in practice, foundations are settled on the soft layers of soil, so the ground must be designed as well as the structure. wave propagation and hysteresis damping of soil layers may alter the seismic response of flexible-base design in comparison to controversial fixed-base. lots of uncertainties about this issue, necessitate most of seismic design standards including iranian standard no. 2800 t...

In seismic resistance design, the design seismic motion is usually defined by elastic response spectra to reflect the characteristic in frequency. Whilst, either the phase of a reference seismic record or random phase is used in generation of artificial wave. The influence of phase on structural response can not be properly defined, as it is often omitted for linear elastic responses. But for t...

the present study presents an algorithm that models uncertainties at the structural component level to estimate the performance reliability of rc structures. the method calculates the performance reliability using a systemic approach and incorporates the improved response surface method based on sampling blocks using the first-order reliability method and conditional reliability indices. the re...

The influence of the near-fault ground motion on the response of long-span bridges must be considered as a critical factor for seismic design because the response indicates different aspects from existing earthquake characteristics. Also, it is important to note that the safety index for the risk assessment of long-span bridges is determined based on the minimum expected lifecycle cost E(LCC). ...

Within the past decade, seismic isolation systems have gained rapid popularity in the earthquake resistant design of bridge structures. This popularity has come in response to the inadequacy of earlier seismic design and retrofit methodologies. The mechanical shortcomings and subsequent failure mechanisms associated with the early elastic seismic design philosophy are first presented, followed ...

Seismic hazard and risk are fundamentally different concepts. Seismic hazard describes phenomena generated by earthquakes that have potential to cause harm, but seismic risk is the likelihood (chance) of experiencing a specified level of seismic hazard in a given time exposure. Seismic hazard occurs naturally and can be evaluated from instrumental, historical, and geological observations. Seism...

The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and “local” tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of met...

a r t i c l e i n f o The purpose of this study is to analytically predict and to experimentally investigate the seismic response of adjacent filled parallel rock fractures with dissimilar properties (e.g., fracture thickness and stiffness). The time-domain recursive method is extended to predict that a P-wave propagates normally across the filled parallel fractures using the specific stiffness...

In recent years, it is considerably attempted to develop the concept of energy dissipation as an applicable technology to overcome the energy released by earthquakes. The passive control systems such as metallic dampers have been widely considered. The dampers are basically used to mitigate the structural responses and reduce the damages in main structural elements by energy dissipation. ...