Repair of bent steel flange on pole sign

[charliealphabravo]

I am going to look at a retail sign that has been hit by a vehicle. From the grainy photos I have it looks like there is a bent flange on one of the two steel columns. I also would not be surprised to see a slight bend in one of the columns. My question is whether it will be feasible to do a field repair of a bend in a vertical steel column. It looks like it is a W6 or W8 and is about 15 feet tall. Basically I need to know if the column could be straightened or if it would have to be taken down and replaced or repaired in a shop on a jig or something.

Thanks in advance.

 

[racookpe1978]

You don't know enough.
We don't know enough (without better pictures and exact measurements) to guess.

 

[XR250]

If you are gonna bring it to a shop, might as well just replace it.

 

[charliealphabravo]

The issue I am dealing with is that the sign is grandfathered and a replacement won't be approved by the city. I am thinking that a repair in place is the safest thing if it is feasible. I will know more later.

 

[dhengr]

Charliealphabravo:
Depending upon what you actually find, and how extensive the damage is, it is likely that you can fix something like that in place. A guy who really knows what he is doing with a heating torch can do amazing things in the way of heat straightening these types of things. When the damage is severe enough it might require some mech. force too; or some cutting and rewelding, and maybe a reinforcing patch or two. Obviously, each situation is different, but the guys who do this well, have much experience and a special intuition as to where to heat, which side to heat, and how much heat, and what shape the heat should be. Surprisingly enough, when done right this really hasn’t reduced the structural capacity by much. All you have done is yielded the steel in that region, by the original impact and then the heating repair; so this region is now acting up on the early plastic plateau of its stress-strain curve when loads are applied. Sometimes, to hide a repair which isn’t too attractive, you can cast a 16" conc. protective pier around the steel columns, maybe 3' above grade and 1 or 2' below grade.

 

[Rich2001]

In general heat cambering is the method of choice.
below is the rough procedure Bold items are important


The following heat cambering procedure shall be used for material with a specified yield strength not greater than 50,000 psi. The heating temperature shall not exceed 1200 degrees Fahrenheit as controlled by temperature indicating devices.

Heat Source: Single or Multiple Torch
Fuel Gas: Optional
Technique: Vee, Strip or Rectangular Heating
Heating Temperature: 600 – 1200 Degrees Fahrenheit

1. The member shall also be supported or braced in such a manner as to prevent the member from overturning. Appropriate blocking, as required, shall be used to attain the required camber and to prevent excessive movement. Camber tolerances shall be specified by the applicable code and contract specifications.

2. Heat cambering shall be performed using triangular Vee, Strip, Block, Edge, and Rectangular heating patterns. The heating patterns shall be spaced and marked throughout the length of the member as required to provide the specified camber. Heating shall be performed using rosebud tip. Rosebud tip selection shall be made to promote heating efficiency while minimizing distortion and excessive heating to the member.

3. Vee heating shall begin at the apex of the heating pattern. As heating progresses toward the top of the Vee, the heating torch shall not be returned to the apex of the heating pattern or to a previously heated area. Heating may be performed either from one side of the web using one torch, or from both sides of the web using two torches. Heat shall not be applied more than three times to one area. If multiple locations are to be heated, do not reheat the same location until after at least three heats at other locations.

4. Heating shall be confined to the planned patterns. The steel shall be brought to a temperature of between 600 1200 degrees Fahrenheit as rapidly as possible. Temperature indicating crayons or other devices for measuring temperature between 600 to 1200 degrees Fahrenheit shall be utilized. All heat measurements shall be taken after the torch has been removed from the steel. Any heating that results in a steel temperature in excess of 1200 shall be brought to the attention of the engineer.

5. Quenching with water or a combination of air and water is not permitted. Cooling with dry compressed air is permitted after the steel has been allowed to cool naturally to 600 degrees Fahrenheit.

6. Required Magnetic Particle testing for the girder shall be performed after all heating is completed.

7. Heating shall not be applied to one location more than three times until all other locations have been utilized.

Richard

 

[charliealphabravo]

Does anyone know of someone in the Edmonton area that does field heat straightening? I've talked with a welder but I don't get the sense he has done this very often if at all.
Thanks again all.

 

[chicopee]

Or you could cut out the bent section and replace it with a new flange in the field. Full penetration welding would be highly desirable.

 

[TLHS]

Alternate method...

If it's just 15 feet tall, you could likely just get a circular concrete form, put it around the column, maybe install a few dowels in the foundation and pour around it. It might take a little bit of thought to decide the best way to prove that it works, but you'd be adding a reasonable amount of capacity, providing a degree of stabilization against local flange buckling and all sorts of other fun things.

It avoids the inherent construction stability risks of screwing around with the existing post either with cutting or heat and it hides the ugly repair.