scholarly journals Soil Densification Effect on The Seismic Response of Structures Taking into Consideration Soil-Structure Interaction

2021 ◽  
Vol 2 (4) ◽  
pp. 13-17
Author(s):  
Radhwane Boulkhiout
Keyword(s):  
Dynamic Response ◽  
Seismic Response ◽  
Soil Structure ◽  
Lateral Displacement ◽  
Motion Vector ◽  
Stability Index ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Seismic Force ◽  
Soil Densification

Soil compaction is a considerable construction activity to ensure safety and durability, notably in the transportation industry. This technique of compaction increases soil bulk density and soil strength, while decreases porosity, aggregate stability index, soil hydraulic conductivity, and nutrient availability, thus reduces soil health. Consequently, it lowers crop performance via stunted aboveground growth coupled with reduced root growth. Therefore, if the characteristics of the soil are changed, it will affect the response of the structures. In this work, the effect of improving soil characteristics by compaction techniques on the dynamic response of foundations and structures, taking into consideration the effect of soil-structure interaction was determined. The dynamic response of foundations is presented by the impedances functions, which are determined numerically by the CONAN program, based on the cone method. In addition, the response of the structure will be presented according to the lateral displacement in each level of it. This motion vector is a function of the forces in each level; for this, the equivalent static method was applied, which allows to calculate the seismic force at the base and its distribution on the height of the structure. The results obtained show the efficiency of soil densification on the seismic response of MDOF frames.

scholarly journals Dynamic Behaviour of Raft Foundation for Tall building with Variable Subsoil

2020 ◽  
Vol 10 (2) ◽  
pp. 230-235
Keyword(s):  
Dynamic Response ◽  
Soil Structure ◽  
Lateral Displacement ◽  
Specific Effect ◽  
Soil Structure Interaction ◽  
Structural Safety ◽  
Natural Period ◽  
Analysis And Design ◽  
Structure Interaction ◽  
Fixed Base

Structures are often constructed on layers of soil unless bedrock is very close to the ground surface. When the ground is stiff enough, the dynamic response of the structure will not be influenced significantly by the soil properties during the earthquake, and the structure can be analysed under the fixed base condition. When the structure is resting on a flexible medium, the dynamic response of the complete structure will be different from the fixed base condition, where the interaction between the soil and the structure has to be incorporate. This behavioural difference because of the phenomenon commonly referred to as Soil-Structure Interaction (SSI), which if not considered in analysis and design properly; the accuracy in assessing the structural safety, response for earthquake excitation could not be reliable solution. Hence evaluation of the site, specific effect of soil stiffness on structure becomes important to understand behaviour of structure. Flexibility of soil increases natural period of structure, which basically turn changes the seismic response of structure. The interaction among structure, their foundation and soil media below foundation alter the actual behaviour of structure. Here G+25 storey building is modelled and analysed, employing Finite Element Method adopting Commercial code SAP2000 V19 under fixed base (no soil-structure interaction) and flexible base considering soil-structure interaction. An attempt has been made to evaluate the effect of soil structure interaction of super structure by considering the systematic parameters like time period, lateral displacement, storey drift, bending moment in dual global structural axis i.e., X-X and Y-Y direction.

Seismic Response Analysis of Soil-Structure Interaction on Base Isolation Structure

2013 ◽  
Vol 663 ◽  
pp. 87-91
Author(s):  
Ying Bo Pang
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Soil Structure ◽  
Base Isolation ◽  
Soil Structure Interaction ◽  
Response Analysis ◽  
Analysis Model ◽  
Seismic Response Analysis ◽  
Structure Interaction ◽  
Calculation Results

As an effective way of passive damping, isolation technology has been widely used in all types of building structures. Currently, for its theoretical analysis, it usually follows the rigid foundation assumption and ignores soil-structure interaction, which results in calculation results distortion in conducting seismic response analysis. In this paper, three-dimensional finite element method is used to establish finite element analysis model of large chassis single-tower base isolation structure which considers and do not consider soil-structure interaction. The calculation results show that: after considering soil-structure interaction, the dynamic characteristics of the isolation structure, and seismic response are subject to varying degrees of impact.

Effect of Pile-Soil-Structure Interaction on the Cable-Stayed Bridge in Response to the Earthquake

2014 ◽  
Vol 539 ◽  
pp. 731-735 ◽  
Author(s):  
Yu Chen
Keyword(s):  
Finite Element ◽  
Seismic Response ◽  
Soil Structure ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Soil Structure Interaction ◽  
Structure Interaction ◽  
Finite Element Software ◽  
Cable Stayed Bridge ◽  
Three Dimensional Finite Element

In this thesis, based on the design of a 140+90m span unusual single tower and single cable plane cable-stayed bridge, free vibration characteristics and seismic response are investigated; three dimensional finite element models of a single tower cable-stayed bridge with and without the pile-soil-structure interaction are established respectively by utilizing finite element software MIDAS/CIVIL, seismic response of Response spectrum and Earthquake schedule are analyzed respectively and compared. By the comparison of the data analysis, for small stiffness span cable-stayed bridge, the pile-soil-structure interaction can not be ignored with calculation and analysis of seismic response.

Effect of Structure-Soil-Structure Interaction (SSSI) between Three Dissimilar Adjacent Bridges

2021 ◽  
Author(s):  
Mohanad Talal Alfach ◽  
Ashraf Ayoub
Keyword(s):  
Seismic Response ◽  
Seismic Behavior ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Numerical Analyses ◽  
Seismic Responses ◽  
Structure Interaction ◽  
Internal Forces ◽  
Isolated Bridge ◽  
Effect Of Structure

Abstract The present study assesses the effect of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar adjacent bridges by comparing their seismic responses with the seismic response of the isolated bridge including Soil-Structure-Interaction (SSI). To this end, an extensive series of numerical analyses have been carried out to elicit the effects of Structure-Soil-Structure-Interaction (SSSI) on the seismic behavior of three dissimilar bridges with different superstructure masses. The studied bridges are based on groups of piles founded in nonlinear clay. A parametric study has been performed for configurations of three dissimilar bridges with superstructure masses ratios of 200% and 300%, concentrating on the influence of the inter-bridge spacing, and the geometrical position of the bridges towards each other and towards the seismic excitation direction. The numerical analyses have been conducted using a three-dimensional finite difference modeling software FLAC 3D (Fast Lagrangian analysis of continua in 3 dimensions). The results of the numerical simulations clearly show that the seismic responses of the dissimilar grouped bridges were strongly influenced by the neighboring bridges. In particular, the results reveal a salient positive impact on the acceleration of the superstructure by a considerable drop (up to 90.63%) and by (up to 91.27%) for the internal forces induced in the piles. Comparably, the influence of bridge arrangement towards the seismic loading were prominent on both of superstructure acceleration and the internal forces in the piles. The responses were as much as 27 times lesser for the acceleration and 11 times smaller for the internal forces than the response of the isolated bridge. Contrarily, the inter-bridge spacing has a limited effect on the seismic response of the grouped bridges.

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