What is the difference between a hinged column base and a steel column base?

The difference between rigid and hinged:

1.The rigid joint can transmit the bending moment combined shear force, while the hinged joint can only transmit the shear force.

2.There are also differences in the structure of the two: if the rigid connection is H-shaped steel, the upper and lower flanges and webs need to have a connection structure; Articulation is such as h

For section steel, only the web needs to have a connection structure. *A little view!!

For the column base, the force is divided into:

a) Hinged column base (b) Rigid column base.

The column bases of the concrete structure are all rigidly connected, that is, there are axial force n, horizontal shear force v and bending moment m at the same time, so the foundation size is larger. There are two common types of column bases in light steel structures: rigid and hinged, and their forces are different, 1. For hinged column bases, there are only axial forces n and horizontal forces.

2. For the rigid column foot, in addition to the axial force n and the horizontal force v, there is also a certain bending moment m, 3. The foundation of the rigid column foot is larger than the hinged column foot. Also note:

For the nodal design of the just-connected column foot:

1. When used in industrial plants and there are bridge cranes, it is advisable to design the column base to be rigid.

2. The following problems should be paid attention to in the rigid column base: The foundation construction unit should have a certain technical level and should be provided with shear parts.

About just connected. The problem of articulation, theoretically speaking, the rigid joint refers to whether the node can rotate, and the completely rigid joint refers to the complete non-rotation, and the joint can rotate freely. Completely rigid connection means that this joint can not only bear the shear force, axial force and bending moment, but also have sufficient stiffness.

The deformation of the node under the action of bending moment is very small. Theoretically, there is no complete rigid joint, as long as there is a role there is deformation, in the actual engineering, after reaching a certain stiffness, we think that it is just connected in the project, if although it can bear the bending moment, but the deformation is larger, we think that it is a semi-rigid connection, is elastic fixation. The articulation is easy to understand and can rotate freely, but it cannot bear the bending moment, so it can only resist shear force and axial force.

Specific to a member, such as an I-shaped member, the flange is mainly bent, and the web is mainly sheared. Since some of the comrades discussed here have not studied mechanics, I will briefly say that for the bending moment, the farther away from the centroid of the shape, the greater the contribution of the bending moment, so the flange is farthest from the centroid of the bending moment contributes greater. The shear stress is the largest at the center of shape, so the web is mainly sheared.

Generally speaking, specific to the node, such as the end plate connection, where there are bolts arranged outside the flange, and the thickness of the end plate meets the requirements, it is a rigid connection. The articulated joint bolts are arranged close to the shaped mandrel.

The former is less rigid, unstable, and cannot bear large loads; The latter is rigid and has high strength.

The difference between steel and hinged column feet:

1. The steel joint column foot can transmit the bending moment and shear force, and the hinged column foot can only transmit the shear hole and sail force.

2. If the steel column foot is H-shaped steel, its upper and lower flanges and webs need to be connected to the hail; If the hinged column base is H-shaped steel, only the web needs to have a connecting structure.

3. For the hinged column foot, only the axial force and the horizontal force exist; In the case of steel column feet, in addition to the axial and horizontal forces, there is also a certain bending moment.

4. The foundation of the steel column foot is larger than the hinged column base.

The difference between steel and hinged column feet:

1. The steel splice foot can transmit the bending moment shear force, while the hinged column foot can only transmit the wide sock shear force.

2. If the steel column foot is H-shaped steel, its upper and lower flanges and web need to have a connection structure; If the hinged column base is H-shaped steel, it is imitated, and only the web has a connecting structure.

3. For the hinged column foot, there is only axial force and horizontal preparation and force; In the case of steel column feet, in addition to the axial and horizontal forces, there is also a certain bending moment.

4. The foundation of the steel column foot is larger than the hinged column base.

Most experienced structural engineers believe that it is quite difficult to achieve a truly full tie base in a metal building system. Therefore, layman designers will habitually think that the column base is hinged, that is, it is impossible to transfer any bend distance to the foundation. Unfortunately, not all of them remember to include this assumption in the contract documents.

Although not written into the contract documents, the assumption of the articulated column base exists in the mind of the person who drafted the technical conditions. Manufacturers may casually propose a flagpole structure with a pin just attached to the column base, which seems to them to be the most economical option. Because manufacturers don't see the increased base costs, they will naively assume that just fitting feet is the most economical.

At this point, the foundation may have been designed as assumed to be a hinged column base, or may even be partially built or contracted with a contractor for the concrete works. Due to the rigid column base design, which can lead to unforeseen bending distances acting on the foundation, the foundation design is almost always redone.

The owner's choice was to either accept a major foundation design change from the foundation contractor or engage in a lengthy war with the metal builder. This can easily be avoided by inserting a sentence in the technical terms and drawings of the contract that the columns of the prefabricated metal building must be hinged to the foundation and not pass any bend to the foundation.

Article 1 of the Technical Regulations for Steel Structure of Gantry Rigid Frame Light Houses (CECS102:2002) stipulates: "The column base of the portal rigid frame is mostly designed according to the hinged support, usually a flat bearing, and one or two pairs of anchor bolts are set.

When used in industrial plants and there are more than 5t bridge cranes, it is advisable to design the column base as a rigid connection. ”

The column base of portal rigid frame is hinged or just connected depends on the height of the house and the size of the wind load, if the height of the house is larger and the wind load is also larger, it is no crane, such as the column base adopts hinging, the displacement of the column top is larger, and the beam and column section should be increased in order to control the displacement of the column top, and the steel beam allowance is increased; In addition, whether the column base of the portal rigid frame is hinged or just connected also needs to consider the soil condition and the foundation cost.

Generally, the rigid column base is adopted, because the foundation has to bear a large eccentric bending moment, the plane size difference of the foundation is larger than that of the foundation that adopts the hinged column foot, and the difference will be greater when the soil quality is poor. Therefore, the choice of what kind of column base form should be considered according to the height of the house, the size of the wind load, whether there is a crane, the tonnage of the crane, the working condition of the virtual liquid and the soil condition.

1.The diameter of the ground anchor at the foot of the hinged column is determined according to the principle that it is coordinated with the thickness of the steel column plate and the thickness of the bottom plate, and is not less than M24

2.The function of the hinged column foot ground anchor is mainly for installation and fixation.

3.In international engineering, it is common to see that there are four ground anchors at a column angle, and there are also two ground anchors, etc., which are generally determined according to the cross-sectional form, size, and installation requirements.

For the rigid column base of light steel structure, the bending moment m and shear force v are often larger, while the axial force n is relatively small, and the design requirements for the shear resistance of the column base are more stringent. The existence of bending moment m and the preload of the anchor bolt will affect the shear resistance of the rigid column foot, and will directly improve the shear bearing capacity of the rigid column foot.

Answer]: The anchor bolt in the hinged column base is different from the anchor bolt in the just joint column base. Under the action of bending moment, tensile stress may occur under the bottom plate of the column foot, and the resultant force of these tensile stresses must be borne by anchor bolts to avoid separation between the base plate and the concrete foundation.

The anchor bolt in the base of the rigid column is an important stress component of the bad judgment, and its diameter needs to be determined according to the force calculation.

The anchor bolt in the hinged column base is mainly used to fix the position branch of the column base roughly, and the column base anchor bolt does not bear the tensile force. The diameter and quantity of the anchor bolt do not need to be calculated, and its diameter is determined according to the structural requirements, and each column base is often provided with 2 4 anchor bolts with a diameter of 20 40mm according to the structural requirements.