Seismic Retrofitting Methods Newly Developed for Railway Concrete Structures

Since the Hyogo-Ken Nanbu Earthquake in 1995, seismic retrofitting of existing RC columns of railway structures has been carried out. This paper first describes conventional seismic retrofitting methods and introduces two new seismic retrofitting methods that can be easily applied in narrow spaces. An outline of experimental results for these new seismic retrofitting methods is provided and the relevant design methods are described. In the first method, called the RB method, retrofitting bars are arranged so as to keep the value of γi·Vyd/Vmu (γi: safety factor, Vyd: shear strength, Vmu: shear at flexural strength) above 1.5. In the second method, called the single-face method, retrofitting bars and retrofitting plates are arranged so as to keep the values of γi· Vyd/Vmu and γi· Vyd/Vmu above 2.0 and 1.4, respectively.