What is the length of the upper reinforcement of the beam when there is an extra row

When there is more than one row, the length of the upper row is one-third of the larger value of the left and right adjacent spans; The lower row is a quarter. There are clear provisions in the 101 atlas.

This is what Qinglai Ge says in the first article of 06g101-6 p37:

When there is more than one row of longitudinal bars, use a diagonal line"/"Separate the rows of longitudinal bars from top to bottom.

This is what it says in the first article:

When the upper part of the foundation connecting beam support needs to be provided with non-through longitudinal reinforcement, all the longitudinal reinforcements including the non-penetrating longitudinal reinforcement and the penetrating longitudinal reinforcement are marked in situ at the upper part of the support.

The length of the bottom non-penetrating longitudinal bar is described in P51 Clauses 1 and 5.

The general idea is that the length of the non-through rib is the support (the span at both ends is larger, the value l) and the left and right l 3 (applicable foundation beam).

The top non-penetrating longitudinal bar is on page P68.

The general idea is that the length of the non-through rib is 3 on the left and right of the support (the greater value of the net span at both ends l) (DKL is applicable).

03G101-1 P60 Multiplier clear span for non-protruding supports.

The minimum spacing of the bent reinforcement of the first row and the second row of the upper cantilever beam is 25mm, see the requirements for the spacing of the upper longitudinal reinforcement of the beam on page 56 of 11G101-1.

According to the requirements of the 18G901-1 atlas, the length of the two rows of steel bars under the beam is shorter than that of the hooks at both ends of the first row of steel bars by 25mm The diameter of the steel bars is shortened, that is to say, the net hook distance of the two rows of steel bars is 25, see the figure below

If the drawings do not specify separately, the second row of reinforcement should also be extended into the support. If it is indicated separately (such as indicated in the note, etc., and marked in situ (-4)4 4), the length of the second row of reinforcement is a multiple of the net span of the beam. Hope!!!

There are 2 rows of steel bars at the bottom of the beam, 4 in each row, and the two rows of steel bars are placed according to the total length of the beam without special requirements, and the two ends are anchored in the column and beam. The spacing between the second row of reinforcement and the first row of reinforcement is the size of the thickness of the protective layer of the main reinforcement.

If not otherwise specified,

The reinforcement of the second row and the base plate is the same.

The reinforcement at the bottom of the beam should be long without special instructions.

The break point of the second row of reinforcement in the upper part of the frame support beam.

The length is 1 3 of the net span, see the red box specification in the figure below, understood!

The upper reinforcement of the beam is 3 rows, 12 and 25 6 6 2, 3 rows are all long ribs, and what is the spacing of the arrangement?

The upper reinforcement of the beam is 3 rows, 12 and 25 6 6 2, 3 rows of royal answer cheats are all long ribs, and what is the spacing of the arrangement? Dear, hello, when the first row is all long ribs, then the second row of reinforcement is L0 3, and the third row is L0 4; In the second way, when the first row is not fully lengthened, the first row is L0 3, the second row is L0 4, and the value of the third row is determined by the designer. In one fell swoop, it's l0 5.

It is very reasonable for the girder reinforcement to be divided into two rows and three rows with a spacing of about three centimeters, and it is also relatively standard and standardized. I hope my answer is helpful to you, and finally I wish you good health and a happy mood! <>

When the longitudinal reinforcement of the beam has two layers, or even multiple layers, the upper and lower reinforcements should be aligned and cannot be staggered. In the case of two layers, the distance between the top and bottom, left and right of each steel bar should be greater than or equal to the diameter of the steel bar, and greater than or equal to 25mm. Also pay attention to the thickness of the rebar cover.

If you are talking about the vertical spacing between the second row of reinforcement and the first row of reinforcement, then it will affect the effective cross-sectional height of the stressed reinforcement, which should not be too large. It should not be too small, the row spacing is too small, which will affect the gripping force between the concrete and the rebar, and affect the force transmission between the rebar and the concrete.

When the beam is higher (hw 450mm), in order to prevent concrete shrinkage and temperature deformation and produce vertical cracks, strengthen the stiffness of the reinforcement skeleton simultaneously, set up a waist bar with a diameter of not less than 10mm at every 200mm along the beam height on both sides of the beam, and connect with the tendon of 6 or 8 between the two waist tendons, and the tendon spacing is generally 2 times that of stirrups.

There are many types of steel bars, which are usually classified according to chemical composition, production process, rolling profile, form, diameter size, and use in the structure

1. Divided according to the size of the diameter.

Steel wire (diameter 3 5mm), thin steel bar (diameter 6 10mm), thick steel bar (diameter greater than 22mm).

Second, according to the mechanical properties.

grade reinforcement (235 420 grade); grade reinforcement (335 455 grade); Grade bars (400 540) and grade bars (500 630).

Third, according to the production process.

Hot-rolled, cold-rolled, cold-drawn steel bars, as well as heat-treated steel bars made by heat treatment of grade steel bars, the strength is higher than the former.

Fourth, according to the role in the structure.

Compression reinforcement, tension reinforcement, erection reinforcement, distribution reinforcement, stirrups, etc.

The first row of steel bars in the upper part of the beam is truncated, and the rise of the old liquid is ().

Correct answer: ln 3

Reinforcement Calculation Formula Summary of the basic method of reinforcement calculation.

Stirrups are calculated according to the net span.

Stirrups are not calculated for the supports of beams.

When calculating the through-length steel (through bar), if there is a column at one end of the beam, and there is a wall at the other end, the reinforcement needs to be anchored.

The length of the anchor is related to the width of the support, and the two ends are not necessarily equal in length.

The stirrup calculation is calculated according to the net span -50*2.

When there is a column in the middle, buckle the column, and the calculation method is the same as the previous one.

The connection relationship of various components of the structure, that is, the problem of whose support is the time.

The foundation is the support of the column and the wall, the column is the support of the beam, the beam is the support of the plate, and the secondary beam is supported by the main beam.

longitudinal reinforcement anchored into the bearing; Transverse reinforcement (stirrups) do not enter the support, and entering the support is also a structural requirement, not a force requirement. The stirrups of the inserted reinforcement of the column and the wall into the support do not play a large stirrup role, only play a stabilizing role, as long as a large square frame hoop is on the line, and the stirrups need to be pulled apart when the stirrups are eliminated in the real column. When the beam enters the bearing, it is also the longitudinal reinforcement entering, but the connecting beam reaches the top layer and requires the stirrups to enter the bearing, because the upper part of the upper part of the connecting beam is in the epidermis, and the anchoring is unreliable, so it must be restrained by the stirrups, and the wild imitation does not collapse out.

The calculation of the gross length of the beam stirrups is the net span length of each span minus 100mm, that is to say, the stirrups of the beam are arranged from 50mm on the side of the column, and the beam stirrups are not arranged in the column, but the column stirrups must be arranged and encrypted; This is clearly stated in the Chinese seismic design code of the Royal Orange;

The anchorage problem of beam reinforcement is only related to the existence of support in the lower part of the beam, and has nothing to do with whether the support is a column or a wall or other main beam;

The problem of the anchorage length of the beam reinforcement in the support is related to the type of beam (frame beam, secondary beam) and support type (side support, middle support);

The anchorage length of the frame beam on the side support is 0 4 times lae (lae is an anchorage length) hook 15d (d is the diameter of the reinforcement); If the width of the side support itself is not less than one time of the reinforcement, the length of the anchor pants is thick, and the reinforcement of the frame beam can be carried out without hooking for straight anchoring, but the length of the straight anchor must not be less than one time of the anchorage length at this time; The anchorage length of the bottom reinforcement of the frame beam in the middle support is doubled, and the face through the long rib is connected in the area of the middle span 1 3 (cold connection or welded or mechanical connection), which must meet the specification of the length of the connection and the pure town;

The anchorage length of the secondary beam at the side support is 12d of the straight section and 15d of the hook, and the anchorage delay length of the pin of the middle support is 12d; Remember, this is the difference between the frame beam and the secondary beam;

About the beam frame rib structure waist bar torsion waist bar connection shot change messy length, is a problem that ordinary people are prone to make mistakes: the beam frame rib and the structure of the waist bar connection length no matter what beam is 15d, the way of torsion waist bar is the same as the main bar in the beam, comply with the connection specification of the stressed main reinforcement;

The problem of the encryption length of the stirrups of the main beam, the average person only knows that it is 1 5 times the height of the beam, and the liquid resistance is wrong In fact, the encryption length of the stirrups of the main beam is 2 0 times the height of the beam, and the second, third and fourth level of seismic Chang material structure is 1 5 times that of the beam high hail

The effective height of the cross-section is Bush wild h. Refers to the distance from the outer edge of the compression zone of the section to the center of gravity of the resultant force of the tension reinforcement. In the actual calculation of the bearing capacity of the beam and slab flexural member, because the tensile force of the concrete in the tension zone is completely borne by the steel bar after cracking, the cross-sectional height of the beam can play a role at this time should be the distance from the centroid of the tension steel section to the edge of compression, which is called the effective height h of the cross-section.

Assuming that the spacing of the double row of reinforcement is s, the thickness of the concrete protective layer is c, the diameter of the longitudinal reinforcement is d, the diameter of the stirrups is d1, the beam height (or plate thickness) is h, and the effective height of the cross-section h0 is calculated as follows: for the beam h0=h-(c+d 2+d1) (a row of reinforcements) h0=h-(c+d 2+s 2+d1) (two rows of seepage reinforcement) for the plate h0=h-(c+d 2), the minimum protective layer thickness nuclear closure is determined according to the environmental category and the concrete strength grade, and there are detailed provisions in the specification; The spacing of the double row of reinforcement S should consider the diameter of the reinforcement, that is to say, S is the distance from the center of the two rows of reinforcement to the center of the circle, so the value is actually safe, because according to the definition of "the distance from the centroid of the tension reinforcement section to the edge of compression", the centroid of the section here is usually closer to the outermost reinforcement.