columns in the form of section. The real abdomen column has an overall cross section. The most commonly used section of the work shape; the cross section of the grid column is divided into two or multi -limbs, and each limb is connected with a strip or dotted plate. The amount of steel is saved. Steel columns can usually be divided into a shaft -hearted pillars and eccentric pillars. The longitudinal pressure of the shaft heart is re -coincided with the cross -sectional shaft of the column. Eccriped by the pressure column and bearing the axis stress and bending moment, also known as the bending component.

The maximum pressure or stress of the strength column should not exceed the design strength of the steel. For a shaft heart, the axis heart pressure causes uniform pressure positive stress in the cross section; for the eccentricity of the pillar, due to the effect of bending moment, it causes uneven positive stress in the cross section. It is usually on the side of the cross -section eccentric side on the side of the section. The outer layer of fiber stress is maximum pressure stress, and the outer layer of fiber stress on the other side is minimal compression stress. The maximum tensile stress may occur when the bending moment is large.

When the stable real abdominal column axis is compressed by the stable and stable stabilized column, when the pressure increases to a certain size, the column will suddenly bend from the straight line to the side with a small rigidity. At the same time, bending and twisting occur; if the pressure increases slightly, the bending, reversing or twisted deformation then increases rapidly, so that the phenomenon of losing the bearing capacity is called the column’s overall stability, and it is called Being bending, unstable, or twisting. The minimum axle pressure that makes the column lose stability is called critical force. The stress that the critical force is removed by the section of the hair section is called the critical stress. Critical stress is often lower than the yield point of steel, that is, the column will lose stability before the strength reaches the limit. The ratio of the critical stress to the yield point is called the stabilization coefficient of the bearing heart. Among the three cases where the axis heart is lost in stability, the most common is bending and unstable.

The main factors that affect the critical stress of the bending of the column are the length ratio of the column, that is, the ratio of the calculation length of the column to the cross -diameter of the cross -section. For given steel, the longer or thinner the column, that is, the larger the size, the smaller the critical stress, and the more easily bending and being stable.

When the length ratio of the two main axis X and the Y -axis direction is not equal, its bending disability always occurs in the direction of weak stiffness, that is, long detail (the basic theory of the column). When the steel column has an open cross section and the thickness of the cross -section wall is small, due to the poor cross -sectional resistance, twisting or stability may occur under the axial heart pressure.

When the cross section is dual axis symmetry (such as cross section) or point symmetry (such as Z -shaped section), the formal axis of the axis heart pressure is overlapped with the shear center shaft. ; When the cross section is a single axis symmetry (such as a slot or T -shaped section), the shaft heart axis of the axis heart pressure is not heavy with the shear center shaft, and the column may be twisted stable; when the section does not have a symmetrical shaft, the column is in the column in the section, the column is in the column in the section, the column is in the column in the section, the column is in the column in the section, and the column is in the column. Under stability under a shaft heart pressure is generally bending and stable. The critical stress of the twisting and bending and being stable is related to the section form and size of the column, the twisted rigidity and the bending stiffness, the length of the column, and the support. The smaller the wall thickness of the open -shaped thin wall, the smaller the twist rigidity, and the more prone to twist.

The steel columns used in the project often have defects, such as the section residual stress and the production deviation of the section residual stress, the initial curved component of the component, and the installation deviations such as the initial bending of the component of the component. These defects will reduce the critical stress and stability coefficients, and the reduction of the stability coefficients in different section forms is different. The stable calculation formula of the shaft heart is σ = n/a≤φf, and the σ in the formula is the cross sectional pressure stress; n is the axis heart pressure; A is the section of the hair section; φ is the stable coefficient; F is the design strength. The stable eccentricity of the actual abdominal eccentric is affected by the pressure column and the axis stress and bending moment.

The combined welding steel column is composed of steel plates connected to each limb. Type steel columns are composed of type steel such as H -shaped steel or industrial steel and connecting steel plates and rivets or connection bolts (the steel pipe column is similar). The bottom of the column is generally set.
The steel can be combined or separated by the steel beams (including 檩, 椽 strips); welded beams include abdominal plates, wing plates, and ribs.

steel columns

Toron is composed of upper and lower string rods and abdominal rods. Each rod is connected at the connection of each pole, and the connection method is welded, riveted, and bolts. The end node set the seat plate to connect to the loading component;

Due to the high strength of the steel, the relative section of the steel structure rod is relatively small, and the intensity is easy to meet the requirements, but the stiffness and stability (the rod is under the axial force, the side bending is generated when it exceeds a certain length. Important concepts are poor, so to strengthen contact between components, set up horizontal support, vertical support, scissors, etc. This is an important part of the steel structure and indispensable.

The multi -layer plane rigid standing system of the embellishment plate and the cylindrical limb, which will bear the bending moment and shear power in the shear action of the column. In order to meet the requirements of the stress, the geometry shape of the column body is unchanged and the twist -resistant rigidity of the column should be set at a large level of force and the end and central part of each transportation unit. Steel plates or corner steel can be made by cross -section.

Essence The pillar and anchor pillar feet are the pillar parts loaded by the pillar body to the basics. In addition to fixing the column to the foundation, the pillar also plays the role of transmission and distributed loads. The pillar feet are generally composed of the bottom plate and the beam of the boots; when the column body is small, there is no boot beam; when the column body is large and the bottom plate is wide, in order to strengthen the stiffness of the bottom plate, reduce its bending moment and thickness, it is necessary to appropriately need to be appropriate. Arrange the partition or rib. The anchor is a connector that fixes the column to the basics.

For the eccentric pillar with a small pressure column and bending moment, the anchor bolt is equipped with a fixed position. Generally, it is configured according to the structure. It usually uses two with a diameter of 20-30 mm. For the eccentric pillar with a large bending moment, the anchor bolt must also resist the bending moment from the column body; at this time, the anchor embolism is tensile, and its diameter and number should be according to the maximum bending moment and the minimum axis heart pressure at the bottom of the column. Calculate OK.

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