The structural carbon fiber reinforcement in columns or pillars of reinforced concrete element can provide the greatest stiffness and by confining.
The concrete confinement effects have been extensively investigated in the past and at present the resulting increase in strength and ductility are relatively defined. In practice, the confinement of the concrete as a structural member is commonly provided by the transverse reinforcement in the form of bands or spirals.
Today there are numerous structures that are in need of some rehabilitation or strengthening for various reasons, or simply errors in execution.
In the case of the pillars built in the past may have an urgent need to be updated due to the more stringent requirements of the new seismic codes stopovers. In this regard, the need to repair or reinforce has increased significantly.
In response to this, new technologies reinforcing with fibers include carbon utilization, resulting in an effect of inner confinement hooping with composite fabrics, usually with fiber reinforced polymer (FRP).
Actually, any material that can provide lateral restraint (confinement) enough can be used to contain or delay the instantaneous rupture of concrete.
Basically the confinement restricts the damage, in compression and shear, thereby increasing the ductility of the structural member during the breakage.
In this regard, in recent years has increased the use of fiber reinforced polymers (FRP) as confining element, due to its excellent mechanical and chemical properties of these materials.
Some researchers have shown that FRP confinement improves the behavior of columns subjected to seismic loading, and applied effectively in seismic rehabilitation of bridge piers in USA, Japan and of course in Chile.
EXPERIMENTAL WORK ON PILLARS WITH FRP CONFINED
Numerous works have been published by researchers about changes in their properties resulting from the confinement of pillars. The results of this research agree that this work directly affects the following properties:
1. Compressive Strength.
APPLICATIONS IN CHILE WITH CONFINING CONCRETE PILLARS
The first application was in Chile confinement pillars was performed on the bridge in Villarrica Rodrigo Bastidas.
This bridge had multiple cracks caused by compression failures of the highest pillars, and faults cutting the shorter pillars. Both were confined with carbon fiber type Adcos Carbotex or Sika Wrap.
Refuerzos en el Mall Plaza Alameda
By increasing loads on upper floors determined after construction of underground, it was required to increase the compressive strength of 47 pillars. The work was done in three weeks so that the delivery of the premises at the time provided was guaranteed.
In conclusion, the confinement of columns by applying a structural carbon fiber reinforcement allows:
• Increase axial load capacity of the column.
• Increase the ductility of the column.
• Larger cutting capacity.
• Requires minimal access.
• Conforms to the various sections.
• Comparative lower cost than traditional reinforcement methods.