Vibrations from Truck Traffic 1

[toddbrsd]

I am looking for suggestions/similar experiences relative to a citizen complaint regarding increased vibrations in his home due to adjacent truck traffic. The home is within 30 feet of the right of way (back of sidewalk) of a major arterial street. I would expect vibrations being this close to the street but the resident claims that the vibrations have gotten worse, so much as to cause his computer to kick out of "power save" mode. I have had a core sample done in the street which indicates a sub base comprised of sandy silt with a trace of clay at a relative compaction of 80% and a moisture content of 20%. My geotech has stated that the substandard compaction in itself would not be the "smoking gun". We have had an abnormally wet winter, which is when I was first contacted by the resident.

The resident has claimed to set up a crude (his words) device comprised of a chalk line tied to two poles with a third pole in the middle to measure the vibrations and has indicated a 3/8" jump in the chalk line. I have stood on the sidewalk while trucks passed and did not notice any vibrations.

The road does need repair which I am certain is contributing to the problem, but I want to make sure that if there is any specific remediation to mitigate the vibrations, that I consider it. We are anticipating the use of a rubberized asphalt at this point.

Any suggestions would help.

 

[DRC1]

A 3/8 inch amplitude is huge. If he were getting that his house would be showing sigs of distress. Cal a vibration engieer (blasters can probably give you some reccomendations)and have him set up a monitering system with some seismographs (I would use at least 2 in different locations, so that the citizen can not jump in front of the transducer) The engineer can take the readings, examine the site and determine if the levels are suffient to warrent the complaints. My guess is no.

 

[Dirtguy4587]

Seismographs may be a bit agressive. Another option that I've had success with for vibration monitoring is to get a small vibration monitor - Instantel makes some easy to use devices that are often used in the mining industry. I've used such products to monitor vibrations during pile driving. This is something that you may be able to rent and is very simple to set up.

 

[MachineryWatch]

Actually, the 3/8 inch deflection for a chalk line does not surprise me. You could get almost any deflection you want with the device you describe by adjusting the length between the poles and the tension on the chalk line. If the road is in poor condition, as you describe, each impact of a truck tire with with a pot-hole will excite the natural frequencies of the chalk line you described. When natural frequencies are excited amplitudes are amplified.

I would say that since you are in a situation of dealing with a citizen's complaint, you probably need to make sure your efforts at quantifying the vibration and interpretting the data are sufficient to stand up to scrutiny. While it is true that anyone can rent instrumentation, a lot of attention to detail is required to assure that you have acquired valid data. Making sure you get someone who knows what they are doing to acquire the data and then properly interpret it, can save you a lot of money in the long run.

Skip Hartman

http://www.machinerywatch.com

 

[BigH]

I would suggest to discuss this issue with an expert in vibration monitoring. This type of monitoring is done quite often especially as the bar for "suing" seems to be coming down all the time. We had one come in once about a compressor station for pipeline company when a neighbour of some 2 miles away complained! I was on a site once in NJ and the vibrations of compaction did resonate in the house some 100m away. Too, my father had a speed bag in our basement tied to the floor joist - and the neighbour (about 20m away) always knew when he was working out!. But, get an expert on board - at least a discussion with him.

 

[toddbrsd]

Thank you all for your responses. We recently patched the potholes adjacent to the residents house and he has reported a dramatic decrease in vibrations. Hopefully the problem will be resolved in the long term when we fully rehabilitate the street later this year.