Seismic Strengthening Design and Analysis of a Boiler Steel Frame

The structural safety of the boiler steel frame of a cast iron plant that has been used for more than ten years was tested, and the frequently and rarely occurred earthquakes under the seismic fortification target were calculated. Five common natural seismic waves were two artificial waves, as well as seven long-period seismic waves of far-field harmonic seismic waves and near-fault pulse seismic waves were selected. Based on the interlayer displacement angle, the deformation characteristics and seismic performance of the structure were analyzed. According to the calculation results, the reinforcement design scheme of the existing structure was proposed, and the seismic calculation of the structure after reinforcement was carried out again. The analysis results after reinforcement showed that the far-field harmonic-like seismic wave had the largest response to the structure, and the ordinary seismic wave had the smallest response. The maximum inter-story drift angles under frequently occurred earthquakes were all less than the limit value of 1/250 in Code for Seismic Design of Buildings (GB 50011—2010); the interlayer displacement angles under rarely occurred earthquakes were all less than 1/50; the maximum value of the average interlayer displacement angle of the structure appeared at the bottom, was 1/88, which was 29.5% lower than that of the original structure. The reinforcement design scheme could meet the requiremerts of GB 50011—2010, and realize the seismic fortification goal of‘no damage under frequently occurred earthquakes and no collapse under rarely occurred earthquakes’.