scholarly journals Numerical analyses of two-pile caps considering lateral friction between the piles and soil

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Rodrigo Gustavo Delalibera ◽  
Gabriel Fernandes Sousa
Keyword(s):  
Soil Parameters ◽  
Structural Elements ◽  
Structural Element ◽  
Strut And Tie ◽  
Load Carrying ◽  
Foundation Model ◽  
Pile Caps ◽  
Continuous Modeling ◽  
Semi Empirical ◽  
Lateral Friction

abstract: Pile caps are structural elements used to transfer loads from the superstructure to a group of piles. The design of caps is normally based on analytical formulations, considering the strut and tie method. Through the advance of computational technology, the use of an integrated soil and foundation model may suggest a behavioral trend to obtain a more realistic modeling for the structural element being studied. This work aimed at analyzing, in numerical fashion, the structural behavior of reinforced concrete two-pile caps considering the lateral friction between the piles and the ground through a continuous modeling, as well as to analyze the portion of the load that is transferred to the ground directly by the cap. The lateral friction was modeled considering node coupling and through contact elements. Simulations were performed considering three soil types (sandy, clayish, and soilless), three cap heights, and three pile lengths. Soil parameters were obtained through semi-empirical correlations. Through these analyses, the conclusion was reached that, on average, 4.50% of the force applied to the pillar is transferred directly to the ground by cap. In terms of the principal compression stresses, in the superior nodal region, the strut tends to form beyond the section of the column. Alternatively, increasing cap stiffness provided, on average, an increase in the load carrying capacity of the models.

Buckling of Perforated Plates Repaired with Composite Patches

2008 ◽  
Vol 385-387 ◽  
pp. 377-380 ◽  
Author(s):  
Jalil Rezaeepazhand ◽  
H. Sabori
Keyword(s):  
Laminated Composite ◽  
Quantitative Measure ◽  
Structural Elements ◽  
Structural Element ◽  
Perforated Plates ◽  
Advanced Composite ◽  
Numerical Studies ◽  
Load Carrying ◽  
Circular Cutout ◽  
Relative Change

Performance level and life span of existing structural elements can be increased by repair and strengthening of these structural elements using advanced composite materials.The performance of damaged metallic plates reinforced with fiber-reinforced polymer composite materials (composite patch) are presented in this study. A square aluminum plate with a central circular cutout is considered as a damaged structural element. Numerical studies using commercial finite element code were conducted to investigate the effects of variation in patch geometries and lamination parameters on buckling responses of repaired plates. The varying laminate parameters such as, fiber angles and stacking sequences are considered in this study. A quantitative measure for the effectiveness of the composite patches is taken to be the relative change in buckling loads of the reinforced plates compare to those of the perfect one. The results presented herein indicated that, for buckling response of a repaired metallic plate with central cutout, a set of laminated composite patches with different shape and stacking sequences can be found which improve load carrying capacity of damaged plates.

scholarly journals Variation analysis effects of square and rectangular columns section with different longitudinal reinforcement rates in the main reinforcement two pile caps analysis

2017 ◽  
Vol 10 (3) ◽  
pp. 760-787 ◽  
Author(s):  
F. S. MUNHOZ ◽  
J.S. GIONGO
Keyword(s):  
Experimental Program ◽  
Longitudinal Reinforcement ◽  
Structural Elements ◽  
Rectangular Section ◽  
Central Section ◽  
Strut And Tie ◽  
Pile Cap ◽  
Pile Caps ◽  
Strut And Tie Model ◽  
Rectangular Columns

ABSTRACT The transition between the columns of building and foundation had been used the pile-cap structural elements. The most appropriate method for the pile caps design is the Strut and Tie model. In most cases in the structural project is not considered the influence of certain parameters: the columns cross section and the amount of longitudinal reinforcement columns. This paper studies the effect of the variability of the geometric section of square and rectangular columns, with different longitudinal reinforcement rates, in the main reinforcement traction two pile caps. The basis for study was development experimental program in the Structures Laboratory of EESC-USP . The traction reinforcement bars strains are reduced the pile-caps central section to pile-caps sections that approximate cutting axis shows the experimental results. In models with columns of elongated rectangular section and with great reinforcement rates this reduction is smaller.

STRUCTURAL RELIABILITY ANALYSIS BASED ON P-BOXES

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Random Variable ◽  
Strength Criterion ◽  
Structural Elements ◽  
Structural Element ◽  
Limit States ◽  
Distribution Shape

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

scholarly journals Strut-and-tie models for linear and nonlinear behavior of concrete based on topological evolutionary structure optimization (ESO)

2019 ◽  
Vol 12 (1) ◽  
pp. 87-100
Author(s):  
R. M. LANES ◽  
M. GRECO ◽  
M. B. B. F. GUERRA
Keyword(s):  
Nonlinear Behavior ◽  
Structure Optimization ◽  
Internal Flow ◽  
Optimization Method ◽  
Topological Optimization ◽  
Structural Elements ◽  
Stress Concentrations ◽  
Progressive Reduction ◽  
Strut And Tie ◽  
Safety And Reliability

Abstract The search for representative resistant systems for a concrete structure requires deep knowledge about its mechanical behavior. Strut-and-tie models are classic analysis procedures to the design of reinforced concrete regions where there are stress concentrations, the so-called discontinuous regions of the structure. However, this model is strongly dependent of designer’s experience regarding the compatibility between the internal flow of loads, the material’s behavior, the geometry and boundary conditions. In this context, the present work has the objective of presenting the application of the strut-and-tie method in linear and non-linear on some typical structural elements, using the Evolutionary Topological Optimization Method (ESO). This optimization method considers the progressive reduction of stiffness with the removal of elements with low values of stresses. The equivalent truss system resulting from the analysis may provide greater safety and reliability.

Profile beams with adaptive bending–twist coupling by adjustable shear centre location

2012 ◽  
Vol 24 (3) ◽  
pp. 334-346 ◽  
Author(s):  
Wolfram Raither ◽  
Andrea Bergamini ◽  
Paolo Ermanni
Keyword(s):  
Flexural Rigidity ◽  
Variable Stiffness ◽  
Structural Elements ◽  
Lightweight Structures ◽  
Load Carrying ◽  
Structural Concept ◽  
Simulation And Experiment ◽  
Coupling Stiffness ◽  
Shear Centre

Semi-active structural elements based on variable stiffness represent a promising approach to the solution of the conflict of requirements between load-carrying capability and shape adaptivity in morphing lightweight structures. In the present work, a structural concept with adaptive bending–twist coupling aiming at a broad adjustment range of coupling stiffness while maintaining high flexural rigidity is investigated by analysis, simulation and experiment.

scholarly journals Modeling the processes of aerogasdynamics of structural elements of a supersonic aircraft

2019 ◽  
Author(s):  
E.S. Studennikov
Keyword(s):  
Stress Transfer ◽  
Aerodynamic Characteristics ◽  
Wind Tunnels ◽  
Transfer Model ◽  
Structural Elements ◽  
Base Region ◽  
Supersonic Aircraft ◽  
Wide Range ◽  
Sharp Cone ◽  
Semi Empirical

The purpose of the research was to study the aerodynamic features of the flow around the simplest structural elements of an aircraft, such as sharp and blunt-nose cones. For calculations we applied the perfect gas model. To describe flows with large adverse pressure gradients, we used the Menter's shear stress transfer model. We analyzed changes in the aerodynamic characteristics of the cones in a wide range of angles of attack α and flow Mach M∞ numbers. Furthermore, we investigated the parameters of the base region of the sharp cone at transonic and supersonic speeds, and compared the simulation results with the data of a physical experiment both in wind tunnels and on a ballistic installation. The comparison showed good agreement with the experimental data. Numerical simulation data can be applied to form the external appearance of aircraft for various purposes, to study the influence of the temperature factor on the flow around bodies, and to create semi-empirical models for calculating the parameters of the base region of conical bodies.

scholarly journals Structural vehicle impact loading

2013 ◽  
Vol 11 (3) ◽  
pp. 285-292
Author(s):  
Dragoslav Stojic ◽  
Stefan Conic
Keyword(s):  
Impact Analysis ◽  
Impact Loads ◽  
Structural Elements ◽  
Structural Element ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Vehicle Impact ◽  
Dynamic Forces ◽  
Force Intensity

In contemporary design, vehicle impact into the structures is paid great attention since they can be dominant, depending on the type of structure. The key issue in the vehicle impact analysis is the proper determination of intensity and way of action of dynamic forces on the structural element and its behavior after the imparted load. The Eurocodes, in the annexes provide recommendations for determination of force intensity depending on mass and velocity of the colliding vehicle. Equivalent static loads causing approximate effects on the structural elements are used as quite approximate and efficient methods. The paper comprises the analysis of deformation of columns having the same characteristics, exposed to impact loads via the equivalent static loads, depending on the stress state in columns, and a comparative analysis has been done.

An evaluation of pile cap design methods in accordance with the Canadian design standard

2004 ◽  
Vol 31 (1) ◽  
pp. 109-119 ◽  
Author(s):  
William Cavers ◽  
Gordon A Fenton
Keyword(s):  
Reinforced Concrete ◽  
Structural Design ◽  
Design Methods ◽  
Building Codes ◽  
Design Models ◽  
Design Standard ◽  
Strut And Tie ◽  
Pile Cap ◽  
Pile Caps ◽  
Strut And Tie Model

There are a number of design methods that have been described for the design of pile caps, but there has been no consensus on which method provides the best approach for the working designer. This paper describes a study conducted to establish the performance of several pile cap design methods, particularly with respect to the Canadian standard, CSA A23.3-94. Previous research was examined to determine the basis of the design methods and the state of current research. The design methods identified were then applied to pile caps for which test data were available. The theoretical loads obtained using the various design methods were compared with the experimental loads. The results of this study indicate that two design models of the five examined are the most suitable. This study also indicates that the provisions of the Canadian design standard are adequate. A possible refinement of the strut-and-tie model incorporating a geometric limit is also outlined.Key words: building codes, footings, pile caps, reinforced concrete, structural design.

Solution of Dynamic Problems of Structural Elements Using Simple Polynomial Approximations

1991 ◽  
Author(s):  
Patricio A. A. Laura
Keyword(s):  
Orthogonal Polynomials ◽  
Optimization Procedure ◽  
Structural Elements ◽  
Dynamic Problems ◽  
Structural Element ◽  
Base Function ◽  
Polynomial Approximations ◽  
Deformable Bodies ◽  
Rational Procedure ◽  
Coordinate Functions

Abstract A survey of studies dealing with vibrating structural elements using simple polynomial approximations in connection with Rayleigh-Ritz or Galerkin-type methods is presented. The classical use of polynomials when solving dynamic problems of deformable bodies consists of constructing a set of coordinate functions in such a way that they satisfy at least the essential boundary conditions and that they represent “reasonably well” the deformation field of the structural element under study. An alternative and more rational procedure has been developed and used in recent years whereby orthogonal polynomials are used. A “base function” is constructed and then one generates a set of orthogonal polynomials using the Gram-Schmidt or equivalent procedure. The present paper presents comparisons of numerical results in the case of different types of vibrating structural elements Special emphasis is placed on Rayleigh’s optimization procedure which consists of taking one of the exponents of the polynomial coordinate functions as an optimization parameter “γ”. Since the calculated eigenvalues constitute upper bounds, by minimizing them with respect to “γ” one is able to optimize the eigenvalues.

Sign in / Sign up

Export Citation Format

Share Document