Furthermore, the corrosion protection systems have been enhanced to enhance the long-term durability of stay cables. Carbon may be considered for ultra long span bridges due to its low self-weight. A: Stay cables are subjected to high tensile forces and, given the fact that cable supported structures are typically very light structures, the stay cables are subjected to high stress variations, thus high fatigue resistant stay cables are of great importance. In addition, excellent corrosion protection features, replaceability of cables, installation expertise and further key factors must be observed to achieve a year design life.
Targeting a year life requires a high level of corrosion protection for the cables — making directly exposed cable surfaces such as locked coil and bar cables obsolete for anything other than architectural applications. Additional considerations should be given to the replaceability of the key components. An important lesson learned on strand as well as wire stay cables — especially by owners and contractors — is that cable installation is the work of the specialist who also provides the stay cable technology.
Practices of the past, where only supply of fully or partially prefabricated stay cables has been contracted to the system suppliers must be avoided. Even newly constructed cable stayed bridges have experienced quite severe vibrations which may result in failures of cables. A careful evaluation is therefore always required and countermeasures, such as dampers are highly recommended. Care should also be taken when designing long cables.
Effects, such as the sag of the cable on the effective damping, rotational bending stresses and other effects can only be appreciated for long cables. A: Today, the state-of-the-art and internationally versatile recommendation for stay cables is fib — International Federation for Structural Concrete, Bulletin 30, Acceptance of Stay Cable Systems using Prestressing Steels. Most modern stay cable systems have been developed and tested to these provisions including axial fatigue and subsequent tensile as well as leak tightness tests. There are other less common and minor national recommendations such as, for example, from CIP Setra in France.
High quality tension elements
National recommendations cover only locally available materials and construction practices and are limited to the knowledge of local suppliers, which lead to an unjustified and incorrect treatment of stay cable systems as a whole. To ensure international and legally correct tenders, such national recommendations should not be considered — they may occasionally only be used as complementary guidelines. What are stay cables?
Q: What are stay cables? Dampers are hydraulic devices depending on load application velocity and are able to dissipate part of the dynamic energy entering into the structure.
Cable-stayed bridge - AccessScience from McGraw-Hill Education
STU are hydraulic devices able to create, only for impulsive external force, a temporary rigid connection between two parts of the structure. The TENSA post tensioning systems are meant to give compression stresses to concrete using post tensioning tendons made of steel strands or steel bars. Decks are currently built with reinforced concrete, steel or composite structures. Post tensioning is a highly efficient structural strengthening system both for concrete and also steel decks that can be used for cable stayed bridges adding its effect to the one given by stay cables stays are used to connect pylons to deck, allowing a considerable increase of span length.
Expansion joints are devices designed to absorb the movements of the structure due to temperature variations, creep, shrinkage, seismic actions and wind, to allow continuous traffic between the decks and among deck and abutments offering a safe and comfortable passage.
The world’s longest cable-stayed bridges
In cable stayed bridges, concrete pylons are often reinforced with post tensioning for both adding compression in vertical direction and increasing horizontal shear forces induced from the cable stays. TENSA offers a complete range of bearings. Almost 30 years of worldwide experience in the field allows TENSA to provide the most appropriate solution to meet all clients' needs.
The internal production facility and laboratory allow to keep full control of quality and of delivery times. Thanks to its experienced team of engineers and technicians, TENSA is able to guarantee the highest and worldwide accepted quality standards to every step of the post tensioning process, from the design, to production and on-site installation. Almost 50 years of worldwide experience in the field allow TENSA to provide customized solutions to meet all the clients' needs.
16 Advantages and Disadvantages of Cable Stayed Bridges
TENSA designs and provides different types of expansion joints, which can be used in any structure. TENSA's joints are capable to absorb the structure movements caused by temperature variations, creep, shrinkage, seismic actions, from the smallest to the largest. Base isolation systems are used to protect constructions and, more importantly, human lives. These solutions are designed to reduce the seismic structural response by adding important energy dissipation to the system.
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Thanks to its high quality displacement dependent devices TENSA is able to guarantee a perfect control of maximum loads activated during an earthquake between the connected elements, independently of the seismic intensity and frequency. Search form Search. Choose language. Cable Stayed Bridges. With over 50 years of experience in the field of specialized engineering, Tensa is leader in the design, production and installation of systems and special components for the construction of cable stayed bridges. Advantages TENSA technologies, widely applied in cable stayed bridges, are meant to: - Increase concrete and steel structure performances by strengthening them and, consequently, allowing for big spans to be reached post tensioning and stay cables - Transfer vertical and horizontal loads and allow deck structural movements and rotations bearings and expansion joints - Protect structures from the seismic action or, in general, from dynamic actions i.
The following types of bearings can be supplied: Fixed bearings, which allow rotation between two structural elements and transfer vertical and horizontal loads Guided sliding bearings, which transfer vertical loads, allow rotation between two structural elements, displacement in one single direction and transfer lateral load in the fixed one Free sliding bearings, which transfer vertical loads, allow rotation between two structural elements and displacements in all plan directions. Related products.
Stay cables. Post tensioning.
Ground anchors. Expansion Joints.
Seismic Isolators. Velocity dependent devices.