Reaction loads at the Support of an overlapping structure

[DarkStar]

Hi,

I wanted some clarification for how would the reaction loads at end supports and joint will be calculated in the case shown in the schematic diagram. The load of right block structure would be supported by roller A however that load would also be transmitted to roller B. So, how are we going to calculate the load at right and left end support and roller A and roller B. This is a simplified version of structure in actual the structure would resemble a passenger boarding bridge where one column is mobile and can move horizontally and roller basically facilitates the movement. The outer block can move over the inner block. 

Thank you in advance.

[G B Reid MIMechE, SIMarEST]

Okay...first you need to get your sketch right...it is important on this as the overhang (the "loading doorway") is a counterbalance that ensures the load is only applied in the correct way against the rollers....don't forget the cantilever masses either.

Once you add the counterbalance the rollers will be loaded in the correct way and it should simply be a case of taking moments - both sides as a double check.

Good luck

[DrD]

There is a major question as to how the two vertical supports are attached to the boxes. Are these simple supports, or is the support rigidly attached to the box so as to transfer a moment between the support and the box? Is the lower end of the support embedded in the ground, or is it simply attached? I think your drawing is incomplete in that these matters are not clear. The question cannot be addressed without this information.

Also, why do you label the figure backwards from t he picture with respect to left and right?

DrD