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Bows and stems are often subjected to wave slamming loads. Stiffened plates with curvatures in both longitudinal and transversal directions are the basic members of these structures. As a result, it is important to investigate the lateral ultimate strength of the doubly curved stiffened plates. In this study, the non-linear finite element method (NFEM) is selected to investigate the collapse modes and lateral ultimate strengths of the doubly curved stiffened plates. Additionally, the influences of curvature and geometrical properties on the collapse modes and ultimate strengths of doubly curved stiffened plates are investigated. In the NFEM analysis, a series of numerical simulations, covering different aspect ratios, curvatures, and structural scantlings are performed. Different collapse modes of doubly curved stiffened plates under lateral loading cases are observed. The relationships between the collapse modes and the geometrical properties are then discussed based on the numerical results. Moreover, the results also show that larger curvatures along the stiffeners and stronger stiffeners contribute more to the lateral ultimate strengths. Subsequently, an empirical formula is derived and verified for predicting the lateral ultimate strength of the doubly curved stiffened plates. The results of the empirical formula match well with numerical calculations.

This paper discusses the seismic behavior of reinforced concrete (RC) bridge structures, focusing on the shear−flexure interaction phenomena. The assessment of reinforced concrete bridges under seismic action needs the ability to model the effective non-linear response in order to identify the relevant failure modes of the structure. Existing RC bridges have been conceived according to old engineering practices and codes, lacking the implementation of capacity design principles, and therefore can exhibit premature shear failures with a reduction of available strength and ductility. In particular, recent studies have shown that the shear strength can decrease with the increase of flexural damage after the development of plastic hinges and, in some cases, this can cause unexpected shear failures in the plastic branch with a consequent reduction of ductility. The aim of the research is to implement those phenomena in a finite-element analysis. The proposed model consists of a flexure fiber element coupled with a shear and a rotational slip spring. The model has been implemented in the OpenSEES framework and calibrated against experimental data, showing a good ability to capture the overall response.