The overall seismic response of Hakka Tulous, massive traditional earth constructions located in the Fujian Province (China) and part of the UNESCO list of World Heritage buildings, is investigated. For this aim, non-linear static analysis (pushover) was used. Since Tulous are complex circular earth structures (about 50 m in diameter) stiffened by wooden frames along the whole inner perimeter of the circular earth wall, non-linear finite element models are hard to implement because convergence is difficult to achieve and very long computation time would be required given the large number of elements and degrees of freedom. For the above reasons, the equivalent frame approach is often used for masonry structures. Even if a few approximations are needed, non-linear static analysis of even very complex masonry structures can be successfully performed with fewer convergence problems and lower computational efforts. The seismic analysis of a representative circular Tulou is carried out. An extension to circular masonry structures of the analysis by macroelements through the equivalent frame method is hence studied. The results provides insight on the Tulou’s failure modes and on its overall seismic response. Since this is the first study on the overall seismic response of these complex earth constructions, further research is needed to deepen our knowledge of their structural behaviour.

After Maillart’s curved bridges, the improved building technologies in structural concrete and steel work led designers to realize different typologies of curved bridges. Jörg Schlaich’s contribution in the design of curved bridges has been fundamental, through developing different typologies of suspended and cable-stayed curved bridges. In the ‘60s of the past century, Sergio Musmeci gave another innovative contribution to bridge design, by shaping shell supported bridges with minimal shell surface, and finally realizing the Basento Bridge in Potenza, Italy, a concrete shell bridge considered as his masterpiece. Accounting for Schlaich’s and Musmeci’s work on, respectively, curved and shell bridges, a curved footbridge supported by an anticlastic concrete shell with minimal surface is herein studied. The influence of the boundary conditions on bridge shape, and the advantages of prestressing the ring girder supporting the cantilevered deck are studied.

Pile buckling is infrequent, but sometimes it can occur in slender piles (i.e., micropiles) driven into soils with soft layers and/or voids. Buckling analysis of piles becomes more complex if the pile is surrounded by multi-layered soil. In this case, the well-known Timoshenko’s solution for pile buckling is of no use because it refers to single-layered soils. A variational approach for buckling analysis of piles in multi-layered soils is herein proposed. The proposed method allows for the estimation of the critical buckling load of piles in any multi-layered soil and for any boundary condition, provided that the distribution of the soil coefficient of the subgrade reaction is available. An eigenvalue-eigenvector problem is defined, where each eigenvector is the set of coefficients of a Fourier series describing the second-order displaced shape of the pile, and the related buckling load is the eigenvalue, thus obtaining the effective buckling load as the minimum eigenvalue. Besides the pile deformed shape, the stiffness distribution in the multi-layered soil is also described through a Fourier series. The Rayleigh–Ritz direct method is used to identify the Fourier development coefficients describing the pile deformation. For validation, buckling analysis results were compared with those obtained from an experimental test and a finite element analysis available in the literature, which confirmed this method’s reliability.

In this paper, structural analysis and design of a tensegrity bridge with prestressed deck is introduced. As a matter of fact, cable pretension results in prestressing of the deck. Nonlinear geometric effects, key load cases, influence of main cable’s rise and modal analysis of this type of structure is studied by finite element. The structural behaviour of the tensegrity bridge appears to be suitable for footbridges, although peculiar with respect to traditional ones. Some suggestions about structural design, material properties and structural behaviour are summarized.

In the paper both a direct method and a sensitivity-based iterative method have been applied to update a finite element model of a curved cable-stayed bridge. The direct method is known as the Douglas-Reid algorithm. The sensitivity-based method is a Trust-Region algorithm. Thirteen experimental modes identified between 0 and 10 Hz under ambient condition have been considered as reference modal data. An a-priori finite element model has been implemented by using the SAP2000 software. The model has been firstly manually tuned and then updated through computational procedures implemented in MATLAB. The results of the direct and the iterative methods have been compared to each other for the specific case study.