3 Member force system-Could use some input

AI Thread Summary
The discussion revolves around a statics problem involving an upside-down L-shaped beam supported by a fixed support and subjected to multiple forces. Key forces include a 3 kN and a 2 kN force acting downward on the horizontal member, and a 4 kN horizontal force on the vertical member. The original poster is uncertain about how to analyze the system, particularly regarding the 4 kN force and its implications for treating the structure as a three-force member. They have attempted to sum moments and forces but are dissatisfied with their results and seek clarification on how to approach the problem effectively. The conversation highlights the need for clear definitions and possibly a visual aid to better understand the force interactions.
M98Ranger
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I have a simple statics problem that I am trying to solve. The rigid body to be analyzed is an upside down L-shaped beam connected together at the corner by a pin. The object has a height of 4.5 meters vertically, by 3.5 meters in the horizontal. Additionally, the object is secured to the ground by means of a fixed support (cemented into the ground). In the corner of the upside down L connected diagonally is a structural element connected by pin joints at both ends. The lower end of the structural element is connected to the upside down L object 3 meters above the ground. The higher end is connected two meters from the corner of the L.

One 3kn force (straight down) is applied at 1 meter from the corner of the upside-down L-shaped object on the horizontal member. On the same member at the very end (3.5m from the corner) is a 2kn force applied straight down. Lastly there is a given 4kn force applied applied horizontally at a point 3.5 meters above the ground on the vertical member of the upside down L.

PS: I have tried to work it out on my own by combining the 3 and 2kn forces and then summing the moments about the fixed support. And summing the forces in the X and Y. I am not happy with my answers though and would like to know what someone else thinks about it. Additionally I have been reading everything I could on the internet since morning.

PHEW! Here is my question. It seems to me that I have a 3 force member problem here. But I am not sure how to deal with the 4kn force. It seems to me that the 4kn force and the X componant of the force at the corner of the upside down L would make a force couple.

As a three-force member is defined as a rigid body with no force couples, acted upon by a system of forces composed of or reducible to, three forces at three different locations I am not sure what I have here. How do I deal with the 4kn force?

SOLVE...find the reactions at the fixed support (where the beam is cemented into the ground).
 
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In order to solve a problem one needs to know what is to be solved for. You have not supplied this information...:wink:
 
A picture would be nice :smile:, but so far is an isostatic problem.
 
There I edited my original post. So far as a picture... I wish I could, but I don't know how. Any suggestions? I could find a similar picture and try to cut and paste it into a post.
 
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