SU808627A1

SU808627A1 - Adhesive-wound wooden truss

Info

Publication number: SU808627A1
Application number: SU792762931A
Authority: SU
Inventors: Владимир Иванович Кулиш; Борис Сергеевич Быков; Игорь Юрьевич Белуцкий; Валерий Дмитриевич Федоров; Егор Андреевич Никитенко
Original assignee: Хабаровский Политехническийинститут
Priority date: 1979-05-07
Filing date: 1979-05-07
Publication date: 1981-02-28

Description

Изобретение относится к строительству и прдназначено для изготовления несущих конструкций, работающих на изгиб·. IThe invention relates to construction and is intended for the manufacture of load-bearing structures working in bending I

Известна клееная деревянная балка, включающая пластины, собранные в пакет, между которыми размещены клеевые прослойки £1] .Known glued wooden beam, including plates assembled in a package, between which are placed adhesive layers £ 1].

Недостатком этого технического ре- | шения является то, что в балке после полимеризации клеевых прослоек возникают значительные внутренние напряжения, обусловленные оставшимися в досках (пластинах) напряжениями после сушки, дефектами формы досок и разме- 1 рами клееных элементов, а также усадкой и набуханием древесины в пакете за счет изменения температурно-влажностных параметров окружающей среды, что в конечном итоге приводит к рас- 2 слаиванию и растрескиванию балки по границам контакта клея с древесиной.The disadvantage of this technical re- | The solution is that, after the polymerization of the adhesive layers, significant internal stresses arise in the beam due to stresses remaining in the boards (plates) after drying, defects in the shape of the boards and sizes of glued elements, as well as shrinkage and swelling of the wood in the bag due to a change in temperature -moisture parameters of the environment, which ultimately leads to delamination and cracking of the beam along the boundaries of glue-wood contact.

Наиболее близкой к предлагаемой является клееная деревянная балка, 2 включающая пластины, собранные в пакет, между которыми размещены клеевые прослойки и накладки, прикрепленные к боковой поверхности по концам балки .Г2]. 3Closest to the proposed is a glued wooden beam, 2 including plates assembled in a package, between which adhesive layers and overlays are attached, attached to the side surface at the ends of the beam. D2]. 3

Недостаток этого технического решения заключается в том, что при изменении равновесного влагосодержания древесины в ней развиваются усадочные деформации и в контакте накладок с боковыми поверхностями балок возникают значительные'напряжения, что неизбежно приводит к отслоению накладок .The disadvantage of this technical solution is that when the equilibrium moisture content of the wood changes, it develops shrinkage deformations and significant stresses arise in the contact of the plates with the side surfaces of the beams, which inevitably leads to delamination of the plates.

Цель изобретения - повышение несущей способности за счет исключения расслаивания и' растрескивания по клеевым прослойкам.The purpose of the invention is to increase the bearing capacity by eliminating delamination and 'cracking on the adhesive layers.

Цель достигается тем, что в клееной деревянной балке, включающей пластины, собранные в пакет, между которыми размещены клеевые прослойки и накладки, прикрепленные к боковой поверхности по концам балки, пластины установлены вертикально в поперечном сечении балки, а накладки выполнены в виде пластин, имеющих переменную длину, уменьшающуюся к опорным концам балки.The goal is achieved in that in a glued wooden beam, including plates assembled in a package, between which there are adhesive layers and overlays attached to the side surface at the ends of the beam, the plates are installed vertically in the cross section of the beam, and the overlays are made in the form of plates having a variable length decreasing to the supporting ends of the beam.

На фиг. 1 изображена предлагаемая балка; на фиг. 2 - то же, вид сверху; на фиг. 3 - поперечный разрез Α-Λ на фиг. 1.In FIG. 1 shows the proposed beam; in FIG. 2 - the same, top view; in FIG. 3 is a transverse section Α-Λ in FIG. 1.

Клееная деревянная балка включает листы шпона в виде пластин 1 и наклад ки 2 по концам балки, установленные на боковой поверхности балки, имеющие переменную длину, уменьшающуюся к опорным торцам балки.The glued wooden beam includes veneer sheets in the form of plates 1 and overlays 2 at the ends of the beam, mounted on the side surface of the beam, having a variable length, decreasing to the supporting ends of the beam.

Между пластинами'1 и 2 размещены клеевые прослойки 3.Between plates'1 and 2 there are adhesive layers 3.

При восприятии балкой нагрузки в ней возникают нормальные и касательные' напряжения. По нормальным напряжениям, подбирают сечение'в середине балки, набираемое из пластин 1, а по касательным напряжениям, интенсивность которых растет от середины к концам балки, подбирают сечение в приопорных зонах, и наклеивают пластины 2 в виде ступенчатых накладок, так как каждая пластина имеет уменьшающуюся к торцу балки длину.When the beam perceives the load, normal and tangential stresses arise in it. According to normal stresses, a section is selected in the middle of the beam recruited from plates 1, and according to tangential stresses, the intensity of which increases from the middle to the ends of the beam, a section is selected in the supporting zones, and plates 2 are glued in the form of stepped overlays, since each plate has length decreasing to the end of the beam.

Клеевые прослойки, размещенные между пластинами, расположены вертикально и в них не возникает касательных напряжений от силового воздействия на балку, так как касательные напряжения действуют по горизонтальным площадкам, поэтому в клеевых прослойках будут действовать только внутренние напряжения, возникающие при лущении шпона и его сушке, а также возникшие· от усадки древесины в монолитном пакете.The adhesive layers placed between the plates are vertically arranged and there are no tangential stresses due to the force acting on the beam, since the tangential stresses act on horizontal platforms, so only internal stresses that occur during peeling and drying of the veneer will act in the adhesive layers, and also arising from shrinkage of wood in a monolithic package.

Перенесение клеевых прослоек из эон силового воздействия и воздействий усадочных напряжений в зону,где действуют только внутренние усадочные напряжения, практически устраняет влияние расслаивания и растрескивания по клеевым прослойкам и повышает несущую способность балки.The transfer of adhesive layers from the eons of force and shrinkage stresses to the zone where only internal shrinkage stresses act, virtually eliminates the effect of delamination and cracking along the adhesive layers and increases the bearing capacity of the beam.

Установка пластин переменной длины, дающих ступенчатую накладку, позволяет скомпоновать балку оптимально, воспринимающую действие нормальных и касательных напряжений.The installation of variable-length plates, giving a stepped overlay, allows you to arrange the beam optimally, perceiving the action of normal and shear stresses.

Claims

The invention relates to the construction and is intended for the manufacture of supporting structures that work in bending. A known glued wooden beam incorporating plates assembled into a bag, between which adhesive layers DI are placed. The disadvantage of this technical solution is that significant internal stresses arise in the beam after the polymerization of adhesive interlayers, due to the stresses remaining after drying, the shape of the boards and the dimensions of the glued elements, as well as shrinking and swelling of wood in the package due to a change in temperature and humidity parameters of the environment, which ultimately leads to delamination and cracking of the beam along the boundaries of the adhesive with the wood. Closest to the present invention, a wooden beam is glued, including plates assembled in a bag, between which adhesive layers and linings are placed, attached to the side surface at the ends of beam G2. The disadvantage of this technical solution is that, when the equilibrium moisture content of the wood changes, it develops severe deformations and significant stresses occur in the contact of the linings with the side surfaces of the beams, which inevitably leads to delamination of the linings. The purpose of the invention is to increase the carrying capacity by eliminating delamination and cracking along adhesive layers. The goal is achieved by the fact that in a glued wooden beam, including plates assembled in a package, between which adhesive layers and linings are placed attached to the side surface at the ends of the beam, the plates are installed vertically in the cross section of the bullet, and the linings are made in the form of plates having variable length decreasing to the supporting ends of the base. FIG. 1 depicts the proposed beam; in fig. 2 - the same, top view; in fig. 3 is a transverse rasp LL in FIG. 1. Glued wooden beam includes veneer sheets in the form of plates 1 and nakley ki 2 at the ends of the beam, mounted on the side surface of the beam, have a variable length, decreasing to the supporting ends of the beam. Between the plates 1 and 2, adhesive layers 3 are placed. When the beam is seen from a beam, normal and tangential stresses arise in it. At normal stresses, a section is selected in the middle of the beam, assembled from plates 1, and at tangential stresses, the intensity of which increases from the middle to the ends of the beam, the section is selected in the support areas, and the plates 2 are glued in the form of stepped overlays, since the plate has a tusk to the end of the beam length. The adhesive layers placed between the plates are arranged vertically and tangential stresses from a force effect on the beam do not arise in them, since the tangential stresses act on horizontal platforms, therefore only internal stresses arising in peeling will act in the adhesive layers. veneer and its drying, as well as arising from the shrinkage of wood in a monolithic package. The transfer of adhesive interlayers from the zones of force action and the effects of shrinkage stresses to the zone where only internal shrinkage stresses act, practically eliminates the effect of delamination and cracking along the glue layers and increases the bearing capacity of the beam. Installing plates of variable length, giving a stepped overlay, allows the beam to be optimally arranged, perceiving the action of normal and tangential stresses. Claims of the invention of a glued wooden beam, including plates assembled in a package, between which adhesive layers and linings are placed attached to the side surface at the ends of the beam, so that, in order to increase the carrying capacity by eliminating delamination and cracking along adhesive interlayers, the plates are installed vertically in the cross section of the beam, and the inlays are made in the form of plates having a variable length decreasing to the supporting ends of the beam. Sources of information taken into account during the examination 1. Carlsen GG Wood constructions, M, Stroyizdat, 1961, p. D97, rice, 113.

2. Authors certificate of the USSR 654772, cl. E 04 B 5/12, 1977.

Rig.Z