KR20240114561A - Reinforcement method to make the timber beam behave plastically and reinforced steel timber beam produced by the same method - Google Patents

Abstract

The present invention discloses a method of manufacturing and designing a wooden beam so that it undergoes plastic behavior. A method of manufacturing reinforcement so that a wooden beam has plastic behavior according to an embodiment of the present invention includes the steps of providing a wooden beam, attaching a plate-shaped steel material to a lower part of the wooden beam, and combining the wooden beam and the steel material into a plurality of pieces. It includes a step of fixing with screws.
The method of designing a wooden beam to have plastic behavior includes designing the plastic bending moment and maximum bending moment of the wooden beam using the tensile yield strength of the steel material and a prediction model that can experimentally verify the actual load bearing capacity.

Description

Method for manufacturing wooden beams to have plastic behavior and steel reinforced wooden beams manufactured by the method {REINFORCEMENT METHOD TO MAKE THE TIMBER BEAM BEHAVE PLASTICALLY AND REINFORCED STEEL TIMBER BEAM PRODUCED BY THE SAME METHOD}

The present invention relates to a method of reinforcing a wooden beam to have plastic behavior and to a steel-reinforced wooden beam manufactured by the method. More specifically, it relates to a method of reinforcing and manufacturing a wooden beam to have plastic behavior using a steel plate and screw.

Reinforced concrete structures and steel structures, which constitute the main structural members of modern buildings, are designed to have plastic behavior against external loads by actively utilizing the ductility of steel materials. On the other hand, wooden buildings are designed with a high safety factor applied to wood due to brittle fracture of wood and within the elastic behavior range. The present invention provides a method of designing a wooden beam to have plastic behavior using steel and a method of manufacturing the same.

In general, wood is often finished and constructed to create eco-friendly trails, walking paths, hiking trails, stair bridges, etc. Wood materials like this are not only environmentally friendly, but are also widely used because they efficiently absorb shock and vibration and provide a visually soft and comfortable feeling.

However, since such wood is made of wood, there is a problem in that cracking or distortion of the wood occurs as it is repeatedly exposed to snow or rain and dried, causing deformation of the wood. To solve the problems of natural wood, synthetic wood, which does not deform compared to natural wood, is sometimes used.

However, such synthetic wood also has problems such as less deformation than natural wood, weakening of durability due to long-term use, and inability to prevent changes in physical properties due to ultraviolet rays, etc. In particular, repetitive temperature changes cause repeated contraction and expansion in synthetic wood, which weakens the durability of synthetic wood. In addition, since synthetic wood uses wood, there is a problem in that its durability is weakened and damaged by pests and diseases.

However, in the past, the synthetic wood itself was made into a hollow body with a space inside, and the space inside the synthetic wood was reinforced by inserting a metal reinforcing core material, so the bonding force between the metal reinforcing core material and the synthetic wood was later reduced. It tends to be bad in many ways, such as falling off and creating many gaps, and furthermore, the widening of the gaps between them can cause the synthetic wood itself to bend, and there is a problem of having to make synthetic wood and re-install the reinforcing core. there is.

Conventional technology for wooden beams requires a large cross-section to construct large spans due to the low rigidity of wood, and a high safety factor is applied because it is particularly brittle and fractures.

Republic of Korea Patent Publication No. 10-2011487 discloses a railing support assembly having a wooden exterior with improved structural strength.

The prior art is designed to insert a reinforcing plate into wood, but the manufacturing process is difficult due to the large amount of material being input and the structure is complex, resulting in low process efficiency and unknown effects.

Republic of Korea Patent Publication No. 10-2011487

An embodiment of the present invention is a method of manufacturing reinforcement so that the wooden beam behaves plastically against the shear force generated between the steel and the wood by fixing the steel material under the wooden beam with a plurality of screws in order to overcome the problems of the prior art, and the method thereof. The aim is to provide steel reinforced wooden beams manufactured by .

The main structures of modern architecture (reinforced concrete, steel structures) are designed to ductile fracture by introducing the concept of plasticity. On the other hand, wooden beams in wooden structures are brittle and fractured, so they are designed with an elastic concept, and the design techniques are different from other structures (reinforced concrete, steel structures), making structural design difficult. This is related to economics and is a major factor that discourages the choice of wooden structures. If we develop a technology that causes ductile (plastic) failure of wood rather than brittle failure, wood can be used more efficiently and safely, and structural experts can easily and economically design wooden buildings in a similar way to other structures (reinforced concrete, steel structures). There will be. Therefore, we would like to provide technology that can design wooden structures based on the plasticity concept.

According to one aspect of the present invention, it includes the steps of providing a wooden beam, attaching a plate-shaped steel material to a lower part of the wooden beam, and obliquely fixing the wooden beam and the steel material with a plurality of screws.

In the step of fixing with the plurality of screws, the wooden beam and the steel are fixed at an angle of 15 to 25 degrees with respect to the plane with the plurality of screws.

In the step of fixing with the plurality of screws, the wooden beam and the steel are fixed at an angle of 40 to 50 degrees with respect to the side of the plurality of screws.

In the step of fixing with the plurality of screws, the plurality of screws are symmetrically fixed with respect to the center line of the side of the wooden beam.

In the step of fixing with the plurality of screws, the plurality of screws are alternately fixed symmetrically with respect to the planar center line of the wooden beam.

The method of manufacturing reinforcement so that the wooden beam has plastic behavior reflects the plastic behavior (yield strength) of the steel material and designs the plastic bending moment using the following equation.

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height of the compression plastic part in the wooden beam (mm).

The method of manufacturing reinforcement so that the wooden beam has plastic behavior is designed with the maximum bending moment using the following equation by reflecting the plastic behavior.

here, is the maximum bending moment (kN·m), is the distance from the neutral axis of the cross section to the compression edge (mm), is the height of the compression plastic section in the wooden beam (mm), is the compressive strength of the wooden beam (MPa), is the distance from the neutral axis of the cross section (mm), is the distance from the neutral axis of the cross section to the tensile edge (mm), is the thickness of the steel (mm), is the flexural modulus of elasticity (MPa) of the wooden beam, is the strain rate of the wooden beam, is the tensile yield strength (MPa) of the steel.

According to another aspect of the present invention, it includes a wooden beam made of wood, a plate-shaped steel material in close contact with a lower part of the wooden beam, and a plurality of screws for obliquely fixing the wooden beam and the steel material, wherein the plurality of screws are It provides a steel-reinforced wooden beam that is symmetrical with respect to the central portion of the side of the wooden beam and is alternately and obliquely coupled with respect to the plane center line of the wooden beam.

The steel-reinforced wooden beam is designed with a plastic bending moment according to the following equation, reflecting the plastic behavior.

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height of the compression plastic part in the wooden beam (mm).

The steel-reinforced wooden beam is designed with the maximum bending moment according to the equation below, reflecting the plastic behavior.

here, is the maximum bending moment (kN·m), is the distance from the neutral axis of the cross section to the compression edge (mm), is the height of the compression plastic section in the wooden beam (mm), is the compressive strength of the wooden beam (MPa), is the distance from the neutral axis of the cross section (mm), is the distance from the neutral axis of the cross section to the tensile edge (mm), is the thickness of the steel (mm), is the flexural modulus of elasticity (MPa) of the wooden beam, is the strain rate of the wooden beam, is the tensile yield strength (MPa) of the steel.

The method of manufacturing reinforcement so that a wooden beam has plastic behavior according to the present invention has the following effects.

First, by improving the bending rigidity and bending moment of wood, the sensitivity to vibration of wooden buildings is lowered, and the structural stability is innovatively improved through plastic behavior.

Second, since wood undergoes ductile (plastic) failure rather than brittle failure, the material utilization of wood increases, and structural experts can easily design wooden buildings in a similar way to other structures (reinforced concrete, steel structures), thereby increasing the economic feasibility of wooden buildings. Innovatively improved.

Third, by providing steel-reinforced wooden beams with improved safety, the structural reliability of wooden construction is improved, and since wood has a carbon storage effect, the carbon-neutral construction market can be expected to be revitalized.

Fourth, since the cross-section of the beam is reduced compared to a typical wooden beam, manufacturing efficiency is improved and transportation is easy compared to a large cross-section. This improves the efficiency of the overall construction process, including manufacturing, transportation, construction, and material management.

Fifth, economic efficiency can be improved by reducing costs resulting from excessive safety design.

Figure 1 is a flowchart of a method for manufacturing a steel-reinforced wooden beam to have plastic behavior according to an embodiment of the present invention.
Figure 2 is a schematic diagram of a steel-reinforced wood beam manufactured by a method of reinforcing the steel-reinforced wood beam to have plastic behavior according to an embodiment of the present invention.
Figure 3 is a plan schematic diagram of a steel material fixed to a steel-reinforced wooden beam according to an embodiment of the present invention.
Figure 4 is a plan schematic diagram of a screw fixed to a steel-reinforced wooden beam according to one embodiment of the present invention.
Figure 5 is a schematic diagram showing the installation angle in the plane and side of the screw fixed to the steel reinforced wooden beam according to one embodiment of the present invention.
Figure 6 is a perspective view showing a combined state of a plurality of screws fixed to a steel reinforced wooden beam according to an embodiment of the present invention.
Figure 7 is a schematic diagram showing a design cross section of a steel reinforced wooden beam according to an embodiment of the present invention.
Figure 8 is a schematic diagram showing the load-displacement curve of a steel reinforced wooden beam according to an embodiment of the present invention.
Figure 9 is a schematic diagram showing the maximum bending stress distribution of a steel-reinforced wooden beam designed to perform plastic behavior according to an embodiment of the present invention.
Figure 10 is a schematic diagram showing the bending stress distribution of a steel-reinforced wood beam at a plastic moment predicted by the tensile yield strength of the steel material in a steel-reinforced wood beam according to an embodiment of the present invention.
Figure 11 is a schematic diagram showing the bending stress distribution of a steel-reinforced wood beam at a plastic moment predicted by the maximum tensile strength of the steel material in a steel-reinforced wood beam according to an embodiment of the present invention.
Figure 12 is a photograph of the plastic behavior of a wooden beam according to an embodiment.

The embodiments described below are provided so that those skilled in the art can easily understand the technical idea of the present invention, and the present invention is not limited thereto. In addition, the matters expressed in the attached drawings may be different from the actual implementation form in the schematic drawings to easily explain the embodiments of the present invention.

When a component is mentioned as being connected or connected to another component, it should be understood that it may be directly connected or connected to the other component, but that other components may exist in between.

Figure 1 is a flow chart of a method for manufacturing steel-reinforced wooden beams so that they behave plastically according to an embodiment of the present invention, and Figure 2 is a method for manufacturing steel-reinforced wooden beams so that they behave plastically according to an embodiment of the present invention. It is a schematic diagram of a steel-reinforced wood beam manufactured by, and Figure 3 is a plan schematic diagram of a steel material fixed to a steel-reinforced wood beam according to an embodiment of the present invention, and Figure 4 is a steel material according to an embodiment of the present invention. It is a plan schematic diagram of a screw fixed to a reinforced wooden beam, and Figure 5 is a schematic diagram showing the installation angle in the plane and side of a screw fixed to a steel reinforced wooden beam according to an embodiment of the present invention, and Figure 6 is a schematic diagram showing the installation angle of the screw fixed to the steel reinforced wooden beam according to an embodiment of the present invention. This is a perspective view showing the combined state of a plurality of screws fixed to a steel reinforced wooden beam according to one embodiment of.

Referring to FIGS. 1 to 6 together, the method of manufacturing steel-reinforced wooden beams so that they exhibit plastic behavior according to an embodiment of the present invention includes providing a wooden beam 110 (S110), and A plate-shaped iron steel material 120 having a greater length-to-width ratio is brought into close contact with the lower part (S120), and the wooden beam 110 and the steel material 120 are fixed at an angle with a plurality of screws 130 (S130). ) Provides steel reinforced wooden beams.

In one specific example, the step (S130) of fixing the wooden beam 110 and the steel material 120 with the plurality of screws 130 is performed by rotating the plurality of screws 130 at an angle of 15 to 25 degrees with respect to the plane. The wooden beam 110 and the steel material 120 are fixed at an angle. By fixing the screw 130 at an angle, a longer screw can be installed on the wooden beam 110 and the steel material 120 of the same thickness. For example, when fixing the wooden beam 110 and the steel material 120 with a plurality of screws 130 at an angle of 20 degrees with respect to the longitudinal direction of the steel material, the angle is 1/cos (20 degrees) compared to the 0 degree angle. Longer screws can be installed into wooden beams. If the angle is too large, the width of the wooden beam must also be widened, so it is advisable to consider the width and thickness of the wooden beam and fix it so that the screw does not break through the wooden beam.

In addition, the step (S130) of fixing the wooden beam 110 and the steel material 120 with the plurality of screws 130 is performed by rotating the plurality of screws 130 at an angle of 40 to 50 degrees with respect to the side. The wooden beam 110 and the steel material 120 are fixed. For example, a plurality of screws 130 connect the wooden beam 110 and the steel material 120 at an angle of 20 degrees with respect to the ground through a plurality of fastening holes 122 drilled in the steel material 120 by 45 degrees. It is desirable to fix it at an angle of degrees.

In the case of fixing in this way, the step (S130) of fixing the wooden beam 110 and the steel material 120 with the plurality of screws 130 is performed by attaching the plurality of screws 130 to the wooden beam 110. It is fixed symmetrically based on the vertical center line of the side.

And, the step (S130) of fixing the wooden beam 110 and the steel material 120 with the plurality of screws 130 is performed by attaching the plurality of screws 130 to a plane along the longitudinal direction of the wooden beam 110. They are alternately fixed symmetrically based on the center line (C-C). That is, some screws are coupled at an angle from one side of the plane center line (C-C) of the wooden beam 110 beyond the center line (C-C). And, some of the remaining screws are inclinedly coupled beyond the center line (C-C) on the other side. In this way, the plurality of screws 130 are alternately sequentially coupled to the wooden beam 110 and the steel material 120.

The plurality of screws 130 according to the present invention are each 1/3 of the entire length of the wood, that is, the length between the left end and 1/3 of the point (P/2) and the right end of the 1/3 of the length (P). /2) In the length between the wooden beam 110 and the steel material 120, the wooden beam 110 and the steel material 120 are fixed at an angle to the ground toward each end.

Figure 7 is a schematic diagram showing a design cross section of a steel reinforced wooden beam according to an embodiment of the present invention.

Referring to FIG. 7, the horizontal axis in FIG. 7 represents the beam width (mm) and bending stress (MPa), and the left vertical axis represents the position (mm) from the lower surface. On the right vertical axis, h1 and h3 represent the plastic state, and h2 represents the elastic state.

The method of manufacturing steel-reinforced wood beams according to an embodiment of the present invention is designed to satisfy the following equations and can be ductilely (plastically) deformed, and the plastic bending moment is calculated by the following equation 1 by reflecting the plastic behavior: It is designed as

[Equation 1]

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height (mm) of the compression plastic part of the wooden beam.

The method of designing the maximum bending moment by reflecting the plastic behavior of wooden beams is designed using Equation 2 below. The design model consists of three terms. The first term is the plastic bending moment when wood has compression plastic behavior, the second term is the elastic bending moment when wood has elastic behavior, and the third term is the plastic bending moment when steel has plastic behavior.

[Equation 2]

here, is the maximum bending moment (kN·m), is the distance from the neutral axis of the cross section to the compression edge (mm), is the height of the compression plastic section in the wooden beam (mm), is the compressive strength of the wooden beam (MPa), is the distance from the neutral axis of the cross section (mm), is the distance from the neutral axis of the cross section to the tensile edge (mm), is the thickness of the steel (mm), is the flexural modulus of elasticity (MPa) of the wooden beam, is the strain rate of the wooden beam, is the tensile yield strength (MPa) of the steel.

The height of the compression plastic section of a wooden beam can be calculated using the model below. It is derived from the theory that the compressive force resisted by the compression plastic section of wood is equal to the tensile force that steel can support.

[Equation 3]

here, is the height of the compression plastic part in the wooden beam (mm), is the tensile yield strength of the steel (MPa), is the thickness of the steel (mm), is the compressive strength (MPa) of the wooden beam.

The method for designing the cross section of the plastic bending moment of a wooden beam is as follows: It is derived from the maximum tensile force that the steel can resist.

[Equation 4]

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height (mm) of the compression plastic part of the wooden beam.

The formula for predicting the concentrated load acting on a wooden beam using the plastic bending moment of a steel-reinforced wooden beam is as follows.

[Equation 5]

here, is the concentrated load (kN) that a steel-reinforced wooden beam can withstand, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the distance (mm) from the point of the steel reinforced wooden beam to the load point.

The formula for predicting the uniformly distributed load acting on the wooden beam using the plastic bending moment of the steel-reinforced wooden beam is as follows.

[Equation 6]

here, is the concentrated load (kN) that a steel-reinforced wooden beam can withstand, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the span (mm) of the steel-reinforced wooden beam.

Figure 8 is a schematic diagram showing the load-displacement curve of a wooden beam according to one embodiment of the present invention.

Referring to FIG. 8 together with the other drawings, a steel-reinforced wood beam designed to perform plastic behavior shows two types of failure: after tensile failure occurs at the finger joint or knot area, when compression failure occurs in the wood, or after wood compression failure occurs. Tensile fracture occurred.

In both cases, the load did not fall to 0 after failure, but a load of approximately 30 kN was supported while large deformation occurred. This indicates plastic behavior and excellent ductility.

In the graph of Figure 8, the horizontal axis represents displacement (mm), and the vertical axis represents load (N). The load-displacement curve of a steel-reinforced wooden beam to perform plastic behavior according to an embodiment of the present invention, where the red horizontal dotted line located on the upper side is a steel-reinforced wooden beam predicted based on the tensile strength of the steel. The load-carrying capacity of the steel-reinforced wooden beam is predicted by the horizontal blue dotted line at the bottom based on the tensile yield strength of the steel.

Figure 9 is a schematic diagram showing the maximum bending stress distribution of a steel-reinforced wooden beam designed to have plastic behavior in a wooden beam according to an embodiment of the present invention, and Figure 10 is a yield strength of steel in a wooden beam according to an embodiment of the present invention. It is a schematic diagram showing the bending stress distribution of a steel-reinforced wood beam at the predicted plastic moment, and Figure 11 is a schematic diagram showing the bending stress distribution of a steel-reinforced wood beam at a plastic moment predicted by the maximum tensile strength of the steel in a steel-reinforced wood beam according to an embodiment of the present invention. This is a schematic diagram showing the bending stress distribution.

Referring to FIGS. 9 to 11 along with other drawings, in the steel reinforced wooden beam, the thickness of the glue laminated timber (GLT) is 120 mm and the thickness of the steel is 4 mm. neutral axis represents the neutral axis.

In the graph of Figure 9, the horizontal axis represents the beam width (mm) and bending stress (MPa), and the vertical axis on the left represents the position (mm) from the lower surface. On the right vertical axis, h1 and h3 represent the plastic state, and h2 represents the elastic state.

In the graphs of FIGS. 10 and 11, the horizontal axis represents the beam width (mm) and bending stress (MPa), and the left vertical axis represents the position (mm) from the lower surface. On the right vertical axis, h1 represents tensile force and h3 represents compressive force.

Figure 12 is a photograph of the plastic behavior of a wooden beam according to an embodiment.

The measured plastic load of the test piece was close to the load-bearing capacity predicted by the maximum tensile strength of the steel material, which means that the steel installed in the test piece was close to the maximum tensile strength. It can be seen that the plastic loads are all higher than the load-bearing capacity predicted by the tensile yield strength of the steel. This means that safe design is possible with the prediction model presented in the present invention and the tensile yield strength of steel.

The flexural performance of a general wooden beam and a steel reinforced wooden beam for plastic behavior according to the present invention are compared.

Table 1 shows the physical properties of the materials used in the experiment, and Table 2 shows the experimental measurements. The bending stiffness of steel-reinforced wooden beams designed for plastic behavior was improved by 44.9 to 72.8% compared to the wooden beam before reinforcement, and the load and bending moment resistance ability was improved by about 75%. In particular, the steel-reinforced wooden beam supported a load of about 30 kN through the tensile force of the steel and the compressive force of the wood while it was greatly deformed even after failure. This ductility ability, which does not collapse immediately after failure, means that it is an excellent member in terms of ensuring structural safety, and economical design is possible because equivalent structural performance can be designed with a smaller cross-section. In addition, when the wood is destroyed, the moment resistance of the wooden beam becomes 0 and the structure collapses. However, the steel-reinforced wooden beam maintains its plastic moment even when the wood is destroyed, so the structure does not collapse before other structural members (joints and columns) are destroyed.

Table 1 shows the physical properties of the materials.

[Table 1]

Table 2 shows the flexural performance of typical wood beams and plastically designed steel-reinforced wood beams.

[Table 2]

Through Table 1 and Table 2, 1) bending stiffness, 2) bending stiffness measured for group classification, 3) bending stiffness measured during destruction test, 4) (bending stiffness measured for group classification / bending stiffness measured during destruction test) × 100 , 5) maximum load, 6) bending moment, 7) coefficient of variation.

Therefore, the method of manufacturing steel-reinforced wooden beams (RGLT) according to the present invention so that they exhibit plastic behavior improves the bending stiffness and bending moment of wood in general wood beams (GLT), thereby lowering the sensitivity to vibration of wooden buildings and improving plasticity. It can provide the effect of innovatively improving structural stability through behavior, and can be expected to have the effect of revitalizing the wooden construction market by providing steel-reinforced wooden beams with improved safety.

Those skilled in the art to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing its technical idea or essential features. Therefore, the embodiments described above are merely presented by selecting the most preferred embodiments among various possible embodiments to aid the understanding of those skilled in the art, and the technical idea of this invention is not necessarily limited or limited only by the presented embodiments. Rather, it is stated that various changes, additions, and changes are possible without departing from the technical spirit of the present invention, as well as other equivalent embodiments.

110: wooden beam
120: steel
122: fastening hole
130: screw

Claims (10)

Preparing wooden beams,
attaching a plate-shaped steel material to the lower part of the wooden beam, and
Characterized in that it includes the step of fixing the wooden beam and the steel material at an angle with a plurality of screws.
A method of manufacturing reinforcement so that wooden beams behave plastically. According to claim 1,
The step of fixing with a plurality of screws,
Characterized in that the plurality of screws secure the wooden beam and the steel material at an angle of 15 to 25 degrees with respect to the plane.
A method of manufacturing reinforcement so that wooden beams behave plastically. According to claim 1,
The step of fixing with a plurality of screws,
Characterized in that the plurality of screws fix the wooden beam and the steel material at an angle of 40 to 50 degrees with respect to the side.
A method of manufacturing reinforcement so that wooden beams behave plastically. According to claim 1,
The step of fixing with a plurality of screws,
Characterized in that the plurality of screws are fixed symmetrically with respect to the center line of the side of the wooden beam.
A method of manufacturing reinforcement so that wooden beams behave plastically. According to claim 1,
The step of fixing with a plurality of screws,
Characterized in that the plurality of screws are alternately fixed symmetrically based on the planar center line of the wooden beam.
A method of manufacturing reinforcement so that wooden beams behave plastically. According to claim 1,
The method of manufacturing reinforcement so that the wooden beam has plastic behavior is,
It is characterized by designing the plastic bending moment according to the following equation by reflecting the plastic behavior.
A method of manufacturing reinforcement so that wooden beams behave plastically.

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height (mm) of the compression plastic part of the wooden beam. According to claim 6,
The method of manufacturing reinforcement so that the wooden beam has plastic behavior is,
It is characterized by being designed with the maximum bending moment according to the equation below, reflecting the plastic behavior.
A method of manufacturing reinforcement so that wooden beams behave plastically.

here, is the maximum bending moment (kN·m), is the distance from the neutral axis of the cross section to the compression edge (mm), is the height of the compression plastic section in the wooden beam (mm), is the compressive strength of the wooden beam (MPa), is the distance from the neutral axis of the cross section (mm), is the distance from the neutral axis of the cross section to the tensile edge (mm), is the thickness of the steel (mm), is the flexural modulus of elasticity (MPa) of the wooden beam, is the strain rate of the wooden beam, is the tensile yield strength (MPa) of the steel. Wooden beams made of wood;
A plate-shaped steel material in close contact with the lower part of the wooden beam; and
A plurality of screws for fixing the wooden beam and the steel material at an angle; Including,
A steel-reinforced wooden beam, characterized in that the plurality of screws are symmetrical with respect to the central portion of the side of the wooden beam, and are alternately and obliquely coupled with respect to the planar center line of the wooden beam. According to claim 8,
A steel-reinforced wooden beam, characterized in that the steel-reinforced wooden beam is designed with a plastic bending moment according to the following equation by reflecting plastic behavior.

here, is the plastic bending moment that a steel-reinforced wooden beam can resist (kN·m), is the tensile yield strength of the steel (MPa), is the width of the steel (mm), is the thickness of the steel (mm), is the overall height of the steel-reinforced wooden beam (mm), is the height of the compression plastic part in the wooden beam (mm). According to clause 9,
A steel-reinforced wooden beam, characterized in that the steel-reinforced wooden beam is designed with a maximum bending moment according to the following equation, reflecting plastic behavior.

here, is the maximum bending moment (kN·m), is the distance from the neutral axis of the cross section to the compression edge (mm), is the height of the compression plastic section in the wooden beam (mm), is the compressive strength of the wooden beam (MPa), is the distance from the neutral axis of the cross section (mm), is the distance from the neutral axis of the cross section to the tensile edge (mm), is the thickness of the steel (mm), is the flexural modulus of elasticity (MPa) of the wooden beam, is the strain rate of the wooden beam, is the tensile yield strength (MPa) of the steel.

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