Search results for "Segmental bridge"
showing 5 items of 5 documents
The Rehabilitation of Segmental Bridges Subjected to Time-dependent Deflections Through Additional Prestressing
2022
Segmental bridges built by cantilevering with in-situ casting in the ‘60s-‘80s of the XX Century present a central hinge on the main span or a central simply supported span between the two cantilevers (drop-in span). Due to time-dependent phenomena like creep of concrete and to unexpected loss of prestressing, several bridges of this typology show an abnormal deflection at hinges causing discomfort of traffic as well as insufficiencies of checks at Service and Ultimate Limit States. Moreover, these bridges are today at the end of their nominal service life, impacting significantly on Italian road network. A methodology for retrofitting these bridges by partial recovering of deflection and o…
TIME-DEPENDENT EFFECTS IN SEGMENTAL BRIDGES: PREDICTIVE MODELS AND ANALYSIS VIA SIMPLIFIED METHODS
2013
Serviceability of segmental concrete arch-frame bridges built by cantilevering
2013
The evaluation of the safety degree in service life for a segmental prestressed concrete bridge built by the cantilever method presents different aspects related to strength, deformability, durability and to effects of time-dependent phenomena as creep and shrinkage. The case-study of a prestressed concrete frame bridge with inclined piers is presented, built by cantilevering, with precast segments. By considering the fundamental items of design and construction stages, the implications due to the arch effect in this static scheme are investigated, with respect to an equivalent bridge with a final scheme of continuous girder on vertical piers. The birth of a significant value of axial force…
Serviceability and Ultimate Safety Checks of SegmentalConcrete Bridges through N-M and M-V Interaction Domains
2015
In current engineering practice, safety checks on serviceability and determinations of ultimate limit states of segmental bridges built by cantilevering are generally performed, either considering separately the contributions of axial force N, bending moment M, and shear force V, or considering the interaction effects through approximate expressions supplied by building codes. During construction stages and service life, the interaction between internal forces can be of fundamental importance in establishing the actual degree of structural safety and, for this reason, a different philosophy for performing checks in segmental bridges is proposed in this paper, plotting N-M and M-V interactio…
Simplified Procedure for Evaluating the Effects of Creep and Shrinkage on Prestressed Concrete Girder Bridges and the Application of European and Nor…
2013
The effects of time-dependent phenomena on concrete prestressed girder bridges are investigated. The study concerns the case of bridges built directly in their final configuration and that of bridges built by a sequence of stages in which geometry, restraints, and loads vary until the final configuration is achieved. An analytical approach based on the principles of aging linear viscoelasticity and the age-adjusted effective modulus method is followed. The paper has two aims: the first is to provide an efficient and simplified tool for the evaluation of the structural response in the early stages of design; the second is to compare the results of the analyses on actual cases of bridges when…