RU2796282C1 - Plank beam - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: plank beam contains boards connected to each other in a package. The beam is composite, single-span or multi-span, and additionally contains a thin steel sheet in the stretched zone between the boards. The boards and the steel sheet are connected into a package by nails located in the support zones and in the upper compressed zone. In the support zones, the boards are connected with nails along the entire height of the beam, and in the upper compressed zone, the nails are located evenly along the length of the beam to connect the boards of the compressed zone to each other and ensure their stability. In addition, the plank beam is tightened in height in the supporting areas with tie bolts to absorb transverse forces. A single-span plank beam contains a thin steel sheet between the bottommost layers of boards along the entire length of the beam. A multi-span plank beam contains thin steel sheets in stretched zones between extreme lower layers of boards of the span, and between the extreme upper layers of boards on a support between spans it contains a thin steel sheet, and steel sheets are nailed to the boards between which the sheet is located.

EFFECT: increased strength of the beam.

7 cl, 6 dwg

Description

The invention relates to the field of construction, in particular to the beams of floors and roofs of buildings made of boards.

From the prior art, wooden beams of composite section on lamellar dowels, developed by V.S. Derevyagin in 1932, consisting of two or three beams, which are rallied in height with lamellar dowels made of hardwood (https://helpiks.org/6-37874.html, viewed on 07/29/2022).

Also known is a wooden beam of a composite section on obliquely glued bonds, which ensure the rallying of the interconnected elements in such a way that they work as a whole. At the same time, the metal rods used as connecting elements are installed at an angle ranging from 30° to 45° and buried in the lower element of the beam (RF patent No. 2173376 C1, priority date 08.06. T. et al., RU).

A combined support beam is known, consisting of two wooden beams, which are treated with a gap or directly adjacent to each other, and for their connection, connecting elements are used that pass through one beam and enter the second beam, and nail plates are also used (RF patent No. 2093647 C1, priority date 02/25/1994, publication date 10/20/1997, author Johann Wolf, AT).

A common disadvantage of analogues of wooden beams of a composite section is that they use a bar as the main elements, the production of which from a log of a certain length and diameter is quantitatively limited.

At present, taking into account a number of advantages, the main type of wooden beams recommended for use in buildings for various purposes are glued beams, the known arsenal of which is quite wide.

A wooden beam is known, consisting of a package of glued boards and reinforcement glued into it, while in the lower stretched zone of the glued package there is a horizontal reinforcement with limbs in the support zones, and in the upper compressed zone there is a horizontal reinforcement with breaks in the sections passing through the inflection points of the reinforcement stretched zone (RF patent No. 117474 U1, priority date 12/19/2011, publication date 06/27/2012, authors: Roshchina S.I. et al., RU).

The disadvantage of analogue is the increased complexity of manufacturing, due to the implementation of the grooves in the components of the beam and ensuring the exact match of the configuration of steel reinforcing bars with limbs, with the position of the grooves intended for their pasting.

A wooden beam is known in the form of a package of glued boards, resting at the ends on supports, provided with lower and upper grooves selected from the side faces of the beam, into which flexible cords and steel rods are respectively pressed on the adhesive compound, and the grooves are sealed with wooden planks. At the same time, the lower grooves have a shape along their length that is close in configuration to the outline of the diagram of the main tensile stresses from the design load, the upper grooves have an orientation coinciding with the longitudinal axis of the wooden beam, and on the supporting sections of the beam through through holes located obliquely to the longitudinal axis with a slope towards the middle of the beam, flexible bundles with ends cut into strips are missing, which are glued to the lower and upper faces of the package of glued boards fan-shaped (RF patent No. 168412 U1, priority date 08.23. .N. et al., RU).

The disadvantage of analogue is the increased complexity of manufacturing, due to the implementation of grooves of complex configuration from the side faces of the beam.

Known glued wooden beam, consisting of a package of glued boards, joined together by adhesive seams. The package of glued boards is equipped in the glue joints with reinforcing elements in the form of fibers made of composite material, and the reinforcing elements are evenly distributed over the width of the package of glued boards and unevenly - along the span and height of the section of the glued wooden beam (RF patent No. 197463 U1, priority date 11/14/2019, publication date 29.04.2020, authors: Veselov V.V. and others, RU).

The disadvantage of the analogue is the complexity of manufacturing associated with the use of reinforcing elements in the adhesive joints in the form of fiber from a composite material and with the specifics of its distribution in sections and along the height of the glued beam.

A wide arsenal of glued laminated beams with load-bearing capacity and durability is also confirmed in the following publications: RF patent No. 171490 U1, priority date 02.22.2017, publication date 06.02.2017, author Veselov V.V., RU; RF patent No. 2022109 C1, priority date 07/16/1991, publication date 10/30/1994, authors: Prokopiev A.S. and others, RU; RF patent No. 2357054 C2, priority date 12/26/2006, publication date 05/27/2009, author Grekov A.V., RU; RF patent No. 2728058 C2, priority date 02/26/2018, publication date 08/27/2019, authors: Zamaliev F.S. etc., RU.

A common disadvantage of these analogs is also the high complexity of manufacturing.

As a prototype, a wooden beam was adopted, made in the form of a package of glued boards, to the side surfaces of which, with the help of C-shaped jagged strips, paired frames are attached, including longitudinal upper rods, longitudinal lower rods and inclined rods. C-shaped toothed strips have teeth in the zone of their attachment to the side surfaces of the package of glued boards and holes on their horizontal faces for fastening with dowels to the package of glued boards. The width of the C-shaped toothed strips increases from the middle of the wooden beam to its supports, and their pitch decreases from the supports of the wooden beam to its middle (RF patent No. N. et al., RU, prototype).

The disadvantage of the prototype is a complex and time-consuming manufacturing technology due to the structural complexity of the paired frames and their fastening to a package of glued boards using C-shaped jagged strips and dowels.

The technical problem solved by the invention is the need to expand the arsenal of plank beams of composite section, both split single-span and continuous, having a high bearing capacity, strength and rigidity, having a simplified manufacturing technology based on the use of a nail connection and tie elements for rallying elements together board beam.

To solve the technical problem, a plank beam containing boards connected to each other in a package is proposed. What is new is that the beam is made of composite, single-span or multi-span, and additionally contains a thin steel sheet in the stretched zone between the boards. At the same time, the connection of boards and a steel sheet into a package is made by means of nails, which are located in the support zones and in the upper compressed zone. In the supporting areas, the boards are connected with nails along the entire height of the beam. And in the upper compressed zone, the nails are located evenly along the length of the beam to connect the boards of the compressed zone to each other and ensure their stability. In addition, in the supporting areas, the plank beam is tightened in height by means of tie bolts to absorb transverse forces.

According to the invention, a thin steel sheet with a thickness of 0.5 mm to 1.5 mm is used as part of a plank beam.

According to the invention, a single-span plank beam contains a thin steel sheet between the extreme bottom layers of boards along the entire length of the beam.

According to the invention, a multi-span plank beam contains thin steel sheets in tension zones between the bottommost layers of boards of the span and the extreme top layers of boards on a support between the spans.

According to the invention, a thin steel sheet is nailed through to boards between which the sheet is located.

According to the invention, a single-span plank beam contains thin steel sheets between adjacent bottom layers of boards along the entire length of the beam.

According to the invention, a multi-span plank beam comprises thin steel sheets in tension zones between adjacent bottom layers of planks of a span and adjacent top layers of planks supported between spans.

In FIG. 1 schematically shows a single-span (split) plank beam resting on two supports, general view.

In FIG. 2 shows view A in Fig. 1.

In FIG. 3 shows a section B-B in Fig. 1.

In FIG. 4 shows a two-span (continuous) plank beam, general view.

In FIG. 5 is a section B-B in FIG. 4.

In FIG. 6 shows a section G-D in Fig. 4.

The drawings show the following symbols:

1 - single-span plank beam;

2 - two-span plank beam

3 - wooden boards stacked in layers in a package;

4 - nails connecting boards 3 to each other;

5 - coupling bolts in the support zones, perceiving transverse forces;

6 - thin steel sheet in the lower tension zone of the beam in the span;

7 - thin steel sheet in the upper tension zone of the beam on the support between spans.

The proposed plank beam in the examples is made of composite, split single-span 1 (Fig. 1) or continuous, for example, two-span 2 (Fig. 4). The composite wooden beam in both examples contains boards 3 connected in a package, between which a thin steel sheet 6, 7 with a thickness of 0.5 mm to 1.5 mm is located in the stretched zone (Fig. 1, Fig. 4). At the same time, the connection of these boards and the steel sheet into a package is made by means of nails 4, which are located in the support zones and in the upper compressed zone. In the supporting zones, the boards are connected by nails 4 along the entire height of the beam, and in the upper compressed zone, the nails 4 are located evenly along the length of the beam to connect the boards of the compressed zone to each other in order to ensure their stability. In addition, in the support areas, the plank beam is tightened in height with tie bolts 5 to absorb transverse forces.

A single-span wooden beam 1 contains the specified thin steel sheet 6 between the extreme lower layers of boards 3 along the entire length of the beam (Fig. 1), and may also contain, if necessary, additional thin steel sheets between adjacent (adjacent) lower layers of boards along the entire length of the beam (conditionally not shown).

A multi-span, in particular, a two-span beam contains the indicated thin steel sheets 6, 7 in tension zones, and between the extreme lower layers of the boards in the spans it contains sheets 6, and between the extreme upper layers of the boards on the support between the spans it contains a sheet 7 (Fig. 4 - Fig. .6). In addition, the multi-span plank beam may, if necessary, contain additional thin steel sheets in tension zones between adjacent (adjacent) bottom layers of planks of the span and adjacent (adjacent) top layers of planks on a support between spans (not shown).

It has been experimentally established that the specified thickness of thin steel sheets 6, 7 is optimal for punching with nails and absorbing tensile forces in the absence of slippage of sheets fixed with nails nailed through to the boards between which the sheet is located.

Plank beam single-span 1 (split), loaded with a transverse load, works as follows. When exposed to a transverse load in the split beam 1, a transverse force occurs with a maximum value in the support zones. This transverse force is perceived by the tie bolts 5 located in the support zones. In this case, tangential stresses arise between the boards, which are perceived by nails 4, connecting the boards to each other in the support zones along the entire height of the beam.

When exposed to a transverse load in the split beam 1, a bending moment occurs with a maximum value in the middle of the span of the beam. In this case, tensile forces arise in the lower part of the beam section, including the specified thin steel sheet 6. These tensile forces are perceived by the thin steel sheet 6. To prevent slippage, the thin steel sheet 6 is nailed 4 to the boards between which the sheet is located.

When bending in the compressed zone in the upper part of the beam section, the boards are compressed, to ensure their stability, the boards of the compressed zone are nailed 4 evenly along the length of the beam.

Two-span plank beam 2 (continuous), loaded with a transverse load, works as follows.

When exposed to a transverse load in a continuous beam 2, a transverse force occurs with a maximum value in the support zones. This transverse force is perceived by the tie bolts 5 located in the support zones. In this case, tangential stresses arise between the boards, which are perceived by nails 4, connecting the boards to each other in the support zones along the entire height of the beam.

When exposed to a transverse load in a continuous beam 2, bending moments occur in the middle of the spans of the beam and on the support. In this case, tensile forces arise in the lower part of the beam section in the span and in the upper part of the beam section on the support. These tensile forces are perceived in the span by a thin steel sheet 6, and on the support by a thin steel sheet 7. In addition, when bending in the compressed zone in the upper part of the section of the continuous beam 2, the boards are compressed, and to ensure their stability, the boards of the compressed zone are nailed 4 evenly along beam length.

The technical result achieved by the invention is to expand the arsenal of plank beams of composite section, both split single-span and continuous, having a high bearing capacity, strength and rigidity, working as a whole and having a simplified manufacturing technology based on the use of a nail connection and tie elements for rallying together the elements of a composite plank beam.

Claims (7)

1. A plank beam containing boards interconnected in a package, characterized in that the beam is made of composite, single-span or multi-span, and in the stretched zone between the boards additionally contains a thin steel sheet, while the connection of the boards and the steel sheet into the package is made by means of nails, which are located in the abutment zones and in the upper compressed zone, in the abutment zones the boards are connected by nails along the entire height of the beam, and in the upper compressed zone the nails are located evenly along the length of the beam to connect the boards of the compressed zone to each other and ensure their stability, in addition, in the abutment In the zones, the plank beam is tightened in height by means of tie bolts to absorb transverse forces. 2. Plank beam according to claim 1, characterized in that it contains a thin steel sheet with a thickness of 0.5 mm to 1.5 mm. 3. A plank beam according to claim 1, characterized in that, when performing a single-span, it contains a thin steel sheet between the extreme lower layers of the boards along the entire length of the beam. 4. A plank beam according to claim 1, characterized in that, when performing a multi-span beam, it contains thin steel sheets in tension zones between the extreme lower layers of the boards of the span and the extreme upper layers of the boards on the support between the spans. 5. Plank beam according to claim 1, characterized in that the steel sheet is nailed through with nails to the boards between which the sheet is located. 6. A plank beam according to claim 1, characterized in that, when performing a single-span, it contains thin steel sheets located between adjacent lower layers of boards along the entire length of the beam. 7. A plank beam according to claim 1, characterized in that, when performing a multi-span beam, it contains thin steel sheets in tension zones located between adjacent lower layers of span boards and adjacent upper layers of boards on a support between spans.

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