transmissiontowers
Structural
- Jul 7, 2005
- 560
I am a structural engineer and have been working for over 30 years analyzing transmission towers and poles that support wire. My boss is an Electrical Engineer with a PE. His boss is a business major. The Vice President is a Mechanical Engineer.
The problem is the analysis of towers with a skewed wind angle. Due to geometry, a wind at an angle will produce maximum loads and cause leg failure. If the wind is only considered normal to the wires, the legs are OK.
Back in the old days, we did not have the software tools to consider skewed wind. With better PC's and better software, we can now analyze hundreds of wind angles and determine which wind angle will control.
My EE boss says it is a management decision of risk vs reward and it costs too much to fix the towers when adding more equipment to the tower. As a PE, I feel it is my duty to inform him that it is my opinion that the tower will fail if the wind hits the maximum design wind speed and at the most critical direction.
The NESC code we work under has some generic guidance that the wind at an oblique angle may cause higher loads. Guying the tower inline will help brace it and reduce the leg loads to acceptable levels, but it costs more and the construction folks don't like to do it and are concerned with trucks running into the guy wires.
I have been told to ignore the oblique wind direction and allow the extra equipment to be installed on the towers. I have a few options:
1) State my concerns to the manager and let him decide
2) Run the oblique wind cases and note the failures, then run the normal wind case and note the loads and write a note in the file that the tower will fail in the right conditions.
3) Prepare a letter and have it signed by the EE and his boss that they are aware that the tower may fail.
4) Report my EE boss to the State Board of Registration for ethics violations.
Is it ethical for the EE to order me to look the other way?
_____________________________________
I have been called "A storehouse of worthless information" many times.
The problem is the analysis of towers with a skewed wind angle. Due to geometry, a wind at an angle will produce maximum loads and cause leg failure. If the wind is only considered normal to the wires, the legs are OK.
Back in the old days, we did not have the software tools to consider skewed wind. With better PC's and better software, we can now analyze hundreds of wind angles and determine which wind angle will control.
My EE boss says it is a management decision of risk vs reward and it costs too much to fix the towers when adding more equipment to the tower. As a PE, I feel it is my duty to inform him that it is my opinion that the tower will fail if the wind hits the maximum design wind speed and at the most critical direction.
The NESC code we work under has some generic guidance that the wind at an oblique angle may cause higher loads. Guying the tower inline will help brace it and reduce the leg loads to acceptable levels, but it costs more and the construction folks don't like to do it and are concerned with trucks running into the guy wires.
I have been told to ignore the oblique wind direction and allow the extra equipment to be installed on the towers. I have a few options:
1) State my concerns to the manager and let him decide
2) Run the oblique wind cases and note the failures, then run the normal wind case and note the loads and write a note in the file that the tower will fail in the right conditions.
3) Prepare a letter and have it signed by the EE and his boss that they are aware that the tower may fail.
4) Report my EE boss to the State Board of Registration for ethics violations.
Is it ethical for the EE to order me to look the other way?
_____________________________________
I have been called "A storehouse of worthless information" many times.