Engineering modeling of semi-rigid joints with dowel-type fasteners for nonlinear analysis of timber structures

Schweigler, Michael; Bader, Thomas K.; Hochreiner, Georg

doi:10.1016/j.engstruct.2018.05.063

Cited by 26 publications

(14 citation statements)

References 19 publications

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“…Non-linear deformation is in progress. These effects were discussed previously in other investigations (Schweigler, Bader, & Hochreiner, 2018). The connection exhibits a relevant rotational movement.…”

Section: Introductionsupporting

confidence: 67%

Duration of load effects on development of deformations in bolted moment connection

Fabriciuss¹,

Ozola²

2020

Research for Rural Development

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Experience saved in the construction industry shows that the timber portal frames with semi-rigid connections at knee joint exhibit permanently increase displacements at the knee and apex point. Normally, timber portal frame with semi-rigid knee joint connection is made with mechanical fasteners located in double circles and cannot be designed without relevant rotation at connection during structures’ exploitation time. The only way to increase connection rigidity is to rise distance from fasteners location at connection, but at the same time, the tension and shear stress become significant at the external section of members. The previous experience is obtained by a model testing showing that deformations at semi-rigid connections are non-linear. These were tests under short-term load and did not disclose creep effects, which can be significant. This study is aimed at the examination of increasing deformations with time under constant static load (creep effects) in semi-rigid dowelled connection. Experimental test models were made and set under long-term load in controlled environmental conditions (heated laboratory room). Results show a significant creep influence to decrease connection stiffness. Corresponding numerical test of orthotropic 3d model by Dlubal RFEM software tools was performed analyzing the value of expected deformations. Results of the numerical test showed that friction between timber elements and extra nuts on bolts can increase connection stiffness. Research results in this stage show that the creep can affect connection stiffness more than expected. Also, experimental test results showed lower deformation values comparing with the ones obtained by the numerical test.

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Section: Introductionsupporting

confidence: 67%

Duration of load effects on development of deformations in bolted moment connection

Fabriciuss¹,

Ozola²

2020

Research for Rural Development

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“…The aim of this is in a first approach to identify the boundary conditions of the connection. Further deeper mechanical modelling could be performed to include the slipping effect of the connection which is not the aim at this stage but FEM or non-linear analysis may be performed [ 35 , 36 ]. The numerical curve showed a slope higher than that one exhibited by the experimental ones.…”

Section: Resultsmentioning

confidence: 99%

Mechanical Characterisation of GFRP Frame and Beam-to-Column Joints Including Steel Plate Fastened Connections

et al. 2022

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The study is part of the MOOVABAT project aiming at defining innovative technological buildings with low environmental impact and characterised by the capacity to constantly adapt to the changing of their users’ needs. In this context, the mechanical performance of a fibre-reinforced polymer (FRP) frame, chosen as a structural solution for the building assembly, was investigated. Specifically, the research study aims to experimentally define the moment–rotation behaviour of screw-connected joints by using steel plates. For this purpose, two different configurations, a beam-to-column joint and a whole portal frame, were tested to evaluate the strength and the stiffness of the connection. In addition, the beam-to-column element was also subjected to cyclic loads to assess the joint energy dissipation capacity. The experimental results show that the strength of the connection is higher than that required to satisfy both serviceability limit state (SLS) and ultimate limit state (ULS) loading conditions. Moreover, it also provided an accurate characterisation of the semi-rigid connection useful for designing purposes and raising the possibility of considering an optimisation of the system. All in all, with respect to mechanical aspects, the study confirms the suitability of pultrude FRP element assemblies for modular building applications and paves the way for further analysis aimed at enhancing their efficiency.

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“…In the current study, the classic model for structural analysis of portal frame (Figure 1) is supplemented with additional effects due to anticipated rotational displacements in semi-rigid knee joints (Schweigler, Bader, & Hochreiner, 2018), as well as taking into account the initial imperfections of the form defined by Eurocode 5 (European committee for standardization, 2008). Duration of load effect is a very important issue for timber structures with dowel-type fasteners.…”

Section: Methodsmentioning

confidence: 99%

Behaviour of timber portal frame depending on rotational stiffness of knee joint

Fabriciuss¹,

Ozola²

2019

Research for Rural Development

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In this article, the topic under discussion is the development of deformations in semi-rigid knee joints made of dowel type fasteners and consequences expected regarding overall deformations of timber portal frame structure. The use of semi-rigid connection resolves the problem of transportation, but development of small rotation in connection reduces the stiffness of the connection that becomes significant during service life. It is assumed that the rotational stiffness modulus K φ (kNm•rad-1) is the relevant characteristic of semi-rigid connection. Timber portal frame structure (span 30 m) designed with dowel type fasteners located around two circles has been subjected to different loading trials by using Dlubal software (RFEM). Results of a numerical study of portal frame model demonstrate the importance of characteristics of semi-rigid knee joints for design. It is found that developing deformations in the semi-rigid knee connection produce up to 90% bigger vertical displacement at an apex point and 96% bigger horizontal displacement comparing with the rigid knee joint model.

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Engineering modeling of semi-rigid joints with dowel-type fasteners for nonlinear analysis of timber structures

Cited by 26 publications

References 19 publications

Duration of load effects on development of deformations in bolted moment connection

Duration of load effects on development of deformations in bolted moment connection

Mechanical Characterisation of GFRP Frame and Beam-to-Column Joints Including Steel Plate Fastened Connections

Behaviour of timber portal frame depending on rotational stiffness of knee joint

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