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davetrotter
Mar 19, 2010, 08:30 AM
hello there,

At point Y I have an overturning moment of 106.5 kN.m

At point X, 4.5m from point Y, load required to resist OTM is 106.5/4.5 = 23.7 kN

My question is, if I have Z directly 4.0m above X, will the load required to resist overturning be reduced @ this point?

thanks

ebaines
Mar 19, 2010, 09:50 AM
In order to counteract the turning moment, you need to apply a force times a distance. However, only the perpendicular component of that force counts - at point Z if there is a component of force that is in line with YZ, it doesn't help. Mathematically speaking, the countering torque is F*d*sin( \alpha ), where d is the distance from Y to Z and \alpha is the angle between the line YZ and the force applied at Z.

If point Z is further away from Y than is X from Y (so that d is bigger), it could be that a smaller force F is needed than at point X, but it all depends on the value of \alpha .