Seismic Assessment and Retrofitting of the National Radio Station in Bangladesh

Bangladesh is located in an earthquake-prone zone near Eurasian Plate Boundary and has a potential risk of hazard in earthquakes. Moreover, the country has a large number of buildings with low strength of concrete, improper members sizing or high axial column load ratio, inadequate shear rebar, improper structural framing, etc. Considering all those limitations, government has started to assess and retrofit government buildings as well as private commercial buildings. Government of Japan through JICA and some other agencies is supporting in this respect to research and prepare several manuals. On behalf of the government, Public Works Department (PWD) is playing a vital role to expedite the process. The Japanese Guidelines for Seismic Assessment and Retrofitting Guidelines are following in Bangladeshi Building with necessary modifications. For last one decade, PWD has assessed and retrofitted several buildings in government and private sectors. This paper will focus on the seismic assessment and retrofitting design and construction of Bangladesh National Radio Station, namely “Betar Bhaban”. The building was designed as a ten-storied building in 1990 and constructed up to fifth floor level before 1998. In the year 2014, the authority of the Radio Station decided to construct rest of the floors and allowed PWD to assess and retrofit as the building found inadequate against seismic forces. The seismic index as found from the assessment was lower in respect to the current code requirements. The seismic index increased after adding retrofitting components. Reinforced Concrete Shear Walls, Steel frame bracing, etc., are used to retrofit the building.