Seismic Retrofit with Carbon Fiber Sheet Applicable in a Short Period
By M. Ichikawa, H. Nakane, K. Abe and T. Takeda
Concrete Journal, Vol.40, No.8, Aug. 2002
- Synopsis
- A seismic retrofit technique using form plates and carbon fiber sheets (CF sheets) has been developed, applicabale in a short work period to columns of existing reinforced concrete buildings. This technique minimizes the generation of dust, offensive smell and noise. The present paper discusses the overview of the technique and work sequence. Incombustible 13 mm thick form plates are processed into channel-shaped forms in the factory. The inner surface of the form is covered with a CF sheet that is impregnated with adhesive resin except for in its joint portion. The forms are erected on site on both sides of the column, and the joints of CF sheets alone are bonded. The 30 mm interstice between the existing column and the channel-shaped form is filled with grout to make an integrated structure. The influence of grout upon the strength of the CF sheet joint during the curing process was evaluated, in order to verify the performance of this retrofit method. In addition, the columns strengthened by the method were subjected to series of alternating loading tests with a constant axial force. Eleven test specimens were involved in the structural tests, including one without retrofit, ones directly covered with CF sheet, and the rest improved by the developed technique. The test results demonstrated that the specimens strengthened by the new technique presented a strength and a ductility of the same level as those of the specimens directly covered with CF sheet.
- Keywords:
- seismic retrofit, reinforced concrete column, carbon fiber sheet, form plates, grout
