Seismic Retrofit

Keywords epoxy resin, seismic retrofit, steel jacketing method, carbon fiber sheet jacketing method, unseating prevention... 

In this paper, the current seismic retrofitting systems for reinforced concrete piers/columns and bridge-falling prevention systems at the abutments and piers in Japan were studied. The application of epoxy resin for both systems was investigated and discussed. Furthermore, seismic design and construction for newly built structures were also introduced. 

Seismic Retrofit of Existing Concrete Piers/Columns... 

In this study, the current seismic retrofitting for concrete piers/columns and bridge falling prevention systems after the Great Hyogo-Ken Nanbu Earthquake in Japan were introduced and discussed. The main results corresponding to polymers are summarized as follows ... 

Three types of jacketing methods using either reinforced concrete, steel or fiber as seismic retrofit to increase the flexural and shearing strength, and ductility of existing concrete piers are adopted. For steel jacketing method, liquid epoxy resin is effectively used for injection in the space between steel jacket and concrete piers. 

Unjoh, S., Sugiyama, T., Sakai, J. and Okada, T. Damage of Bridge Structures during Recent Earthquakes and the Effectiveness of Seismic Retrofit, Proc. of the 4(f" Joint Meeting of UJNR Wind and Seismic Effects, pp.1-13. (2008). 

Ministry of Land, Infrastructure, Transportation and Tourism, Kanto Regional Development Bureau Tentative manual of Seismic Retrofitting methods for existing bridges (in Japanese), p. 2.1-2.43 (construction). MLIT, (2005). 

Seismic retrofitting of a masonry shear wall using GFRP fabric and additional CFRP strips, which are anchored in concrete using end plates school building at Zollikofen in Bern, Switzerland (from Motavalli and Czaderski 2007). 

Seismic retrofitting of a masonry shear waii using CFRP strips Shariati iViuseum in Tehran, iran (from Radyab Co., Tehran, iran). 

Figure 4.29 shows the seismic retrofitting of a masonry wall of the Shariati Museum in Tehran, Iran, where CFRP strips were applied. 

Mitsubishi Chemical manufactures a seismic retrofit material Replark and have formed a joint venture with Fiberite in the USA. Replark is a UD carbon fiber tape with low epoxy resin content with a fiberglass scrim backing to facilitate handling in the field. The application entails the preparation of the concrete, application of an epoxy primer, putty and resin, followed by the requisite number of layers of Replark tape and additional resin, to form a cured composite and finally, the application of a surface coat to improve the appearance. Fiberite use type 12k T300 or AS4C carbon fiber and the Replark is offered in areal weights from 175 300 gm . ... 

Marsh G,Seismic retrofit provides opportunities for FRP, Reinforced Plastics, 38-43, Mar 1998. Meier U, Rehabilitation and retrofitting of existing structures through external bonding of thin carbon-fiber sheets. Materials and Structures, 28(176), 105-106, 1995. 

Thermosetting epoxy fibre composite materials are widely used for infrastructure rehabilitation and seismic retrofit of concrete members. However, for rehabilitating steel structures, thermoplastic polymers offer significant advantages over thermosetting matrices. When bonded to steel substrates, the toughness of thermoplastic allows the material to strain under applied stresses (thermal or flexural) without compromising the metal/composite bond. 

Ehsani M, Saadatmanesh H (1996) Seismic retrofit of URM walls with fibre composites. TMS J 14(2) 63-72... 

Lukose N, Gergely P, White RN (1982) Behaviour of reinforced concrete lapped splices for inelastic cyclic loading. ACI Struct J 79(5) 355-365 Ma R, Xiao Y (1999) Seismic retrofit and repair of circular bridge columns with advanced composite materials. Earthq Spectra 15(4) 747-764 Melek M, Wallace JW (2004) Cyclic behaviour of columns with short lap splices. ACI Struct J 101(6) 802-811... 

Added concrete walls are very popular for seismic retrofitting of concrete buildings. A simple, cost-effective way of adding them is by infilling with reinforced concrete (RC) some bays of the existing frame, especially at the perimeter. The technique is... 

It is popular in seismic retrofitting of concrete buildings to add reinforced concrete (RC) walls, which reduce, thanks to their stiffness, the storey drifts and hence structural and non-structural seismic damage. A simple and cost-effective way of adding walls is by infilling with RC strategic bays of the frame, especially at the perimeter of the building. If the new wall takes up a full frame bay, it can incorporate the beams as well as both columns, at the location normally taken up by the wall boundary elements. The web is totally new and should be fastened to the... 

Three 4-storey, one-bay frame specimens were infilled with RC in one of them two options were employed to coimect the RC web to the surrounding members. The walls were considered as part of a seismic retrofitting of a non-ductile frame building and were tested pseudo-dymamically for a 0.25g seismic excitation of the entire building, with the rest of it substructured as elastic. Some conclusions are ... 

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