Question 17

Posted in: Beams, ST1

Okay,  this is definitely a simple question to start with.


Question:  If x= L/3 what is the vertical reaction at support A?

Solution: To solve this  we  need to take moment about  a  point that we know  the  moment for. Point  B  is a pin  support for must have  zero moment.

  1. So taking  moments about B we  have acting clockwise the moment  generated  by the vertical reaction A (Va * L).
  2. This must be equal to the anticlockwise moments  generated  by  the  applied   loads, which are  equal to
  • P*(2L/3) for the moment from the point  load
  • (wL/2)*(L/4) for the uniform loading - the first  term in brackets is the total load the  second term is the lever arm to the centre of the load.

3. equating  clockwise and  anticlockwise and dividing  by L we get Va=(2P/3) +(wL/8)

Posted in: Beams, ST1


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