# Stress Behaviors at Rib-to-Floorbeam Weld and Cutout Details under Controlled Truck Loading
## 3 FEA of OSD Panel Model under Wheel Loading
### FEA Results and Discussion  
The stress responses at the RF-R, RF-F, RF-W and Cutout details on F3 (i.e., \(Z\) = 3 m) at its intersection with R11, R12 and R13 are presented under the three typical transverse loading locations. The same position as the gauges was applied, and the stress at the Cutout detail was obtained at the location of 6 mm away, which is parallel to the free edge of the Cutout detail, while stresses at the other three details were obtained at the location of 6 mm away and are perpendicular to the weld toe [29], as illustrated in Figure 3b. In order to make a direct comparison with the results from the controlled truck tests, a similar numbering method was employed in the FEA model to mark their stress locations, with \"A\" being added before the gauge number in the field tests, as shown in Figures 16-18. Figure 16: _Cont._  
Figure 15: Three typical transverse loading locations on the panel model. Figure 16: Calculated stress of four details under LC1. (**a**) RF-R; (**b**) RF-F; (**c**) RF-W; (**d**) Cutout. Figure 17: Calculated stress of the four details under LC2. (**a**) RF-R; (**b**) RF-F; (**c**) RF-W; (**d**) Cutout. LC1  
This is the over-rib loading case, with eight pairs of details symmetrical to the wheel center. The stress curves under this loading case present several features. First, as shown in Figure 16, details transversely symmetrical to the wheel center produce almost equal stress. Second, if the details are underneath the deck plate, which is covered by the tire width, there are high stress responses, otherwise the stresses are small, such as the details on the east side of R11 and on the west side of R13, because they are not underneath the deck plate covered by the tire width. Third, only when the wheel loads on the deck plate are supported by the tested floor beams, the apparent stress could be observed, which confirms that the wheel loading effects are limited between the adjacent floor beams. Fourth, the stress at the RF-W detail is in tension, while stresses at the RF-R, RF-F and Cutout details are in compression. Finally, based on the relationship between the fatigue life and cubic stress range at fatigue detail per AASHTO LRFD [30], under the passage of the tandem axles, only one stress cycle is produced at the four details, which is quite clear at the RF-W and Cutout details, and their maximum stress range is 12.3, 9.6, 33.1 and 43.0 MPa at the RF-R, RF-F, RF-W and Cutout details, respectively. These maximum stress ranges are very close to the LC1 in the crawl test. It is clear that relatively high stress ranges appear at the RF-W and Cutout details. Figure 18: Calculated stress of the four details under LC3. (**a**) RF-R; (**b**) RF-F; (**c**) RF-W; (**d**) Cutout. In the riding-rib-wall loading case, the stress curves for a specific detail generally looked similar to each other. Compared to LC1, the same details show similar stress curves, as shown in Figure 17. It is confirmed that, if the details are underneath the deck plate that is covered by the tire width, there are high stress responses. Otherwise, the stresses are small, such as those details on the east side of R11. In addition, stresses at the RF-R and Cutout details are in compression, and the RF-W detail is in tension, which is in agreement with the crawl tests. Stress curves after the rear axle passing the F3, as shown in Figure 8 in the crawl test and in Figure 12 in the dynamic test, share almost the same trends with the FEA results. The maximum stress ranges are 15, 10.4, 40.2 and 44.1 MPa at the RF-R, RF-F, RF-W and Cutout details, respectively, which also agree well with the dynamic test. When the wheel load is centered between R12 and R13, the details on the east side of R12 and those on the west side of R13 are symmetrical to the wheel center. Hence, these two groups of details generate almost equal stress.