Editor's Note

摘要

Papers selected for this issue of the Journal cover the following topics: seismic effects, reinforced concrete structures, and wood structures. One paper on metal structures and another on analysis and computation followed by a discussion item and corresponding closure wrap up the issue.rnAn efficient approximate method that uses multi-degrees-of-freedom (MDOF) modal equations of motion is presented by Lin et al. in "Seismic History Analysis of Asymmetric Buildings with Soil-Structure Interaction." The response of two-way asymmetric shear buildings excited by two-directional seismic ground motions is considered wherein soil-structure-interaction (SSI) forces are simulated using frequency-independent soil springs and dash-pots. The MDOF modal response histories are obtained using step-by-step integration and the seismic response of the whole SSI system are determined from the arithmetic summation of the modal response histories. The efficiency of the proposed method was validated using numerical examples of a two-way asymmetric four-story building with large and small SSI effects.rnIn "Application of Energy Balance Concept in Seismic Evaluation of Structures," Leelataviwat et al. present a seismic evaluation procedure based on a framework that utilizes energy demand and capacity diagrams. The monotonic force-displacement curve of the structure is converted into an energy capacity plot that is superimposed over the corresponding energy demand plot for the given hazard level to determine the expected peak displacement demand.