How to calculate the bending length of the rebar head?

What you said is to calculate the calculation of steel bar cutting, it is not difficult to do it.

The cutting length of the beam plate reinforcement = the axis size of the beam and plate - the protective layer (generally 25) + the size of the upper bending hook.

180 degree hook = 6 25d

90 degree hook 3 5d

45 degree hook 4 9d

Subtract the measurement difference: 30 degrees, take 0 3d, 45 degrees, 0 5d, 60 degrees, 1d 90 degrees, 2d 135 degrees, 3d

If it is a general construction drawing, it can be calculated according to the above method, such as the distribution of the plate reinforcement, the longitudinal stress rib of the negative disc beam, and the frame reinforcement. If it is a flat construction drawing, then refer to 03G101-1B.

The length of the stirrup, the outer length + the length of the hook - 6d

The length of the hook is 6 plus 100 8 plus 120 10 plus 140

The theoretical calculation of the increased length of the budget reinforcement hook is: 135° hook, 180° hook for the opposite semicircle, straight hook, and oblique hook.

Rebar refers to steel for reinforced concrete and prestressed reinforced concrete, which has a circular cross-section and sometimes a 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.

When calculating the length of the bent reinforcement, the length is calculated according to the straight reinforcement, and the length of the bending part is added and the adjustment value is cut.

The length of the bent steel bar is cut The length of the straight section The length of the inclined section The length of the bending adjustment value The length of the hook is increased.

Straight bar cutting length, component length, protective layer thickness, hook increase length.

If the above-mentioned steel bars need to be lapped, the lap length of the steel bars should also be increased.

The anchorage length of the steel bar refers to the length of the steel bars that should be anchored to each other at the junction of various components.

The anchorage length of the reinforcement is calculated according to the drawing; When there are no specific requirements for the design, it will be calculated according to the provisions of the Code for the Design of Concrete Structures.

GB50010-2002 specification first old provisions:

1) The anchorage length of the tensile reinforcement.

The anchorage length of the tensile reinforcement should be calculated according to the following formula:

Ordinary reinforcement la=a(fy ft)d

The design value of tensile strength of ordinary steel bar and prestressed steel bar in the formula la=a(fpy ft)d; ft—the design value of the axial tensile strength of the concrete, when the concrete strength grade is higher than C40, the value is taken according to C40; d—diameter of reinforcing bar; a—the shape coefficient of the reinforcement (smooth reinforcement a=, ribbed reinforcement a=.)

a.When the diameter of HRB335, HRB400 and RRB400 grade steel bars is greater than 25mm, the anchorage length should be multiplied by the correction factor;

b.When HRB335, HRB400 and RRB400 epoxy coated steel bars, the anchorage length should be multiplied by the correction factor;

c.When the thickness of the concrete protective layer of HRB335, HRB400 and RRB400 grade steel bars in the anchorage area is greater than 3 times of the diameter of the steel bar and is equipped with stirrups, the anchorage length can be multiplied by the correction factor;

d.The anchorage length after the above correction should not be less than the multiple of the anchorage length calculated according to the formula, and should not be less than 250mm;

e.The anchorage length of the longitudinal compression reinforcement should not be less than a multiple of the anchorage length of the tension reinforcement. The seismic anchorage length of the longitudinal tensile reinforcement lae=la

2) The anchorage length of the reinforcement of the ring beam and the structural column.

The anchorage length of the ring beam and the structural column reinforcement shall be implemented in accordance with the relevant provisions of the "Detailed Drawing of the Seismic Structure of the Building" GJBT-3) (4).

Calculation of the 90 degree hook: the diameter of the rebar is d, and the bending diameter is d. According to the outer skin calculation of the length of the steel bar, the length of the shed

L1 = 300 + 100 Calculate the length of the reinforcement according to the central axis: L2 = AB horizontal section length + BC section arc length + CD section vertical length = 300-D 2-D +, bending adjustment value = L1-L2 = feel useful shed chain praise it.

Summary. Hello Glad to answer for you, the 45 degree hook increase is; The hook increase of 90 degrees is; The hook increase of 135 degrees is. The rebar bending adjustment value is an increase value generated by the bending of the rebar at different angles during the rebar machining.

Hello, I'm glad to answer for you, the hook value of 45 degrees is early; The hook increase of 90 degrees is; The hook increase of 135 degrees is. The adjustment value of steel bar bending and vertical bending is an increase value generated by the bending of steel fiber rebar at different angles during steel bar processing.

Hello Calculation of 90 degree bent branch lead hook: the diameter of the rebar is d, and the bending diameter is d. Calculate the length of the reinforcement according to the outer skin:

L1 = 300 + 100 The length of the reinforcement is calculated according to the central axis: L2 = AB horizontal section length in the middle lap pin degree + arc length of BC section + vertical length of CD section = 300-D 2-D +, bending adjustment value = L1-L2 =

Dear, hello, I am glad to answer for you the 25mm steel lack of rib bending with elbow ] specification stipulates that the bending radius is not less than the multiple of the diameter of the steel bar, calculated by the minimum multiple. 25mm rebar, 25*, this is the radius, then the diameter is 125. Usually the bending anchor length of the steel bar is 15d (d is the diameter of the steel bar), that is, its bending length is 25mm, 15 = 375mm.

If the hook of 25 steel bars is round steel, the hook length must be 10 times the diameter of the steel bar, that is, multiplied by 10, it is equal to 25 cm.

Bend up the steel bar and balance it.

Increase the length of the hook + the straight length of the bend.

Hook length (90 degrees).

135 degrees) 180 degrees).

Straight length of bend = (self-search).

1. How much is the length of 25 steel bar bending 90 degrees according to the formula: 25 steel bar bending 90 degrees long = 3 times the diameter of the steel bar + times the diameter of the steel bar Diameter of the steel bar = times the diameter of the steel bar = . In the process of construction, the reinforcement needs to be cooperated by many people, and the coordination of the action should be ensured, so as to facilitate the daily installation and reduce the damage of the reinforcement at the same time.

The stacking of steel bars should be uniform, stable and neat, and should not be excessively concentrated, so as to avoid the situation of tilting of steel bars and the danger of collapse.

1) According to the dimensions shown in the rebar diagram - i.e. the outer skin is summarized.

When the software chooses to summarize according to the dimensions shown in the rebar diagram - i.e. the outer skin, the software calculates the length of the component minus the protective layer plus the bending length.

Take the following diagram as an example:

According to the calculation of the above figure, it can be obtained: the length of the reinforcement = L1 + L2 + L3

l2 = member length l-2 * protective layer.

The bending adjustment values for the bending at both ends are not taken into account in the reinforcement calculation results.

2) According to the size of the steel bar cutting - that is, the centerline is summarized.

When the software chooses to summarize by the rebar cut size, i.e. the centerline, the rebar calculation length needs to be subtracted from the rebar bending adjustment. Because the outer surface is stretched long and the inner surface is compressed and shortened, the centerline length of the steel bar remains unchanged. On both sides of the bending point of the rebar, there is a length difference between the outer size and the centerline arc length, which is the rebar bending adjustment value.

Reinforcement adjustment value = Sum of outer skin dimensions within the rebar bending range - Arc circumference of the rebar centerline within the rebar bending adjustment range.

The following is an example of the calculation process of the 90° hook bending adjustment value

According to the principle that the centerline is invariant:

The length of the rebar shown in the figure = ab + bc arc length + cd

Suppose the r= of the reinforcement

ab=l2-(r+d)=

cd=l1-(r+d)=

BC arc length = 2 r + d 2) 90° 360° =

The length of the rebar is shown in the diagram =

The bend adjustment value is.

The specific value of r needs to be specified according to the specification.

According to the above derivation, it can be concluded that the length of the reinforcement "according to the cutting size of the reinforcement - i.e., the centerline summary" is the length of the component minus the protective layer plus the specified bending length, and the bending adjustment value is deducted.

The above diagram is an example:

Rebar length = L1 + L2 + L3-2 * Bending adjustment value.

l2 = (member length l-2 * protective layer) -2 * bending adjustment value.

The software selects the calculation results of different summary methods (d=12mm).

1.According to the dimensions of the rebar diagram - i.e. the sheath is summarized, and the result is calculated.

2.According to the size of the rebar cutting - i.e. the centerline is summarized, and the result is calculated.

The difference between the two summarizations is whether or not the bend adjustment value is deducted.

Rebar bending adjustment value = Sum of outer dimensions - centerline arc length.

Rebar bending 90° bending adjustment value =

Rebar bending 60° bending adjustment value =

Rebar bending 45° bending adjustment value =

Rebar bending 30° bending adjustment value =

This is what I found online, but it doesn't seem to be quite the same as I remember. Look closely. It's usually in books.

I'll tell you some of the data of the technical training of reinforcing steelers that year: bending angle:

135° elongation: Thank you.

The outer surface of the steel bar is stretched for a long time during the bending process, and the center line of the inner surface and the steel bar remains unchanged.