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Experimental Study on Wood-Adhesive-Steel-Bolts Hybrid Connections with Slotted-in Steel Plates

Kawecki Bartosz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 4

76--88

EN

Structural connections are one of the most important parts influencing the overall performance of a wooden structure. The way of design of these can lead both to increasing and decreasing internal stresses occurring in the load-carrying elements and structure’s total deformations. Typical mechanical joints in wooden structures are defined as plastic hinges or, at best, semi-rigid. The innovative hybrid one proposed in the paper with adhesive added between elements can be much stiffer than typical connection, which can lead to assuming rigid joint and significant reduction in stresses and deformations of a structure. The research comprised 30 specimens in three groups (10 per each group: reference - without adhesive, hybrid with one-component PUR - polyurethane adhesive and hybrid with one-component PVAc – polyvinyl acetate adhesive) tested on the MTS 809 testing machine up to failure. An innovative idea was to connect elements initially by applying an accurately predicted tightening torque value to bolts. This resulted in obtaining enough clamping pressure between elements for adhesive curing, with none other equipment. The load was applied in parallel-to-grain wood direction. The results showed that utilising hybrid connection caused, both for PUR and PVAc adhesive, a huge increase in stiffness. When comparing to the reference no-adhesive, bolted connection, this was 2365% stiffer (nearly 24 times). Load-carrying capacity was higher too, however, the increase was not that significant and was at the level of 14.4% and 27.1%, for PUR and PVAc adhesives, consecutively. Worth noting is that the hybrid connection could continue to work after adhesive failure with 60% higher stiffness than the reference one and its load-carrying capacity was only 10% lower than the reference. Hybrid connections of this type can potentially serve as structural joints because of the innovative concept of combining components. Steel plates can be covered with adhesive and then inserted between wooden parts. Next, the tightened bolts can work as clamps producing enough pressure for adhesive curing, enabling the joint to be assembled directly on the construction site. Despite the mentioned advantages, before providing the connections’ design methods, the idea needs to be tested towards various effects influencing wooden structures. Incorporating numerical modelling can be extremely important too.

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Beam–to-column connection calculations using robot software

Pashechko M., Latos A

Advances in Science and Technology. Research Journal

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2015

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Vol. 9, nr 27

45--49

EN

A beam–to-column connection design and results of engineer calculations using Autodesk’s Robot Structural analysis are shown in the article. Two types of connections, bolted and welded, were calculated. The tensile resistance amounted to 912.74 kN, bending resistance to 100.87 kN·m and effective design capacity of the bolt amounted to 27.69 kN. Normal stress in the weld amounted to σ⊥max = τ⊥max = 72.72 MPa, in the vertical weld to σ⊥= τ⊥= 63.34 MPa and tangent stress amounted to τ|| = 4.37 MPa. The results allowed us to implement minor changes such as increasing the distance between the bolt and the edge and decreasing the size of the fillet welds. The design is fully compliant with the EN 1993-1-8 norm. Using Robot Structural Analysis substantially increased the pace of calculations giving precise and clear outcomes.

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Nowe metody badania efektywności mechanizacji produkcji w aspekcie zmian restrukturyzacyjnych w rolnictwie

Sawa J.

Problemy Inżynierii Rolniczej

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2000

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R. 8, nr 1

71-78

PL

Stwierdzono, że kierunek zmian restrukturyzacyjnych w polskim rolnictwie jest niewłaściwy z uwagi na coraz luźniejsze powiązania gospodarstw z przedsiębiorstwami przetwarzania lub obrotu płodami rolnymi. Pogarsza to sprawność gospodarowania w rolnictwie i ogranicza wdrażanie tam nowych technologii produkcji, w tym mechanizacji procesu pracy. Dotychczas badania efektywności mechanizacji nie zawsze odnoszono do końcowych efektów gospodarowania oraz nie uwzględniano mierników stosowanych, w ocenie efektywności rolnictwa w państwachn UE.

EN

It was started that the trends of restructurization changes in Polish agriculture are inappropriate because of more and more loose connections of the farm with the enterprises processing or trading in agricultural products. Such a situation gets worse the efficiency of farm management and limits the introduction of new production technologies on the farm, including labour mechanization. So far the studies on mechanization effectiveness were not always related to the final effects of farming; the standards being applied to evaluating agricultural efficiency in the EU countries were disregarded either.