Abstract
The shear strength of structural and glued laminated timber (GLT) is comprehensively discussed. This
is done in respect to quantification of characteristic shear strengths, the influence of stressed volume,
the crack coefficient kcr according EN 1995-1-1 [1] as well as the influence and specification of an
adequate test method for the investigation of reliable and reproducible standardised properties relevant for standards (e.g. EN 338 [2], prEN 14080 [3] and EN 1995-1-1 [1]).
The shown research project involves a comprehensive literature survey and testing of structural timber in shear. State-of-the-art includes structural timber and GLT, the examination of various test methods as well as physical and mechanical influences on shear strength, in particular the influence of size.
Furthermore, a test configuration was developed which enables coherent determination of shear
strength of structural timber and GLT. The examination of shear strength performed on structural
timber of Norway spruce involved series of various dimensions and grades. Therefore, I-beams were
tested in three-point bending. The specimens of interest (webs) were chosen randomly from a specific
nominal grading class. Preparation of flanges included stiffness grading and proof loading. Evaluation of shear strength was done by application of simple beam theory assuming composite action between web and flanges. Afterwards the values of more plate-like specimen were corrected based on comparative computations by means of FEM. By testing, the influence of stressed volume, the size effect, and the relationship between bending and shear strength as given in EN 384 [4] and EN 338 [2] were investigated. Additionally, shear deformation was measured in the largest test specimens by means of shear fields placed in zones of constant shear force.
The aim of the research work is to support a comprehensive study and a basis for decision finding
regarding the standardisation of characteristic shear strengths of structural timber and GLT of
softwoods, in particular Norway spruce, providing a coherent system of testing, material, evaluation
and design standards. In conclusion, it can be noted that there is a significant dependency between the shear strength and the shear-stressed zones. According to this, an adjustment of current standards, in which the geometrical dimensions are taken into account by means of a correction factor, is proposed.
is done in respect to quantification of characteristic shear strengths, the influence of stressed volume,
the crack coefficient kcr according EN 1995-1-1 [1] as well as the influence and specification of an
adequate test method for the investigation of reliable and reproducible standardised properties relevant for standards (e.g. EN 338 [2], prEN 14080 [3] and EN 1995-1-1 [1]).
The shown research project involves a comprehensive literature survey and testing of structural timber in shear. State-of-the-art includes structural timber and GLT, the examination of various test methods as well as physical and mechanical influences on shear strength, in particular the influence of size.
Furthermore, a test configuration was developed which enables coherent determination of shear
strength of structural timber and GLT. The examination of shear strength performed on structural
timber of Norway spruce involved series of various dimensions and grades. Therefore, I-beams were
tested in three-point bending. The specimens of interest (webs) were chosen randomly from a specific
nominal grading class. Preparation of flanges included stiffness grading and proof loading. Evaluation of shear strength was done by application of simple beam theory assuming composite action between web and flanges. Afterwards the values of more plate-like specimen were corrected based on comparative computations by means of FEM. By testing, the influence of stressed volume, the size effect, and the relationship between bending and shear strength as given in EN 384 [4] and EN 338 [2] were investigated. Additionally, shear deformation was measured in the largest test specimens by means of shear fields placed in zones of constant shear force.
The aim of the research work is to support a comprehensive study and a basis for decision finding
regarding the standardisation of characteristic shear strengths of structural timber and GLT of
softwoods, in particular Norway spruce, providing a coherent system of testing, material, evaluation
and design standards. In conclusion, it can be noted that there is a significant dependency between the shear strength and the shear-stressed zones. According to this, an adjustment of current standards, in which the geometrical dimensions are taken into account by means of a correction factor, is proposed.
| Original language | English |
|---|---|
| Title of host publication | International Council for Research and Innovation in Building and Construction, Working Commission W18 - Timber Structures, Meeting |
| Number of pages | 23 |
| Publication status | Accepted/In press - 2012 |
| Event | International Council for Research and Innovation in Building and Construction, Working Commission W18 - Timber Structures, Meeting - Växjö, Sweden Duration: 27 Aug 2012 → 30 Aug 2012 |
Conference
| Conference | International Council for Research and Innovation in Building and Construction, Working Commission W18 - Timber Structures, Meeting |
|---|---|
| Country/Territory | Sweden |
| City | Växjö |
| Period | 27/08/12 → 30/08/12 |
Fields of Expertise
- Advanced Materials Science
Treatment code (Nähere Zuordnung)
- Application
- Theoretical
- Experimental
- Review