PSI - Issue 64

Fernando Nunes et al. / Procedia Structural Integrity 64 (2024) 1081–1088 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

1086

6

stresses. The system was ingeniously designed to absorb and distribute forces effectively, protecting the supported structural elements, and is entirely dismantlable, facilitating the disassembly and reuse of components. The development methodology included variations in the length of the IPE80 profile, specifically 3000mm, 3500mm, and 4000mm (Fig.7a), to cater to the specific needs of each bridge structure. Furthermore, the studied arrangements considered the positioning of screws at the center, interior, and exterior of the plate opening (Fig.7b), aiming to explore different assembly configurations and their impact on the structural integrity of the system.

Fig. 7. (a) Illustrates the model used for dimensioning; (b) Presents details of the connection between the structure and the bridge, including details of the metal plate, bolt fixation aperture, and the possibility of varying the bolt fixation.

For structural analysis, geometric modeling with solid bodies was employed to represent the complex geometries of the components accurately. Due to their intricate shapes and the presence of holes, second-order hexahedral elements were selected for bolts and second-order tetrahedral elements for other components. Finite element sizes were precisely defined - 30.0mm for the beam, 10.0mm for the IPE80 profile and adjustment plate, 5.0mm for clamps, and 4.0mm for bolts - enabling a realistic simulation of structural behavior under operational conditions. Material selection emphasized durability and structural integrity, with structural steel S235 chosen for clamps, steel members, and plates, while bolts were made from high-tensile steel grade 8.8, following the standards (CEN, 2018; Holst et al., 2011b). The interaction between contact surfaces was modeled using the classic Coulomb friction model with a friction coefficient 0.2, as specified in the European codes. Load simulations were pivotal in evaluating component deformation and resistance under conservative loads, designed to simulate the combined weight of a maintenance worker and their equipment, totaling 100kg distributed every 500mm along the IPE80 profile, incorporating a safety factor of 1.5. 10. Results and discussion In developing the maintenance platform model, it was essential to ensure that all materials used remained within their elastic limits to avoid reaching their plastic limits, thereby preventing permanent deformations. This was achieved by carefully selecting materials with ideal mechanical properties. For instance, structural steel S235 was chosen for clamps, steel members, and plates, and grade 8.8 steel for bolts due to their high tensile strength and elasticity modulus. This behavior is crucial for ensuring the safety and durability of the maintenance platform under anticipated operational conditions (Cabaleiro et al., 2017, 2021; Pongiglione et al., 2021). Load simulations, which included deformation and strength analyses of each component under conservative load estimates, confirmed that the metal sheet used in the connections could absorb the forces subjected to it without transferring additional forces to the historic structure. This ensures that the maintenance platform's installation does not compromise the integrity of the anchored structure. The numerical modeling and fixation strategy adopted considered various installation configurations of the bolts (centered in the openings, positioned more internally, and more externally), ensuring the fixation method's adaptability to the specificities of each bridge structure. This contributes to an efficient and safe installation of the maintenance platform.