Lower-Bound Limit Analysis of Masonry Arches with Multiple Failure Sections

A computational method is proposed for the lower-bound limit analysis of masonry arches with multiple failure sections. Main motivation is the observation that, not only the position, but also the orientation of the failure sections in an arch might not be known in advance in practical applications. The lower-bound limit analysis problem is formulated as a straightforward linear programming problem. Numerical simulations highlight the predicting capabilities of the proposed approach, enabling an accurate and safe prediction of the loading capacity of masonry arches

The Unbuilt Musmeci Parabolic Cross Vault Reinvented as a Dry-Masonry Structure

This paper investigates the unbuilt Musmeci parabolic vault, reinventing the original reinforced concrete structure as a dry-masonry vault. In the framework of rigid no-tension constitutive model with no sliding, the equilibrium analysis is conducted with the aim ofevaluating the design thickness of the masonry vault, respecting the original Musmeci shape. A parametric survey is performed to assess the minimum thickness of the vault, and its structural capacity under spreading supports. Attention is focused on the different collapse mechanisms and the corresponding crack patterns. For a better insight into the behaviour of the parabolic vault, the relevant case of the parabolic arch is first analysed and discussed. The numerical results show the feasibility of the project, with a thickness comparable with that proposed by Musmeci

State update algorithm for associative elastic-plastic pressure-insensitive materials by incremental energy minimization

This work presents a new state update algorithm for small-strain associative elastic-plastic constitutive models, treating in a unified manner a wide class of deviatoric yield functions with linear or nonlinear strain-hardening. The algorithm is based on an incremental energy minimization approach, in the framework of generalized standard materials with convex free energy and dissipation potential. An efficient algorithm for the computation of the latter, its gradient and its Hessian is provided, using Haigh-Westergaard stress invariants. Numerical results on a single material point loading history and finite element simulations are reported to prove the effectiveness and the versatility of the method. Its merit turns out to be complementary to the classical return map strategy, because no convergence difficulties arise if the stress is close to high curvature points of the yield surface