辛亥革命元勋王天培将军遗文

辛亥革命元勋贵州籍将领王天培,一生追随孙中山先生革命,笃信三民主义,由于性情直率,胸怀坦荡,遭到蒋介石、何应钦等人嫉妒,以＂莫须有＂罪名陷害,英年早逝。从他撰写的一些对联、讲话、题词、诗歌、信函等遗文里,不难看出王天培聪颖的才华,直率的性格,忠诚的思想,坦荡的胸怀,以及坚定的信念和高尚的气节,不愧是贵州人民的好儿女。     

Empirical Green's Functions Modified by Attenuation for Sources Located at Intermediate and Far Distances from the Original Source

We present a scheme to modify empirical Green's functions by attenuation considering: (1) geometrical spreading; (2) decay in high frequency; (3) regional attenuation; and (4) phase of the signal. The accelerograms computed with the proposed simulation method are compared, in time and frequency domains, with strong ground motions from subduction and intermediate-depth earthquakes recorded in Mexico. It is shown that this simple empirical Green's functions technique can synthesize both the shape and amplitude of the response spectra in the site, considering a postulated seismic source located at different distances from the original one.     

A Damage Index for the Seismic Analysis of Reinforced Concrete Members

This article proposes a damage index for the seismic analysis of Reinforced Concrete members using the hysteretic energy dissipated by a structural member and a drift ratio related to failure in the structure. The index was calibrated against observed damage in laboratory tests of 76 RC column units under various protocols. Values obtained in this calibration had acceptable agreement with the levels of damage observed in the test specimens. An analysis of the parameters involved in the definition of the proposed damage index shows the importance of displacement history in the drift ratio capacity of structures.     

Optimal Control of Accelerations in a Base-Isolated Building using Magneto-Rheological Dampers and Genetic Algorithms

This article presents a numerical study aimed at improving effectiveness of the isolation system of an actual building by adding magneto-rheological (MR) dampers that act in parallel to the existing rubber bearings (RB). The building itself is modeled with uniaxial elastic elements. Additional elements that include the RBs and the MR dampers are added at the base of the building and two different genetic algorithms are used to optimize operation of the MR dampers. Maximum acceleration and relative displacement at the top of the building are taken as the variables to be minimized. Records of destructive earthquakes are used as input. A comparison is made between the building responses with RB and the one with the additional control system.