When a specific building is examined and analysed for its architectural merits, it is the visible, superficial aspects, which are considered, for example: aesthetics, function, spatial relationships, and landscape. One of the most important invisible factors that should be considered in the DESIGN process is the safety of buildings against natural hazards, particularly against earthquakes. While the provision of earthquake resistance is accomplished through structural means, the architectural DESIGNs and decisions play a major role in determining the SEISMIC performance of a building. In other words, the SEISMIC DESIGN is a shared architectural and engineering responsibility, which stems from the physical relationship between architectural forms and structural systems. It is economic to incorporate earthquake resistance in the stage of DESIGN than to add it later in the structural calculation or strengthening after completion. In addition, a building with proper earthquake-proof DESIGN will be more effective against earthquakes than the one with complementary strengthening. This paper will demonstrate that evidence for this lies in many historical buildings, which have withstood earthquakes throughout the hundreds of years without having been reinforced with special material. The fact is that the master builder or Mimar (traditional architect) of historic buildings was simultaneously DESIGNing the architecture as well as choosing the suitable form, proportion, and material for the best structural performance.

The DESIGN of facilities to resist SEISMIC loads requires selection of an appropriate safety level. This paper will discuss the requirements of different international standards and will suggest that the criteria might be established on the basis of a quantitative risk analysis. The paper will, furthermore, discuss the experience oil companies have gained through working in Norway and North Western Europe in DESIGNing facilities to withstand the relevant SEISMIC loads. Although this area of the world is an intraplate area with relatively low SEISMICity, it is suggested that the experience gained in using risk based SEISMIC DESIGN criteria and quantitative risk analysis could be of value to those working in more SEISMIC regions of the world. The paper will mainly refer to onshore terminal facilities on the Western Coast of Norway, which is the area of the North Western Europe with highest SEISMIC hazard, and to offshore platforms in the Northern North Sea. Finally, the paper will present considerations related to upgrading of existing facilities with particular emphasis on facilities in the oil and gas industry

The DESIGN of earthquake-resistant buildings starts with defining the maximum lateral earthquake forces or their resultant. The amount of these forces depends on various factors, including coefficient of system behavior which depends on over strength and its ductility. In this study, a method is proposed in order to DESIGN an earthquake-resistant system in which the distribution of lateral forces is adjusted based on equal distribution of the SEISMIC demand ratio in structural elements for the optimum use of SEISMIC capability of the structure. To this end, three types of 4-, 7-, and 10-story structures are Applied. Firstly, the above-mentioned structures are DESIGNed based on gravity loads and consequently analyzed based on linear and nonlinear dynamic analyses, applying the accelerograms of some major earthquakes. Pursuant to that, the average loading ratio to the allowed capacity of the elements of each story in linear analysis and the average ratios of plastic rotations to the allowed capacity of elements in nonlinear analysis are applied as the modified shear ratio in the Iranian National SEISMIC Code. On that account, the new lateral loading distribution is measured and identified. Based on this new distribution, the above-mentioned structures are DESIGNed and their SEISMIC behaviors are identified, applying linear and nonlinear dynamic analyses of the same accelerograms. The findings indicate an ameliorated SEISMIC behavior of the beams and the columns. Moreover, the distribution of the SEISMIC demand ratios attains more uniformity along the height of the structures.

In this paper a simple tool for SEISMIC DESIGN of steel structures for a selected ductility level is presented. For this purpose, a consistent set of earthquakes is selected and sorted based on the maximum acceleration of ground surface. The selected records are applied as the base motion to a single-degree-of-freedom system with strain hardening and the maximum response acceleration is determined for three levels of ductility. The response results of the nonlinear dynamic analysis are presented in the shape of the maximum acceleration of the system versus the peak ground acceleration for a certain ductility demand. Using these graphs, the maximum acceleration and base shear of the system are calculated by accounting for its nonlinear behavior, hence eliminating the need for the response modification factor. This is the main advantage of the presented diagrams for nonlinear SEISMIC DESIGN of steel moment frames.