Holz Roh Werkst (2008)66:363-372 31 20 tion between the dowel and the surrounding timber were estimated.For joints with a smooth surface dowel u was es 10 merical resul 5 ■Numeric3 result,=O.4 u=0.1.A=2 mm(Group 1) 15.0m h perpendicular to the grair 20 40 0 References =0.4.A=7 mm (Group 2) to the grai ABAQUS Ine (00)ABAQUS/Standard and ABAQUS/CAE Version x=23.2mm Aiche(d).) 40 60 Bla HJ(2003)Joints with -5 X.distance (mm) Figa Load-bearing capacities,b the location of the mean stres . Daver Abb.Traigkeiten bLage der mittleren Span 5 Conclusion The experimental resuls of the joints tested show that the nng capacity increases wh smooth esiha6 f timb for the rough surface dowels these ex tionsconfirm the advantagesof using rough surface dowelsas reported in previousstudies.The current version of the Euro pean timber code.EC5.does not explicitly take into account rder to take the enecto in order to able to Rod system and the numerical analyses both indicate the strain distribution around the dowel to be affected by the surface CIB WIs Meeting p CIB-WKyot. 包SpringerHolz Roh Werkst (2008) 66: 363–372 371 Fig. 9 a Load-bearing capacities, b the location of the mean stress length (x0), c shear stresses and normal stresses perpendicular to the grain along the x-axis in the picture up to the right. NB, x = 0 is located at the outside of the dowel Abb. 9 a Tragfahigkeiten ¨ b Lage der mittleren Spannungslange (x ¨ 0) c Schubspannungen und Normalspannungen rechtwinklig zur Faser entlang der x-Achse gemaß Abb. 6. ¨ x = 0 befindet sich auf der Au- ßenseite des Dubels ¨ 5 Conclusion The experimental results of the joints tested show that the load-bearing capacity increases when rough surface dowels are used as compared to using smooth surface dowels. In add￾ition, the scatter of the load-displacement response was lower for the rough surface dowels. These experimental observa￾tions confirm the advantages of using rough surface dowels as reported in previous studies. The current version of the Euro￾pean timber code, EC5, does not explicitly take into account the effect of friction. In order to take the effect into account embedding tests have to be performed in order to be able to consider the benefits of using dowels with rough surface. The results obtained using the contact free measurement system and the numerical analyses both indicate the strain distribution around the dowel to be affected by the surface characteristic of the dowel. By comparing the experimental results with the numerical results, the coefficients of fric￾tion (µ) between the dowel and the surrounding timber were estimated. For joints with a smooth surface dowel µ was es￾timated to lie between 0 and 0.3. For joints with a rough surface dowel µ was estimated to lie between 0.3 and 0.5. Predicting the load-bearing capacity of the joints by fi- nite element analyses, including a failure criterion based on LEFM, showed good correlations to the experimental results. Acknowledgement This research was made possible thanks to fi- nancial support obtained from the Development Fund of the Swedish Construction Industry (SBUF), the Wood Science Program at Vaxj ¨ o¨ University (WDAT- Wood Design and Technology), the foundation CBBT (“Centre for building and living with wood”) and Skanska AB. The work was carried out at Vaxj ¨ o University. Special thanks to Mr. ¨ Arne Emilsson of Limtrateknik AB for the valuable comments on ¨ the manuscript, and for the fruitful discussions during planning and execution of the experiments. References ABAQUS Inc (2004) ABAQUS/Standard and ABAQUS/CAE Version 6.5, User Manuals Aicher S, Gustafsson PJ (ed), Haller P, Petersson H (2002) Fracture mechanics models for strength analysis of timber beams with a hole or a notch – a report of RILEM TC-133. Report TVSM- 7134, Lund University, Sweden Blaß HJ (2003) Joints with dowel-type fasteners. In: Thelandersson S, Larsen HJ (eds) Timber Engineering. 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