The 8.5+ magnitude, AD365 earthquake in Crete: Coastal uplift, topography changes, archaeological and historical signature

The damage of structures induced by earthquake ground motions depends primarily on three parameters: (1) the characteristics of earthquake source properties and ground motions (magnitude, epicentral distance, duration, frequency content, amplitude and local soil type), (2) the properties of the structure (natural frequencies, mode shapes, damping properties, material of construction, structural system and ductility capacity), and (3) how close the structure’s fundamental natural frequency to the dominant frequency of the ground motion. The 2011 off the Pacific coast of Tohoku earthquake has demonstrated these facts clearly. In general, the ground motion characteristics involve large inherent uncertainties and cannot be controlled while the structure’s properties have smaller variability and can be managed to some extent in general. For instance, the material and members of construction can be selected and the seismic-resistance of the structure can be improved to fairly high levels through member detailing for enhancement of ductility capacity.

Critical Earthquake Loads for SDOF Inelastic Structures Considering Evolution of Seismic Waves

Santo Domingo church is analyzed as part of a broader research with the goal of reporting earthquake-resistant features in the masonry architectural heritage of the historic center of Santiago, Chile. Considering that Chile is one of the most seismic countries in the world, it is interesting how some historic buildings built between the XVI and the XVIII century still remain, despite construction with vulnerable building techniques such as unreinforced masonry. Among those buildings, Santo Domingo church is the only one built in stone ashlar and one of the few that has never suffered strong structural damages after earthquakes. Built between 1747 and 1771, this church has withstood around 11 earthquakes of magnitude over 7 without serious mechanical failures. Constructive and structural characteristics of Santo Domingo Church are assessed through historical research, field analysis and tests, damage assessments and finite element analysis. This analysis identifies early earthquake-resistant design criteria of the church, and determines vulnerable areas and their behavior during the last seismic events.

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Analysis of seismic design criteria of Santo Domingo Church, a Colonial Heritage of Santiago, Chile

Dynamic Finite Element Analysis

In this paper, a simple hand calculation method to predict lateral stiffness and fundamental period of concentrically braced frame buildings with either fixed or pin base, which can also be used for unbraced frame buildings, is theoretically derived. To verify the reliability of the developed equations, the estimated lateral stiffness and fundamental periods are compared with the corresponding values obtained from pushover and Eigenvalue analyses for a wide range of low to medium rise buildings (i.e. up to ten storeys) with varying geometrical configurations. Systematic investigation of parameters affecting the fundamental period of frame buildings is also carried out. Although the basic formulation considers X and chevron brace configurations explicitly, its applicability to other types of brace configurations is also investigated. The suitability of the proposed equation for the braced frames with linear variation of section properties along the building height and pin beam-column connections is also scrutinized. Reliability of the developed hand calculation method is verified using the experimental test and numerical analysis results available in the literature. Finally, a flowchart and two worked examples are provided to explain the sequence of steps to calculate the fundamental period of concentrically braced frame buildings.

M.Y.H. Bangash

Papers

Earthquake Resistant Buildings