Effect of foundation flexibility on seismic response of reinforced concrete TV-towers

2001 ◽  
Vol 28 (3) ◽  
pp. 465-481 ◽  
Author(s):  
Amir M Halabian ◽  
M Hesham El Naggar
Keyword(s):  
Reinforced Concrete ◽  
Soil Structure ◽  
Dynamic Behaviour ◽  
Bending Moment ◽  
Soil Structure Interaction ◽  
Earthquake Ground Motion ◽  
Element Formulation ◽  
Base Shear ◽  
Deep Foundation ◽  
Structure Interaction

The analysis of tall reinforced concrete TV-towers is commonly simplified by assuming a fixed base and ignoring the effect of soil–structure interaction. However, the foundation flexibility affects the dynamic characteristics of tall structures and influences their dynamic behaviour. To design these towers for dynamic loading, the fundamental natural periods, base bending moment, and base shear force as the most important parameters are needed and must be evaluated properly. In the current study, a finite element formulation for the response analysis of TV-towers subjected to earthquake ground motion accounting for soil–structure interaction is presented. The effects of foundation flexibility on the dynamic behaviour of TV-towers were evaluated for two different types of foundation, shallow footing and deep foundation, and various soil profiles. A typical example for these towers is analysed and the results for a range of soil dynamic parameters are presented. It was found that the foundation flexibility increases the natural periods, alters the natural mode shapes, and decreases the base bending moment. It was also concluded that the effect of soil–structure interaction may have a large effect on the base shear of the tower and should be considered in the analysis, especially for the design of horizontal reinforcement.Key words: soil–structure interaction, TV-towers, natural period, base forces, foundation flexibility.

A numerical study on the influences of underlying soil and backfill characteristics on the dynamic behaviour of typical integral bridges

Bauingenieur ◽  
2020 ◽  
Vol 95 (11) ◽  
pp. S 2-S 11
Author(s):  
H. D. B. Aji ◽  
M. B. Basnet ◽  
Frank Wuttke
Keyword(s):  
Soil Structure ◽  
Dynamic Behaviour ◽  
Numerical Study ◽  
Coupled System ◽  
Soil Structure Interaction ◽  
Dynamic Resistance ◽  
Soil Characteristic ◽  
Structure Interaction ◽  
Integral Bridges ◽  
Underlying Soil

Abstract The identification of the dynamic behaviour of a structure is one of the crucial steps in the design of the dynamic resistance of the structure. The dynamic behaviour is represented by the natural frequencies and damping which are subsequently used along with the considered dynamic actions in the design process. In regard of integral bridge concept, one of the consequences of the omission of joints and bearings is the substantial soil-structure interaction which in turn increases the sensitivity of the dynamic behaviour of the bridges to the surrounding soil characteristic. In this article, we extended our hybrid BEM-FEM steady-state dynamic numerical tool to the 3D regime, developed by utilizing an in-house BEM and the commercial FEM software ABAQUS and use it to analyse the dynamic interaction between the bridge and the underlying soil as well as the backfill. The numerical results from four typical integral bridges show that underlying soil characteristic has great effect on the resonant frequencies and the damping. The backfill material properties tend to have less significant role due to the abutment wingwalls dominating the force transfer between the soil and the superstructure. The results also show that the degree of influence of the soil-structure interaction on the coupled system is affected by the type of load pattern in addition to the flexural stiffness of the superstructure.

Soil-Structure Interaction in Buildings from Earthquake Records

1990 ◽  
Vol 6 (4) ◽  
pp. 641-655 ◽  
Author(s):  
Gregory L. Fenves ◽  
Giorgio Serino
Keyword(s):  
Soil Structure ◽  
Dynamic Properties ◽  
Strong Motion ◽  
Longitudinal Direction ◽  
Soil Structure Interaction ◽  
Base Shear ◽  
Foundation Soil ◽  
Soil System ◽  
Structure Interaction ◽  
Building Foundation

An evaluation of the response of a fourteen story reinforced concrete building to the 1 October 1987 Whittier earthquake and 4 October 1987 aftershock shows significant effects of soil-structure interaction. A mathematical model of the building-foundation-soil system provides response quantities not directly available from the records. The model is calibrated using the dynamic properties of the building as determined from the processed strong motion records. Soil-structure interaction reduces the base shear force in the longitudinal direction of the building compared with the typical assumption in which interaction is neglected. The reduction in base shear for this building and earthquake is approximately represented by proposed building code provisions for soil-structure interaction.

scholarly journals Soil-structure interaction analysis in reinforced concrete structures on footing foundation

2021 ◽  
Vol 44 (2) ◽  
pp. 1-12
Author(s):  
Yago Ryan Pinheiro dos Santos ◽  
Maria Isabela Marques da Cunha Vieira Bello ◽  
Alexandre Duarte Gusmão ◽  
Jonny Dantas Patricio
Keyword(s):  
Reinforced Concrete ◽  
Soil Structure ◽  
Interaction Analysis ◽  
Soil Structure Interaction ◽  
Structural Elements ◽  
Reinforced Concrete Structure ◽  
Load Path ◽  
Structure Interaction ◽  
Load Redistribution ◽  
Field Instrumentation

Soil-structure interaction (SSI) evaluates how soil or rock deformability imposes on the structure a different load path in a hypothesis of fixed supports, altering the loads acting on the structural elements and the ground. This paper discusses the results of the SSI effects in two buildings with a reinforced concrete structure and shallow foundations in a rock mass. The settlements were monitored by field instrumentation in five stages of their construction, making it possible to estimate through interpolation curves the settlements values of some points. The numerical modeling and structural analysis of the buildings were obtained for two different cases of soil-structure interaction. The structure was considered having fixed supports (non-displaceable) and displaceable supports (with stiffness spring coefficients K). The results reveals the occurrence of SSI effects, with a load redistribution between the columns that occurred differently for the different construction stages. Structural modeling proved to be quite representative, pointing to higher vertical load values than the average values present in building edge zones, which contradicts the conventional idea that central columns are more loaded than the edge columns. The soil-structure interaction analyses resulted in different behaviors regarding both towers; pointing out that low settlements and building symmetry in plan minimize the effects of interaction, with no tendency of load redistribution between columns as the structure rigidity increases, as construction development.

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