Timber Constructions

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- Tasks / Main focus
- Special facilities
- Contact person

Department 12 Timber Constructions is subdivided into the following Units:

  • Unit 121  Timber Structures, Composite Constructions, Timber Protection
  • Unit 122  Solid Wood Products, Panel Materials, Renewable Resources
  • Unit 123  Joining Technologies, Adhesives, Metallic Fasteners

This department covers the total range of timber construction, wood composite constructions, wood-based panels, mechanical fasteners and adhesives for wood bonding.

The department Timber Construction deals especially with investigations and developments for Technical Approvals of new construction products, testing and surveillance of wood products with regard to their agreement with building rules as well as the certification of manufacturing plants.

The research activities of the department are based on intensive, theoretical and application-oriented research/competence with focus on numerical simulation, non-destructive testing and destructive testing of construction materials and composite constructions in view of their fitness for use and their load bearing capacity.

The department has been active in the field of testing and certification of adhesives for wood bonding and the certification of glued timber products with a unique selling proposition and very high self-obliged clients acceptance.

 Tasks / Main focus
Research

  Focus:

  • Numerical simulation and experimental testing of composite materials and complex structural components under static and transient loads
  • Material laws, (statistical) modelling of materials, modelling of the reliability of structural components
  • Theory and applications of non-destructive test methods (NDT) for wood and wood-based panels, NDT to characterise defects in glue lines
Miniature tensile test machine Crack path in a specimen
Miniature tensile test machine with microscopic tracing of the crack growth and recording of the sound emission activity Crack path in a specimen (wood species : spruce) in the radial-tangential (RT-) plane at tensile loading perpendicular to the grain

  Current research projects:

  • German Research Foundation DFG (Special) research area 381 "Charakterisierung des Schädigungsverlaufes in Faserverbundwerkstoffen mittels zerstörungsfreier Prüfmethoden" ("Characterisation of the damage process in fibre composite materials using non-destructive test methods"), partial project A11: "Damage of components made of cellulosic short fiber composite materials"
  • Deutsche Gesellschaft für Holzforschung (German Society for Wood Research), Arbeitsgemeinschaft industrieller Forschungsvorhaben (Working Committee of Industrial Research Projects): "Nondestructive detection of defects in glue lines "
  • Studiengemeinschaft Holzleimbau (Association of the Manufacturers of Glued Timber Products) : "Einfluss des Astabstandes auf die Keilzinkenfestigkeit von Brettschichtholz-Lamellen" ("Influence of the knot distance on the fingerjoint strength of lamellas in glulam")
  • Holzabsatzfonds: "Verklebte Vollholzprodukte aus Eiche im Außenbereich" ("Glued wood products made of oak for exterior applications")
laser-optical strain measurement Fractured surface of a specimen

Determination of the local strain-softening behaviour of a fiber-reinforced gypsum panel by means of laser-optical strain measurement

Fractured surface of a specimen (wood species : spruce) photographed with a scanning electron microscope

Development and assessment of new construction products

Development and assessment of products amongst others in the context of National Technical Approvals for Deutsches Institut für Bautechnik DIBT (German Approval Body), Berlin, and for European Technical Approvals:

  • Testing methods for new adhesive systems for wood bonding
  • High-strength, rigid and ductile mechanical fasteners, such as steel dowel connectors spilled with adhesive, rigid frame corners
  • Wood- / wood-based material composite constructions for ultra-light structures, such as CELLTEC-element, sandwich-elements
  • Elements for solid constructions made of wood/wood-based materials, such as elements made of crosswise multilayered face-glued wood lamellas, multilayered face-glued OSB-panels
  • Composite structural components for high loads (bridges), e.g. timber-concrete composite elements
Bending test of a timber-concrete composite element Bending resistant frame corner made of glulam with a novel timber-steel joint

Bending test of a timber-concrete composite element

Bending resistant frame corner made of glulam with a novel timber-steel joint

Testing and certification of adhesives for wood bonding
  • This department is the sole body in Germany responsible for testing, accreditation and certification of adhesives for load-bearing wood constructions
  • List of tested adhesives
Creep test rigs for comparative determination of the long-term deformation behaviour of wood gluelines Creep test rigs for comparative determination of the long-term deformation behaviour of wood gluelines

Creep test rigs for comparative determination of the long-term deformation behaviour of wood gluelines

Surveillance and certification of building products based on standards or approvals

Certification according to German and European standards (Ü-mark, CE-mark)

  • Machine-graded timber (initial and follow-up tests)
  • Fingerjointed wood (e.g. KVH)
  • DUO / TRIO - beams
  • Glued laminated timber
  • Concrete forming beams

Gluing license:

  • This department is the sole body in Germany for issuing qualifying certificates to manufacturers producing glued load-bearing timber constructions including the required initial and follow-up surveillance
  • Listing of recognized manufacturers
Testing of wood, wood-based materials and mechanical fasteners

Determination / measurement of

  • Tensile / compression / bending / shear / torsion strengths
  • Displacements, strains
  • Temperature, moisture content, density
  • Sound velocity, flexural vibrations
  • Ultrasonic transmission, ultrasonic pulse echo, sound emitting activity
Surveillance and certification of manufacturers of timber frame elements
  • Surveillance (ÜZ) testing and certification according to DIBt guidelines
  • Quality control tests within the scope of the RAL quality mark 422
Consulting service and expertise
  • Damage analyses of timber constructions, especially concerning failed glued structures
  • Expertise in case of biotic damage and for historical, protected monuments
  • Damage due to temperature and moisture impacts
  • Approved by Couts of Justice and Public Prosecution Services: Issue of Expert Evidence
Cooperation in Committees
  • Cooperation in German and European standardization organizations and expert committees such as CEN, DIN, DIBt, COST, RILEM, DGfH
Information, Publications and Courses
 Special facilities

Selection of test equipment:

Testing machines:

  • - Electromechanical tension-compression universal test machines for a range of forces between 5 kN and 100 kN (partly equipped with climate chamber and optical strain measuring devices

  • - Hydraulic bending test machine (4 × 40 kN)
  • - Hydraulic bending test machine 8 × 200 kN for beams / elements up to 1 m in depth, 9 m in length and 3 m in width
  • - Servohydraulic bending test machine 8 × 200 kN for beams / elements up to 2.5 m in depth and 10 m in length
  • - Servohydraulic tension-compression universal test machine 600 kN, specific grips for large cross sections
  • - Servohydraulic tension-compression universal test machine 1600 kN for specimens up to 6 m in length
  • - Servohydraulic test equipment for frame corners 600 kN
  • - Servohydraulic test equipment for shear walls up to 100 kN horizontal force
Determination of the tensile load bearing capacity of a novel timber-steel joint Bending test of a glulam beam

Determination of the tensile load bearing capacity of a novel timber-steel joint

Bending test of a glulam beam with round holes reinforced by means of glued-in rods (depth : 1.3 m)

Non-destructive test equipment:

  • - Laser-optical device for measurement of strain fields

  • - Device for sound emission analysis (6 channels)
  • - Ultra-sonic device for transmission- and echo recordings
  • - Pulse generator for impact sound recordings

Miscellaneous:

  • - Climate chambers, climate exposure test cabinet
  • - Formaldehyde chamber, perforator and gas analysis equipment
  • - Multi-channel measurement amplifiers (60 channels) and measurement amplifiers for recording displacements, loads, strains, temperatures etc.
  • - Device for determining the dynamic modulus of elasticity by means of flexural vibrations
Further information
 Contact person

Secretary

Mrs. A. Heinicke


Mrs. A. Graze



 ++49 (0)711/685-62284
  ++49 (0)711/685-63307
 

Head of Department

Mr. Dr.-Ing. S. Aicher



 ++49 (0)711/685-62287
 ++49 (0)711/685-66829
 

Mr. Dr.-Ing. G. Dill-Langer

 ++49 (0)711/685-62280
 ++49 (0)711/685-66829
 

Units

Timber Structures, Wood Based Materials,
Timber Protection



Mr. Dr. rer. nat. S. Aicher

Mr. Dipl.-Ing. W. Klöck



 ++49 (0)711/685-62287
 

 ++49 (0)711/685-62289
 

Solid Wood Products, Panel Materials,
Renewable Resources

Mr. Dr.-Ing. G. Dill-Langer

N.N.

 ++49 (0)711/685-62280
 

Joining Technologies, Adhesives, Metallic Fasteners

Mr. Dr. rer. nat. S. Aicher

Mr. Dipl.-Ing. C. Rothkopf

 ++49 (0)711/685-62287
 

 ++49 (0)711/685-62288