I am trying to design a roof truss and have run into a problem. I don't know if I have done something wrong with the joint method or what might have gone wrong.
I have got an unreasonably(?) large normal force in one of the members. A normal force that is 6 times larger than the total load on the truss. I think I have all the negative signs in the right places and have a handle on the trigonometry.
Does anyone have the energy to check what might have gone wrong? Alternatively, does anyone know a site where all the member forces can be calculated so that one can compare?
I have attached the calculations for joint 1 and 2.
