Recorded responses of Four Tall buildings in South China to the M 7.9 Myanmar Earthquake on March 28, 2025

This paper reports the recorded structural responses of four 170m to 320m tall buildings in China to the mainshock of the M7.9 Myanmar earthquake on March 28, 2025. The buildings are located approximately 1200 to 2000 km away from the epicenter. The following observations are made by preliminary analysis of the data: (1) the base motion of the buildings exhibited significant long-period components in the range of 2s to 10s; (2) the identified fundamental periods were much larger than the empirical equations in the design codes, suggesting that the empirical equations may be overly conservative; (3) the amplification of floor accelerations was much more significant than code provisions for determining the seismic demands on non-structural elements, possibly attributing to the overly high damping ratios assumed in the design codes; (4) the buildings exhibited large enough equivalent lateral stiffnesses to satisfy the drift limit under frequent earthquakes by the Chinese seismic provisions; and (5) the significant durations of the shaking of the upper floors of the buildings were comparable to those of the base motions.