PSI - Issue 73

Marek Johanides et al. / Procedia Structural Integrity 73 (2025) 38–44 Marek Johanides and Antonín Lokaj/ Structural Integrity Procedia 00 (2025) 000–000

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Fig.8 presents the load–deformation curves for Experiment A, which used bolts and dowels, comparing the behavior of reinforced and unreinforced segments within the semi-rigid connection. Fig.9 shows the corresponding curves for Experiment B, which utilized full-threaded screws, also comparing reinforced and unreinforced configurations. Both figures indicate the individual limit state levels: ULS represents the calculated value for the Ultimate Limit State , and SLS represents the calculated value for the Serviceability Limit State , in accordance with Eurocode 5 [11]. The Ultimate Limit State ( ULS ) was calculated using partial safety factors—specifically, γ con for joints and k mod , γ M for timber. The Serviceability Limit State ( SLS ), on the other hand, was calculated without applying these partial factors, resulting in a higher load-bearing capacity.

(a) (b) Fig. 8. (a) Load–deformation curves of individual specimens of static cyclic stress of experiment A, using bolts and dowels, (b) Load– deformation curves of individual specimens of static cyclic loading of experiment B, using full-threaded screws. The results of the individual tests are summarized in the tables below. Table 1 presents the results for the semi rigid connection in Experiment A, which used bolts and dowels. Table 2 presents the corresponding results for Experiment B, which used full-threaded screws. In both tables, the first column (Test) identifies the specific test configuration: Test 1 represents the unreinforced segments, Test 2 represents the configuration with reinforcement applied to the cross-member (rung), Test 3 represents reinforcement applied to both the cross-member and the struts. The second column ( F max,test ) shows the maximum load achieved during the experiment. The third column ( F max,d ) provides the design load capacity at the Ultimate Limit State (ULS) according to Eurocode 5 [11]. The fourth column ( F max,k ) provides the load capacity at the Serviceability Limit State (SLS), also according to Eurocode 5 [11]. The fifth column (d) gives the ratio between the ultimate limit state value and the experimentally obtained value. The sixth column (k) shows the ratio between the serviceability limit state value and the test result. The seventh column (u) indicates the maximum vertical deformation measured at the free end of the cross-member. The final column (ε) represents the relative deformation ratio between the different reinforcement configurations, where the deformation of the unreinforced specimen is taken as the reference (baseline) value.

Table 1. Results of experiment A, using bolts and dowels Test F max,test (kN) F max,d (kN) F max,k (kN)

d (-)

k (-)

u (mm) 290.60 398.85 457.05

ε (-)

A1 A2 A3

22.29 25.27 25.22

2.62 2.97 2.96

1.82 2.06 2.06

-

8.51

12.26

1.37 1.57