Are the beam reinforcement angle bars and middle bars the same force?

Whether it is the reinforcement of the upper part of the beam or the reinforcement of the lower part of the beam, the stress of the reinforcement in the same section is the same!

The corner ribs are generally larger than the middle ribs, or they are the same size, and the differences are:

1. The corner bars are the erectors of the beam frame, and they are also the four corners of the first stirrup! !

2. The middle rib is also subjected to force, why is the middle rib set? The first is to meet the needs of the beam to have sufficient strength, and the second is to meet the needs of the frame!!

The general corner tendons are long, but the middle tendons are not necessarily!

Also, if the strength is not reached, the corner ribs and middle ribs will be set up in two rows!! But the force is the same!

Hope it helps!!

The steel bar at the bottom is tensile (equivalent to finger bending, the bottom ** is straightened, and the upper ** becomes the same as Zou), and the middle steel bar may be torsion-resistant (the beam is twisted by lateral force), which is not necessarily a mistake, it depends on what the drawing says.

If 22 is set in length, it must be placed in the corners. The middle one is not necessarily long.

The components are designed with gold horns, silver edges, and grass belly. There is no difference between the angle bars and the side bars in terms of stress from the perspective of bearing bending moments alone, but if the integrity of the beam under various loads is taken into account, the corner bars are much more important. So generally the stronger reinforcement is placed on the corners.

There are exceptions in the actual design: sometimes only individual spans are stressed greatly, usually the reinforcement is a smaller diameter reinforcement, and the reinforcement of a span is larger, and the design will set the larger reinforcement at the side reinforcement; Because "if you can do it, you can do it" is also one of the principles of reinforcement.

There are bottom reinforcement, gluten (support reinforcement), stirrup and waist reinforcement in reinforced concrete beams.

1. The bottom reinforcement is used to bear the positive bending moment of the beam, also called the main reinforcement, in the concrete structure, the basic components such as bending, compression, and tension are mainly used to bear the tensile stress or compressive stress caused by the load. Those that bear tensile stress are usually called longitudinal tensile steel bars and tensile steel bars, and those that bear the stress of pressing silver branches are usually called longitudinal compression steel bars and compression bars, collectively referred to as stressed tendons.

2. Gluten (support bar) is used to bear the negative bending moment of the beam and the erection effect.

3. Stirrups are used to connect the stressed main reinforcement and the frame reinforcement to form a reinforcement skeleton, which mainly bears the shear force and torque. The beam will be subjected to the joint action of shear force and bending moment in the bending and shear area, and the main tensile stress trace in this section is oblique, which will produce oblique cracks, because the stirrups are vertical and intersect with oblique cracks, so they can prevent or limit the generation and development of oblique cracks! Torque works on a similar principle.

4. The effect of the waist tendon is the torsion resistance of the beam It belongs to the structural reinforcement in the design, that is, the mechanics do not need to design to calculate the size of the specific force, and this data can be found according to the structural requirements of the national design code. When the beam is high to a certain requirement, it is necessary to add waist reinforcement, according to how much, how much to add specifications according to the structural requirements and specifications.

5. The hanging bar is a kind of steel bar that transmits the concentrated force acting on the bottom of the concrete beam component to the top, and is a kind of steel bar that improves the shear resistance of the beam to bear the concentrated load, and the shape is like ingots, also known as ingots.

The main effect is: because a certain part of the beam is subjected to a large concentrated load, it may cause oblique cracks on the beam, especially the force acts in the tension zone, in order to make the beam body not produce local serious damage, and at the same time make the material of the beam body play its respective role and set up, mainly arranged in the shear force has a large abrupt change in the part, to prevent the part from producing excessive cracks, causing the destruction of the structure, it is necessary to be equipped with suspension bars, but also with additional stirrups.

The steel bar hook facing north and west is the bottom bar, and the steel bar hook facing south and east is the gluten. And the right angle is gluten.

Usually, the reinforcement line marked by the electronic version of the design has 45 bends at both ends is the bottom of the slab rebar, and the 90-degree bend is the negative reinforcement or gluten.

There is no 45-degree bending at both ends of the reinforcement line on the figure, which is the steel bar at the bottom of the slab, and the others are negative reinforcements.

Gluten and bottom reinforcement are mainly used to bear the tensile stress or compressive stress caused by the load, and their function is to make the bearing capacity of the component meet the functional requirements of the structure.

Difference in location:

1. The position of the structural reinforcement in the beam: placed in the erection reinforcement cage to fix the position of the reinforcement, the erection reinforcement is used to erect stirrups in the beam, which generally appears in the beam above the three limb hoops, the ribs on both sides are long, and the middle ribs are only additional reinforcements.

2. The position of the torsional steel bar is placed in the hall

Torsional steel bars generally refer to the steel bars arranged on the side of the frame beam when the load on both sides of the frame beam is different and a certain torque is generated on the frame beam.

3. The difference between the functions:

The structural reinforcement in the beam is used to fix the reinforcement for the erection of the reinforcement cage to prevent cracks at the junction of the shoulder ribs of the flange beam. Torsional steel bars are used to resist the torsion of the beam body, and can also be used as erection steel bars. When the load on both sides of the frame beam is different and a certain torque is generated on the frame beam, the torsional reinforcement bar is arranged on the side of the beam.

There are two differences between the reinforcement distribution rib and the stress rib

First, the role of the two is different:

1. The function of the distributed reinforcement: the distributed reinforcement is located at 90 degrees above the stressed reinforcement to fix the position of the stressed reinforcement, and the load on the plate is distributed to the stressed reinforcement, and it can also prevent cracks in the direction perpendicular to the stressed reinforcement due to the shrinkage of concrete and temperature changes.

2. The role of stress reinforcement: in the concrete structure, the basic components such as bending, compression, and tension are mainly used to bear the tensile stress or compressive stress caused by the load, and its function is to make the bearing capacity of the component meet the structural functional requirements.

Second, the classification of the two is different:

1. Classification of distributed reinforcements: including structural reinforcements, waist reinforcements, embedded anchoring reinforcements, anti-torsion reinforcements, and additional suspension reinforcements.

2. The role of tensile reinforcements: those that bear tensile stress are usually called longitudinal tensile steel bars and tensile steel bars, and those that bear compressive stress are usually called longitudinal compression steel bars and compression bars, collectively referred to as tensile tendons.

When the initial load is small, the steel bar does not enter the working state, the rectangular plain concrete beam section is compressed above and tensioned below, and the high stress is linearly distributed along the cross-section, and the stress at the upper line of the rectangular center is zero, that is, the neutralization axis coincides with the center line.

With the increase of load, the tensile stress of the lower edge exceeds the tensile strength limit of the concrete, the concrete exits the work and is borne by the tensile reinforcement, and the neutralization axis gradually moves upward, (the distance between the neutralization axis and the upper edge is called the height of the compression zone x) x gradually decreases to a certain extent (b·x·fc as·fy) when it is the ultimate equilibrium state.

The load increases again, the reinforcement reaches the flow limit and elongation (the reinforcement is destroyed), at the same time, the compression zone height x is drastically reduced (the compression area is reduced), and the concrete compressive strength exceeds the limit at this time, and it is also destroyed. The so-called suitable reinforcement beam, theoretically, is to the condition that the steel bar and the concrete basically reach the limit.

The reason why reinforced concrete can work together is determined by its own material properties. First of all, steel and concrete have approximately the same linear expansion coefficient, and will not be overstressed due to different environments. Secondly, there is a good adhesion between the steel bar and the concrete, and sometimes the surface of the steel bar is also processed into spaced ribs (called deformed steel bars) to improve the mechanical closure of the wheel occlusion between the concrete and the steel bar.

When this is still not enough to transmit the tensile force between the car letter steel bar and the concrete, the end of the steel bar is usually bent up 180 degree hook. In addition, the alkaline environment provided by calcium hydroxide in concrete forms a passivation protective film on the surface of the steel bar, making the steel bar less susceptible to corrosion than in neutral and acidic environments.

The bottom reinforcement of the beam is a stressed reinforcement.

Stress ribs: Refers to the lower part of the beam or slab. The part of the steel bar that is subjected to tensile force and the shear-resistant bending bar. Hanging bars, etc.

Related extension: distinguish by the opening and depth span of the slab: if it is a single slab, then the reinforcement parallel to the short span direction is the stress bar, and the steel bar parallel to the long span direction is the erection bar. If it is a two-way slab, then the reinforcement in the direction of the long span and the short span is all stressed ribs.

Distinguish by the diameter of the steel bar: the diameter of the steel bar is the stress bar, and the steel bar with a small diameter is the distribution bar;

Distinguish by arrangement: the reinforcement under the positive moment reinforcement is the stressed reinforcement, the reinforcement vertically distributed above is the distribution reinforcement, the negative moment reinforcement (such as the cantilever plate) is the opposite, the reinforcement below is the distribution reinforcement, and the reinforcement above is the stressed reinforcement.

Distributed Bars: Appear in the slab and are arranged in the upper part of the stressed bar, perpendicular to the stressed bar. The function is to fix the position of the stressed reinforcement and distribute the load on the slab to the stressed reinforcement, and at the same time, it can also prevent cracks perpendicular to the direction of the stressed reinforcement due to the shrinkage of the concrete and temperature changes.

It belongs to the construction reinforcement. (To meet the structural requirements, for various factors that are not easy to calculate and not taken into account, the steel bar that is set is the structural steel bar.) ）

If you want to say that there is force, it is force.

1. The upper reinforcement of the simply supported beam is compressed, the lower reinforcement is tensioned, and the stirrups of the bending ribs and the 1 3 places of the bearing are sheared, and the waist reinforcements are torsional.

2. The upper rib is tensile at 1 3 places of frame beam bearing, and the lower rib is compressed, and the upper rib is compressed at 1 3 places in the middle of the span, and the lower rib is tensile, and the waist tendon is torsional.

Theoretically speaking, the tendons are tensile ribs.

Generally speaking, the middle part of a frame beam is called the mid-span, and the two ends near the column are called the supports. In the middle of the beam span, the lower reinforcement is a tensile reinforcement, and the upper reinforcement is a compression reinforcement; At the beam support, the upper reinforcement is a tensile reinforcement, and the lower reinforcement is a compression reinforcement.

Generally speaking, the tendon is the bottom bar. To be precise, the stressed steel bars are called stressed tendons, but tension and compression are distinguished.

The bottom gluten is a stressed tendon, and the gluten may be a tendon or a structural tendon.

1. The upper reinforcement beam of the beam is a simply supported beam and a pick-up beam.

Second, the difference between the upper reinforcement frame reinforcement is that the role is different.

1.In the absence of torque:

Charpy beam: the upper reinforcement compressive and erection action, the lower reinforcement tensile resistance.

Pick beam: the upper steel bar is tensile and the lower steel bar is compressive.

Continuous beam: the upper part of the end support is compressive, and the lower part of the steel bar is tensile resistant; The upper part of the middle support is tensile and the lower part is compressive.

2.When there is torque, all the upper and lower reinforcements of the beam are under tension.

Steel in concrete does not work the same way as animal bones. Concrete itself has a high compressive strength, and it can support a certain external force without putting steel bars. However, the tensile strength and flexural strength of concrete are very low, and if it is subjected to tensile force, it is easy to crack and break.

At this time, the steel bar plays a major role, after the small cracks in the concrete, the steel bar bears all the tensile force, so that the component will not be pulled off, and the small cracks will not continue to expand. On the other hand, the stirrups that form an enclosure can also constrain the lateral deformation of the concrete, avoid the cracking of the concrete under the action of pressure, and thus improve the compressive ability of the components. The stirrups of this enclosed restraint are also subjected to tensile forces.

In order to ensure that the steel bar and the concrete can work together when it is tensiled, and the steel bar will not slip out of the concrete, it is necessary for the steel bar and the concrete to have enough adhesion and wrapping force, which is why the steel bar should be added to the transverse rib to make a deformed steel bar. If the concrete component is equipped with more reinforcements, it is only based on the calculation of how much reinforcement is needed to withstand the force, not so many reinforcements are needed to support the skeleton of the component itself. In addition, there are some smaller and sparser reinforcement arrangements in the actual project to support and fix the main reinforcement to ensure its position and shape before pouring concrete, as well as to meet some structural requirements.

This is called "erecting reinforcement". All these steel bars are combined together to form a complete grid, which is called "steel cage", "steel mesh", "steel skeleton" and so on. A complete reinforcement grid is conducive to restraining concrete and improving the integrity of concrete components.

Reinforcement mesh generally refers to the combination of reinforcement in the plane, such as the longitudinal and transverse reinforcement in the floor slab; Reinforcement skeleton generally refers to a three-dimensional combination of reinforcement, such as reinforcement in beams and columns.

The upper reinforcement is a compression reinforcement. Erecting steel bar is the position where the stressed steel bar cannot reach the erection steel bar, mainly for the tie of the stirrups of the redundant 2 limbs;

The erection reinforcement is arranged on both sides of the outer edge of the compression zone of the beam, which is used to fix the stirrups and form the reinforcement skeleton. If the compression zone is equipped with longitudinal compression reinforcement, the erection reinforcement can no longer be configured. The diameter of the erection reinforcement is related to the span of the beam.