Influence of Diaphragm Flexibility on Seismic Response of Unreinforced Masonry Buildings

The effects of diaphragm flexibility on the seismic response of low-rise unreinforced masonry buildings are examined using one-way stiffness- and strength-eccentric single-story systems subjected to unidirectional ground excitation. A wide range of diaphragm stiffnesses are considered. Results show that diaphragm flexibility can induce different effects depending on the configuration of the system and the level of diaphragm flexibility. When diaphragm is relatively stiff, amplified displacement demands can be imposed on the flexible side of the structure. When diaphragm is relatively flexible, peak displacements of in-plane loaded walls generally reduce. A diaphragm classification is developed to capture these salient effects.     

Book reviews

Traditionelle und moderne Formen der Landwirtschaft in Iran: Siedlung, Wirtschaft und Agrarsozialstruktur in nördlichen Khuzistan seit dem Ende des 19. Jahrhunderts. [Traditional and Modern Forms of Agriculture in Iran: Settlement, Economics, and Agrarian Social Structure in Northern Khuzistan since the End of the Nineteenth Century.] By Eckhart Ehlers. With a contribution by Grace Goodell, “Agricultural Production in a Traditional Village of Northern Khuzistan.” A publication of the Geographical Institute of Marburg University in the series, Marburger geographische Schriften, Vol. 64, 1975. x + 289 pp., 12 charts, DM33.

Unity in the Ghazals of Hafez. By Michael C. Hillmann. Minneapolis and Chicago: Bibliotheca Islamica, 1976. 181 pp.

Afghanistan in the 1970s. Edited by Louis Dupree and Linette Albert. New York: Praeger Publishers, 1974.     

Evaluation of 2D Seismic Site Response due to Hill-Cavity Interaction Using Boundary Element Technique

This paper deals with the evaluation of two-dimensional site-effects due to the seismic interaction between hills with various configurations and underground cavities. The time-domain boundary element method is used to evaluate the site-effects of hill-cavity interaction subjected to vertically propagating in-plane SV and P waves. The presence of an underground cavity and the hill topography are expected to induce significant effects on the surface ground motion. To further examine the contribution of the amplification ratio of the hill-cavity system, a fairly simple approach, which can compute the response spectra of the hill’s surface motion above a cavity based on the real input motions, is also used to input motions.     

Medieval Arab Contributions to Optics

The year 2015 was the United Nations’ International Year of Light and Light‐based Technologies. The year long activities created a forum for scientists and engineers and all others inspired by light, to interact with each other and with the public so as to learn more about the nature of light and its many applications. It was also a time to promote and celebrate the Medieval Arab contributions to optics. The year 2015 marked the 1000th anniversary of the seven volume encyclopedia on optics written by the great Arab scientist, Ibn al‐Haytham. Here, we present the Medieval Arab achievements in optical sciences and its impact on the European renaissance.