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Taskforce Meeting Zurich 6./7.09.2004. Summary and Progress Jochen Köhler, ETH Zurich, Switzerland. Contents. Stress Strain Relation Serviceability DOL GLULAM Connections Quantification of model parameters. Stress Strain Relation. According to Glos (1978). Stress Strain Relation.

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Taskforce meeting zurich 6 7 09 2004

Taskforce Meeting Zurich 6./7.09.2004

Summary and Progress

Jochen Köhler, ETH Zurich, Switzerland


Contents
Contents

  • Stress Strain Relation

  • Serviceability

  • DOL

  • GLULAM

  • Connections

  • Quantification of model parameters


Stress strain relation
Stress Strain Relation

  • According to Glos (1978)


Stress strain relation1
Stress Strain Relation

  • According to Glos (1978)


Stress strain relation2
Stress Strain Relation

  • According to Glos (1978)

Conditions:


Stress strain relation3
Stress Strain Relation

  • According to Glos (1978)

Conditions:


Stress strain relation4
Stress Strain Relation

  • According to Glos (1978)

Discussion:

MOE in tension = MOE compression ?

Quantification of asymptotic compression strength and strain.

Modelling of N ?

Typical values:


Stress strain relation5
Stress Strain Relation

Actions:

  • Quantify asymptotic stress

  • Include into the Model Code

    Coordination:

    Jochen Köhler


Serviceability
Serviceability

  • According to Torratti (1992):

    The following conditions apply

    • The deformations are calculated in the grain direction only

    • The maximum stress bending stress is 20 Mpa

    • Natural conditions environment conditions apply (temperature and humidity)

    • The model has been successfully compared to tests on European softwoods, both solid wood and glulam of different sizes



Serviceability2
Serviceability

Actions:

  • Producing a matrix for different load and climate situations. Therefore the following is needed:

    • quantify moisture loads (Lars-Oluf Nielsson (Lund)/study from DTU 2003)

    • quantify load sequences

    • acquiring data, quantify model parameters

    • doing calculations and sensitivity analysis

      Coordination: Tomi Toratti


DOL

Limit state function:

Model (Nielsen):

Applied stress:

combined with climate deviations


DOL

Limit state function:

Model (Barrett):

Applied stress:

combined with climate deviations


DOL

Gaps:

  • DOL - Tension perpendicular to the grain

  • DOL - Connections


DOL

Actions:

  • Acquire North American data

  • Review data, quantify model parameters

  • Distribute tasks according ‘Tension perpendicular to the grain’ and ‘Connections’

    Coordination: John D. Sorensen


Glulam
GLULAM

  • Glued laminated timber in BENDING

  • Load carring capacity depending on the outermost lamination

  • Lamination = timber boards with length a; jointed by finger joints

  • a is assumed to be Poisson distributed

  • The tensile strength and stiffness of each board is assumed to be constant and lognormal distributed.

  • The strength of the finger joints is assumed to be lognormal distributed


Glulam1
GLULAM

Standard deviations?


Glulam2
GLULAM

Actions:

  • Proposal of a simple model

  • Test data acquisition

    Coordination: Hans-J. Larsen


Connections
Connections

Probabilistic Framework:

  • Johansen equations

  • “Splitting Mode parallel”

  • “Splitting Mode perpendicular”


Connections1
Connections

Probabilistic Framework:

  • Johansen equations


Connections2
Connections

Probabilistic Framework:

  • Johansen equations


Connections3
Connections

Probabilistic Framework:

  • “Splitting Mode parallel”


Connections4
Connections

Mixed Mode Fracture Energy


Connections5
Connections

Probabilistic Framework:

  • “Splitting Mode perpendicular”


Connections6
Connections

Probabilistic Framework:

  • Effective number of fasteners


Connections7
Connections

Actions:

  • Acquire test data

  • Case study – reliability analysis

    Coordination: André Jorissen



Quantification of model parameters1
Quantification of Model Parameters

Actions:

  • Collecting Data for a Data Base

    Coordination:



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