Moment in a Beam: Consider Both Spans AB & BC

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Discussion Overview

The discussion revolves around the analysis of a beam with two spans, AB and BC, focusing on why only span AB is considered in calculations while span BC is seemingly overlooked. Participants explore the implications of statically indeterminate structures and the methods used for analysis.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions why the calculation for span BC is not included, suggesting that it should be considered as well.
  • Another participant explains that the slope-deflection method is applicable for statically indeterminate beams and notes that the free end span can be solved using statics alone, implying that indeterminate analysis is unnecessary for that span.
  • There is confusion expressed by participants regarding the classification of span AB as statically indeterminate, with one participant seeking clarification on the reasoning behind this classification.
  • A participant identifies that span AB is fixed at point A and has a pin support at point B, leading to four unknowns and only three equations of static equilibrium, which contributes to its indeterminate status.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of including span BC in the calculations, indicating a lack of consensus on the approach to the problem. There is also confusion regarding the classification of span AB, suggesting that the discussion remains unresolved.

Contextual Notes

Participants have not fully clarified the assumptions regarding the supports and loading conditions of the beam, which may affect the classification of spans as statically determinate or indeterminate.

fonseh
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Homework Statement


In this problem , why only caluclation of span AB is considered ? why the span BC isn't required ?

Homework Equations

The Attempt at a Solution


I think there's soemthing wrong with the question , We have to consider the calcilation of span BC also
 

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The slope-deflection method is used to solve for statically indeterminate beams using deflection and rotation equations to make the beam statically determinate. The free end span from the free end to the nearest support can be solved by statics alone, so there is no need for the indeterminate analysis in this span. I haven't used this method in ages.
 
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PhanthomJay said:
The slope-deflection method is used to solve for statically indeterminate beams using deflection and rotation equations to make the beam statically determinate. The free end span from the free end to the nearest support can be solved by statics alone, so there is no need for the indeterminate analysis in this span. I haven't used this method in ages.
sorry , i am confused now , why for span AB , it's statically indeterminate ?
 
fonseh said:
sorry , i am confused now , why for span AB , it's statically indeterminate ?
It is fixed at A and with a settled pin support at B. So there are 4 unknowns and just 3 equations of static equilibrium
 
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