Earthquake resistant structures

About: Earthquake resistant structures is a research topic. Over the lifetime, 1126 publications have been published within this topic receiving 27467 citations.

Improved Geometric Design of Earthquake-Resistant RC Slender Structural Walls. I: Parametric Study

Abstract: In multistoried RC wall-frame buildings, properly designed and detailed RC slender structural walls significantly improve earthquake resistance. In walls on isolated spread footings with marginal taper, severe stress concentration is observed at the wall-footing junction during earthquake shaking. In this paper, new tapered configurations are proposed in the bottom portion of walls with and without enlarged boundary elements. Analytical correlations are derived among salient structural and soil parameters of the tapered wall-footing. An extensive parametric study is carried out through linear-elastic finite-element analysis of an isolated wall-footing system under estimated actual vertical and lateral forces. Under the estimated forces, significant loss of contact is observed at the bottom of the wall-footing; thus, soil or rock anchors need to be provided to ensure stability of the wall-footings during strong shaking. Force flow from wall to footing improves significantly in the proposed integrat...

Evaluation of foundation tie requirements in seismic design

Abstract: A simple structural model is proposed to evaluate the axial force acting on tie beams interconnecting spread footings or pile caps due to differential ground motion estimated on the basis of the travelling wave assumption. The approach is intended to supplement the "ten percent rule" or similar multipliers specified by seismic codes as design axial forces on tie beams. It is shown that the axial force demand is rather modest. However, shear forces between footing and soil may be quite large depending on maximum column displacements and superstructure rigidity. Key words: foundations, tie beams, earthquake, travelling waves, seismic codes.

Seismic Fragility of Weir Structures due to Sliding Effect

Abstract: The failure of hydraulic systems as flood defence structures can cause extensive catastrophic damage in upstream and downstream areas during an earthquake. Consequently, dams or weir structures as hydraulic systems must remain functional and operational during and after an earthquake. In recent years, in order to mitigate the risk or secure the safety of the hydraulic systems, the Probabilistic Seismic Risk Assessment (PSRA) has been issued as a key area of research. The primary objective of this paper was to evaluate the seismic fragility of weir structures by incorporating a nonlinear Finite Element (FE) model for the contact interfaces among weir-mass concrete-soil foundation in the weir structure. Gangjeong-Goryeon weir, located in Daegu Metropolitan City in the southeastern part of Korea was selected in this study. The seismic fragility of the weir structure corresponding to the sliding Limit State 13 mm (LS I) and 153 mm (LS II) was determined from multiple nonlinear time-history analyses based on Monte-Carol simulation accounting for the uncertainties such as material nonlinearity and ground motions with respect to near field faults and far field faults. The results showed that the sliding failure of the weir structure corresponding to LS I started from 0.1 g, but the weir system under LS II had no failure up to 0.4g. Besides, in the case of LS I and LS II, the weir subjected to both near field faults and far field faults was more fragile than that subjected to far field faults.

Effects of soil deposits on seismic behavior of prefabricated highway tunnels

Abstract: A comprehensive study was made of the earthquake resistance of prefabricated highway tunnels embedded into soft undersea soil deposits to establish design methodology for providing adequate structural resistance to seismic disturbances. Measurements of seismic motions were carried out employing downhole accelerometers at three sites around Tokyo Bay, and dynamic analyses were conducted by utilizing seismic records obtained and applying the multi-reflection theory. Model experiments and dynamic analyses on the dynamic response of a highway tunnel embedded in soft soil deposits were also conducted. The following conclusions were drawn: (1) accelerations at deeper locations of soft soil deposits are small in comparison with the surface accelerations, and shapes of vertical distribution of maximum accelerations are different among various earthquakes; (2) the multi-reflection theory may be employed satisfactorily in estimating seismic response of multi-layered subsoils, provided that soils properties, primarily elastic moduli, are appropriately evaluated; (3) for estimating three-dimensional behavior of long structures embedded in soft subsoils during earthquakes, model experiments would be effective, and in the model experiments gelatin can be advantageously used as soft soil; (4) dynamic analyses by means of the finite element method would be also effective in obtaining seismic response of underground structures; and (5) deformation of soft soil deposits has significant effects on the dynamic behavior of the embedded structures, and soil deposits in resonance to seismic motions might exert the structures into critical state, and furthermore, the structures would be affected extensively in the vicinity of a site where depth of soft soil deposits varies steeply due to the fact that the deformation of deeper soil deposits is larger than that of the other section.