Search results for "Girder"
showing 7 items of 17 documents
COMPORTAMENTO DI IMPALCATI DA PONTE A CASSONE IN ACCIAIO-CALCESTRUZZO CON ANIMA ONDULATA
2013
La memoria riguarda il comportamento di un impalcato di ponte stradale a cassone avente le anime sagomate secondo una sinusoide, con soletta in c.a. collaborante. L'impalcato presenta schema statico longitudinale di trave continua su 4 appoggi. The paper concerns the behaviour of a box-girder bridge deck road having a steel box and a concrete slab. The steel webs are shaped according to a sine wave. The deck has a width of 13.70 m and a length of 182 m, with the longitudinal static scheme as a continuous beam on four supports. The study highlights the reliability of this constructive solution.
Unified theory for analysis of curved thin-walled girders with open and closed cross section through HSA method
2016
Abstract The behaviour of thin-walled structures is deeply influenced by non-uniform torsion and cross section distortion. In this paper the extension of the Hamiltonian Structural Analysis (HSA) Method to thin-walled straight and curved beams is presented. The proposed method solves the structural elastic problem of thin-walled beams through the definition of a Hamiltonian system composed of 1st order differential equations. The method allows engineers to solve the elastic problem by introducing the degrees of freedom and the corresponding compatibility equations, founding equilibrium equations in the variational form. The methodology is explained in the framework of the so-called Generali…
Symplectic analysis of thin-walled curved box girders with torsion, distortion and shear lag warping effects
2022
Shear lag effect and torsional and distortional warping can significantly affect the performance of thin-walled curved box girders used in modern bridge engineering. The structural behaviour of these bridges exhibits complexity due to coupled bending and torsion together with warping effects of non-uniform torsion, distortion and shear lag. A practical method of analysis, based on the symplectic approach, with the same perspective as the Higher Order Beam Theories, is presented for overcoming the difficulties of numerical approaches via the Finite Element Method. In this paper, the Hamiltonian Structural Analysis method implements the analysis of the shear lag effect together with non-unifo…
Analysis of non-uniform torsion in curved incrementally launched bridges
2014
Abstract Incremental launching is a common and convenient methodology to build continuous girder bridges on several piers. Although it has mainly been applied to straight bridges with box sections, today it is also used for construction of horizontally curved bridges with concrete and composite steel–concrete closed or open sections like I-girders. In these cases the contribution of torsion to the stress state becomes of primary importance when the construction stages of these bridges are analysed. Moreover, the presence of thin-walled cross-sections, makes the analysis of non-uniform torsion fundamental when the angle of twist per unit length is not constant or warping is prevented in thos…
A Viscoelastic Model for the Long-Term Deflection of Segmental Prestressed Box Girders
2017
Most of segmental prestressed concrete box girders exhibit excessive multidecade deflections unforeseeable by past and current design codes. To investigate such a behavior, mainly caused by creep and shrinkage phenomena, an effective finite element (FE) formulation is presented in this article. This formulation is developed by invoking the stationarity of an energetic principle for linear viscoelastic problems and relies on the Bazant creep constitutive law. A case study representative of segmental prestressed concrete box girders susceptible to creep is also analyzed in the article, that is, the Colle Isarco viaduct. Its FE model, based on the aforementioned energetic formulation, was succ…
Generalized curved beam on elastic foundation solved by Transfer Matrix Method
2011
A solution of space curved bars with generalized Winkler soil found by means of Transfer Matrix Method is presented. Distributed, concentrated loads and imposed strains are applied to the beam as well as rigid or elastic boundaries are considered at the ends. The proposed approach gives the analytical and numerical exact solution for circular beams and rings, loaded in the plane or perpendicular to it. A well-approximated solution can be found for general space curved bars with complex geometry. Elastic foundation is characterized by six parameters of stiffness in different directions: three for rectilinear springs and three for rotational springs. The beam has axial, shear, bending and tor…
Evaluation of web reinforcements in prestressed concrete box girders through shear-transverse bending domains
2020
In concrete box girders, the amount and distribution of reinforcements in the webs have to be estimated considering the local effects due to eccentric external loads and cross-sectional distortion and not only the global effect due to the resultant forces of a longitudinal analysis: shear, torsion and bending. This work presents an analytical model that allows designers to take into account the interaction of all these effects, global and local, for the determination of the reinforcements. The model is based on the theory of stress fields and it has been compared to a 3D finite element analysis, in order to validate the interaction domains. The results show how the proposed analytical mode…