1. By John Liedig & Jouline Nour
Tower Crane
By John Liedig & Jouline Nour

3. Counter Weight
Cables
Main Tower

4. Jib

5. Introduction
Tower cranes are a common fixture at any major construction site.
They often rise hundreds of feet into the air, and can reach out just as far.
Tower cranes are used to lift steel, concrete, large tools like acetylene torches and generators, and a wide variety of other building materials.

6. Arm and Tower Sections
Tower Section
Jib section

7. Dimensions The tower crane is approximately 120m tall 10m wide
The counter weighted arm is 60m long
And the main jib can be as long as 90m

8. Modelled Tower Crane Looked at 2 scenarios
The aim was to determine the differences in both 2D and 3D cases in relation to displacement and stress analysis

9. Objectives
To use Strand 7 on a complicated structure such as a tower crane
Model the tower crane to the dimensions given from relevant data
Determine stresses and displacements associated from various locations of loads on the structure
Try and improve the structure

10. Objectives
To see if there was a better way of modelling the tower crane on Strand 7
Through using different materials
Modifying the shape

11. Method
Determined the dimensions of the tower crane using data from the internet and other relevant crane construction guides
Determined various components involved in the tower crane
Identified the materials for each of the various components and then selected these from the strand 7 library

12. Method
Drew a 2D representation of the tower then the arm and then used strand 7 commands to convert into a 3D structure
Entered various loading scenarios
Ran analysis
Modified the elements accordingly to meet acceptable limits in the results.

13. Materials
The materials used were predominantly structural steel of various sizes
The cable also is made from steel with a free length ranging from 50 to 80m
All sections are circular hollow sections

14. Load Cases Taken a variety of load cases
Loads were placed at individual nodes along the arm of the tower crane
In the final report the natural frequency is also going to be considered but hasn’t been included now due to time constraints

15. Simplifications The main simplifications were:
Simplifying the concrete counterweights into a few point loads
Not having a pivoting base. I.e. the nodes at the bottom of the tower are fixed in all directions and rotations
The 3d case didn’t incorporate the service crane and the extra cables

16. 2D Tower Crane
Service Crane
Cables

17. 3D Tower Crane
Cables
Loads
Fixed Nodes

18. 2D Displacement Analysis Case1

19. 2D Displacement Analysis Case 2

20. Displacement Analysis
1ST Case load at the end of the jib
Maximum displacement 1.5m
Loads : counterweight = 3x 30kN
Jib =150kN

21. Displacement Analysis 3D
Load case 2 : Maximum Displacement 0.41m
Loads : counterweight = 4x 20kN
Jib =150kN

22. Displacement Analysis 3D
Third Load Case : Maximum Displacement 0.6m
Loads : counterweight = 4x 20kN
Jib =150kN

23. Displacement Analysis
The 2 and 3D cases give quite similar displacements
Up to 1.5m depending on the loads applied
The worst case is when the load is applied at the end of the jib, which is what is to be expected.

24. Stress Analysis
The stresses observed are not realistic ie. In the thousands of MPa
This result is evident in all of the load cases

25. 2D Stress Analysis Case 1

26. 2D Stress Analysis Case 2

27. Stress Analysis
In all cases the stress is beyond the yield strength of the steel used.
Therefore there are errors that need to be corrected.
This will be done by making the critical tension members solid and looking at the weights of each member.

28. Errors
The main errors involved so far have been in relation to the units associated with the loads applied to the structure.
The high stress involved may be due to the weight of the structure as a whole.
Initially we were faced with problems relating to the stiffness matrix “K”.
This involved, free or unconnected elements and also defining an element more than once in the same position.

29. Modifications Main modification factors are :
Modifying the cross-sections of some members to decrease the high stresses observed
Wind load scenario
Natural frequency analysis
Seeing the effect of other materials and how they affect the results.

30. Thank you for listening Any Questions??