scholarly journals ON APPLICATION OF COMBINED PILE-RAFT FOUNDATIONS FOR ROAD STRUCTURES

2020 ◽  
Author(s):  
Steffen Leppla ◽  
Arnoldas Norkus
Keyword(s):  
Soil Structure ◽  
Soft Soil ◽  
Structure Design ◽  
Bridge Engineering ◽  
Soil Structure Interaction ◽  
Design Solution ◽  
Natural Soil ◽  
Soil Layers ◽  
Structure Interaction ◽  
Raft Foundations

Roads and road infrastructure systems are designed to satisfy ultimate and serviceability conditions under long-term actions caused by transport loadings and environmental effects. Selected design solutions must be safe and rational in terms of construction and maintenance costs. In cases when weak or soft soil layers of natural soil profiles are shallow and/or the traffic loads are very large, the Combined Pile-Raft Foundation (CPRF) is the economical road and railway structure design solution. Application of CPRF is cheaper geotechnical solution comparing with soil change or usual piled foundation alternatives. The development of this system is based on the analysis of relevant mechanical properties of soil layers and the evaluation of the soil-structure interaction. The soil-structure interaction is of highest importance allowing proper evaluation of load bearing resistance and deformation transmitted by raft and piles to soil layers. The soil and foundation system usually is subjected by loadings, resulting elastic-plastic resistance range. Therefore, relevant nonlinear physical laws due to the stress levels are used. The paper purpose is summarizing the experience of application of Combined Pile-Raft Foundations used in road and railway construction and bridge engineering.

scholarly journals Effect of Resonance in Soil-Structure Interaction for Finite Soil Layers

2018 ◽  
Author(s):  
Zsuzsa B Pap ◽  
László P Kollár
Keyword(s):  
Seismic Design ◽  
Soil Structure ◽  
Soft Soil ◽  
Infinite Medium ◽  
Soil Structure Interaction ◽  
Soil Layers ◽  
Earthquake Loads ◽  
Practical Applications ◽  
Structure Interaction ◽  
The Common

In case of seismic design the deformability of the soil should be considered, which can be performed in several ways. Most of the methods do not take into account the finite dimensions of the soil, which results significantly different behavior than the spring-dashpot systems. For an infinite medium, which is used in many cases, there are no eigenmodes, however in practical applications the soft soil is always bounded by rocks. For these cases the soil has eigenmodes and the resonance may influence considerably the response of the system. This question was investigated numerically by FE calculations, and it was found that in certain cases the resonance, which is neglected in the common design process, may significantly enhance the earthquake loads. In this paper this phenomenon is investigated and the parameter range is defined when this effect must be taken into account.

Seismic Soft Soil-Structure Interaction Using RLBRB-Equipped Strut in Deep Excavations

2020 ◽  
pp. 1-29
Author(s):  
Abdolghafour Khademalrasoul ◽  
Arash Shirmohammadi ◽  
Mohammad Siroos Pakbaz ◽  
Mojtaba Labibzadeh
Keyword(s):  
Soil Structure ◽  
Soft Soil ◽  
Soil Structure Interaction ◽  
Deep Excavations ◽  
Structure Interaction

scholarly journals Effect of Soil-Structure Interaction on the Seismic Response of Existing Low and Mid-Rise RC Buildings

2020 ◽  
Vol 10 (23) ◽  
pp. 8357
Author(s):  
Ibrahim Oz ◽  
Sevket Murat Senel ◽  
Mehmet Palanci ◽  
Ali Kalkan
Keyword(s):  
Seismic Response ◽  
Seismic Performance ◽  
Soil Structure ◽  
Soft Soil ◽  
Soil Structure Interaction ◽  
Soil Conditions ◽  
Existing Buildings ◽  
Structure Interaction ◽  
Fixed Base ◽  
New Buildings

Reconnaissance studies performed after destructive earthquakes have shown that seismic performance of existing buildings, especially constructed on weak soils, is significantly low. This situation implies the negative effects of soil-structure interaction on the seismic performance of buildings. In order to investigate these effects, 40 existing buildings from Turkey were selected and nonlinear models were constructed by considering fixed-base and stiff, moderate and soft soil conditions. Buildings designed before and after Turkish Earthquake code of 1998 were grouped as old and new buildings, respectively. Different soil conditions classified according to shear wave velocities were reflected by using substructure method. Inelastic deformation demands were obtained by using nonlinear time history analysis and 20 real acceleration records selected from major earthquakes were used. The results have shown that soil-structure interaction, especially in soft soil cases, significantly affects the seismic response of old buildings. The most significant increase in drift demands occurred in first stories and the results corresponding to fixed-base, stiff and moderate cases are closer to each other with respect to soft soil cases. Distribution of results has indicated that effect of soil-structure interaction on the seismic performance of new buildings is limited with respect to old buildings.

scholarly journals A comparative study of soil-structure interaction in the case of frame structures with raft foundation

2016 ◽  
Vol 63 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Balázs Móczár ◽  
Zsuzsanna Polgár ◽  
András Mahler
Keyword(s):  
Elastic Foundation ◽  
Soil Structure ◽  
Structural Engineering ◽  
Soil Structure Interaction ◽  
Engineering Practice ◽  
Subgrade Reaction ◽  
Element Analysis ◽  
Structure Interaction ◽  
Beam On Elastic Foundation ◽  
Raft Foundations

AbstractDesign and modelling of raft foundations and selecting the value of coefficient of vertical subgrade reaction are still actively discussed topics in geotechnical and structural engineering. In everyday practice, soil–structure interaction is mostly taken into account by using the theory of ‘beam on elastic foundation’, in which the soil is substituted by a certain set of coefficients of subgrade reaction. In this study, finite element analysis of a building was performed using a geotechnical software (Plaxis 3D), which is capable of modelling the subsoil as a continuum, and a structural software (Axis VM), which uses the concept of ‘beam on elastic foundation’. The evaluation of the results and recommendations for everyday engineering practice are introduced in this paper.

Effects of Soil-Structure Interaction on the Response of a Structure With Tuned Mass Dampers

2015 ◽  
Author(s):  
Chong-Shien Tsai ◽  
Hui-Chen Chen
Keyword(s):  
Soil Structure ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Soil Structure Interaction ◽  
Entire System ◽  
Mass Ratio ◽  
Tuned Mass Dampers ◽  
Soil Layers ◽  
Structure Interaction ◽  
Multiple Tuned Mass Dampers

This paper aims at examining the effects of soil-structure interaction (SSI) on the response of a structure which is equipped with multiple tuned mass dampers (MTMD) and founded on multiple soil layers overlying bedrock. Closed-form solutions have been obtained for the entire system, which consists of a shear beam type superstructure, multiple tuned mass dampers, and multiple soil layers overlying bedrock, while subjected to ground motion. The proposed formulations simplify the problem in terms of well-known frequency ratios, mechanical impedance and mass ratio, which can take into account the effects of SSI, mass ratio of the MTMD at each excitation frequency and damping ratio in the entire system. These formulations are capable of explicitly interpreting the major dynamic behavior of a structure equipped with multiple tuned mass dampers and interacting with the multiple soil layers overlying bed rock. The SSI effects on the dynamic response of a tuned-mass-damped structure as a result of multiple soil layers overlying bedrock were extensively investigated through a series of parametric studies.

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