CA1196169A - Sturdy i-girder - Google Patents
Sturdy i-girderInfo
- Publication number
- CA1196169A CA1196169A CA000415638A CA415638A CA1196169A CA 1196169 A CA1196169 A CA 1196169A CA 000415638 A CA000415638 A CA 000415638A CA 415638 A CA415638 A CA 415638A CA 1196169 A CA1196169 A CA 1196169A
- Authority
- CA
- Canada
- Prior art keywords
- girder
- web
- wood
- plies
- ply
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E04—BUILDING
- E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
- E04C3/00—Structural elongated elements designed for load-supporting
- E04C3/02—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces
- E04C3/12—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members
- E04C3/14—Joists; Girders, trusses, or trusslike structures, e.g. prefabricated; Lintels; Transoms; Braces of wood, e.g. with reinforcements, with tensioning members with substantially solid, i.e. unapertured, web
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Rod-Shaped Construction Members (AREA)
Abstract
Abstract The invention relates to a sturdy I-girder. In the previously used corresponding girders, for example in I-girders made of laminated wood, it has not been possible to adjust the dimensioning so that bending stress, shearing stress and bending flexure would all have been equal dimensioning factors, and so it has been necessary to overdimension the girder. The object of the invention is in particular to eliminate this disadvantage and to achieve thereby a considerable saving in material. This is achieved by making the web of the girder from continuous multi-ply wood with 10-60 %, preferably 30 %, of its plies being such that their grain orientation is transverse in relation to the web length and the remainder of the plies being such that their grain orientation is parallel to the web length. The booms of the girder are made from multi-ply wood the plies of which have their grain orientation parallel to the web length.
Description
-A sturd~ I-girder The invention relates to a sturdy I-girder. Sturdy timber girders are currently manufactured b~ gluing laminae of sawn timber together, and the product is called laminated wood. The strength/weight ratio of laminated wood is rather advantageous. However, it is characterized in that the strength property which determines the dimensioning in different load situations varies, whereupon the timber girder in ~uestion is overdimensioned as regards other properties.
As regards strength, three main factors are primarily concerned. First there is bending flexure, which is in general approximately girder span/200-300, e.g. 50 mm for a span of 15 m.
The second one is the bending stress produced by the load in the girder. It is a-t its greatest in the middle of the span in the case of a single-span girder. A certain theoretical bending stress, characteris~lc of the material, must not be exceeded, since otherwise there is the risk that the girder breaks in the middle.
The third factor is the shearing stress produced by the load in the girder; the ends of the girder are subjected to shearing stress by the supports. With great loads, the sheariny Eorce tends to split a laminated-wood girder a-t its ends in the longitudinal direction in such a way that the lower edge of the girder is stretched because of the bending flexure and the upper surface resists this displacement, whereupon the girder splits at its ends on the horizontal level along the center line.
.
Starting from one of the extremes of the capacity range of laminated wood, namely, a long span and a small load, the dimensioning factor is bending flexure (span 1 in Figure 1). In the middle of the range the dimensioning factor is bending stress (span 2, Figure 1), and in the opposite extreme, in which the load is great and the span is short, the dimensioning factor is shearing stress (span 3 in Figure 1).
As noted above, when one factor determines the dimensioning, laminated wood is overdimensioned in other respects. To correct this situation, laminated wood has been glued also in the form of an I-profile (Figure 3).
Bending flexure and bending stress can in this way be optimized so that there is no overdimensioning with respect to either one of these factors, which results in a considerable saving in raw material. However, this cannot be realized except in certain special situations, since shearing stress will, when the load increases, dimension the narrowed web in such a way that it should be widened. Thus, sufficient benefit cannot be drawn from this profile so as to make its manufacture economically sensible. Therefore such laminated wood is currently not manufactured to a significant degree.
The use of plywood between wide booms has been studied as a second alternative. The shear strength of plywood is sufficient, but the tendencies of crinkling and buckling owing to the very slim and narrow structure (Figure 4A) have become a problem. Attempts have been made to solve these problems by gluing so-called box structures (Figure 4B), but in this case expensive joint alternatives have been required, because if economical use oE plywood sheets is desired~ they must be made into sheets having the same lenyth as the girder. The fact that plywood-webbed sturdy composite girders are generally not manufactured is evidently due, in addition to the above, to the difficult control of the behavior of the girder in question in conditions of varying dampness and to its non-existent fire resistant properties.
Multi-ply wood is a prior known product, in which there is first manufactured from plies over 2 mm thick, by weather-proof gluing, a 25-75 mm thick and up to 2 meters wide, continuous, up to 30 m long sheet. The grain of most of the plies is longitudinally oriented. Laminated-wood girders, planks or various small profiles are obtained by cutting the sheet. The product has been on the market since the beginniny of 1978.
Multi-ply wood has an advantage in being usable for many distinctly different purposes, since ik has been possible to vary its structure within a wide range, when necessary.
For this reason, the sturdy I-girder was consciously developed through the optimization of multi-ply wood.
The objec~ive set was a sturdy, continuous and fire-resistant girder in which bendin~ flexure, bending stress and shearing stress would all be e~ual dimensioning factors, whereby a maximal saving of material would be achieved. Surprisingly, this objective was achieved when the solution according to the characteristics of the accompanying claim was invented, by applying multi-ply wood.
For example, in the fire resistance classification, I-girders having a minimum web of 65 mm are prescribed for use in public areasi~l~inland- The fire resistance o-E an I-girder according to the invention is at minimum 1/2 hour.
With an I-girder according to the invention, long spans can be achieved in such a way that the cross section is clearly smaller than that of a laminated-wood girder dimensioned for the corresponding span. A table of comparison is enclosed. The table shows the maximum spans for a multi-ply I-girder and corresponding laminated wood, when the effects of the three main dimensioning factors, bending stress, shearing stress and bending flexure, have been taken into consideration separately. The maximum final span of the girder is the minim~un of -these three span values.
The following advantages can be recorded for the benefit of a multi-ply I-girder as compared with a laminatecl-wood girder:
- A cross section 37-84 % smaller than with laminated wood can be achieved with a structure of the same height, see table.
- Owing to the cross ba~nds of the web and the booms, the expansion of the girder in the vertical direction is almost completely prevented, whereas in laminated wood there is a difference of about 4 % between completely dry and wet wood.
- Owing to the cross bands in the web, the jointing technique is simpler at the ends of the I-girder.
- Owing to the cross bands and the vertical glued joints of the booms, the pressures, or forces, by which the surfaces oE the girder and the underlying support press against each other do not constitute a problem.(The end of a narrow girder collapses, when this pressure is too great.) - The fire resistance of the multi-ply I-girder, adequate as such, is easily improved by means of fire-resistance classified wool.
- The same manufacturing technique can be used for ~9~
manufacturing very sturdy box girders, and since the materials of the web and the booms are to a great extent similar, warping due to dampness can be controlledO
- In addition to being used as a sturdy girder, the profile in question can be used as a pillar, in which case it has very high stability values and makes jointing teahniques very simple in such a way that in the pillar the booms continue beyond the pillar web tothe extent of the height of the web of the horizontal girder, and the web of the horizontal girder continues beyond the booms of the horizontal girder to the extent of the height of the pillar web. Thus the booms of the pillar can be easily joined to the web of the horizontal girder (Figure 6).
The invention is illustrated below with reference to the accompanying drawinys, in which Figure 1 depicts graphically different load cases of laminated wood and Figure 2 depicts graphically a comparison of the strength properties of a laminated wood girder and a multi-ply I-girder. Figure 3 depicts a known I-girder made of laminated wood, and Figure 4 a known I-girder and a box girder made from plywood. Figure 5 depicts a multi-ply I-girder according to the invention, and Figure 6 a special application of an I-girder according to the invention.
Figure 1 shows graphically, with the span L of the girder as the vertical axis and the load F as the horizontal axis, the effect of bending flexure lw, bending stress lb and shearing stress lv on the dimensioning of ordinary laminated wood. The proportions are presented arbitrarily, and so bending stress does not necessarily have -the sector width of the type plotted. Bending flexure is the dimensioning factor withln span 1, bending stress within span 2, and shearing stress within span 3. Figure 2 depicts ~lg~
~raphically the cross-sectional area of laminated wood L (dotted lines) and corresponding multi-ply I-girders K
(solid lines) as functions of the product which is obtained by multiplying by each other the maximum span values for bending and shearing strengths and bending flexure. The spacings of the supports are 4.8, 6.0 and 7.2 m (cf. the table). Three spans have been taken for each spaciny, and both a laminated-wood girder and a multi-ply I-girder have been optimized for each span, and so the differences indicate that a certain strength property of laminated timber has overcapacity.
Figure 3 shows a known laminated-wood girder made in the shape of an I-profile, having a web u and booms p. Figure 4A depicts a known I-girder, in which the web u is made of plywood and fitted between wide booms p. Figure 4B for its part shows an also known box-structured plywood girder.
Figure 5 depicts one example of the dimensioning of a girder according to the invention.
Figure 6 shows how an I-girder according to the invention can be used as a pillar and be joined in a simple manner to a horizontal girder in such a way that the booms pp of the pillar continue beyond the pillar web up to the extent of the height of the web UV of the horizontal girder, and the web UV of the horizontal girder for its part continues beyond the booms Pv of the horizontal girder to the extent of the height of the pillar web up.
Figures5 and 6 illustrate clearly the general structure of the I-girder according to the invention. Thus, the girder comprises a web u and a total of four booms p, which have been glued t.o the edges of t.he web on both sides of the web. The booms also consist of multi-ply wood, and their grain orientation is always in t.he longitudinal direction of the web, in addition to which the grains of most of the different plies of the web are in the Longitudinal direction of the web. One conventional arrangement is such that the web is assembled from a great number of plies, for example 26 plies one on top of the other, the second, fourth and tenth ply, calculated from each surface of the web, having a transverse grain orientation. In the arrangement of the grain orientation, an arrangement symmetrical in relation to the center plane is generally used, and the installation of transverse-grain plies on the surface is avoided so that they would not be destroyed first in a fire.
Table Profile Mutual Maximun span ror opti~al Girder ~utual Max~mum span for optimal Ratio between height distan oe multi-ply I-girderl) width x distan oe lamLnated-wood girder, a~unts of wood (mm)between (m) height between with the same span and load Optimal laminat2d w03d/
S PP Bending Shearing Flexure (m ) suppo ts . (m) optimal multi-ply w03d (m) (m) Ben~ing .S~ri ng Flexure 9004.8 14.8 16.9 14.2 140x1080 4.8 15.3 17.2 14.6 6.0 13.1 13.~ 12.8 6.0 13.6 13.6 13.6 ~ 1.37 7.2 11.9 11.1 11.5 7.2 12.4 11.1 12.2 J
12004.8 19.0 24.1 18.4 165x1260 4.8 19.4 24.1 18.7 6.0 17.0 19.1 16.7 6.0 17.4 19.3 17.0 t 1.60 702 15.0 15.1 15.0 7.2 15.4 15.2 15.5 o~ ~, 18004.8 28.1 34.9 27.1 210x1710 4.8 28.2 39.3 27.2 600 24.9 27.5 24.6 6.0 24.9 30.7 25.1 ~ 1.84 7.2 22.5 22.6 22.9 7.2 22.8 25.6 22.9 1) 6 of the plies in the web structure have a transverse grain orientation and 17 of them longitudinal grain orientation in relation to the longitudinal direction of the girder.
As regards strength, three main factors are primarily concerned. First there is bending flexure, which is in general approximately girder span/200-300, e.g. 50 mm for a span of 15 m.
The second one is the bending stress produced by the load in the girder. It is a-t its greatest in the middle of the span in the case of a single-span girder. A certain theoretical bending stress, characteris~lc of the material, must not be exceeded, since otherwise there is the risk that the girder breaks in the middle.
The third factor is the shearing stress produced by the load in the girder; the ends of the girder are subjected to shearing stress by the supports. With great loads, the sheariny Eorce tends to split a laminated-wood girder a-t its ends in the longitudinal direction in such a way that the lower edge of the girder is stretched because of the bending flexure and the upper surface resists this displacement, whereupon the girder splits at its ends on the horizontal level along the center line.
.
Starting from one of the extremes of the capacity range of laminated wood, namely, a long span and a small load, the dimensioning factor is bending flexure (span 1 in Figure 1). In the middle of the range the dimensioning factor is bending stress (span 2, Figure 1), and in the opposite extreme, in which the load is great and the span is short, the dimensioning factor is shearing stress (span 3 in Figure 1).
As noted above, when one factor determines the dimensioning, laminated wood is overdimensioned in other respects. To correct this situation, laminated wood has been glued also in the form of an I-profile (Figure 3).
Bending flexure and bending stress can in this way be optimized so that there is no overdimensioning with respect to either one of these factors, which results in a considerable saving in raw material. However, this cannot be realized except in certain special situations, since shearing stress will, when the load increases, dimension the narrowed web in such a way that it should be widened. Thus, sufficient benefit cannot be drawn from this profile so as to make its manufacture economically sensible. Therefore such laminated wood is currently not manufactured to a significant degree.
The use of plywood between wide booms has been studied as a second alternative. The shear strength of plywood is sufficient, but the tendencies of crinkling and buckling owing to the very slim and narrow structure (Figure 4A) have become a problem. Attempts have been made to solve these problems by gluing so-called box structures (Figure 4B), but in this case expensive joint alternatives have been required, because if economical use oE plywood sheets is desired~ they must be made into sheets having the same lenyth as the girder. The fact that plywood-webbed sturdy composite girders are generally not manufactured is evidently due, in addition to the above, to the difficult control of the behavior of the girder in question in conditions of varying dampness and to its non-existent fire resistant properties.
Multi-ply wood is a prior known product, in which there is first manufactured from plies over 2 mm thick, by weather-proof gluing, a 25-75 mm thick and up to 2 meters wide, continuous, up to 30 m long sheet. The grain of most of the plies is longitudinally oriented. Laminated-wood girders, planks or various small profiles are obtained by cutting the sheet. The product has been on the market since the beginniny of 1978.
Multi-ply wood has an advantage in being usable for many distinctly different purposes, since ik has been possible to vary its structure within a wide range, when necessary.
For this reason, the sturdy I-girder was consciously developed through the optimization of multi-ply wood.
The objec~ive set was a sturdy, continuous and fire-resistant girder in which bendin~ flexure, bending stress and shearing stress would all be e~ual dimensioning factors, whereby a maximal saving of material would be achieved. Surprisingly, this objective was achieved when the solution according to the characteristics of the accompanying claim was invented, by applying multi-ply wood.
For example, in the fire resistance classification, I-girders having a minimum web of 65 mm are prescribed for use in public areasi~l~inland- The fire resistance o-E an I-girder according to the invention is at minimum 1/2 hour.
With an I-girder according to the invention, long spans can be achieved in such a way that the cross section is clearly smaller than that of a laminated-wood girder dimensioned for the corresponding span. A table of comparison is enclosed. The table shows the maximum spans for a multi-ply I-girder and corresponding laminated wood, when the effects of the three main dimensioning factors, bending stress, shearing stress and bending flexure, have been taken into consideration separately. The maximum final span of the girder is the minim~un of -these three span values.
The following advantages can be recorded for the benefit of a multi-ply I-girder as compared with a laminatecl-wood girder:
- A cross section 37-84 % smaller than with laminated wood can be achieved with a structure of the same height, see table.
- Owing to the cross ba~nds of the web and the booms, the expansion of the girder in the vertical direction is almost completely prevented, whereas in laminated wood there is a difference of about 4 % between completely dry and wet wood.
- Owing to the cross bands in the web, the jointing technique is simpler at the ends of the I-girder.
- Owing to the cross bands and the vertical glued joints of the booms, the pressures, or forces, by which the surfaces oE the girder and the underlying support press against each other do not constitute a problem.(The end of a narrow girder collapses, when this pressure is too great.) - The fire resistance of the multi-ply I-girder, adequate as such, is easily improved by means of fire-resistance classified wool.
- The same manufacturing technique can be used for ~9~
manufacturing very sturdy box girders, and since the materials of the web and the booms are to a great extent similar, warping due to dampness can be controlledO
- In addition to being used as a sturdy girder, the profile in question can be used as a pillar, in which case it has very high stability values and makes jointing teahniques very simple in such a way that in the pillar the booms continue beyond the pillar web tothe extent of the height of the web of the horizontal girder, and the web of the horizontal girder continues beyond the booms of the horizontal girder to the extent of the height of the pillar web. Thus the booms of the pillar can be easily joined to the web of the horizontal girder (Figure 6).
The invention is illustrated below with reference to the accompanying drawinys, in which Figure 1 depicts graphically different load cases of laminated wood and Figure 2 depicts graphically a comparison of the strength properties of a laminated wood girder and a multi-ply I-girder. Figure 3 depicts a known I-girder made of laminated wood, and Figure 4 a known I-girder and a box girder made from plywood. Figure 5 depicts a multi-ply I-girder according to the invention, and Figure 6 a special application of an I-girder according to the invention.
Figure 1 shows graphically, with the span L of the girder as the vertical axis and the load F as the horizontal axis, the effect of bending flexure lw, bending stress lb and shearing stress lv on the dimensioning of ordinary laminated wood. The proportions are presented arbitrarily, and so bending stress does not necessarily have -the sector width of the type plotted. Bending flexure is the dimensioning factor withln span 1, bending stress within span 2, and shearing stress within span 3. Figure 2 depicts ~lg~
~raphically the cross-sectional area of laminated wood L (dotted lines) and corresponding multi-ply I-girders K
(solid lines) as functions of the product which is obtained by multiplying by each other the maximum span values for bending and shearing strengths and bending flexure. The spacings of the supports are 4.8, 6.0 and 7.2 m (cf. the table). Three spans have been taken for each spaciny, and both a laminated-wood girder and a multi-ply I-girder have been optimized for each span, and so the differences indicate that a certain strength property of laminated timber has overcapacity.
Figure 3 shows a known laminated-wood girder made in the shape of an I-profile, having a web u and booms p. Figure 4A depicts a known I-girder, in which the web u is made of plywood and fitted between wide booms p. Figure 4B for its part shows an also known box-structured plywood girder.
Figure 5 depicts one example of the dimensioning of a girder according to the invention.
Figure 6 shows how an I-girder according to the invention can be used as a pillar and be joined in a simple manner to a horizontal girder in such a way that the booms pp of the pillar continue beyond the pillar web up to the extent of the height of the web UV of the horizontal girder, and the web UV of the horizontal girder for its part continues beyond the booms Pv of the horizontal girder to the extent of the height of the pillar web up.
Figures5 and 6 illustrate clearly the general structure of the I-girder according to the invention. Thus, the girder comprises a web u and a total of four booms p, which have been glued t.o the edges of t.he web on both sides of the web. The booms also consist of multi-ply wood, and their grain orientation is always in t.he longitudinal direction of the web, in addition to which the grains of most of the different plies of the web are in the Longitudinal direction of the web. One conventional arrangement is such that the web is assembled from a great number of plies, for example 26 plies one on top of the other, the second, fourth and tenth ply, calculated from each surface of the web, having a transverse grain orientation. In the arrangement of the grain orientation, an arrangement symmetrical in relation to the center plane is generally used, and the installation of transverse-grain plies on the surface is avoided so that they would not be destroyed first in a fire.
Table Profile Mutual Maximun span ror opti~al Girder ~utual Max~mum span for optimal Ratio between height distan oe multi-ply I-girderl) width x distan oe lamLnated-wood girder, a~unts of wood (mm)between (m) height between with the same span and load Optimal laminat2d w03d/
S PP Bending Shearing Flexure (m ) suppo ts . (m) optimal multi-ply w03d (m) (m) Ben~ing .S~ri ng Flexure 9004.8 14.8 16.9 14.2 140x1080 4.8 15.3 17.2 14.6 6.0 13.1 13.~ 12.8 6.0 13.6 13.6 13.6 ~ 1.37 7.2 11.9 11.1 11.5 7.2 12.4 11.1 12.2 J
12004.8 19.0 24.1 18.4 165x1260 4.8 19.4 24.1 18.7 6.0 17.0 19.1 16.7 6.0 17.4 19.3 17.0 t 1.60 702 15.0 15.1 15.0 7.2 15.4 15.2 15.5 o~ ~, 18004.8 28.1 34.9 27.1 210x1710 4.8 28.2 39.3 27.2 600 24.9 27.5 24.6 6.0 24.9 30.7 25.1 ~ 1.84 7.2 22.5 22.6 22.9 7.2 22.8 25.6 22.9 1) 6 of the plies in the web structure have a transverse grain orientation and 17 of them longitudinal grain orientation in relation to the longitudinal direction of the girder.
Claims
1. An I-girder assembly, which comprises: a web member of a predetermined length and width and having side surface multi-ply wood having from 10% to 60% of plies having grain orientation transverse to said length of said web member with a remainder of said plies having grain orientation parallel to said length of said web member;
and boom members mounted lengthwise to said web member on said side surfaces thereof, said boom members formed of multi-ply wood having ply grain orientation parallel to said length of said web member.
and boom members mounted lengthwise to said web member on said side surfaces thereof, said boom members formed of multi-ply wood having ply grain orientation parallel to said length of said web member.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI813663 | 1981-11-18 | ||
| FI813663A FI62887C (en) | 1981-11-18 | 1981-11-18 | GROV I-BALK |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1196169A true CA1196169A (en) | 1985-11-05 |
Family
ID=8514880
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000415638A Expired CA1196169A (en) | 1981-11-18 | 1982-11-16 | Sturdy i-girder |
Country Status (5)
| Country | Link |
|---|---|
| EP (1) | EP0079761B1 (en) |
| CA (1) | CA1196169A (en) |
| DE (1) | DE3269471D1 (en) |
| DK (1) | DK511282A (en) |
| FI (1) | FI62887C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809735A (en) * | 1996-08-19 | 1998-09-22 | Les Bois Laumar Inc. | Steel-wood system |
| US6167675B1 (en) | 1996-08-19 | 2001-01-02 | Les Bois Laumar, Inc. | Steel-wood system |
| US6701690B2 (en) | 2001-07-17 | 2004-03-09 | Guildo Deschenes | I-shaped wooden beam |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4669243A (en) * | 1985-11-06 | 1987-06-02 | Truswal Systems Corporation | Fire protective system and method for a support structure |
| FR2599770B1 (en) * | 1986-06-09 | 1991-11-15 | Jomard Daniel | Gantry cranes made from CTBX, traditional timber cuts and tube spindles |
| US5377472A (en) * | 1992-02-06 | 1995-01-03 | Terenzoni; Bob | Timber system |
| US5974760A (en) * | 1993-03-24 | 1999-11-02 | Tingley; Daniel A. | Wood I-beam with synthetic fiber reinforcement |
| US6173550B1 (en) | 1993-03-24 | 2001-01-16 | Daniel A. Tingley | Wood I-beam conditioned reinforcement panel |
| FR2764622A1 (en) * | 1997-06-17 | 1998-12-18 | Paul Henri Mathis | Vegetable fibre base composite beam used in constructions, especially of support structures |
| EP3919698B1 (en) | 2020-06-05 | 2023-08-02 | Phylem Structures, Sl | Engineered wood structural system |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1825643U (en) * | 1960-11-22 | 1961-01-26 | Wilhelm Poppensieker Fa | MULTI-PANEL MADE OF SEVERAL ALTERNATING LAYERS GLUED TOGETHER WITH PLYWOOD LAYERS. |
| AT298013B (en) * | 1970-01-12 | 1972-04-25 | Oesterr Doka Schalung | Box girder made of wood |
| FR2367883A1 (en) * | 1976-10-12 | 1978-05-12 | Uhalde Bernier Sa | Compound plywood section for construction industry - has box or I=section and is fabricated of plywood sheets with staggered joints |
| GB1514879A (en) * | 1976-10-22 | 1978-06-21 | Nickerson & Co Ltd W | Joints in wooden structural elements |
| DE8033681U1 (en) * | 1980-12-18 | 1981-05-27 | Achberger GmbH & Co KG, Karl, 8903 Bobingen | DEVICE FOR SUPPORTING COMPONENTS, SHUTTERING OR THE LIKE |
-
1981
- 1981-11-18 FI FI813663A patent/FI62887C/en not_active IP Right Cessation
-
1982
- 1982-11-11 DE DE8282306003T patent/DE3269471D1/en not_active Expired
- 1982-11-11 EP EP19820306003 patent/EP0079761B1/en not_active Expired
- 1982-11-16 CA CA000415638A patent/CA1196169A/en not_active Expired
- 1982-11-17 DK DK511282A patent/DK511282A/en not_active Application Discontinuation
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5809735A (en) * | 1996-08-19 | 1998-09-22 | Les Bois Laumar Inc. | Steel-wood system |
| US6167675B1 (en) | 1996-08-19 | 2001-01-02 | Les Bois Laumar, Inc. | Steel-wood system |
| US6701690B2 (en) | 2001-07-17 | 2004-03-09 | Guildo Deschenes | I-shaped wooden beam |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0079761B1 (en) | 1986-02-26 |
| FI62887B (en) | 1982-11-30 |
| DE3269471D1 (en) | 1986-04-03 |
| FI62887C (en) | 1983-12-05 |
| EP0079761A1 (en) | 1983-05-25 |
| DK511282A (en) | 1983-05-19 |
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