# Sidewalk weirdness **URL:** \ **Category:** Factual Questions\ **Created:** [May 26, 2014, 8:50pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310 "2014-05-26T20:50:50Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [May 26, 2014, 8:50pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/1 "2014-05-26T20:50:50Z")
I was walking down a residential street in Fredericksburg, VA today. I noticed a strange pattern with the sidewalk. In regular intervals (about every 30 feet), a small section of the cement was swapped out for dirt. The dirt was fine gravel, not like the regular dirt you’d expect to find underneath a sidewalk. The dirt patches stretched across the sidewalk, not just where the tree box would go, and were about two feet wide. Except for these dirt patches, the sidewalk looked relatively new. No cracks or buckling anything. The whole street was like this. I counted twenty five patches in my little walking tour of the town. Can someone come up with a WAG for what this is all about? I’m afraid I won’t fall asleep until I find the answer. Thanks. ---
**Author:** ![Terr](https://avatars.discourse-cdn.com/v4/letter/t/839c29/32.png) [@Terr](https://boards.straightdope.com/u/Terr)\ **Post date:** [May 26, 2014, 8:58pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/2 "2014-05-26T20:58:40Z")
Concrete expands and contracts with temperature changes. If you have a long slab of concrete, it will eventually crack. That’s why people put in “[control joints](http://www.concretenetwork.com/concrete/slabs/controljoints.htm)”. An alternative to that would be the patches you’re describing. 30 feet is a bit much, but I don’t know what thickness the concrete in the sidewalk is. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 26, 2014, 9:09pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/3 "2014-05-26T21:09:56Z")
I was thinking expansion strips, too, but 2’ seems much too wide, and 30’ spacing seems too far apart. ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [May 26, 2014, 9:18pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/4 "2014-05-26T21:18:05Z")
The dirt patches were about a third of the size of this [one](http://www.prairiedogmag.com/good-candidate/). And the dirt was gray, not brown. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [May 26, 2014, 9:30pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/5 "2014-05-26T21:30:33Z")
Perhaps the sidewalk was dug up to replace the water or gas mains, or sewer lines? ---
**Author:** ![Ranger\_Jeff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ranger_jeff/32/2065_2.png) [@Ranger\_Jeff](https://boards.straightdope.com/u/Ranger_Jeff)\ **Post date:** [May 26, 2014, 10:28pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/6 "2014-05-26T22:28:08Z")
> [@Dewey\_Finn](#): > > Perhaps the sidewalk was dug up to replace the water or gas mains, or sewer lines? This is what I’m thinking. Maybe they had to put valves or something in? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [May 26, 2014, 10:35pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/7 "2014-05-26T22:35:06Z")
someone desperate for pavers and didn’t want the theft to seem so obvious. ---
**Author:** ![Space\_Vegetable](https://avatars.discourse-cdn.com/v4/letter/s/6de8d8/32.png) [@Space\_Vegetable](https://boards.straightdope.com/u/Space_Vegetable)\ **Post date:** [May 27, 2014, 2:59am UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/8 "2014-05-27T02:59:44Z")
The dirt patches were every 30 feet. Were the houses on the block also every 30 feet? ---
**Author:** ![monstro](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@monstro](https://boards.straightdope.com/u/monstro)\ **Post date:** [May 27, 2014, 11:15am UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/9 "2014-05-27T11:15:16Z")
> [@Space\_Vegetable](#): > > The dirt patches were every 30 feet. Were the houses on the block also every 30 feet? Yeah, this seems about right. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [May 27, 2014, 11:27am UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/10 "2014-05-27T11:27:04Z")
In preparation for planting trees? ---
**Author:** ![SeaDragonTattoo](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeaDragonTattoo](https://boards.straightdope.com/u/SeaDragonTattoo)\ **Post date:** [May 27, 2014, 11:43am UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/11 "2014-05-27T11:43:41Z")
Sounds like the filler the gas company used in my neighborhood last year, on the sections of sidewalk they took out to lay new gas lines, and before new concrete was put down. ---
**Author:** ![bobkitty](https://avatars.discourse-cdn.com/v4/letter/b/c67d28/32.png) [@bobkitty](https://boards.straightdope.com/u/bobkitty)\ **Post date:** [May 27, 2014, 5:12pm UTC](https://boards.straightdope.com/t/sidewalk-weirdness/689310/12 "2014-05-27T17:12:45Z")
Yeah, that’s most likely utility line work, though I can’t say whether it’s water, sewer, or gas. You weren’t very far from me! Wish I’d known, I would’ve bought you a beer. 🙂