Seismic Performance Evaluation of Retrofitted Bridge by Isolation Bearings

2015

Polymer Composites

In this study, a series of flexural tests were performed to evaluate the energy capacity and debonding strain of reinforced concrete beams strengthened with a carbonfiber-reinforced polymer (CFRP). Seven reinforced concrete beams were fabricated and loaded up to failure in a three-point bending test. The type of CFRP laminate (plate or sheet), bonded length (1.44 or 2.16 m), and wrapping of the CFRP sheet were selected as the key test variables. The test results showed that beams strengthened with CFRP sheets were more effective than those strengthened with CFRP plates. The CFRPstrengthened beams showed an elastic energy greater than that of the control beam, but the opposite result was obtained for the plastic energy. The average debonding strains of the CFRP plates and sheets were 4,309 and 11,649 l, respectively, which corresponded to 21.5% and 77.1% of their respective ultimate tensile.

Section: Introductionmentioning

confidence: 99%

Effect of bonded lengths and wrappings on energy capacity and debonding strain of reinforced concrete beams strengthened with carbon‐fiber‐reinforced polymer

2015

Polymer Composites

“…Structural engineers have extensive experience of repairing concrete structures above water [3][4][5][6]. The conventional approach to the repair of reinforced concrete columns that have shallow damages, however, is to use patch repair for the damaged zones where cracking and spalling occur [7,8].…”

Section: Introductionmentioning

confidence: 99%

Behavior of Concrete Columns Repaired with Polymer Mortar and Epoxy Fiber Panel

Advances in Materials Science and Engineering

2013

Underwater structures are not easy to check for the degree of damage or to repair and strengthen damaged regions. Even during repair and strengthening, quality control is very difficult, because the work is done under water. Moreover, underwater structures severely deteriorate, owing to special environmental conditions. If this deterioration continues, the structures face serious structural problems, because of the corrosion of steel rods and the loss of concrete sections. Repairing or strengthening underwater structures requires effective, economic underwater repair and reinforcement techniques that allow the same working conditions as on the ground while maintaining dry condition for the repair sections. However, systematic studies on the repair and strengthening techniques for underwater structures are insufficient. This study proposes a new repair method for underwater structures, which applies epoxy fiber panel forms and shear connectors. To demonstrate the repair effects, this study compared and evaluated the failure modes and repair effects by the surface condition of repair sections, by applying various repair methods, in consideration of the ground and underwater conditions.

“…9 Various engineering methods have been developed, and used to repair or strengthen reinforced concrete structures. [10][11][12][13] The conventional approach to the repair of reinforced concrete columns that have corrosion damages due to chloride attack, however, is to use patch repairs for the damaged zones where cracking and spalling occur. 14,15 Columns are typically repaired by removing the damaged concrete cover beyond the steel reinforcement.…”

Section: Introductionmentioning

confidence: 99%

Load capacity and chloride resistance of circular concrete columns with repair mortars

Journal of Composite Materials

2013

An experimental investigation was conducted to evaluate the structural behavior and chloride penetration characteristic of reinforced concrete columns to which patch repair was applied. A total of 24 reinforced concrete columns were fabricated. Four repair materials, with different types and contents of admixtures, were selected. The contents of the three admixtures (silica fume, zeolite, and polymer dispersion) were 0%, 10%, and 15%, based on the weights of the admixture and cement. For the experimental methods, a chloride penetration test and an axial compression test were used. As a result of the experiments, compression failure occurred in the control column. For the repaired columns, however, interfacial failure was observed, as the concrete core and repair material were debonded. The repair material that showed the greatest effect was mortar, for which polymer dispersion was used as the admixture. The ultimate strength and the strain at ultimate strength of the column that was repaired with this mortar increased by 40% and 80%, respectively, compared to the control column. Furthermore, the repair mortars that were mixed with the admixture showed much lower chloride concentrations than the control column. In particular, the chloride concentration of the mortar that was mixed with 15% polymer dispersion decreased by 95%, in the section with a depth of 20–30 mm from the column surface.