# What are these metal things on concrete benches **URL:** \ **Category:** In My Humble Opinion\ **Created:** [December 7, 2025, 8:05pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500 "2025-12-07T20:05:25Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 7, 2025, 8:05pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/1 "2025-12-07T20:05:25Z")
In a number of places, I’ve seen concrete benches (or low walls that might be used as benches) with metal objects attached at intervals, like this: [![](https://greenwoodsoftware.com/misc/concrete-bench.jpg) ](https://greenwoodsoftware.com/misc/concrete-bench.jpg) Sometimes they are decorative, shaped like leaves or other things; other times like in this photo they are just straight pieces of metal. I had assumed that they were intended to divide up the bench into individual seats, although I don’t know why that is desirable. Why do they care if I want to sit closer to my wife or farther from a stranger? But then I noticed at the same place where I took the previous photo, there was a tall wall with the same objects attached to the top of it: [![](https://greenwoodsoftware.com/misc/concrete-wall.jpg) ](https://greenwoodsoftware.com/misc/concrete-wall.jpg) This clearly has nothing to do with seating; the wall is at least 4 feet high. So is there some other purpose for these things? ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 7, 2025, 8:07pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/2 "2025-12-07T20:07:52Z")
They keep the skateboarders off of it. ---
**Author:** ![thelurkinghorror](https://avatars.discourse-cdn.com/v4/letter/t/7c8e57/32.png) [@thelurkinghorror](https://boards.straightdope.com/u/thelurkinghorror)\ **Post date:** [December 7, 2025, 8:07pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/3 "2025-12-07T20:07:59Z")
Anti-skateboarding/grinding measures. E.g. [http://www.skatestoppers.com/](http://www.skatestoppers.com/) ---
**Author:** ![pkbites](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pkbites/32/204_2.png) [@pkbites](https://boards.straightdope.com/u/pkbites)\ **Post date:** [December 7, 2025, 8:21pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/4 "2025-12-07T20:21:07Z")
As said, to dissuade skateboarders. They’ve been putting in occasional textured sidewalk squares in some locations for the same reason. The bench studs also deter homeless from stretching out and setting up camp. Some places have been installing studs on their heating grates in their vestibules to deter folks from coming in and sitting on them. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 7, 2025, 8:33pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/5 "2025-12-07T20:33:36Z")
Since the FQ itself has been thoroughly answered … Those devices have been around for 20-25 years now that I know of. I’m wondering if they just recently came to the OP’s area, or just recently came to the OP’s attention, or has this question been sloshing around in their head since the turn of the century? I’ve sure got a few ancient wannabe FQs I’ve never gotten up the gumption to ask. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [December 7, 2025, 8:36pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/6 "2025-12-07T20:36:31Z")
Ignorance fought, thanks all. I’ve noticed them for maybe 10 years, definitely less than 20. But yesterday was the first time I’ve seen them on a wall that clearly couldn’t be used for seating, which suggested to me that my assumption about their purpose might be mistaken. ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [December 7, 2025, 8:38pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/7 "2025-12-07T20:38:58Z")
> [@pkbites](#): > > The bench studs also deter homeless from stretching out and setting up camp. And, sometimes, the anti-homeless-sleeping attachments on benches are quite large and elaborate. TIL that there’s even a term for it: “hostile architecture.” [![](https://images.ctfassets.net/vlp0dhcdis5o/1ysXwQtDtBbBm4dpJv1pBZ/c703bf50b542e371d0cf97748f4e52cc/hostile-architecture-example-1.jpg?w=1500&h=1001&fl=progressive&q=50&fm=jpg) ](https://images.ctfassets.net/vlp0dhcdis5o/1ysXwQtDtBbBm4dpJv1pBZ/c703bf50b542e371d0cf97748f4e52cc/hostile-architecture-example-1.jpg?w=1500&h=1001&fl=progressive&q=50&fm=jpg) [![](https://www.providencejournal.com/gcdn/authoring/authoring-images/2023/08/09/NPRJ/70560425007-20230807-175201.jpg) ](https://www.providencejournal.com/gcdn/authoring/authoring-images/2023/08/09/NPRJ/70560425007-20230807-175201.jpg) [![](https://cdn.theatlantic.com/thumbor/Gxudf0MO2HMBQ5oajBgeLPNpyCc=/570x428/media/img/posts/2014/06/PICT0040/original.jpg) ](https://cdn.theatlantic.com/thumbor/Gxudf0MO2HMBQ5oajBgeLPNpyCc=/570x428/media/img/posts/2014/06/PICT0040/original.jpg) ---
**Author:** ![needscoffee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/needscoffee/32/1076_2.png) [@needscoffee](https://boards.straightdope.com/u/needscoffee)\ **Post date:** [December 7, 2025, 8:42pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/8 "2025-12-07T20:42:34Z")
> [@LSLGuy](#): > > I’ve sure got a few ancient wannabe FQs I’ve never gotten up the gumption to ask. (_taps foot impatiently_) We’re waiting… ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [December 7, 2025, 8:47pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/9 "2025-12-07T20:47:21Z")
Also, TIL that those devices are specifically placed there to discourage a skateboard move called “grinding” (as noted in @thelurkinghorror 's link), in which the skateboarder slides along an edge (like in the pictures in the OP) on the metal truck(s) of their board, rather than on the wheels. Grinding is known to cause damage and wear to the edges of those surfaces. [![](https://as2.ftcdn.net/jpg/01/44/97/15/1000_F_144971550_DcnIB3Gykx08iMtPQ5gKcFoH0GgOA5gE.jpg) ](https://as2.ftcdn.net/jpg/01/44/97/15/1000_F_144971550_DcnIB3Gykx08iMtPQ5gKcFoH0GgOA5gE.jpg) ---
**Author:** ![hajario](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hajario/32/171_2.png) [@hajario](https://boards.straightdope.com/u/hajario)\ **Post date:** [December 7, 2025, 8:51pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/10 "2025-12-07T20:51:49Z")
> [@kenobi\_65](#): > > Grinding is known to cause damage and wear to the edges of those surfaces. And injure the skateboarder. So thwarting attractive nuisance and law suits ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [December 7, 2025, 9:02pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/11 "2025-12-07T21:02:17Z")
IIRC there are similar grinding-like maneuvers commonly done with BMX bicycles and their axle pegs. The same **[Hostile architecture - Wikipedia](https://en.wikipedia.org/wiki/Hostile_architecture)** features work against them. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 7, 2025, 11:01pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/12 "2025-12-07T23:01:48Z")
I always thought this one was funny. As I read in the caption the first time I saw a picture “the person is in a wheelchair, they can literally sit anywhere”, IOW, there’s no reason to cut out the middle of a park bench for that. [![](https://pbs.twimg.com/media/GRR2aC4XMAAMWWw.jpg) ](https://pbs.twimg.com/media/GRR2aC4XMAAMWWw.jpg) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 7, 2025, 11:11pm UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/13 "2025-12-07T23:11:27Z")
I could, though, see cutting the end off of a park bench for wheelchair access. Like, if there’s a whole layout of them, in front of an outdoor stage (there’s a setup like that at a park near me). That way, a person in a wheelchair can still sit with their family or friends, without blocking the aisle. ---
**Author:** ![Marvin\_the\_Martian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/marvin_the_martian/32/2898_2.png) [@Marvin\_the\_Martian](https://boards.straightdope.com/u/Marvin_the_Martian)\ **Post date:** [December 8, 2025, 1:04am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/14 "2025-12-08T01:04:46Z")
> [@kenobi\_65](#): > > And, sometimes, the anti-homeless-sleeping attachments on benches are quite large and elaborate. TIL that there’s even a term for it: “hostile architecture.” Similar to how the seating at airports is hostile to anyone stuck in the terminal overnight, at least at O’Hare. Ended up sleeping on the floor. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [December 8, 2025, 1:12am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/15 "2025-12-08T01:12:32Z")
my fav. “hostile architecture” → as it has to be disguised as **nice looking** … seats/benches at airports … everything possibly done to prevent people sleeping on them … ---
**Author:** ![DrDeth](https://avatars.discourse-cdn.com/v4/letter/d/b487fb/32.png) [@DrDeth](https://boards.straightdope.com/u/DrDeth)\ **Post date:** [December 8, 2025, 1:13am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/16 "2025-12-08T01:13:38Z")
> [@kenobi\_65](#): > > And, sometimes, the anti-homeless-sleeping attachments on benches are quite large and elaborate. TIL that there’s even a term for it: “hostile architecture.” Yeah, that sort of thing is all over San francisco. That city is run on homeless issues it seems. The bus shelters are horrible- so the homeless….the public restrooms closed- homeless- the turnstyles coin slots blocks- homeless, etc etc. Geez. ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [December 8, 2025, 2:33am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/17 "2025-12-08T02:33:06Z")
I get it. It’s one thing to be homeless, but it’s another to not take care of public spaces or make a nuisance of yourself in them. Despite what some people think, they’re not any _more_ entitled than anyone else to use public spaces, and they’re certainly not entitled to mess them up, stink them up horribly, or hog them by laying across the benches others may need to sit on. I mean, is a homeless person sleeping on a subway bench _more_ entitled to lay on it than an elderly person who needs to sit? Is a homeless person entitled to make a bathroom nasty because it’s the only place they have to go, versus someone else who just wants a clean bathroom? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 8, 2025, 3:28am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/18 "2025-12-08T03:28:57Z")
Except that homeless people sleeping on park benches mostly aren’t there at the same time that others would be using it. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [December 8, 2025, 4:32am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/19 "2025-12-08T04:32:45Z")
> [@bump](#): > > I get it. It’s one thing to be homeless, but it’s another to not take care of public spaces or make a nuisance of yourself in them. Despite what some people think, they’re not any _more_ entitled than anyone else to use public spaces, and they’re certainly not entitled to mess them up, stink them up horribly, or hog them by laying across the benches others may need to sit on. They are “entitled” by the fact that they exist, and have to be _somewhere._ And being homeless, they have no choice _but_ to be in those public spaces. They aren’t going to magically vanish because they are inconvenient or unsightly. They can’t be blamed fairly for something they have no choice in. ---
**Author:** ![Banksiaman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/banksiaman/32/3334_2.png) [@Banksiaman](https://boards.straightdope.com/u/Banksiaman)\ **Post date:** [December 8, 2025, 4:49am UTC](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500/20 "2025-12-08T04:49:09Z")
[Stuart Semple](https://stuartsemple.com/stuart-launches-anti-hostile-design-campaign/), perhaps best known as the inventor of the world’s pinkest pink, is also an advocate against the creeping advance of hostile architecture and hostile design. There’s a whole lot of commentary about how these different ways of discouraging inconvenient people from hanging around your part of the free-open-accessible to all urban landscape is intended to drive them away. Not to give an alternative, let alone address the issues that underlie the cause of homelessness and disadvantage, but just getting them to clear off. And as for accommodating the kids who actually listened to their parents and got out of the house and off their phones for a bit of exercise … [Next page](https://boards.straightdope.com/t/what-are-these-metal-things-on-concrete-benches/1025500.md?page=2)