Does stripping our buses make them weaker?

[pengyou]

First of all, thanks to all of you who have spent so much time detailing your work so that bone-heads like me will have a chance! It is fascinating to read every post. I have watched a number of videos about the construction of school buses and had a question. When you remove the interior metal panels and either just spray foam them and cover them with wall covering, or cover them with wood, does that weaken the overall strength of the bus?

[Sleddgracer]

Originally Posted by pengyou

First of all, thanks to all of you who have spent so much time detailing your work so that bone-heads like me will have a chance! It is fascinating to read every post. I have watched a number of videos about the construction of school buses and had a question. When you remove the interior metal panels and either just spray foam them and cover them with wall covering, or cover them with wood, does that weaken the overall strength of the bus?

my reasoning says yes

[HazMatt]

Probably, yes. The better question might be, does doing so weaken the structural integrity TOO much?

Given how solidly busses, particularly those meant to transport tomorrow's leaders, are constructed, I suspect that the difference is negligible...

[gs1949]

To rephrase hazz.matt.1960's answer, definitely, yes, but sometimes there's no choice. Like with removing the seats, which are part of the rollover protection system. That's what attaching the seats to the chair rail is all about.

When I regularly rode schoolbuses, in the 1950s and 60s, schoolbus seats had 4 legs, which were all bolted to the floor. I don't know when they came up with the chair rail, but it was later.

Likewise the ceiling with all those rivets is a crucial part of the rollover protection system. I've been trying to remember what the ceiling was like in the 1940 Ford bus I rode to grades 1-3 but I can't. I guess I wasn't tall enough to pay as much attention to ceilings as I do now.

But now, if I wasn't nearly 6-and-a-half feet tall, I would not hesitate to leave the existing ceiling in place and insult over it. But since I am, I will take it out and hope to come up with a replacement ceiling that will have at least a little strength in a rollover.

[GWRider]

I know several Crown enthusiasts have discouraged people from removing the interior panels because they say it weakens the overall strength. The question is to what degree? The aluminum interior panels on my Crown were thin and any one piece or section is not likely going to add that much strength. However, it would as a unit if everything is intact with seats bolted down and panels all riveted together by a couple thousand rivets.

I am not that concerned about it for the following reasons:

1. Plan on adding sheet metal to conceal drywall gap.
2. Plan on adding additional bracing since the roof will be raised.
3. Framing for walls adds additional strength.
4. I am already safer than most other buses on the roads (Crowns have almost double the steel tensile strength as Bluebirds and Thomas's).
5. Already safer than just about any manufactured sticks-n-staples RV, Car, Truck or SUV.
6. My Crown is no longer a School Bus so don't need to comply with federal safety standards regarding that.

[musigenesis]

Originally Posted by pengyou

First of all, thanks to all of you who have spent so much time detailing your work so that bone-heads like me will have a chance! It is fascinating to read every post. I have watched a number of videos about the construction of school buses and had a question. When you remove the interior metal panels and either just spray foam them and cover them with wall covering, or cover them with wood, does that weaken the overall strength of the bus?

A bus body is designed to remain intact in a rollover and protect the occupants. If you remove the interior ceiling panels, this resistance to crushing will be lessened somewhat (it won't be entirely gone because the roof skin is more important structurally). But for safety reasons, nobody should ever be riding in the back of a skoolie anyway, so the body's resistance to crushing is kind of irrelevant.

[gs1949]

@GWRider, those are all good good points you make about the things you're doing that will strengthen the roof.

I agree with you that those individually weak interior ceiling panels become much stronger working together. And they have an important specific function in the case of a rollover. Those thin aluminum panels, and all the rivets that hold them in place, do a lot more than just to keep the kids from picking at the insulation.

Each aluminum panel may be thin, but together as a unit they provide tensile strength to help keep the structural components that actually support the roof the same distance from each other as they collapse, which spreads the load and makes them collapse less.

The chair rail is also basically useless except in a rollover or side impact situation, when it serves to transfer energy from the side of the bus to the floor, which is stronger because of the frame.

So the chair rail serves a similar but different function than the ceiling panels. What I don't quite agree with in your post is the implicit assumption that because the seats have been removed it's ok to remove the interior paneling.

The rollover protection system is a system. If you remove one component, in this case the seats, the rest of the system will still work together, just not quite as effectively. When you remove a second component, in this case the interior panels, especially on the ceiling but also on the walls, the effectiveness of the rollover protection system will be even more significantlly reduced.

As you point out the things we do inside the bus will strengthen the bus. But I think most of these projects will do little or nothing to provide any tensile strength to replace the removed ceiling panels. So I am thinking of including several strips of sheet metal running lengthwise, as long as possible, in my ceiling.

I look forward to hearing the thoughts of others on this.

[Willie_McCoy]

Originally Posted by musigenesis

But for safety reasons, nobody should ever be riding in the back of a skoolie anyway, so the body's resistance to crushing is kind of irrelevant.

I disagree, where exactly should they be riding? When it was a bus, obviously it held passengers front to rear. In a class A motorhome passengers are all riding in the back. Some states even allow passengers in travel trailers!!

I am building a skoolie so that while we travel long distances they can be as far away as my design will allow. I will have seatbelts as required by law, but 99.99% of the reason I'm doing this is so they can ride in the back.

[gs1949]

@Willie McCoy, I agree. Some people build a wall behind the driver. I think I will do that, for the reason you mention, but also because it will make the living area easier to heat.