SEISMIC ANALYSIS OF A HIGH RISE BUILDING
by Prof Santiago Hernandez
Professor Santiago Hernandez gave a special seminar at Ashurst Lodge describing the Seismic Analysis of a High Rise Building in Benidorm in which he described a special problem arising during the analysis of a large building on the Mediterranean Coast.
The structure was built in concrete rather than steel as is customary. It was also unusual in that there were no columns but only concrete shear walls which made the building unusually strong. The computational simulation was done using finite elements (66,518 elements and 181,828 nodes) resulting in more than 1 million degrees of freedom for the whole system after taking boundary conditions into consideration. It was analysed on a large PC using matrix partitions.
The dynamic analysis of the building produces a series of modes and frequencies. With these results, one can use the earthquake design spectrum defined by the Spanish codes. Due to the lack of earthquake data these codes have adapted a series of design spectra which are not too severe as the country has low seismicity.
Based on the seismic analysis as required by the codes, a new reinforcement scheme was proposed for the concrete structure. The building is now under construction and Santiago hopes to report on new developments next year when he plans to visit the Lodge again.