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Evidence of past earthquakes highlighted the seismic vulnerability to buildings due to soil liquefaction and lateral spreading phenomena. Damage to buildings on a liquefiable site, especially on a gently sloping site, can be severe. The liquefied soil can undergo permanent lateral ground displacements as large as several meters in some cases, which can be severely disastrous to buildings. Recent physical tests and effective stress analyses of nonlinear dynamic soil-structure interaction (SSI) proved that simplified empirical processes are often improper for evaluating liquefaction-induced building settlements. A better understanding of the SSI effects is also essential in cases where the underlying soil is susceptible to liquefaction. In this respect, the interaction of the earthquake excitation and ground failure (i.e. soil liquefaction and lateral spreading) for buildings considering SSI is investigated herein. Typical low-code reinforced concrete (RC) frame buildings of different heights with shallow spread footings on liquefiable level-ground or sloping soils subjected to ground shaking are considered. The direct SSI approach is implemented. Predictive relationships are established between the maximum normalized differential displacements (horizontal or settlement) and the permanent ground displacement (PGD) vector at the level of foundation for low-code RC frame buildings with shallow spread footings on soils with high liquefaction potential subjected to ground shaking. Finally, vulnerability is expressed in terms of fragility and vulnerability curves as well as in terms of fragility surfaces as a function of two intensity measures. [ABSTRACT FROM AUTHOR]

Highlights • A multi-level framework for stress testing port infrastructures is presented. • Regulatory requirements do not exist, and risk objectives are based on judgments. • Critical components are identified, and recommendations are provided. • The results depend on the stress test level, analysis approach, and risk metrics. • The systemic risk for the tsunami hazard is very low compared to seismic risk. Abstract An engineering risk-based methodology for stress testing critical infrastructures is introduced and applied to the port of Thessaloniki in Greece exposed to seismic, geotechnical and tsunami hazards. The methodology workflow consists of four phases: Pre-Assessment, Assessment, Decision and Report phase. In the pre-assessment phase, all the necessary information is collected and archived. For the pilot study, the inventory includes the main port components namely buildings, waterfronts, cranes and the electric power system. Generic or site-specific fragility models are used for all exposed elements and considered hazards. Risk metrics and objectives are defined related to the functionality of the system and the structural losses. In the first level of the assessment phase, the performance of each component is evaluated using a risk-based approach. Then, a system level probabilistic risk analysis is conducted separately for earthquake and tsunami hazards. A complementary scenario-based risk analysis is carried out aiming to investigate the impact of site-specific response and extreme seismic events to the performance of the port. In the Decision phase, the results are compared with predefined objectives to decide whether the infrastructure passes, partly passes or fails the test. Guidelines and strategies to improve the performance and resilience of the port are summarized. [ABSTRACT FROM AUTHOR]