Name: eccentric load stresses in structural columns
Uploaded: 2024-05-23T13:00:08.000Z
Duration: 1 min 21 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Physics

PHYS.2

PHYS.2.D

design-of-columns-under-an-eccentric-load

Design of Columns under an Eccentric Load

Para una columna cargada con una carga axial excéntrica en el plano de simetría, las tensiones normales debidas a la carga excéntrica se pueden escribir como tensiones debidas a una carga céntrica y flexión equivalentes.
Al diseñar columnas con cargas excéntricas, la tensión máxima desarrollada en la columna no debe exceder la tensión máxima permitida. Esta condición puede satisfacerse utilizando dos enfoques distintos.
El método de tensión permitida supone que la tensión permitida para la columna con carga excéntrica es la misma que la tensión máxima para la columna con carga central. La tensión permitida para la columna se puede expresar en función de la relación de esbeltez.
La tensión permitida para la carga céntrica es menor que la debida al momento de flexión. Esto da como resultado que el método de tensión permitida sea demasiado conservador. 
Por otro lado, el método de interacción tiene en cuenta la tensión admisible debida a la carga céntrica y la flexión.
Proporciona una ecuación para la tensión máxima bajo carga céntrica cuando no hay momento de pareja. Del mismo modo, define la tensión máxima de la flexión pura cuando no hay carga.

diseño de columnas bajo carga excéntrica

Diseñar columnas para soportar cargas excéntricas es un aspecto crítico de la ingeniería estructural, ya que garantiza que las estructuras puedan soportar cargas descentradas sin fallar. Este proceso de diseño debe tener en cuenta las tensiones normales adicionales introducidas por la carga excéntrica, que puede influir significativamente en la distribución de tensiones y la estabilidad general de una columna. Una carga excéntrica aplicada a una columna induce esfuerzos normales que pueden conceptualizarse como una combinación de esfuerzos debidos a una carga céntrica equivalente y esfuerzos de flexión adicionales. Esto conduce a una distribución no uniforme de la tensión que debe analizarse cuidadosamente para evitar fallas estructurales. Se emplean dos métodos principales en el diseño de columnas bajo cargas excéntricas: el método de esfuerzo permisible y el método de interacción.

El método de tensión permitida es un enfoque sencillo en el que la tensión permitida para una columna cargada excéntricamente se equipara con la tensión máxima permitida para una columna cargada centralmente. Este método simplifica el proceso de diseño al tratar la tensión permitida como una función de la relación de esbeltez de la columna, que es una medida de su propensión a pandearse bajo carga. Sin embargo, este método supone que la tensión permitida para la carga céntrica abarca las tensiones adicionales debidas a la flexión, lo que lleva a diseños conservadores que pueden no utilizar todo el potencial del material. El conservadurismo inherente a este enfoque garantiza la seguridad, pero puede dar lugar a columnas más grandes y más caras de lo necesario.

El método de interacción ofrece un enfoque más matizado al considerar tanto las tensiones permitidas debidas a la carga céntrica como las tensiones que surgen de los momentos de flexión. Este método proporciona un marco para calcular la tensión máxima que la columna puede soportar sin un momento de par (carga céntrica pura) y la tensión máxima debida a flexión pura (sin carga axial). Al tener en cuenta estas condiciones simultáneamente, el método de interacción permite una estimación más precisa y menos conservadora de las tensiones permitidas en columnas cargadas excéntricamente.

En la práctica, el método de interacción suele ser el preferido por su capacidad para equilibrar la seguridad con la eficiencia del material. Requiere un análisis detallado de la distribución de tensiones dentro de la columna, considerando tanto cargas axiales como momentos flectores.

Diseño de columnas bajo carga excéntrica

Para una columna cargada con una carga axial excéntrica en el plano de simetría, las tensiones normales debidas a la carga excéntrica pueden escribirse como tensiones ...

Education

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JoVE Core

Mechanical Engineering

Ingeniería Mecánica

Unit 1

Unidad 1

Columns

Columnas

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

eccentric load stresses in structural columns

Structural columns under eccentric load must be designed for both axial force and bending stress. An eccentric load is an off-center load, and it creates a non-uniform stress pattern across the column. Engineers must analyze this stress distribution carefully to reduce the risk of failure.

The stress in an eccentrically loaded column can be treated as the sum of two parts. One part comes from an equivalent centric load, which is a load applied through the center of the column. The other part comes from bending stresses caused by the load being off-center.

Two common design approaches are used for these columns. The allowable stress method sets the allowable stress for an eccentrically loaded column equal to the maximum stress allowed for a centrally loaded column. This method uses the column slenderness ratio, which describes how likely a column is to buckle.

The allowable stress method is simple, but it is also conservative. It assumes the centric-load allowable stress already covers the extra bending stress from eccentric loading. As a result, the column may be larger and more expensive than needed, even though the design is safe.

The interaction method gives a more detailed design check. It considers both the allowable stress from centric loading and the stress from bending moment at the same time. It compares the case of pure centric loading, with no couple moment, and the case of pure bending, with no axial load.

Because it includes both effects, the interaction method can estimate allowable stress more accurately. It is often preferred when engineers want a better balance between safety and material use. The method requires careful stress analysis of the column under both axial load and bending moment.

Eccentric Load Stresses in Structural Columns

eccentric-load-stresses-in-structural-columns

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design of columns under an eccentric load

Structural columns under eccentric load must be designed for both axial force and bending stress. An eccentric load is an off-center load, and it creates a non-uniform stress pattern across the column. Engineers must analyze this stress distribution carefully to reduce the risk of failure. The stress in an eccentrically loaded column can be treated as the sum of two parts. One part comes from an equivalent centric load, which is a load applied through the center of the column. The other part...

key terms and concepts

Learn how eccentric loads create combined axial and bending stresses in columns, and compare the allowable stress and interaction methods used in design.

Eccentric Load Stresses in Structural Columns | JoVE K12

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Eccentric Load Stresses in Structural Columns

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