Numerical Investigation of Residual Strength and Energy Dissipation Capacities of Corroded Bridge Members Under Earthquake Loading

Recent damage examples of aged steel bridge infrastructures around the world are so alarming. They intensified the importance of careful evaluation of existing structures for the feasibility of current usage and to ensure public safety. Corrosion and fatigue cracking may be the two most important types of damages in aging structures. Furthermore, recent earthquakes demonstrated potential seismic vulnerability of some types of steel bridges. Corrosion and its effects can trigger the damages caused by earthquakes, and it will be vital to understand the behavior of existing steel bridges which are corroding for decades in future severe seismic events as well. This article comprises the results of nonlinear FEM analysis of many actual corroded plates with different corrosion conditions and proposes a simple and reliable methodology to estimate remaining seismic strength and energy dissipation capacities by measuring only the minimum thickness of a corroded surface, which can be used to make rational decisions about the maintenance management plan of steel infrastructures.     

THE SEISMICITY OF THE EASTERN MEDITERRANEAN REGION 550-1 BC: A RE-APPRAISAL

A re-appraisal of the seismicity of the Eastern Mediterranean and Middle East during in 550-1 BC shows that although the historical record is very incomplete, analysis of the original sources, as opposed to reliance on secondary works, can provide valuable insights into the long-term seismicity of that region. Although this method has resulted in the rejection of some events noted in previous catalogues, the end-product should be a more reliable seismic record.     

DEFORMATION-CONTROLLED EARTHQUAKE-RESISTANT DESIGN OF RC BUILDINGS

A procedure for deformation-controlled, or displacement-based, seismic design of multistorey RC buildings is proposed, implemented and applied for the full design of a four-storey RC structure. It is integrated into the overall structural design, along with the design for the non-seismic actions and consists of a ULS verification against the conventional strain limits for a frequent “serviceability” earthquake and of proportioning the compression reinforcement and the transverse reinforcement of critical regions of members to meet the member peak inelastic chord rotation demands under the “life-safety” seismic action. Quantitative rules and expressions are proposed for the estimation of (a) mean and upper-characteristic peak inelastic chord rotation demands, through appropriate linear-elastic analyses, and (b) mean and lower-characteristic values of member ultimate chord rotations, in terms of member geometric and material data.     

Geographic Zonality and Polar Asymmetry

The author disagrees with Markov's suggestion that polar asymmetry, as a structural element of the earth's geographic envelope, takes precedence over geographic zonality. Sochava proposes instead that asymmetry be regarded merely as an additional characteristic of zonality).     

General Circulation of the Atmosphere as an Essential Link in the System: Sun—Climatic Change

The author reviews the work done by himself and by Bezrukova-and Rubashev at the Pulkovo Observatory in relating fluctuations in the characteristics of the general circulation of the earth's atmosphere over the Northern Hemisphere to fluctuations in solar activity, on the one hand, and to climatic fluctuations, on the other. The general circulation of the atmosphere is thus found to meet the requirements of an intermediate link in the research system: sun—climatic change. This paper was read at the New York conference on solar variations, climatic change and related geophysical problems in January 1961.     

The World's Water Resources and their Changes Over Space and Time

A moisture cycle of 1800 to 2000 years has been established for the earth as a whole, and the present period represents a transition from a wet to a dry phase in which the amount of water in oceans is gradually increasing at the expense of water from the land surface. Runoff fluctuations on the land surface also follow cycles of varying duration. It has been established that wet periods in some sections of the earth's surface are always matched by dry periods elsewhere. A definite geographic localization of zones of synchronous and asynchronous runoff fluctuations can be used in long-range runoff forecasts, which are needed for water-budget and waterpower-potential calculations. Prospects for future elimination of the disproportion between water needs and water resources are suggested. Steps to overcome the growing pollution problem are also proposed.     

The Development of Geography in the Soviet Republics of Transcaucasia

A review of geographic research in Transcaucasia during the 50 years of Soviet rule. A great diversity of natural conditions within a relatively limited area has made the region a miniature laboratory and testing ground for a variety of geographic concepts, especially in climatology and hydrology.     

Achievements of Soviet Geography in Kazakhstan

A review of geographic research on Kazakhstan over the last 50 years, with a survey of major research projects and publications. Although Moscow geographers long assumed a large share of the research, a local group of geographers under N.N. Pal'gov has been playing an increasingly active role since the 1950's.