Figure 1
a. Wooden bridge in Kenozero National Park, Russia (Alexey Kudenko/RIA Novosti). b. Wooden bridge (160 m), designed with glulam beams in the Crie de Mistissini, Canada.
Table 1
Values of fatigue characteristics of wood (Ry).
| Image of the stressful element state | Special symbols used | Value of the calculated resistance fatigue for first-grade wood, MPa |
|---|---|---|
| Bending along the fibres | Rу | 12.00 |
| Compression along fibres | Rусо | 12.00 |
Figure 2
Dependence of the coefficient of endurance on the coefficient of the asymmetry of the loading cycle.
Table 2
Comparison of the experimental and calculated values of the endurance factor.
| No. | Determination method | Endurance factor at | |
|---|---|---|---|
| ρ = 0.20 | ρ = 0.25 | ||
| 1 | Experimental | 0.459 | 0.470 |
| 2 | Calculated | 0.451 | 0.475 |
| 3 | Error, % | -1.77 | +1.05 |
Figure 3
Dependence of the endurance coefficient corresponding to the number of loading cycles of N = 2 million depending on the coefficient of the asymmetry of the loading cycle.