SEISMIC STRENGTHENING OF BEAM-COLUMN JOINTS WITH CFRP ROLLS

Abstract

In the seismic behavior of frame structures, it is known that beam-column joints carry high stresses, so that they play an important role in seismic safety. Earthquake forces create high shear forces  in the joint region and  the inclined principal  tensile stresses formed by this action induce diagonal cracks, which eventually lead to disintegration of concrete.  To resist these stresses, use of ties is needed in the joint region. The seismic codes in effect require  continuation of a certain ratio of closely spaced ties used in the region at the column ends, in the joint region. Since the placement of ties required by the code in this region is rather difficult, this condition is hardly fulfilled and in some cases even no ties are placed in the joint at all.  As a result of this, in the majority of existing structures, beam-column joints are in a very deficient state in terms of their seismic behavior.  In the case of a beam-column joint, where it is known that there are not sufficient shear reinforcement, it is thought that new reinforcement, which can carry inclined principal tensile stresses developing in the joint due to earthquake forces, are provided by placing carbon fiber reinforced polymer rolls into the inclined holes drilled from the outside and by gluing them there using epoxy and by anchoring the ends from the outside.  This research mainly aims to develop a practical joint strengthening technique on this principle.

The experimental study was carried out at the METU Structural Mechanics Laboratory and using T-shaped test specimens reflecting an exterior joint region of a frame having normal dimensions, to a scale of 2/3.  Test results of five specimens, one reference and four strengthened with diagonal CFRP rolls are reported in the present paper.

Keywords

• Kiriş-Kolon Birleşim Bölgesi; Karbon Fiber Güçlendirmeli Polimer (CFRP) Ruloları; Depreme Karşı Güçlendirme; Epoksi.

KİRİŞ-KOLON BİRLEŞİM BÖLGESİNİN CFRP RULOLARLA DEPREME KARŞI GÜÇLENDİRİLMESİ

Abstract

Keywords

• Kiriş-Kolon Birleşim Bölgesi, Karbon Fiber Güçlendirmeli Polimer (CFRP) Ruloları, Depreme Karşı Güçlendirme, Epoksi

References

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