Rails –a camel built by bureaucrats and engineer

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Mark Mandell - Gone Round in New Jersey

That was a committee of lawyers trying to build a horse.

Re: Close

Bill Tindall, E.Tn.

Add and engineer to the mix and you got it.

A typical too tall bike trail rail

Bill Tindall, E.Tn.

Creeper trail. 54" height, more than 4" spacing. go figure. Trail passes over some scenic creeks crossings but only the tall can see them without climbing the rail.

To get this picture rotated correctly it was stored rotated 90 degrees to the right. go figure than!

Re: Rails –a camel built by bureaucrats and engi

Sgian Dubh

"Our design engineer demands a rail height of 46” and a rail spacing of less than 4”. Where these values came from I do not know."

Bill, I wonder if the 4" rail spacing regulation (if that's what it is) or smaller could be linked to stair spindle or rail spacing regulations in the US? I don't know if such a regulation exists in the US, but here in the UK regulations stipulate that new made stairs cannot have a spacing of more than 100mm (horizontally) between spindles at their widest point. The reasoning here is that this dimension is too small for a child's head or body to pass through which could lead to injury or death, e.g., strangulation, broken bones, or even death. In fact the regulations require that a 100 mm diameter sphere cannot be passed through any gaps in spindles, rails, handrail, panels, etc. 100 mm, of course, is close to 4".

There are also UK stipulations or regulations determining the height of stair handrails, both internal stairs and external stairs.

I might be wrong, but maybe such safety inspired links exists? Slainte.

Re: Rails –a camel built by bureaucrats and engi

Bruce, a MN Galoot

The four inch spacing is my guess, too. I rebuilt my deck a few years back and the only thing the inspector cared about was that spacing between the spindles.

Re: Rails –a camel built by bureaucrats and engi

John in New Mexico

The version of this code I've heard before is that a 4" diameter ball cannot pass through the openings for a railing. We usually use livestock panels from Tractor Supply as fill in below the railing, quick, easy, and less than 4" Only pain is painting the stuff!

Re: Rails –a camel built by bureaucrats and engi

Bruce, a MN Galoot

The ball is how the inspector tested the spacing.

Re: Rails –a camel built by bureaucrats and engi

Barry Irby

The discussion of the 4" spacing and the child's head is correct. The largest part of a small child's body is the head and if the rest of them slips through, they end up hanging by the head.

There was a brief period when horizontal rails were unacceptable because people could climb over. I suspect the cable rail people got that changed.

Re: Rails –a camel built by bureaucrats and engi

Bill Tindall, E.Tn.

The can't pass a 4" sphere is International Residential code. The engineer is applying this code to a remote trail, inappropriately in my mind. National Forest trail code is 6" for lower 36" of rail and 9" above that and for even more remote trails simply 2 rails.

Nothing good was ever designed by a committee

mark hennebury

The basics of good construction with timber is not complicated or new, it has been understood for thousands of years, There are wooden buildings that have stood the ravages of hurricanes, tornadoes earthquakes, wind, snow and rain for hundreds of years, all built by people that have worked with and understand wood. This is not rocket science, and I struggle to understand how so many bad designs get to see the light of day when we live in the age of easy access to all of the knowledge known to mankind. You are to be commended for your patience and perseverance in the struggle against the foolishness.

The result of thousands of years of woodworking..

mark hennebury

This is a park bench on a hiking trail that I was on this week.

Committee of two

Tom Dunlap

And when the bench falls off resulting in an injury will the person who designed/made the bench be liable? Will they be publicly 'shamed' some how?

For all the complaints about design by committee all it might have taken was a committee of two to nix that poor design.

What a dangerous waste of material and time. Hopefully no wages for such work.

Re: Committee of two

mark hennebury

We are on vacation and just had a walk around the neighborhood,all newly constructed upscale homes, most have wooden step's up to the front door. There was only one or two that had the stringers properly supported, some had the half of the bottom overhanging, some the top and some both top and bottom. These are open stringers, cut halfway through for the treads to sit on, and are only supported by the top short grain. If you stamped your foot you would break the step. No consistentcy in construction. Simply haphazard bad design. Who approves this stuff?

Re: Committee of two

mark hennebury

Lots of this type of stuff around.

sure enough

Bill Tindall, E.Tn.

that is the counter sink procedure that was foisted upon us early on, to be replaced by engineered screws. One has to ask , why are hidden screws counter sunk? Otherwise I like the efficiency of the design.

Re: sure enough

mark hennebury

Bill, when I saw the design of the post joint I was a little disappointed, maybe not surprised as I have seen far to much of this, this is probably the weakest way to fasten a post, compensated by heavy metal fasteners. In my opinion it waste of time materials and effort, for a result that won't last. You made a gallant attempt to make sensible improvements to a bad design. The method that I proposed is a simple solution that follows standard timber construction methods, is incredibly strong, will last as long as the wood, minimal use of materials, easy to precut, easy to assemble.etc..whoever paid an engineer to come up with that got robbed, and the engineer. that came up with it should be fired. You have an 8x8 to fasten that post to and the engineer ignored it, and fastened the end to an angle iron. That's absurd. That's how you make a lever to break things apart.

bridge examples

GolfSteve in Calgary

I haven't had time to reply to Bill's earlier question about post attachment, but my first thought was also that the angle iron was not a great idea as it is a huge lever.

I've been busy doing a lot of back country mountain biking recently. These areas were heavily flooded 5-6 years ago, taking out many of the bridges. The heavily tracked bridges have been replaced with lightweight composite (like fibreglass) Bailey type bridges that can be backpacked in 6-8 ft lengths and bolted together. They look pretty flimsy, but they are plenty strong. I don't have a picture of these.

The less travelled bridges have been replaced by two 8x12 beams with a couple posts bolted onto one beam in the manner that Marc suggested. The beams have a single bolt at each end holding the two beams together. They are strong...but they are simply dropped onto two gabion foundations, and a piece of tie wire holds the bridge onto the gabion! A good kick would move the bridge or a dozen stupid kids that decide to rock the railing back and forth could tip the bridge.

For larger spans they've been going to very lightweight aluminum trusses with a very lightweight deck. This would easily support a quad, and I'm sure it would carry a car, but I would get nervous after that. There's no warning sign about maximum load capacity, so the engineer has probably designed the bridge to carry a load equivalent to one person per square foot or square meter, assuming that at some point in the future a wedding party will pose on the bridge with all 200 of their guests, or a marathon might decide to use this bridge as a starting point.

reply, you are wrong

Bill Tindall, E.Tn.

When I reply in post about rails I will show that your analysis is wrong structurally and economically. In the mean time go look at nearly any trail bridge and you will see essentially what we are using with minor variation. I have examined dozens of bridges on trails around the south east. The whole world hasn't gravitated to an flawed post attachment.

For starters do you think you could mount a post the way you suggested in 3 minute on a RR tie?

Opinions don't count..

mark hennebury

Show me the money. And tell me how many posts that we have to do, and the life expectancy of you engineered method.

Data

Bill Tindall, E.Tn.

I just finished building 434 feet of bridge and you are claiming my conclusions are based on opinion. There is a post on each side every four feet. Do the math.

Not my engineered method. The first design was done by a RR engineer and the second a mechanical engineer.

Explain how either post attachment would differ in service life.

I presume you are advocating the notched post and tie pictured earlier? How long do you estimate it will take to cut the notch in the post and 10 inch tall tie using what tools? How will bolt hole be drilled?

Re: Data

mark hennebury

Bill, I wasn't suggesting you were offering opinion, what I suggested was opinion, my opinion, you are the one with all the data, all the engineering calculations, mine is just my opinion, but I would like to see a comparison, because the engineers design doesn't make sense to me. As for the speed, I would need some information from you,. How many posts need to be cut? Can the posts and ties be precut at a shop, or need to be done on site? What is the life expectancy of the screwed in posts? Do you have a generator on site? Chainsaws? Give me the info and we maybe can make an overall Comparison. Meanwhile get your engineer friend to do some quick calculations on the strength of the method that I proposed in comparison to the original design, see where that goes,Then we can work on time and cost.

Re: Data *LINK*

mark hennebury

There are lots of ways of getting a job done. It depends on the specific situation which you choose.


Router video

reply

Bill Tindall, E.Tn.

I have provided these data in previous posts, but the compelling cost advantage will be discussed when I explain rail installation.

because the engineers design doesn't make sense to me. ....then I did not make it clear. See engineering print that was part of previous post. The post is 4 x 6 with the 6" dimension parallel to the bridge length to accommodate butt joints on rails. Do you understand that any anticipated force on the rail is from the bridge deck outward? There isn't any meaningful difference between the strength of your costly to implement joint and the angle bracket. In fact your arrangement could be weaker because you have reduced the size of the post below the tie. Keep in mind too that ties fail by their ends splitting. As soon as the end of the tie begins to fail your arrangement will be compromised .

1 post per 2 feet of bridge.

Can the posts and ties be precut at a shop, or need to be done on site? Haul posts and ties to a shop and back to site for installation? It takes seconds to size a post to length on site and 3 minutes to install it in place.

What is the life expectancy of the screwed in posts? bridge rails last for decades. The important strength providing fastener is the 1/2" structural steel through bolt with its plate washer to distribute bolt stress across the post.

Do you have a generator on site? Of course

Chainsaws? yes What experience have you had chain sawing a tie that has been retrieved from RR service? We occasionally trim one for retaining walls. Chain life is not favorable.

Meanwhile get your engineer friend to do some quick calculations on the strength of the method that I proposed in comparison to the original design. Before modifying angle bracket to 1/4th the stress on the screws that failed the assembly failed at 840 pounds of force at the top of the post unsupported by rails and adjacent posts. Calculations predict strength of post wood is now limiting factor.

question

Bill Tindall, E.Tn.

I think you don't understand how our posts are fastened for it is not clear to me why you think the angle bracket design deficient. see print. What deficiency do you see in it? It can't be strength as a single unrailed post exceed code by 4X and that was before reducing the stress on the vertical screws by 4X. Once assembled into the rail with supporting posts and rails as part of a rail structure it vastly exceeds code. It can't be cost as the angle bracket design will be times if not orders of magnitude less labor to fabricate and install.