Where should the distributed reinforcement be placed when subjected to positive bending moments

Because the reinforcement joint should be arranged at the place where the stress is smaller, and the span normal bending moment of the beam is the largest, and the shear force at the support is the largest (and there is a negative bending moment at the support), so the joint of the lower reinforcement (resisting the normal bending moment in the span) must not be in the span, is located in the range of the beam end span (in fact, because the end shear force is the largest, the stirrups need to be encrypted, and the joint should also avoid the stirrup encryption area mm of the beam end). The reinforcement of the upper part of the concrete mainly resists the negative bending moment of the beam end, so the joint position should be located in the middle of the span. According to the position of the floor slab, the main beam, the secondary beam determines the arrangement of the reinforcement at the intersection, it is obvious that the reinforcement of the slab is on the top, the reinforcement of the secondary beam is centered, and the reinforcement of the main beam is below.

When there is a ring beam or pad beam, the reinforcement of the main beam is on the reinforcement of the ring beam or cushion beam. According to the normal load transfer sequence, the load should be transmitted to the secondary beam through the floor slab, the secondary beam is transmitted to the main beam, and the main beam is transmitted to the columns at both ends, but if the beam is bent and deformed, the load can not be evenly transmitted down in the normal way, and a pad beam is added under the beam at this time, so that the load can be better transmitted downward. The spacing of the upper main reinforcement is too dense, and the spacing of mm that can not meet the requirements of the specification leads to the inability to pour and vibrate smoothly, and will eventually cause the frame beam, the column joint to reach the design strength after pouring the concrete to remove the bottom mold, and the bottom appears serious honeycomb surface and hole phenomenon.

Electromechanical [Date: [Test Center Display] Technical Points for the Installation of Power Station Steam Turbines Cylinders and Bearing Seats Installation The low-pressure cylinders of general power station steam turbines arrive in sections and need to be assembled on site; For the high and medium pressure cylinders of the steam turbine, they are supplied as a whole and do not need to be reassembled on site; For steam turbine medium and medium pressure cylinders assembled in the factory and then dispersed to the site, on-site assembly is required, and the assembly data needs to be measured and adjusted. The bearing seat is installed according to the requirements of the shafting center and the spacing of each bearing, and the center and elevation are measured and adjusted, so that the bearing seat meets the technical requirements of the manufacturer.

The lower part of the beam reinforcement is generally required to be penetrated, and it can also be partially penetrated, and part of it is bent at the support to bear the negative bending moment of the support. For continuous beams, the bending moment of the support under the action of vertical load can be adjusted by amplitude, and the amplitude modulation coefficient is not less than, and the bending moment in the middle of the span should be increased accordingly.

Combine the lower beams in different directions. Poof, lay the line. Except to earn it. Stick figures. How do you think it should be matched?

Bending steel bars, distributed steel bars, longitudinal stressed steel bars, and frame bars are configured in the slab?

Bending brother messes up the steel bar, distributes the steel bar, the longitudinal stress steel bar, and the frame reinforcement is configured in the plate: the three-way reinforcement refers to the reinforcement in the X, Y, and Z directions. 1. The spatial coordinates are divided into x-axis, y-axis and z-axis, the x, y-axis represents the plane layout, the z-axis represents the longitudinal distribution of the elevation, and the three-way reinforcement refers to the reinforcement in the direction of the three axes of the spatial coordinates.

2. Steel bar refers to steel for reinforced concrete and prestressed reinforced concrete, and its cross-section is round, sometimes square with rounded corners. Including round steel bars, ribbed steel bars, and torsion steel bars. The steel bar for reinforced concrete refers to the straight bar or wire strip steel used for reinforced concrete reinforcement, and its shape is divided into two types: light round steel bar and deformed steel bar, and the delivery state is straight bar and disc round.

3. The beam belongs to the flexural member in the reinforced concrete member. The reinforcement configured in it mainly includes: longitudinal stress reinforcement, bending reinforcement, stirrups and erection reinforcement.

The longitudinal stressed steel bar is arranged in the tensile area of the beam, and its main function is to bear the tensile force generated by the bending moment in the beam; The bending section of the bent steel bar is used to bear the main tensile stress generated by the bending moment and shear force, the horizontal section after bending can bear the negative bending moment at the bearing, and the horizontal section in the middle of the span is used to bear the tensile force generated by the bending moment. There are two kinds of bending angles of bending steel bars: 450 and 600; The stirrups are mainly used to bear the main tensile stress generated by the shear force and bending moment in the beam, fix the longitudinal stressed steel bar, and form a steel skeleton together with other steel bars. The buried form of the steel hoop is divided into two types: open type and closed type.

The most commonly used type is closed; The erection bars are arranged on both sides of the outer edge of the compression zone of the beam, which are used to fix the stirrups and form a steel skeleton. 4. The slab belongs to the flexural member in the reinforced concrete component. There are two kinds of stressed steel bars and distributed steel bars in the slab.

The stressed reinforcement is arranged in the tension zone along the span direction of the slab. The one-way plate is arranged along the short direction, and the four-sided supporting plate should be arranged along the long and short side directions. The distribution ribs are arranged on the inner side of the stressed ribs, perpendicular to the stressed ribs.

The function of the distributed reinforcement is to evenly transfer the load on the plate surface to the stressed reinforcement, and at the same time fix the position of the stressed reinforcement when pouring concrete, and can resist temperature stress and shrinkage stress. 5. The column plays a compressive and bending role in the reinforced concrete component. According to the different shapes, there are two kinds of columns: ordinary stirrup columns and spiral stirrup columns.

The reinforcement configured in the column includes longitudinal reinforcement and stirrups. The longitudinal reinforcement mainly plays the role of bearing pressure, and the stirrups play a role in limiting the transverse deformation, helping to improve the compressive strength, positioning the longitudinal reinforcement and forming a reinforcement skeleton with the longitudinal reinforcement. The stirrups in the column should be closed.

6. The reinforced concrete wall can be configured with single-layer or double-layer reinforcement mesh according to the need, and the wall reinforcement mesh is mainly composed of vertical reinforcement and transverse reinforcement. The function of the vertical bar is mainly to bear the tensile stress of the horizontal load on the wall, and the transverse bar is mainly used to fix the position of the vertical bar and bear a certain shear force. In the wall with double-layer reinforcement mesh, in order to ensure the correct position of the two reinforcement mesh, a bracing iron should usually be arranged between the two reinforcement mesh.

1. The length and position of the negative moment reinforcement on the plate should be determined according to the span of the plate, under normal circumstances, the length of the negative reinforcement is approximately equal to 1 3 of the span of the plate, and the position of the negative reinforcement is on the top of the beam, and the spacing of the negative reinforcement is determined according to the force of the plate.

As shown below:

1. In the anti-cracking stage, the load effect is small, and the concrete at the lower edge of the beam does not reach its tensile strength.

limit value, the beam is in the elastic stage;

2. In the cracking stage, with the increase of the load effect, the concrete at the lower edge of the beam exceeds the limit value of its tensile strength and cracks, and the tensile stress is all borne by the steel bar. It is the normal use stage of the project.

3. In the limit stage, the load effect increases, the concrete crack at the lower edge of the beam continues to develop, the neutralization axis rises, and the stress distribution pattern in the compression zone of the upper beam develops plastically towards the rectangle, and at this time, the bearing capacity of the most unfavorable positive section of the beam reaches the maximum.

In a steel frame, the bending moment usually specifies which side of the steel frame is tensile to be positive.

Dear, I am glad to answer for you: in the steel frame, the bending moment usually stipulates which side of the steel frame is tensile as positiveAnswer: In the rigid frame, the bending moment is often specified to make the inner side of the rigid frame is positive (if it is inconvenient to divide the inner and outer sides, it can be assumed that either side is positive when it is tensiled), and the bending moment drawing is on the side of the member that is tensile without marking the positive and negative signs.

Steel frame: It is all steel welded structure, which is generally used in super high-rise office buildings, or large venues and exhibition halls. For example, Shenzhen's Diwang Building and High-tech Fair Hall are such structures.

The rigid frame is the upper concept of the steel frame. The rigid frame emphasizes the stiffness of the structure, not necessarily the steel structure, and the consolidation of the three points. The steel structure emphasizes the material, as the name suggests--- all-steel structure.

What conditions should be met when determining the bending position of the bending reinforcement of the bending member? What does it do?

Dear, I am glad to answer for you: when the steel bar is bent according to the design requirements, there will be a vertex at this time, and the location of this vertex is the position of the bend starting point. After we bend the steel bar, we should use a steel ruler to check and accept, according to the relevant specifications, the deviation of the bending starting point position does not exceed 20 mm to meet the requirements.

The bending section can withstand the main tensile hail stress generated by the bending moment and shear force. The bent horizontal section can sometimes also withstand negative moments at the support. The lower part (or upper part) of the concrete structural component is bent by the longitudinal tension source type historical steel bar, which is bent to the upper part (or lower part) of the component according to the specified position and angle, and meets the anchoring requirements.