Near-source directivity effects on medium-long period structures

Abstract eng:
This study presents a new definition of the strong motion duration, combining the alternative bracketed and significant duration definitions. Based on the time integral of the absolute ground velocity, a new index is defined, as the cumulative absolute displacement CAD. The index is used in order to evaluate the strong motion duration. The proposed bracketed-significant duration is well correlated with the strong motion part of the records, especially in the case of near-source events. The duration and the CAD index are correlated with the structural behaviour of medium-to-long period structures. Two normalized parameters representing the amplification of structural response and the number of equivalent loading cycles are determined in terms of the proposed duration and CAD indices. The proposed parameters appear to be better correlated with the structural response than other well-known indices. As a case study the dynamic response of a reinforced concrete frame-wall structure subjected to nearfault excitations with forward directivity characteristics is study. The design of the structure resulted as a part of a US-Japan cooperative research program and was based on UBC provisions. Both analytical studies and experimental work results are available for the prototype; thus, allowing comprehensive modeling and study of the nonlinear dynamic behavior. The frame was considered as an excellent design example according to the strong column – weak beam philosophy and was able to undertake the ductility demands of a pulse-type excitation with pulse-period similar to the period of the structure.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket