We are willing to help assignments in our free time. However we need to know where we can help you, I mean, in what particular part of this assignment you need the help. Show us your preliminary work so that we can see where we can extend the help.

thank you very much sir. Honestly my problem is I don't know how to attack the problem. I don't know where to start. Our professor just assigned this particular problem without explaining anything. He hasn't explained anything about our machine design course. I'm in my 4th year in college and I have solved a lot of different problems but this is the first time I encountered a Jib crane problem. Basically if you guys can tell me how I can approach this problem, I may be able to do the rest.

Any input will be appreciated. thank you very much

Try this,
cQ = LF to solve for Q. Use Q to design the coupling. The jib acts as a beam with bending equal to LF. Use the flexure formula to design the jib. The column pipe is subjected to both bending and compression, the bending is equivalent to LF acting at the top and the compression is F. Design the column using the analysis of combined stresses (bending and compression). Find the forces acting on the base to design the bolt. I encountered this problem more or less 30 years ago, that's all I can remember,I already forget the design codes we are using.

Ron

DESIGN FOR 270 DEGREE JIB CRANE

The problem has to be tackled this way;

1. The I section is subjected to bending moemnt and direct shear. Calculate the required section modulus by diving the moment by allowable stress. Find the maximum shear stress in the I section beacuase of direct load. Use mohr's circle to find the prinicpal stresses and combine the principal stresses using Von-Mises theory to find the combined stress. The combined stress should be less than allowable bending stress of the I beam material.

2. The bolt connecting the i beam frame to the pole are subeced to direct shear and torsion. add the two stresses directly and compare it to the allowable shear stress of the bolt material.

3. The bole is subledtec to bending moment and axial compression. This column has to be designed iteratively by assuming some section modulus and using either the Jhon's formula or Euler's formula as the case may be, the column needs to be designed.

4. The grouting prevents the column from lifting due to moment. This over turing momment has to be balanced by tensile forces in the bolt. You can refer to any book on design of tubular structures. If couldn't find one, I shall provide you the details.

regards

The problem has to be tackled this way;

1. The I section is subjected to bending moemnt and direct shear. Calculate the required section modulus by diving the moment by allowable stress. Find the maximum shear stress in the I section beacuase of direct load. Use mohr's circle to find the prinicpal stresses and combine the principal stresses using Von-Mises theory to find the combined stress. The combined stress should be less than allowable bending stress of the I beam material.

2. The bolt connecting the i beam frame to the pole are subeced to direct shear and torsion. add the two stresses directly and compare it to the allowable shear stress of the bolt material.

3. The bole is subledtec to bending moment and axial compression. This column has to be designed iteratively by assuming some section modulus and using either the Jhon's formula or Euler's formula as the case may be, the column needs to be designed.

4. The grouting prevents the column from lifting due to moment. This over turing momment has to be balanced by tensile forces in the bolt. You can refer to any book on design of tubular structures. If couldn't find one, I shall provide you the details.

regards
raghu
email raghunandan.hv@gmail.com

I tried to analyze the problem but I don't understand how the jib will rotate. Will it rotate in vertical plane or in horizontal plane. My intial thought is that it will rotate in horizontal plane so the jib I-beam is subjected to shear and bending but no compression force.

With jib always horizontal, these are my thoughts to it:
The pipe column will be in combined load of bending and compression. The eccentricity of the bending is so large, you need to consider it carefully. The figure is not clear specially in the bearing connection (connection of I-beam and pipe column). In the design of bolts at the footing, some bolts are subjected to shear force at the head, others are shear force at the thread, and of course all are subject to shear force in its section. Consider all of it in your design.

Given:
Overturning Moment = 112.76 KPSI
Axial Load = 6.236 KPSI
Thrust and Pull = 17.348 KPSI

How do you calculate the size of the I beam required for a column mounted Jib crane with 2 ton capacity?