Point of contraflexure - Revision history

Designing Buildings at 08:54, 27 October 2020

2020-10-27T08:54:41Z

← Older revision		Revision as of 08:54, 27 October 2020
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	* Uniformly Distributed Load.		* Uniformly Distributed Load.

−	[[Category:~~Education~~]] [[Category:~~DCN_Education_and_Training~~]] [[Category:Theory]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:Education]] [[Category:Theory]]

Editor at 16:56, 12 April 2019

2019-04-12T16:56:24Z

← Older revision		Revision as of 16:56, 12 April 2019
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	* Structural principles.		* Structural principles.
	* Structural steelwork.		* Structural steelwork.
		+	* Torsion.
	* Types of beam.		* Types of beam.
	* Types of structural load.		* Types of structural load.
	* Uniformly Distributed Load.		* Uniformly Distributed Load.

−	[[Category:Education]] [[Category:Theory]]	+	[[Category:Education]] [[Category:DCN_Education_and_Training]] [[Category:Theory]]

Designing Buildings at 13:44, 26 February 2019

2019-02-26T13:44:24Z

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	{\|		{\|
−	\| [[File:Contraflexure.jpg]]	+	\| [[File:Contraflexure.jpg\|link=File:Contraflexure.jpg]]
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−	\| The PoC occurs where bending is zero and at the point of change between positive and negative (or between compression and tension).	+	\| The point of contraflexure (PoC) occurs where bending is zero and at the point of change between positive and negative (or between compression and tension).
	\|}		\|}
−
−	~~= Point of contraflexure =~~

	In a beam that is flexing (or bending), the point where there is zero bending moment is called the point of contraflexure. At that point, the direction of bending changes its sign from positive to negative or from negative to positive. (It may also be thought of as a change from compression to tension or vice versa).		In a beam that is flexing (or bending), the point where there is zero bending moment is called the point of contraflexure. At that point, the direction of bending changes its sign from positive to negative or from negative to positive. (It may also be thought of as a change from compression to tension or vice versa).

−	For this change to happen, it must pass through zero – the point of contraflexure. On a bending moment diagram, it is the point ~~where~~ the bending moment curve intersects with the zero line.	+	For this change to happen, it must pass through zero – the point of contraflexure. On a bending moment diagram, it is the point at which the bending moment curve intersects with the zero line.

	An analogy may be made with a speeding train travelling west on a single track. In order to reverse direction and travel east, it must decelerate, stop then accelerate in the opposite direction. The point it stops, even if momentary, is zero – the neutral point, where it is not travelling.		An analogy may be made with a speeding train travelling west on a single track. In order to reverse direction and travel east, it must decelerate, stop then accelerate in the opposite direction. The point it stops, even if momentary, is zero – the neutral point, where it is not travelling.

Editor: Created page with "{| | File:Contraflexure.jpg |- | The PoC occurs where bending is zero and at the point of change between positive and negative (or between compression and tension). |} = Poi..."

2019-02-22T18:43:33Z

Created page with "{| | File:Contraflexure.jpg |- | The PoC occurs where bending is zero and at the point of change between positive and negative (or between compression and tension). |} = Poi..."

New page

{|
| [[File:Contraflexure.jpg]]
|-
| The PoC occurs where bending is zero and at the point of change between positive and negative (or between compression and tension).
|}

= Point of contraflexure =

In a beam that is flexing (or bending), the point where there is zero bending moment is called the point of contraflexure. At that point, the direction of bending changes its sign from positive to negative or from negative to positive. (It may also be thought of as a change from compression to tension or vice versa).

For this change to happen, it must pass through zero – the point of contraflexure. On a bending moment diagram, it is the point where the bending moment curve intersects with the zero line.

An analogy may be made with a speeding train travelling west on a single track. In order to reverse direction and travel east, it must decelerate, stop then accelerate in the opposite direction. The point it stops, even if momentary, is zero – the neutral point, where it is not travelling.

Theoretically, when considering a structural member under load, such as a reinforced concrete beam, the point of zero bending moment would seem to suggest no reinforcement would be required. However, omitting reinforcement at that point is considered inadvisable as, in a real-life situation, it may be difficult to locate the exact point of contraflexure.

= Related articles on Designing Buildings Wiki =

* Biaxial bending.
* Cantilever.
* Concept structural design of buildings.
* Lateral loads.
* Long span roof.
* Shear force.
* Stiffness.
* Structural principles.
* Structural steelwork.
* Types of beam.
* Types of structural load.
* Uniformly Distributed Load.

[[Category:Education]] [[Category:Theory]]