Reduction Of Structural Response Research Articles

Effect of Ambient Temperature on Viscoelastically damped structure

Seismic response characteristics of a 2/5‐scale steel frame structure with added viscoelastic dampers are studied experimentally. The major emphasis is placed on the ambient temperature effect. It is shown that, while seismic response characteristics of a structure can be significantly improved with added dampers, their degree of effectiveness depends on the surrounding temperature within which they operate. Results also show that, even at very high temperatures, the viscoelastically damped structure can still achieve a significant reduction of structural response as compared with when no dampers are added. Designing viscoelastic dampers by considering the ambient temperature is addressed. Empirical equations are established based on regression analysis using data obtained from component tests of the dampers. These equations can satisfactorily estimate the dynamic properties of dampers under various ambient temperatures, excitation frequencies, and deformations. Numerical simulations are carried out on equivalent structural damping and structural response under various ambient temperatures. It has been demonstrated that the dynamic behavior of structures with added viscoelastic dampers can be satisfactorily predicted by conventional analytical tools.

Stochastic analysis of rigid foundation filtering

AbstractThe effect of the space–time variation of earthquake ground motion on the translational response of structures supported on large rigid mat foundations is considered. A stochastic space–time ground motion model, based on the analysis of recordings from the SMART‐1 seismograph array in Lotung, Taiwan, is used. Random vibration theory is utilized to obtain an expression for the reduction in the maximum structural response, for a specified probability level and strong motion duration. Numerical computations are performed to examine the sensitivity of the reduction in structural response to various ground motion and structural parameters. The results indicate that spatial correlation and travelling wave effects give rise to significant reductions in structural responses when the seismic waves have low apparent propagation velocities. Utilization of this result in the design of structures on large foundations should yield substantial cost savings.