PSI - Issue 54

Anna Karolak et al. / Procedia Structural Integrity 54 (2024) 460–467 Karolak A., Jasieńko J. / Structural Integrity Procedia 00 (2019) 000 – 000

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of destructive force in this series was approximately 16 kN. The test results confirmed the role of the additional strengthening elements, such as metal bolts, clamps and wooden keys in the joints. Beams with the applied metal bolts – series B, C, D, E and H, were fastened and strengthened by them and also some part of the load was taken by them, as indicated by the plasticization oof the connectors. This phenomenon, however, was not observed beams with metal clamps and wooden keys – series F and G. What is more, in the comparison of the beams with the joints with only steel clamps and the beams with the joints with steel clamps and wooden keys applied, some part of the load was taken by the wooden keys. The images of the joints failure modes are presented in Fig. 4. The mean values of the destructive forces and the calculated load-carrying capacities in bending for each series of beams A-H and the comparison of the values noted for the beams with the joints with the reference beams of series A are presented in Tab. 2 below.

a)

b)

c)

d)

e)

f)

g)

Figure 4: Failure images of joints a) B-series, b) C-series, c) D-series, d) E-series, e) F-series, f) G-series, g) H-series

Table 2 – Mean values of destructive forces and load-carrying capacities in bending for beam series A-H

Beam series

Destructive force [kN]

Load-carrying capacity [kNm]

Ratio of load-carrying capacity for beam with joint to reference solid beam [%]

A B C D E F G H

46.07 15.89 19.38 18.72 12.67 13.04 14.26 16.37

24.88 8.58 10.46 10.11 6.84 7.04 7.70 8.84

100 34.5 42.1 40.6 27.5 28.3 31.0 35.5

4. Summary and conclusions In the paper the mechanical behaviour of selected carpentry longitudinal joints under bending was presented: lap joints, inclined lap joints, stop-splayed scarf joints. These are the joints that were used in the flexural elements in the historical objects. In the 4-point bending tests the load-carrying capacity of the beams with the joints was examined and compared to the capacity of the solid beam. The experimental tests confirmed that the studied joints in the flexural elements could carry some small bending moments. The obtained flexural load-carrying capacity of the jointed beams was approximately 30% up to 40 % of the value of the capacity of the solid beam. The capacity ratios for the specific jointed beams series were calculated and