Earthquake ground motion characteristics and seismic energy dissipation

This study presents a large-scale experimental investigation on the seismic performance of an innovative, low-cost seismic isolation system for developing countries. It is based on the beneficial effect of the encapsulation of sand grains between two PVC surfaces on the initiation of sliding and the dissipation of seismic energy between the surfaces. A three-times scaled-down, idealized, seismically isolated model of a prototype single-story structure located in Nepal is subjected to an ensemble of recorded earthquake ground motion excitations. The experimentally derived response of the seismically isolated structure is compared with the response of the corresponding fixed-base structure. This system is part of a wider hybrid design approach where the structure is designed to resist the seismic forces at the design acceleration level. The seismic isolation system sets an upper bound to the response of the structure for ground motion excitations exceeding the design level.

Download Full-text

Damage and Crack Analysis for Reinforced Concrete Energy Dissipation Braced Frame (EDBF) under Low Cyclic Loads

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.324-325.611 ◽

2006 ◽

Vol 324-325 ◽

pp. 611-614

Author(s):

Mei Ling Xiao ◽

Liao Yuan Ye ◽

Sheng Miao ◽

Ben Yu Liu

Keyword(s):

Reinforced Concrete ◽

Energy Dissipation ◽

Ground Motion ◽

Damage Variable ◽

Dissipated Energy ◽

Earthquake Ground Motion ◽

Displacement Curve ◽

Cyclic Loads ◽

Braced Frame ◽

Factor C

Application of Miner criterion, cumulate damage variable was estimated based on pseudo-static experiment study for reinforced concrete energy dissipation braced frame (EDBF) under low cyclic loads, accordingly, the constitutive relations about damage was established; the linear hook law turned into non-linear stress-strain relations; the dissipated-energy factor c β was determined based on following factors: the cumulate damage variable, hysteretic energy determined by load-displacement curve, maximum deformation and yield force of EDBF; it supplied a quantitative basis of dissipated-energy for EDBF; There were two reasons in energy dissipation for EDBF: one was energy dissipation equipment acting, the other was concrete damaged and cracked or low cycle fatigue failure in this structure, and the latter part of energy was associated with amounts of cracks and crack size; then the forced mechanism of EDBF was analyzed, and the reason caused cracks and crack type of EDBF columns, beam and braces were explained based on forced mechanism: the columns, beam and braces of EDBF were compressed or tensed under low cyclic loads, so most of cracks of columns, beam and braces belonged to mode I cracksThis study supplied a method for estimating energy of EDBF under earthquake ground motion, and the results showed: columns in EDBF are easily damaged under earthquake ground motion, so the structural elements must be designed strong column, weak beam and weak brace.

Download Full-text