Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


Building 'Bangs' in Cold Weather

Building 'Bangs' in Cold Weather

Building 'Bangs' in Cold Weather

Greetings -

Since a recent cold spell in our area (10-20°F daily average) we've been hearing occasional loud bangs in the office from above the ceiling. It's a one-story building with a high ceiling plenum. The ceiling is truss steel holding up corrugated metal. Sort of like your typical K-mart ceiling. The building's pretty wide & flat, like a large square. Maybe 30,000 square feet total.

I think the snow accumulation up there's pretty minor.

Some of these bangs are significant - like taking a baseball bat to a dumpster kind of sound. Other times it's minor metallic popping sounds. No steam or water in the ceiling so it's not hammer. I'm pretty sure it's not coming from the HVAC system. Someone suggested building contraction... any thoughts on this? Thanks.  -CB

RE: Building 'Bangs' in Cold Weather

We get daily temperature variations up to 40 degrees F and loud noises due to expansions and contractions are a regular occurence, even in fairly old buildings.


Greg Locock

RE: Building 'Bangs' in Cold Weather

I used to live in a house with a flat roof, in the winter you'd hear the occasional bangs, sounded similar to a shotgun. What we finally figured out was the ice on the roof was cracking as it expanded and contracted, it would scare the s**t out of someone that wasn't used to it. After awhile you didn't even hear it....Mike

RE: Building 'Bangs' in Cold Weather

Are there any expansion/contraction joints in your building?

RE: Building 'Bangs' in Cold Weather

Mike - I'm buying the ice theory. It makes sense as today was freezing again but the sun was beating on the roof during daylight, no popping/banging. Come 3:30 and after when the sun stopped hitting the room, the bangs came back, intensifying up until about 5:30.

I'll go up there tomorrow and re-post what I see.

Watermelon, I'm not sure. I only see joints in sheetrock in long corridors. Roof is membraned over, exterior is stucco'd. If I had to bet, probably not sufficiently, if at all!

Thanks for your inputs! -CB

RE: Building 'Bangs' in Cold Weather

Could there be the equivalent of finger clickers in the roof, i.e., shells that are dimpled in one direction and forced to deform into the other?  That would make a nice pop or bang.


RE: Building 'Bangs' in Cold Weather

Hi ChasBean1:

Good idea to check the roof load and not make any assumption.  The old adage comes to my mind: when I ASS-U-ME, I make an ASS out of U and ME.

My understanding of expansion/contraction joints is they should be added when buildings approach 120 feet.  I will probably be shot down on this site for saying that, but oh well.  Your building measures approx 175 x 175, so one might expect to see a joint.

Next, they are easy to I.D.  You should see joints in the exterior, in the floors and maybe columns very close together at the joint.  If you had them, you'd know.

It sounds to me like there is some kind of movement taking place as a result of temperature changes.  Maybe some joists that are not welded down.

My only concern is this: (and I don't want to ring any alarm bells)  When a weld snaps suddenly, it makes a sound like a gun being fired.

Best you grab a flashlight, remove some ceiling tiles and have a look-see.  Due diligence.  Get the snow off the roof first.  And don't stockpile it on the roof.

RE: Building 'Bangs' in Cold Weather

A common cause of banging in steel buildings is bolted connections.  More likely to occur than the failure occurance of the weld, this occurs when the bolt overcomes the friction force of the nut and the bolt slides into contact with the side of the hole thus banging and becoming a bearing condition.

RE: Building 'Bangs' in Cold Weather

I experienced this peculiar phenomenon a few years back from my house. Repeated violent bangs coming from the roof (typical sloped wood trusses and plywood construction) that woke us from our sleep and it was scary. No damage to the roof. Later that evening, it was on the news, so it was fairly widespread in our area. If I recall the explanation was "Ice snapping/breaking off the roof surface"

I have not experienced such "bangs" since.

With regard to bolt slipping, I have witnessed several full scale transmission tower tests. These towers are loaded until they collapse. Loud noises are normal and they come from bolts slipping into bearing. However, they are different from the "roof bangs" Also, we start hearing "bolt bangs" when loading is beyond 75%. I don't think buildings are ever loaded beyond 75% of their structural capacity.

No doubt, an interesting topic.

RE: Building 'Bangs' in Cold Weather

AISC has a lot of information on the banging bolt phenomenon.  This may or may not be germaine to your case since it may be temperature and not load dependent and the banging bolts can only occur once per connection after the slip into bearing.  An interesting way to check this phenomenon is to loosen a bolt in the top row of a beam connection and listen to the sound.  The company I used to work for investigated this about fifteen years ago and that proved to the then skeptical AISC that this can sporadically occur with TC bolts due to the high initial pretension.  Here's a link from AISC on the subject of banging bolts: http://www.aisc.org/Template.cfm?Section=Search&template=/Search/SearchDisplay.cfm

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


White Paper - The Criticality of the E/E Architecture
Modern vehicles are highly sophisticated systems incorporating electrical, electronic, software and mechanical components. Mechanical systems are giving way to advanced software and electronic devices, driving automakers to innovate and differentiate their vehicles via the electric and electronic (E/E) architecture. As the pace of change accelerates, automotive companies need to evolve their development processes to deliver and maximize the value of these architectures. Download Now
White Paper - Model Based Engineering for Wire Harness Manufacturing
Modern cars, trucks, and other vehicles feature an ever-increasing number of sophisticated electrical and electronic features, placing a larger burden on the wiring harness that enables these new features. As complexity rises, current harness manufacturing methods are struggling to keep pace due to manual data exchanges and the inability to capture tribal knowledge. A model-based wire harness manufacturing engineering flow automates data exchange and captures tribal knowledge through design rules to help harness manufacturers improve harness quality and boost efficiency. Download Now
White Paper - Modeling and Optimizing Wire Harness Costs for Variation Complexity
This paper will focus on the quantification of the complexity related costs in harness variations in order to model them, allowing automated algorithms to optimize for these costs. A number of real world examples will be provided as well. Since no two businesses are alike, it is the aim of this paper to provide the foundational knowledge and methodology so the reader can assess their own business to model how variation complexity costs affect their business. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close