Safety margin of ultimate lateral strength of buildings based on calculation sheets: questionnaire survey to inspection agencies

Ultimate lateral strengths of 208 buildings, designed after 2007, were obtained by the questionnaire survey to inspection agencies. The building strength is represented by the safety margin index which is the strength divided by the required strength of the Building Standard Law of Japan.The safety margin is clarified to fit a log-normal distribution with considerable accuracy regardless of structural types and systems. The distribution for all structural types and systems has the mode of 1.05 and the average of 1.34. The average for RC moment framed structures is 1.16, while that for Steel moment framed structures is 1.60.