JP3238540B2 - Steel perforated beams and structures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a perforated steel beam and a building, and more particularly, to a perforated steel beam having a seismic and windproof structure and having unreinforced holes, and the perforated steel beam. Related to the building.

[0002]

2. Description of the Related Art When a structural body composed of structural members of columns and beams receives a large horizontal force due to an extremely rare earthquake or strong wind, the ends of the beams are plastically deformed. In general, a structural method of absorbing the energy of the horizontal force by making the structure into a structure is adopted.

On the other hand, in a building, heating and cooling of the building,
In many cases, plumbing equipment such as plumbing is placed under the floor (or behind the ceiling). At this time, holes are drilled in the beams below the floor (or behind the ceiling) in order to make effective use of the building's floor height. In many cases, the pipes are passed through the bored holes.

[0004] When a hole is formed in a beam, the load-bearing capacity of the beam in the portion where the hole is formed (perforated portion) is reduced. The donut-shaped plate 12 is formed on both sides of the beam 10 where the hole is formed.
Welding method, a method of fitting a sleeve made of a short circular steel pipe with the same outer diameter as the hole diameter to the hole and welding it to the web, and welding a plate equivalent to the width of the flange in an oblique cross shape This method is used to reinforce the reduction in proof stress caused by drilling holes. This reinforcement is usually carried out in all the holes drilled in the beam, and this reinforcement requires a great deal of expense in the manufacture of steel beams.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and has a structure in which a beam is provided with a hole for installation piping in a beam without impairing the resistance of a structure to seismic force and wind power. It is an object of the present invention to provide a low-cost perforated steel beam with reduced cost required for reinforcement and a building using the perforated steel beam.

[0006]

According to the first aspect of the present invention,
Cross section with multiple holes drilled and rigid or semi-rigid contact with the column
Is a uniform perforated steel beam, and at least one of an earthquake load and a wind load and a loading load act on a perforated steel frame beam rigidly or semi-rigidly connected to a column, and the perforated portion of the perforated steel beam When the plastic bending strength of the perforated portion becomes equal to the acting bending moment, the holes perforated in the area where the shearing strength is larger than the acting shearing force are not reinforced and the holes perforated outside the area are not strengthened .
The hole is reinforced .

[0007]

[0008]

The invention according to claim 2 is a steel beam with a uniform cross section, in which a hole is drilled and rigidly or semi-rigidly connected to the column, which is rigidly or semi-rigidly connected to the column. When at least one of seismic load and wind load and a load load act on a perforated steel beam and the plastic bending strength of the perforated portion of the perforated steel beam becomes equal to the acting bending moment, the shearing strength of the perforated portion is affected. Do not drill and reinforce the hole in the area larger than the force
And the hole is not formed outside the area .

According to a third aspect of the present invention, a plurality of holes are drilled and rigidly or semi-rigidly contacted with the column, the central section is uniform, and both end sections have a width-to-thickness ratio greater than that of the central section. A small perforated beam in the center of a perforated steel beam that is subjected to seismic load and / or wind load on a perforated steel beam that is rigidly or semi-rigidly connected to a column. When the plastic bending strength of the hole becomes equal to the acting bending moment, the hole drilled in the area where the shear strength of the perforated portion is larger than the acting shear force is not reinforced , and the hole drilled outside the area is not strengthened.
Is characterized in that it is reinforced .

[0011] Incidentally, in the steel perforated Anahari according to claim 3, when the plastic bending strength of the perforated portion of the both end portions of the steel Yuanahari equals the working bending moments, shear strength is the action of the perforated portion It is possible not to reinforce the holes drilled in the region of the ends where the shear forces are greater.

According to a fourth aspect of the present invention, there is provided a steel frame having a hole formed therein and rigidly or semi-rigidly contacted with a column, having a uniform cross section at a central portion and a smaller width-to-thickness ratio at both end cross sections than the cross section at the central portion. A seismic load and a wind load and a loading load act on a perforated steel frame beam that is rigidly or semi-rigidly connected to a column and the plastic bending strength of the perforated part of the perforated steel beam is reduced. Do not reinforce the hole by drilling it in the area where the shear strength of the perforated part is greater than the acting shear force when it becomes equal to the acting bending moment.
And the hole is not formed outside the region .

[0013] Incidentally, in the steel perforated Anahari according to claim 4, when the plastic bending strength of the perforated portion of the both end portions of the steel Yuanahari equals the working bending moments, shear strength is the action of the perforated portion The holes can be further drilled in the region of the ends where the shear forces are greater .

According to a fifth aspect of the present invention, there is provided a steel frame perforated beam,
In a region of the web which is composed of a flange and a web, and whose distance d from the beam end of the H-section steel having a uniform cross section satisfies the following expression,
Drill unreinforced holes and do not drill holes outside the area
And it said that there was Unishi.

[0015]

(Equation 7)

Here, M _{ph is} the total plastic moment of the beam in consideration of the hole section loss d is the distance from the beam end to the center of the hole L is the total length of the beam h is the beam length of the inner part M _{p is} the entire H-shaped section Plastic moment w: Load density of beam Q _ph : Yield shear force of perforated portion of web in consideration of the feed- _endal effect M _phf : Total plastic moment of flange in consideration of the feed-end-effect.

The invention according to claim 6 comprises a flange and a web, wherein the width-to-thickness ratio of the central portion of the flange is a predetermined value and the width-to-thickness ratio of both ends of the flange is smaller than the predetermined value. In the region of the web where the distance de satisfies the following equation, unreinforced holes are drilled and no holes are drilled outside the region.
Characterized in that the odd.

[0018]

(Equation 8)

[0019] However, M _eh: elastic limit moment d _e of the perforated portion a distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : The load density of the beam Q _eh : The value obtained by multiplying the yielding shear force of the perforated portion of the web by taking into account the _Feirendiel effect by the yielding shear strength coefficient M _ehf : The elastic limit moment of only the flange taking into account the _Vielendel effect is there.

According to a seventh aspect of the present invention, in the steel perforated beam according to the sixth aspect, an unreinforced hole is formed in a region of the web where the distance d from the beam end of the H-section steel satisfies the following expression. It is further characterized by being drilled.

[0021]

(Equation 9)

Where, M _ph : total plastic moment of the beam in consideration of the hole cross section defect d: distance from the beam end to the center of the hole L: total length of the beam h: beam configuration of the inner part M _p : total of the H-shaped section Plastic moment w: Load density of beam Q _ph : Yield shear force of perforated portion of web in consideration of the feed- _endal effect M _phf : Total plastic moment of flange in consideration of the feed-end-effect.

[0023]

[0024] The invention according to claim 8 is directed to a building having a rigid or semi-rigid frame composed of a column and a beam with a perforated steel frame having a uniform cross section. When at least one of seismic load and wind load and a load are applied to the beam and the plastic bending strength of the perforated part of the perforated steel beam is equal to the acting bending moment, the shear strength of the perforated part is greater than the acting shear force. Do not reinforce by drilling the hole in the area
And the hole is not formed outside the area .

According to a ninth aspect of the present invention, there is provided a pillar and a steel perforated beam having a hole formed therein, a cross section at the center portion being uniform and both end cross sections having a smaller width-to-thickness ratio than the cross section at the center portion. In buildings with rigid or semi-rigid frames, at least one of seismic load and wind load and a load are applied to the perforated steel beam, and the plastic bending strength of the perforated portion of the perforated steel beam is applied. When the moment becomes equal to the moment, the hole is drilled and supplemented in a region where the shear strength of the perforated portion is larger than the acting shear force.
And do not drill the hole outside the area
Characterized in that way the.

According to the ninth aspect of the present invention, when the plastic bending strength of the perforated portions at both ends of the perforated steel beam is equal to the acting bending moment, the shearing strength of the perforated portion is smaller than the acting shear force. The holes can be further drilled in the region of the larger ends .

According to a tenth aspect of the present invention, there is provided a building in a web region where a distance d from a beam end of an H-section steel beam having a uniform cross section including a column, a flange, and a web satisfies the following expression. , Do not reinforce by drilling holes and out of the area
A rigid or semi-rigid frame composed of a perforated steel beam in which the hole is not drilled .

[0028]

(Equation 10)

Where, M _ph : total plastic moment of the beam in consideration of the hole cross-sectional defect d: distance from the beam end to the center of the hole L: total length of the beam h: beam configuration of the inner part M _p : total of the H-shaped section Plastic moment w: Load density of beam Q _ph : Yield shear force of perforated portion of web in consideration of the feed- _endal effect M _phf : Total plastic moment of flange in consideration of the feed-end-effect.

[0030] A structure according to an eleventh aspect of the present invention comprises a pillar, a flange, and a web, wherein a width-to-thickness ratio at a central portion of the flange is a predetermined value and a width-to-thickness ratio at both ends of the flange is smaller than the predetermined value. Do not reinforce by drilling holes in the area of the web where the distance de from the beam end of the H-section steel satisfies the following formula:
And a rigid or semi-rigid frame constructed from a steel perforated beam in which the hole is not drilled outside the region .

[0031]

[Equation 11]

[0032] However, M _eh: elastic limit moment d _e of the perforated portion a distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : The load density of the beam Q _eh : The value obtained by multiplying the yielding shear force of the perforated portion of the web by taking into account the _Feirendiel effect by the yielding shear strength coefficient M _ehf : The elastic limit moment of only the flange taking into account the _Vielendel effect is there.

According to a twelfth aspect of the present invention, in the building according to the eleventh aspect , an unreinforced hole is further formed in an area of the web where the distance d from the beam end of the H-section satisfies the following expression. It is characterized by being installed and not reinforced .

[0034]

(Equation 12)

Where M _ph : total plastic moment of the beam taking into account the hole cross-section defect d: distance from the beam end to the center of the hole L: total length of the beam h: beam configuration of the inner part M _p : total of the H-shaped section Plastic moment w: Load density of beam Q _ph : Yield shear force of perforated portion of web in consideration of the feed- _endal effect M _phf : Total plastic moment of flange in consideration of the feed-end-effect.

[0036]

The steel perforated beam according to claim 1 has a uniform cross section,
A plurality of holes are drilled and rigidly or semi-rigidly connected to the columns and used in buildings. In this steel perforated beam, at least one of the seismic load and the wind load and the loading load act on the steel perforated beam rigidly or semi-rigidly connected to the column, and the plastic bending strength of the perforated portion of the perforated steel beam is reduced. Holes drilled in areas where the shear strength of the perforated portion is greater than the acting shear force when equal to the acting bending moment are unreinforced. A hole may be formed outside this area, but in that case, it is necessary to reinforce.

[0037]

[0038]

Further, as in the case of the perforated steel frame beam according to the second aspect , a hole can be formed only in the above-mentioned region.

According to a third aspect of the present invention, there is provided a beam with a perforated steel frame, wherein the cross section at the center is uniform, the cross section at both ends is smaller in width to thickness ratio than the cross section at the center, the hole is perforated, and the column is rigidly or semi-rigidly connected. And used for buildings. In this perforated steel beam, at least one of the seismic load and the wind load and the loading load act on the perforated steel beam rigidly or semi-rigidly connected to the column, and the elasticity of the perforated portion at the center of the perforated steel beam When the ultimate bending strength is equal to the acting bending moment, the holes drilled in the region where the shear strength of the perforated portion is greater than the acting shear force are not reinforced. A hole may be formed outside this area, but in that case, it is necessary to reinforce.

In addition, as in the steel beam perforated beam according to claim 4 ,
Holes can be drilled only in these areas.

[0042] Incidentally, in the steel perforated Anahari according to claim 3, nor drilled holes is reinforced in the region of opposite ends shear strength of the perforated portion is larger than the acting shear forces. Holes may be formed in the region at both ends outside this region, but in that case, it is necessary to reinforce.

[0043]

In the case of an H-shaped steel beam having a uniform cross section, as in the case of a beam with a perforated steel frame according to the fifth aspect, an unreinforced portion is provided in a region of the web where the distance d from the beam end satisfies the above equation. Holes can be drilled.

In a case where the width ratio of the width of the central portion of the flange is a predetermined value and the width ratio of the both ends of the flange is smaller than the predetermined value, as in the case of the steel perforated beam according to claim 6 , In the area of the web where the distance de from the beam end satisfies the above equation,
Unreinforced holes can be drilled.

As in the case of a perforated steel beam according to claim 7 , when the width of the beam at the center of the flange is a predetermined value and the width at both ends of the flange is smaller than the predetermined value, the beam is formed. An unreinforced hole is drilled in the area of the web where the distance de from the end satisfies the above equation, and an unreinforced hole is added in the area of the web where the distance d from the beam end satisfies the above equation. it can be formed in.

[0047]

FIG. 2 to FIG. 8 show a first embodiment of the present invention.
It will be described based on.

As shown in FIGS. 2A and 2B, the steel frame perforated beam 16 of this embodiment is provided with a plurality of unreinforced holes 18 and both ends are rigidly connected or semi-rigid with columns 20. Touched. Hole 18
The shape, circular, oval, square, rectangular, triangular, but may be any of trapezoid, in order to simplify the description below, the flange 16A of the width B, thickness t _f, the beam of clear width formed is described as an example a case where bored circular holes 18 on the beam 16 of H-shaped steel having a thickness in the h is made from the web 16B of the t _w.

The shortest distance d from the beam end where the unreinforced hole 18 can be formed is determined as follows. First, it is assumed that a vertical load and a seismic force (or wind force) having hinges at both ends of the beam are acting on the steel perforated beam as a stress distribution in an ultimate state. If the bending moment and the shearing force at the beam end are determined in this state, the distribution of the bending moment and the distribution of the shearing force acting at an arbitrary position on the beam having the set cross section are known.

Next, the ultimate strength of the non-perforated portion and the perforated portion of the set beam is set. When the beam is subjected to a shearing force simultaneously with the bending moment, the value of the total plastic moment decreases depending on the magnitude of the shearing force. This can be represented by a correlation diagram between the bending moment M and the shearing force Q, and the correlation between the bending moment of the non-porous portion and the shearing force is as shown in FIG. Where M _p is the total plastic moment, M
_pf is the total plastic moment of the flange only, and Q _y is the shear yield strength.

The bending moment M of the perforated portion and the shear
The correlation with the force Q can be expressed as shown in FIG. Where M_ph
 Is the total plastic moment of the beam in consideration of the hole cross-sectional defect, M
_phfIndicates only flanges that take into account the fieldend effect
Total plastic moment and Q_phIs a fieldend effect
It is the yield shear force of the perforated partial web considering the result. Soshi
In the final state at both ends of the beam using the correlation in FIG.
Bending moment M _PL(Left end in FIG. 5), M_PR(Figure
5 is calculated. Bending moment M_PL, M
_PRThe bending moment and shear force at any point on the beam
Can be determined. Thus, using the correlation shown in FIG.
The bending strength of the perforated part is equal to the acting bending moment.
And the shearing force of the perforated part is greater than the acting shearing force
Is obtained.

How to determine the shortest distance d will be described in further detail. First, the following four conditions are considered as application conditions.
Here, R is the radius of the hole, h is clear width RyoNaru, t _W is the web thickness.

(1) The hole is made at the center of the beam.

[0054]

(Equation 13)

That is, the diameter 2R of the hole is 60% or less of the beam diameter. (3) The web width / thickness ratio h / t _W is an FA rank determined by the standard method.

(SS41, SM50) (4) In the case of a plurality of holes, the pitch P of the holes (the distance from the center to the center of the holes) is P> h.

Consider the stress distribution in the final state under the above-described application conditions (however, in the following, complete consideration is given without considering strain hardening).
This is performed using the σ-ε relationship of the elastoplastic shape). In addition, the shear force generated by the axial deformation of the column and the rotation of the nodal point under the vertical load is ignored.

The shear force Q _{x at} a position x from the origin is
Assuming that the beam length (span length) is L and the vertical load density is w, it is given by the following equation (1).

[0059]

[Equation 14]

In the right-handed coordinate system as shown in FIG. 5, Q _x is a negative sign, but is represented by a positive sign because the absolute value is a problem.

As understood from the equation (1), the shear force Q
_x increases from left L to right R as x increases.

[0062] bending moment M _PL, M _PR takes different values depending on the size of the shear force. In the case of a composite beam, the value differs depending on the positive bending and the negative bending.

Here, the problem is simplified, and the contribution of the slab is ignored, and only the steel beam is considered. The slab's contribution to proof stress is reserved.

The relationship between the bending moment M _x and the shear force Q _x in the final state of the non-porous portion of the H-shaped section, that is, MQ
The correlation is approximately given by the following equation from FIG.

[0065]

(Equation 15)

Where Q _x ≦ Q _y and M _pf is Bt _f
(H + t _f ) The total plastic moment of only the flange _represented by σ _yf (B: flange width, t _f : flange thickness, σ _yf : yield point of flange material), Q _y is h
the yield shear force of the web that can be represented in the t _w τ _yw (However,
t _w: web _{thickness, τ yw = σ yw / √3} (σ yw:
Yield point of web material)).

[0067] In (1), shear force Q _L, Q _R when the x = 0, L is as follows.

[0068]

(Equation 16)

[0069] substituted This shear force Q _L, the Q _R (2) in equation Qx,

[0070]

[Equation 17]

[0071] _{and, Q y = ht w σ yw} / √3 bending moment M _PL by using the relationship, and seek M _PR is as follows.

[0072]

(Equation 18)

Shear force _d acting at a distance d from the beam end
Q _{L, d} Q _R are each (1), x = d, x = L
Substituting -d, and can be expressed as (3) of the M _PL, using M _PR (4) below.

[0074]

[Equation 19]

The bending moment M _x acting on the position x from the origin is given by the following equation.

[0076]

(Equation 20)

From the above equations (3) and (5), x =
d, x = L-d bending moment _d M _L at the position of, _d M
_R is as follows.

[0078]

(Equation 21)

In the above equation, the negative sign of _d M _{R is} eliminated and considered as an absolute value. From the above equations (4) and (6), it is clear that _d Q
_{L <d Q R, d M} L> is _d M _R, the bending moment and shear forces at a distance d from the beam end magnitude relation in the left and right ends are reversed.

In the event of an earthquake or a strong wind, the moment distribution repeatedly reverses. Therefore, it is only necessary to consider which one of the left side and the right side has more severe conditions.

The correlation equation between the bending moment M _h and the shearing force Q _h at the hole position in the final state shown in FIG. 5 is given by the following equation (7), similar to the above equation (2).

[0082]

(Equation 22)

In the above α and β, the third term may be neglected in design. The symbols in the above equations (7) and (8) are as follows.

M _ph : Total plastic moment of the beam in consideration of hole cross-sectional defects M _pf : Total plastic moment of the flange only M _phf : Total plastic moment of the flange only in consideration of the _Feederend effect Q _ph : _Feederend effect When the end of the beam is in the final state, that is, when the bending strength of the perforated portion is equal to the acting bending moment, the shear strength of the perforated portion is smaller than the acting shear force. As it gets larger, the holes need not be reinforced.

First, from the above conditions, it is necessary that the bending strength of the perforated portion is equal to the acting bending moment.
Is at the left edge L may be equal and the _d M _L and (7) of M _h of the equation (6). Than this, and determine the shear force Q _h,

[0086]

(Equation 23)

[0087] Further, since the shearing force Q _h from the condition (4) is larger needs than acting shear force _d Q _L of formula following equation (10) is obtained.

[0088]

(Equation 24)

[0089] On the other hand, at the right end R, as in the case of left L, we are equal and _d M _R and (7) of M _h of equation (6). Than this, and determine the shear force Q _h,

[0090]

(Equation 25)

[0091] In addition, from the above-mentioned conditions, the shear force Q _h (4)
Since it is necessary to be larger than the action shearing force _d Q _R of formula,
The following equation (11) is obtained.

[0092]

(Equation 26)

The distance d is obtained from the conditions at the right end and the left end of the equations (10) and (11), and the larger one is the value of the allowable distance d. The quantities in equations (10) and (11) are as follows.

[0094]

[Equation 27]

The yield shear force Q _ph of the perforated partial web in consideration of the _feeler deal effect: Equation (9) The total plastic moment M _phf of the flange in consideration of the _feeler deal effect: Equation (8) A plurality of circular through-holes can be provided at intervals (pitch: P) larger than the beam height h (the inner diameter of the flange) in the web region in the middle of the beam span at a distance d or more from both ends. The hole diameter is less than 60% of the beam diameter. In addition, as a beam having seismic performance, the width-to-thickness ratio in the plastic region forming the hinge at the beam end is determined by the Society of Japan P-I Class or Center F
Satisfies the width-to-thickness ratio of class A.

Next, the application limit will be considered. The application limit is that no plastic hinge (maximum moment) occurs in the middle of the beam span. The shear force is zero at the plastic hinge point, that is, the first derivative of the bending moment is

[0097]

[Equation 28]

[0098] Conditions seeking plastic hinge point position x from equation (5) satisfying the, (3) when M _PL, erases the M _PR with formula, x ≦ 0 and L ≦ x from the following conditions can get.

[0099]

(Equation 29)

In practical calculations, it is preferable to first confirm that Q _h ≦ Q _ph in the above equation (7), which represents the correlation equation between the bending moment M _h at the hole position and the shear force Q _h. .

Next, the following equations (13) can be obtained by rewriting the above equations (10) and (11) by introducing dimensionless quantities into the relations of the following symbols.

[0102]

[Equation 30]

Since the second term on the right side is clearly positive, the case of a positive sign may be considered.

[0104]

(Equation 31)

That is, if d satisfying the expression (14) is adopted, the holes need not be reinforced. For short span beams, it is often difficult to satisfy equation (14), but 1) to make the hole smaller,
Measures such as 2) increasing the yield point of the web, 3) reducing the area of the flange, and 4) increasing the thickness of the web may be taken.

Next, the above contents will be examined by experiments. First, if no vertical load is applied, w
= 0. From this condition, the above (10), (11)
The formula is as follows:

[0107]

(Equation 32)

In the following, only the experimental data before the hole position breakdown is collected to verify the validity of the theoretical value. In theory evaluation formula, the width-thickness ratio of the cross-section _{(h / t w, b /} t f), the hole size,

[0109]

[Equation 33]

It is difficult to make a universal evaluation because the strength of the material is involved.
Do a review. Table 1 is a list of comparisons.

[0111]

[Table 1]

FIG. 6 shows this on one figure. Line A is subjected to pure shearing, HS-1, HS-2, HS-
Specimen No. 3, line B is HBS-1, HB subjected to bending shear
S-2, HBS-3, and HBS-4. ○, ● mark is H
Experimental values of S-1 to HS-3 and HBS-1, □ and Δ represent H
The experimental values of BS-2 to HBS-4, each white mark is the yield load, and each black mark is the ultimate proof stress. Regarding the yield strength, the correspondence between the theoretical value and the experimental value is good. Since the problem is the ultimate strength and deformation capacity of the perforated beam, the ultimate strength after yielding of the perforated part (total plastic state) to the ultimate strength and the total plastic strength of the non-porous part of the beam end It is necessary to compare the remaining capacity to the proof strength.

Table 2 shows the ratio of the ultimate strength to the yield strength of each specimen.

[0114]

[Table 2]

On the other hand, the ultimate endurance at the material end of the H-shaped section member
Total plastic moment M of H-shaped section of force _pThe rate of increase from
Stress-strain relationship (yield ratio) of steel materials, local buckling of cross-sectional elements
Determined by strength, h / t_w, B / t_fAre its main parameters
However, it is also affected by the stress-strain relationship (yield ratio) of steel materials.
You. The stress-strain relationship of this test specimen was
When evaluated as

[0116]

(Equation 34)

S: Rate of increase in proof stress from the all-plastic state to the maximum proof stress When the rate of increase in the strength of the test specimens of Group A and Group B is calculated by the above equation, Group A: S = 1.133 Group B: S = 1.141 There is no significant difference from the rate of increase in the strength of the perforated portion, and the rate of increase in the strength of the hole is generally larger. Therefore, the evaluation of the necessity of reinforcement may be performed on a yield (total plasticity) basis.

Next, the deformation ability is

[0119]

(Equation 35)

Is evaluated. Table 3 shows the deformation capacity of the pre-hole yielding type beam discussed in this paper (see FIG. 7).

[0121]

[Table 3]

On the other hand, when beam end yielding precedes (bending shear force; R = 0.23) and the deformation capacity of the H-section steel without holes are shown in Table 4.
(See FIG. 8).

[0123]

[Table 4]

As can be seen from Tables 3 and 4, there is a marked difference in the deformability between the hole yielding advance type and the beam end yielding advance type, indicating that the latter is superior in the deformability. B-1 to B-2
Considering that the width-to-thickness ratio of the H-shaped steel flanges is considerably larger than that of the H-shaped steel, it can be said that these deformation abilities are comparable to those of the H-shaped steel having the same dimensions.

In conclusion, in designing a steel beam with a perforated beam, it is preferable to design the beam end yielding advance type according to the above equation (10) or (11).

In the first embodiment, an example in which two holes are formed has been described. However, three or more holes may be formed as shown in FIG.

Next, a second embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 10 (1) and (2), the steel frame perforated beam 26 of the present embodiment is a non-reinforced hole 1
8A and 18B are formed in a plurality, and both ends are rigidly or semi-rigidly connected to the column 20. The steel Yuanahari 26, the longitudinal central portion and the first H-beam 28 (portion of the length L _1), the second H-shaped steel 30. welded to both ends of the H-beam 28 Become. In addition, the steel frame perforated beam 26 may be one in which a first H-shaped steel part 28 and a second H-shaped steel part 30 are integrally formed.

The width of the first H-shaped steel part 28 is B₁, Thickness
Is t_f1Of the flange 28A and the beam of the home₁In thick
Miga t_w130 parts of the second H-section steel 28B
The width of the end from the center in the longitudinal direction is B₁In the longitudinal direction
B at both ends_Two, Thickness is t _f2 With the flange 30A
Chinori's beam is h_TwoAnd the thickness is t_w2Web 30B
You. Here, the width-to-thickness ratio of the flange is the flange 28A portion.
In the academic society P-III class or center FC class,
Society PI class or center at flange 30A
FA class. Therefore, in the flange 28A portion,
The strength against local buckling three times that of the flange 30A is maintained.
Proven.

The shape of the holes 18A and 18B may be any of a circle, an ellipse, a square, a rectangle, a triangle, and a trapezoid. However, in order to simplify the description, the first of the steel perforated beam 26 will be described below. The case where circular through holes 18A and 18B having radii R ₁ and R ₂ are respectively formed in the H-shaped steel 28 and the second H-shaped steel 30 will be described as an example.

In this embodiment, d is determined in the first embodiment.
It can be determined in the same way as in the example,
The width of the edge is not constant and varies along its length
Is sufficient. In addition, the necessary
Thickness t_w2In determining the _h≤ Q_phTo confirm
Is based on the following equation.

[0131]

[Equation 36]

[0132] In this case, the actual height h _e a is h when there is scallop the beam member end as shown in Figure 13.

[0133] the shortest distance d _e from beam end which can be bored unreinforced hole 18A is determined as follows.

First, it is assumed that a vertical load and a seismic force (or wind force) in which both ends of the beam become plastic hinges are acting on the steel perforated beam as the stress distribution in the final state.
In the case of the present embodiment, the cross-sections of both ends of the beam are used, and the ends are plasticized to absorb the horizontal force and energy.

If the bending moment and the shearing force at the beam end are determined under the above assumption, the distribution of the bending moment and the distribution of the shearing force acting at an arbitrary position on the beam having the set cross section are known.

Here, as the prerequisite application conditions, the same conditions as in the first embodiment are used. That is, (1) The hole is made at the center of the beam.

[0137]

(37)

Note that h ₁ ≒ h ₂ ≒ h. That is, the diameters 2R ₁ and 2R ₂ of the holes are set to 60% or less of each beam structure.

(3) The web width / thickness ratio h / _tw2 is determined by the
I class or center FA class, web width to thickness ratio h
/ _Tw1 shall be the academic society P-III class or the center FC class.

(4) In the case of a plurality of holes, the pitch P of the holes (the distance from the center to the center of the holes) is P> h.

[0141] forces acting on the hole position provided on the beam mid-span region (part of the distance L1) (M, Q) is, elastic limit strength _{(e M h, e Q h} ) of the perforated section than smaller as determine the distance d _e from a beam end.

Assuming that the feelerend effect is not changed by elasticity and plasticity, the MQ correlation diagram of the perforated portion is as follows.
As shown in FIG.

[0143] From FIG. 14, the shearing force _e when reaching the moment _e M _h and the elastic limit of the time to reach the elastic limit of the perforated section
The relationship with Q _h can be approximated by the following equation (16).

[0144]

(38)

Where M _eh is the elastic limit moment (sh
ape factor is assumed to be about 1.15)

[0146]

[Equation 39]

M _ehf : Elastic limit moment of only the flange taking into account the _Feeendel effect expressed by the following equation

[0148]

(Equation 40)

M _ef : elastic limit moment of only the flange expressed by the following equation

[0150]

[Equation 41]

Q _eh : Yield shear strength of the perforated portion of the web in consideration of the Feeendel effect expressed by the following equation (coefficient 0.8 is determined by referring to the theoretical equation of buckling)

[0152]

(Equation 42)

Here, when the elastic limit bending strength of the perforated portion at the center of the beam becomes equal to the acting bending moment, if the shearing strength of the perforated portion becomes larger than the acting shear force, the holes need not be reinforced. , The distance from the beam end of the limit beam that satisfies this condition, that is, the forces M, Q,
[Equation (6), (4)] satisfies equation (16).
_e is obtained as follows. In _e Q _h ≦ Q _eh confirm the above (15), may be used expressions with different d to d _e. The value of the cross section of the beam end is used as M _p . From the above conditions, the elastic limit bending moment (elastic bending strength) of the perforated portion needs to be equal to the acting moment, so the shear strength at this time is determined. That is, equation (6)
_d M _L, and equi-spaced and _d M _R and (16) of the _e M _h, obtaining the shear strength _e Q _h of the perforated portion of the time.

[0154]

[Equation 43]

[0155] From the above conditions, _e Q _h obtained above is acts shear force _d Q _L, since larger needs than _d Q _R, the following equation (17) is obtained.

[0156]

[Equation 44]

[0157] The above equation (17) obtains a distance d _e (above equation corresponding to the solution there are two in the composite code) by solving, the value of d _e that whichever greater is acceptable. The value of this d _e in consideration, to determine both ends of the extra partial length L ₂ in the manner shown in FIG. If you want to shorten the length of the d _e is the assumption section t
_{Increase w} and recalculate.

The quantities in the equation (17) are as follows. M _eh : elastic limit moment (sh
ape factor is assumed to be about 1.15)

[0159]

[Equation 45]

M _p : total plastic moment of H-shaped section expressed by the following equation

[0161]

[Equation 46]

Q _eh : Yield shear strength of the perforated portion of the web in consideration of the Feeendel effect expressed by the following equation (coefficient 0.8 is determined with reference to the theoretical equation of buckling)

[0163]

[Equation 47]

M _ehf : Elastic limit moment of only the flange in consideration of the _Feeendel effect expressed by the following equation

[0165]

[Equation 48]

[0166] As a result, the web region of the two ends from the distance d _e above the beam center of the beam (of the length L ₁₎ providing a plurality of circular through-holes in RyoNaru h larger pitch (P) be able to. The hole diameter is less than 60% of the beam diameter. In addition, as a beam having seismic performance, the width-to-thickness ratio in the plastic region that forms the plastic hinge at the beam end satisfies the width-to-thickness ratio of the Society P-I Class or Center FA Class, and in the elastic region at the center of the beam. The width-to-thickness ratio satisfies the width-to-thickness ratio of the Society P-III class or Center FC class.

Next, the application limit will be considered. The limits of application are that there is no plastic connection (maximum moment) in the middle of the beam span and that no shear yielding of the web precedes at the ends. Check that the maximum bending moment is not within the span area.

By substituting the above-mentioned M _Pf and M _Pw into the equation (12),
When you make dimensionless,

[0169]

[Equation 49]

Check that no shear yielding of the web precedes the end of the material. Material end shear beam, by substituting d = 0 in the aforementioned equation (4), condition resulting larger timber end shear force Q _R is less than the shear yield Q _y equation as follows become.

[0171]

[Equation 50]

When the above equation is made dimensionless,

[0173]

(Equation 51)

[0174] In this case, since when a scalloped the wood ends are h (18) right side of the equation becomes h _e, the right side

[0175]

(Equation 52)

It is assumed that Next, a practical calculation for confirming that the first hole position at the center section does not yield will be described.

A cross section at the center is assumed to satisfy the width-thickness ratio of the P-III class of the academic society or the center FC class. At the same time, it is assumed that the material end cross section satisfies the width-thickness ratio of the academic society PI class or the center FA class.
Since the web thickness _tw2 at the material end is also assumed, this _tw2
May be modified.

[0178] forces acting on the first hole position of the central cross section region (region of length L ₁₎ (M, Q) is determined the distance d _e such that less than elastic limit strength of the opening. First, it Shear Strength Q _eh of the perforated portion is larger than the acting shear force _e Q _h, i.e. ascertain Q _{eh <e} Q _h.

[0179]

(Equation 53)

However,

[0181]

(Equation 54)

When the above equation (19) is dimensionlessly expressed,

[0183]

[Equation 55]

However,

[0185]

[Equation 56]

Next, when expression (17) is dimensionally displayed,

[0187]

[Equation 57]

However,

[0189]

[Equation 58]

The length L _{2 of the} split cross section at both ends is L ₂ <d _e −R ₁
(See FIG. 10), the holes need not be reinforced.

Next, the required web thickness t of the additional cross section is
A practical calculation for determining _w2 will be described.

The hole position d and the hole diameter R ₂ from the column end are obtained. Beam flange width B _o in d _{position, B o = B 2 - (} B
₂ -B ₁₎ is a (d / L _2). Q _h <Q _ph , confirming that equation (15) holds.

[0193]

[Equation 59]

When dimensionlessly displayed,

[0195]

[Equation 60]

Consider the equations (10) and (11).

[0197]

[Equation 61]

However,

[0199]

(Equation 62)

When dimensionlessly displayed,

[0201]

[Equation 63]

When the expressions (22) and (23) are not satisfied, t
_{Increase w2} (opening reinforcement may be performed).

[0203] Incidentally, in the second embodiment, a case where holes in the beam longitudinal section extra portion (the length L ₂ portions) at both ends and longitudinally central portion (the portion of the length L ₁₎ is bored Although illustrated, it goes without saying that a hole may be formed in only one of the portions.

In the first and second embodiments, only the beam has been described. However, this beam can be applied to a building.

[0205]

As described above, according to the present invention, an unreinforced hole is formed at a position where the resistance of the beam to seismic force and wind strength is not impaired, so that the cost required for reinforcement is reduced. The advantage is that it is possible to provide a low cost steel beam, and therefore it is possible to provide a low cost building.

[Brief description of the drawings]

FIGS. 1 (1) and 1 (2) are a front view and a sectional view taken along line aa of a conventional reinforced perforated beam.

FIGS. 2A and 2B are a front view and a cross-sectional view taken along line bb of the first embodiment of the present invention.

FIG. 3 is a correlation diagram between a bending moment and a shearing force.

FIG. 4 is a correlation diagram between a bending moment and a shearing force.

FIG. 5 is a schematic diagram for obtaining a moment.

FIG. 6 is a diagram showing a comparison between a theoretical value and an experimental value.

FIG. 7 is a diagram showing a comparison of the deformation capability of a hole yielding advance type.

FIG. 8 is a diagram showing a comparison of the deformation capability of a beam with a beam end yielding advance type.

FIG. 9 is a front view showing another embodiment of the present invention.

FIGS. 10 (1) and (2) are a front view and a plan view of a second embodiment of the present invention.

FIG. 11 is a sectional view taken along line 11-11 of FIG.

FIG. 12 is a sectional view taken along line 12-12 of FIG.

FIG. 13 is a partially omitted front view of a beam in a case where scallops are present at beam beam ends.

FIG. 14 is a diagram showing a correlation between a bending moment and a shear force acting on a beam in an elastic state.

[Description of Signs] 16 beams 18 holes 18A holes 18B holes 20 pillars 26 beams

Claims (12)

(57) [Claims] 1. A perforated steel beam having a uniform cross section, in which a plurality of holes are drilled and rigidly or semi-rigidly connected to a column, wherein the beam is rigidly or semi-rigidly connected to a column. When the seismic load and / or the wind load and the load are applied to the steel plate and the plastic bending strength of the perforated part of the steel perforated beam becomes equal to the acting bending moment, the shear strength of the perforated part becomes larger than the acting shear force. Do not reinforce the holes drilled in the area, and
A perforated steel beam, characterized in that a hole formed outside is reinforced . 2. A steel perforated beam having a uniform cross section, in which a hole is drilled and rigidly or semi-rigidly connected to a column, wherein the beam is rigidly or semi-rigidly connected to the column. load and 塑 at least one and a perforated portion of the live load is applied to steel Yuanahari wind load
When the bending strength is equal to the acting bending moment, the hole is not drilled in a region where the shear strength of the perforated portion is greater than the acting shear force so as not to reinforce,
A steel perforated beam characterized by not having a drilled hole. 3. A plurality of holes are drilled and rigidly or semi-rigidly contacted with a column, the central section is uniform, and both end sections are medium.
A perforated steel frame beam with a width-to-thickness ratio smaller than that of the central section , where at least one of an earthquake load and a wind load and a loading load act on a perforated steel frame beam rigidly or semi-rigidly connected to a column. When the plastic bending strength of the perforated part at the center of the beam is equal to the acting bending moment, do not reinforce the hole drilled in the area where the shear strength of the perforated part is larger than the acting shearing force.
And a hole perforated outside the region is reinforced . 4. A hole is drilled and rigidly or semi-rigidly contacted with a column, the central section is uniform, and both end sections are centrally cut.
A perforated steel beam with a width-to-thickness ratio smaller than that of the surface , where at least one of the seismic load and the wind load and the loading load act on the perforated steel beam rigidly or semi-rigidly connected to the column. When the plastic bending strength of the perforated portion is equal to the acting bending moment, the hole is not drilled in a region where the shearing strength of the perforated portion is larger than the acting shearing force so as not to reinforce, and
A perforated steel beam , wherein the hole is not formed outside the region . 5. The steel perforated beam includes a flange and a web.
Is a uniform H-section steel, and the distance d from the beam end is
Drilling the hole in a region of the web that satisfies the following equation :
3. The method according to claim 2, wherein no hole is formed outside said area.
Steel perforated beam. (Equation 1) However, M _ph: hole section the full plastic moment deficient considering beam d: distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : Load density of the beam Q _ph : Yield shear force of the perforated portion of the web in consideration of the _Feederend effect M _phf : Total plastic moment of the flange in consideration of the _Feederend effect. 6. The steel perforated beam includes a flange and a web.
The width-to-thickness ratio of the central part of the flange
An H-section steel having a width-to-thickness ratio of both end portions smaller than the predetermined value,
Area of web where distance de from beam end satisfies the following formula
Drilling the hole, and do not drill the hole outside the area.
The perforated steel frame beam according to claim 4, wherein (Equation 2) However, M _eh: elastic limit moment d _e of the perforated portion a distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: the full plastic moment w of H-shaped cross-section: Beams Load density Q _eh : The value obtained by multiplying the yielding shear force of the perforated portion of the web in consideration of the _Feederendel effect by the yielding shear strength coefficient M _ehf : The elastic limit moment of only the flange in consideration of the _Feederendel effect. 7. The distance d from the beam end of the H- section steel is expressed by the following formula:
Claims wherein said holes are further drilled in the area of the web satisfying
Item 7. A perforated steel beam according to item 6. (Equation 3) However, M _ph: hole section the full plastic moment deficient considering beam d: distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : Load density of the beam Q _ph : Yield shear force of the perforated portion of the web in consideration of the _Feederend effect M _phf : Total plastic moment of the flange in consideration of the _Feederend effect. 8. A column and a steel frame having a uniform cross section with a hole formed therein.
Building with rigid or semi-rigid frame composed of perforated beams
In structures, seismic and wind loads
At least one side and the perforated part of the perforated beam
Plastic bending strength equals the acting bending moment
When the shear strength of the perforated part becomes larger than the acting shear
Drilling holes in the area to prevent reinforcement and
The hole is not drilled outside the area
Building. 9. A pillar, a hole is drilled, and a center section is formed.
Uniform and the cross-section at both ends is smaller in width-to-thickness ratio than the cross-section at the center
Rigid or semi-rigid frame composed of steel perforated beam
Seismic and wind loads on steel perforated beams
Of at least one of the steel beams with perforations
The plastic bending strength of the perforated part is equal to the acting bending moment
When the shear strength of the perforated area is greater than the
Drilling the hole in the area to be reinforced so as not to reinforce, and
The hole is not drilled outside the area.
Building. 10. A cross section comprising a column, a flange and a web.
Where the distance d from the beam end of the H-beam is uniform satisfies the following equation
Holes in the area of the web to be
And a perforated steel frame which does not drill the hole outside the region
Building with rigid or semi-rigid frame composed of beams
object. (Equation 4) However, M _ph: hole section the full plastic moment deficient considering beam d: distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : Load density of the beam Q _ph : Yield shear force of the perforated portion of the web in consideration of the _Feederend effect M _phf : Total plastic moment of the flange in consideration of the _Feederend effect. 11. A structure comprising a pillar, a flange and a web,
The width-to-thickness ratio at the center of the flange is a predetermined value and the flange
Distance from the beam end of the H-section steel whose width-to-thickness ratio is smaller than the predetermined value
the web regions d _e satisfies the following equation, drilled holes
Not to reinforce and drill the hole outside the area
Rigid beams or steel beams with perforations
A building with a semi-rigid frame. (Equation 5) However, M _eh: elastic limit moment d _e of the perforated portion a distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: the full plastic moment w of H-shaped cross-section: Beams Load density Q _eh : The value obtained by multiplying the yielding shear force of the perforated portion of the web in consideration of the _Feederendel effect by the yielding shear strength coefficient M _ehf : The elastic limit moment of only the flange in consideration of the _Feederendel effect. 12. The distance d from the beam end of the H- section steel is as follows:
In the area of the web that satisfies the formula, further holes are drilled to reinforce
The building according to claim 10, wherein the building is not provided. (Equation 6) However, M _ph: hole section the full plastic moment deficient considering beam d: distance from the beam end to the center of the hole L: entire length of the beam h: clear width of RyoNaru M _p: H-type full plastic moment w sectional : Load density of the beam Q _ph : Yield shear force of the perforated portion of the web in consideration of the _Feederend effect M _phf : Total plastic moment of the flange in consideration of the _Feederend effect.