Performance of Existing Reinforced Concrete Arch Bridges Under Current Non Seismic Loads

Abstract

The present analytical work deals with the assessment of the performances of Reinforced Concrete (RC) Deck Arch Bridges under the non-seismic loading conditions required by the current mandatory Italian codes. In particular, the attention is focused on a specific RC deck arch bridge typology, better known as the "Maillart Type Arch Bridge", which is characterized by a very stiff deck beam and a slender and wide vault. As well as other existing RC structures which were designed under only gravity loads and without specific structural details, such as lower limits for longitudinal and transverse reinforcement bars, these bridges could be damaged by loading conditions not considered at the time of design. For the evaluation of the main critical issues related to the current performance of such bridges under the current non-seismic loading conditions, it has been defined a large inventory of simulated arch bridges in accordance to the design procedures usually adopted in 1950s which considered only gravitational loads, i.e. self-weight and moving loads. Each bridge of the inventory is modelled and studied by means of a Linear Gravitational analysis implemented in the structural software SAP2000, with support of an Application Programming Interface (API), such as Matlab. Due to the differences between the current loads and those considered at the design time and to the approximations of the design strategies of the time, a performancebased analysis of the existing bridges under non-seismic loads is important for the stakeholders as much as for the decisionmakers in order to plan risk mitigation programs and prioritize eventual retrofit interventions for risk reduction.

Influence of strengthening interventions on the structural performance of a Maillart‐type arch bridge: the case of “Ciolo Bridge” in the South of Italy

“…In the studied case the arch supports the upper stiffening deck, and in order to avoid the presence of additional stresses due to service conditions and thermal variations, the piers that connect the lower arch with the deck, were designed to behave as pure trusses with hinges at the ends. Other acting loads, such as vehicular working load, tend to cause the arch to deviate from its funicular configuration, but its low stiffness means that it is relieved of most of the flexural stresses even when traffic loads act, and at the same time it is predominantly compressed even in service [7].…”