Articolo in rivista, 2020, ENG, 10.1061/(ASCE)BE.1943-5592.0001514

TVT(delta) concept for long-span glass-steel footbridges

Froli M.; Laccone F.; Natali A.

Dept. of Energy, Systems, Territory, and Construction Engineering, Univ. of Pisa, Pisa, Italy; CNR-ISTI e Dept. of Energy, Systems, Territory, and Construction Engineering, Univ. of Pisa, Pisa, Italy; Dept. of Civil and Industrial Engineering, Univ. of Pisa, Pisa, Italy

Transparency and structural lightness are inspiring ideas in the design of footbridges. Glass is the most performing transparent material to be used for structural purposes because of its high compressive strength, chemical stability, and absence of fatigue and viscosity phenomena at room temperature. However, its fragility constitutes a challenging limit in structural applications. This research provides and discusses a specific concept named TVT? (Travi Vitree Tensegrity) for lightweight long-span beam-like footbridges made of structural glass. Hence, two design approaches of fail-safe design (FSD) and damage avoidance design (DAD) are applied to guarantee adequate safety levels and postcracking serviceability, respectively, with low damages on the main components. FSD provides the adoption of structural collaboration between glass and steel. Following DAD, glass is segmented into triangular panels, and reciprocal diffuse prestress is performed by steel tendons. This strategy assures low rehabilitation costs because only collapsed elements should be replaced once failed. At ultimate limit state (ULS), the TVT? footbridge attains a global ductile behavior in which the yielding of steel tendons occurs before any fragile failure. Such result is achieved through a hierarchic calibration of the chain of failures. In glass panels, which are mostly precompressed, the buckling failure, representing the main risk, is delayed by the mutual stabilization of the panels' compressed edges with steel clamping. However, because an accidental event may cause a localized or diffuse brittle failure of glass components, the system is designed to maintain a residual load bearing capacity in this scenario. At the serviceability limit state (SLS), the TVT? footbridge is highly stiffened by the presence of glass panes, partially encased in metallic frames. Crack initiation is delayed by precompression.

Journal of bridge engineering (Online) 25 (1)

Keywords

Structural glass, Fail safe design, Damage avoidance design, Buckling, Post-tensioning

CNR authors

Laccone Francesco

CNR institutes

ISTI – Istituto di scienza e tecnologie dell'informazione "Alessandro Faedo"

ID: 408460

Year: 2020

Type: Articolo in rivista

Creation: 2019-10-25 17:15:42.000

Last update: 2020-09-30 12:25:25.000

External IDs

CNR OAI-PMH: oai:it.cnr:prodotti:408460

DOI: 10.1061/(ASCE)BE.1943-5592.0001514

Scopus: 2-s2.0-85074233445

ISI Web of Science (WOS): 000497650100008