Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil

In this paper, a formula for the spring constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow>&l...

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Main Author: Wojciech Pakos
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Applied Sciences
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Online Access:https://www.mdpi.com/2076-3417/15/9/4906
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author Wojciech Pakos
author_facet Wojciech Pakos
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description In this paper, a formula for the spring constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> for the horizontal movement of rigid rectangular foundations resting on elastic subsoil and spring coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> in this formula was derived, which demonstrates that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> depends on Poisson’s ratio <i>ν</i>. It was also shown that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>, which has already been presented in the literature, was determined for a constant value <i>ν</i> = 0.3. It was shown that the values of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>, obtained from the formulas derived in this paper and the calculations based on the formulas and nomogram for the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> given in the literature, may differ by 8–11%. For the adopted parameters, among others <i>ν</i> = 0.5, and for the side ratio α = 10, the value of spring constant is in the first case <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>=</mo><mn>1</mn></mrow></semantics></math></inline-formula>45.9 MN/m and in the second case <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 158.3 MN/m (differ by 8%), while for <i>ν</i> = 0.1, is, respectively, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 517.8 N/m and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 464.3 MN/m (differ by 11%). Numerical FEM 3D analysis verified analytical solutions for the concrete foundation footing and the soil layer beneath it. This paper also provides useful nomograms that can be used to easily read the values <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>. The use of the proposed formulas in this paper, refined formulas for determining <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub><mtext> </mtext></mrow></semantics></math></inline-formula>and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> in engineering calculations, can improve the accuracy of the analyses related to the influence of soil stiffness in horizontal movement.
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spelling doaj-art-bde12862e283474b883a42a1b0cae7f32025-08-20T03:49:22ZengMDPI AGApplied Sciences2076-34172025-04-01159490610.3390/app15094906Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic SubsoilWojciech Pakos0Faculty of Civil Engineering, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, PolandIn this paper, a formula for the spring constant <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> for the horizontal movement of rigid rectangular foundations resting on elastic subsoil and spring coefficient <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> in this formula was derived, which demonstrates that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> depends on Poisson’s ratio <i>ν</i>. It was also shown that <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>, which has already been presented in the literature, was determined for a constant value <i>ν</i> = 0.3. It was shown that the values of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>, obtained from the formulas derived in this paper and the calculations based on the formulas and nomogram for the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> given in the literature, may differ by 8–11%. For the adopted parameters, among others <i>ν</i> = 0.5, and for the side ratio α = 10, the value of spring constant is in the first case <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub><mo>=</mo><mn>1</mn></mrow></semantics></math></inline-formula>45.9 MN/m and in the second case <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 158.3 MN/m (differ by 8%), while for <i>ν</i> = 0.1, is, respectively, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 517.8 N/m and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> = 464.3 MN/m (differ by 11%). Numerical FEM 3D analysis verified analytical solutions for the concrete foundation footing and the soil layer beneath it. This paper also provides useful nomograms that can be used to easily read the values <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula>. The use of the proposed formulas in this paper, refined formulas for determining <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>x</mi></mrow></msub><mtext> </mtext></mrow></semantics></math></inline-formula>and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mrow><mi>β</mi></mrow><mrow><mi>x</mi></mrow></msub></mrow></semantics></math></inline-formula> in engineering calculations, can improve the accuracy of the analyses related to the influence of soil stiffness in horizontal movement.https://www.mdpi.com/2076-3417/15/9/4906foundationspring constantfoundation stiffnesselastic subsoil
spellingShingle Wojciech Pakos
Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
Applied Sciences
foundation
spring constant
foundation stiffness
elastic subsoil
title Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
title_full Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
title_fullStr Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
title_full_unstemmed Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
title_short Determination of the Spring Constant for the Horizontal Movement of Rigid Rectangular Foundations Resting on Elastic Subsoil
title_sort determination of the spring constant for the horizontal movement of rigid rectangular foundations resting on elastic subsoil
topic foundation
spring constant
foundation stiffness
elastic subsoil
url https://www.mdpi.com/2076-3417/15/9/4906
work_keys_str_mv AT wojciechpakos determinationofthespringconstantforthehorizontalmovementofrigidrectangularfoundationsrestingonelasticsubsoil