0000000000894000
AUTHOR
M. Arici
Stressing sequence of steel cable-stayed bridges built by cantilevering
The construction of cable-stayed bridges by cantilevering implies several changes of geometry, stress and strain patterns during the assemblage of segments. The main target to be satisfied in the construction process is the achievement of the required final geometry and of a convenient state of stress for self-weight and sustained loads. The sequence of stay stressing and the values of prestressing forces at each stage of segment assembling have the main role for reaching the desired result of design, due to the large redundancy of cable-stayed structures.Among the different procedures proposed in the literature for initial cable force determination, the Partial Elastic Scheme (PES) Method …
Conceptual design of bowstring bridges with steel-concrete composite deck
The behaviour of tied-arch (bowstring) bridges is very sensitive to the conceptual design of arch and deck. The geometry of the arch shape and the arch-tie joint as well as the construction sequence can modify the global behaviour. When the arch geometry moves away from the anti-funicular shape, bending moments appear in the arch and in the deck even for dead loads; additional bending moments can increase the total value of tension in the deck becoming critical for a composite deck because of possible cracking of the upper concrete slab. The conceptual design of tied arches with composite deck is presented here, in order to reduce the danger of concrete slab cracking and the amount of reinf…
Creep effects and stress adjustments in cable-stayed bridges with concrete deck
In construction stages of cable-stayed bridges with prestressed concrete deck, the influence of creep on stresses and strains is very important in order to foresee the final patterns of internal forces and displacements. In cantilever construction, the concrete deck can be considered, in each stage, as a continuous beam resting on elastic restraints, which modify with successive additions of new segments, until the last one has been assembled. In these stages stress relaxation in concrete occurs as well as vertical displacements increase. Ehen structure has been closed by inserting midspan segment, stress redistribution begins, due to creep. Deformation and internal force development in con…
Applicazione delle Linee guida italiane alle valutazioni di sicurezza strutturale del ponte Corleone sulla tangenziale di Palermo
The "nominal life" of a large part of existing reinforced and prestressed concrete bridges, in Italy, is expiring, often in the absence of ordinary or extraordinary maintenance. Consequently, the Italian infrastructural network is in a critical phase, followed by the alarmed awareness of the public opinion, especially after the collapse of the Polcevera viaduct. Specific guidelines on risk classifi-cation, management, safety assessment, monitoring of existing bridges have been issued by the Superior Council of Public Works in 2020, to address the emergency. Between ‘50s and ‘70s of the last century, important examples of reinforced and prestressed concrete bridges were built in Italy by the…