REINFORCEMENT CONCRETE STRUCTURES WITH FRP
During his lifetime, the reinforced concrete structure must meet several requirements, which may not be fully known at design moment. Therefore, you may need at some point the structural reinforcement by the following reasons:
Increase in load.
Damage to structural parts (aging building materials, fire damage, corrosion of reinforcing steel, impact of vehicles).
Improving serviceability (limitation of deformations, effort reduction in the steel, reducing the width of the cracks).
Modification of the structural system. Design errors or construction calculation.Various methods for strengthening, such as adhesion of steel sheets with epoxy, installing an external prestressing system, increasing the section of concrete with or without additional armor (using shotcrete, for example).
Adcos CARBOSTRIP SYSTEM.
Since 1967, it has been possible to increase the resistance to bending and cutting of existing reinforced concrete structures by means of externally bonded steel bands. Although the method has a "State of the Art", recorded the same advantages and also some disadvantages (Table N ° 1, figures No.1 and No. 2).
|Reinforced ADCOS CARBOSTRIP||
Reinforcement with Band Steel
|Resistance to flexion||More High||High|
|Drive||Flexible, easy||Dificult, rigid|
|Load capacity||In longitudinal direction only||Any direction|
|Cost of materials||High||Low|
|Aplication||without tools||Lifting equipment and fasteners|
Table N°1: Advantages and disadvantages of CFRP reinforcement system compared with steel flat bars.
LÁMINAS DE ADCOS CARBOSTRIP
|Contenido volumétrico de fibras||> 68%|
|Módulo de elasticidad longitudinal||> 4500 - 5500 N/mm2|
|Resistencia a la tracción||> 23 N/mm2|
|Deformación específica a la rotura||> 1.70%|
|Fluencia||Inexistente. Rotura frágil|
|Resistencia a la fatiga||Sobresaliente|
Table No. 2: Technical data sheets of CFRP
|Módulo de elasticidad*||4500 - 5500 N/mm2|
|Esfuerzo de adherencia (húmedo)*||
Falla del hormigón
|Resistencia a la flexión||
Falla del hormigón
|Resistencia a la tracción||23 N/mm2|
|Punto de transición al vidrio*||80°C|
|Resistencia a la compresión||75N/mm2|
Table No. 3: Technical data of the epoxy formulation Carbostrip
Adcos CARBOSTRIP SYSTEM. SCHEME OF WORK TO DO
Adcos Carbotex System
Because of different requirements for tissue reinforcement in composite construction are also used in the form of cloth bonded with an epoxy resin. Adcos Carbotex having carbon fiber fabrics and fibers, respectively, unidirectional fiberglass, high strength and high modulus.
Are saturated at work using the epoxy system Carbotex systems for forming fiber reinforced polymer (FRP) used for reinforcing structural elements.
Among its main applications, highlighting the flexural reinforcement, and compression to cut structural elements of reinforced and prestressed concrete such as beams, columns or walls in buildings, bridges, tunnels, tanks, parking lots, docks, industrial plants, water , energy, etc.. for the following reasons:
|Propiedades de la lámina curada|
|Carbotex UD 200||Carbotex UD 300|
|Resistencia a la tracción||>450 kN/m||>450 kN/m|
|Módulo de elasticidad||>236 Gpa||>236 Gpa|
|Grosor||0,3 mm||0,4 mm|
|Peso por metro cuadrado||200 g/m2||300 g/m2|
|Longitud por rollo||250 m||250 m|
|Ancho||300 mm||300 mm|
It can be seen advancing this technology by many tangible advantages: shorter commissioning work (as desired property in many jobs today), retail operators amount work dispensability of skilled and struts and scaffolding work special support, excellent mechanical and chemical resistance, etc.. All this is in fact a general economy in the transport, assembly, maintenance of the structure, etc.., Which could not be visualized by the high initial cost of using CFRP strips and woven fibers.
The use of these technologies in Argentina is quite recent, although there are already many works executed. However in the U.S. and Japan have been working for years with such products; Switzerland also researched, developed and implemented this system in a lot of work and, in hindsight, was introduced in the rest of Europe. A South American level, Colombia leads the field of innovations in reinforcing structures with CFRP numerous works (bridges, office buildings and parking lots).
This method of reinforcement is a tool that the structuralist engineer has at its disposal to reach the technical-economical solution that best suits the conditions, failures and evident in each particular case to resolve technologies.