Building A Bridge

Hi Manfred, (sorry about last time...I went back a change Hell to Hello...my mistake.)


I understand what you are thinking about, but I should be clear that I am not projecting guesses at what this would take or cost...even in Europe. I consult internationally as a Timberwright and have been building timber frames for over 35 years. I try to always stay "positive" with folks contemplating a project that may involve some timber framings, as well as realistic. Some of your shared "concepts of cost and logistics" are just not accurate, even for Europe.

The first point I would make, is that no traditional Timberwright, with any experience, or worth hiring for a project, would ever do a project by the hour...it simply is a sign of a "non professional," and/or at best, a general contractor or lay carpenter guessing what timber frames should cost. Professionals do projects by the square or cubic meter (here by the board foot or square foot.) The average price starts at $35/foot square (~250 Euros per meter squared) though $15 can be found for simple frames, plus material costs. Variables are dependant on wood species, frame complexity, methods used, and region respectfully of course, with some places higher or lower than others.

As for having to "know what you are doing," that is dependant on the individual trying to do it, the advice they follow, and from whom they take the advice. I have seen 6 students in the age range of 14 to 17 build a simple "A frame" timber frame span bridge in 7 days. It was a simple design for foot traffic that had to span ~20 feet (6 m.) They made the material in one case from round log, to hand hewn cant, to jointed timbers with simple hand tools. I have seen 3 students with wood provided do the same in 3 days with similar design. So for the sake of the original poster Jerry...lets not make this too daunting a task. A challenge yes, without a doubt (depending on design) but not as challenging as you would present it as being.

Regards,

j

@Jay:
I did a half year internship with an engineering company as part of my Master program. There we calculated building projects as you describe it: This type of wall does cost x per m2 and this type of roof does cost y per m2 and joinery including work cost z per m3 etc.
But all the small building companies around here are calculating by material and man hour.
Of course you can have a fixed price offer. But in this case they usually hedge their bets and you end up paying more.
During the last 3 years a had a barn roof exchanged and two single pitch roof halls built and all bidders calculated in material and working hours.
I have picked out the invoice for the last one: They accounted 43,50 Euro/h (net, you have to add 19% VAT) for the forman and 42 Euro/h for the journeyman.
This includes all the hand tools they use, insurance, etc. Big machinery like an excavator is accounted separately.
This approach is absolutely common around here.

As an expert, can you give us a rough number how much such a roofed wooden bridge (28’ span length, 8’ wide, 5000 pound live load) would cost (including material and fundaments) in your area, if all the work is done by a contractor?

Hi Manfred, et al,

I will try and cover some of your points...

But all the small building companies around here are calculating by material and man hour. Of course you can have a fixed price offer. But in this case they usually hedge their bets and you end up paying more.

Thank you for validating what I shared about professionals and their pricing modalities by way of set matrix. This has been the way of it around the globe for millenia, and not until the"industrial revolution" practice of hiring of "unskilled labor" did we see the spread from Europe and North America the deficient and inferior habit of "time and materials" pricing modalities. As you reflected, many small companies do this, not only in Europe, but here as well. I would suggest that these are not companies to contract with...whether small or large, as it is an indication of not having a real secure grip on all the aspects of the work they put themselves out for contract to do. I also agree that many over inflate a price if you are able to get them to a set price matrix, which too is a poor habit for the consumer to endure. "Buyer beware," is something that any good consumer must keep in mind, even when hiring for architectural or engineer work.

During the last 3 years a had a barn roof exchanged and two single pitch roof halls built and all bidders calculated in material and working hours.

I am sorry you could not find any skill craftspeople to do contracting work for a set matrix, that is unfortunate. I have met several German Timberwrights (Fachwerk Schreiner?) that work by a set matrix on most projects, so it is regrettable that you could not find any other contractors to do the work this way. I also agree that it is common for many to do so, yet it is just as common to find better companies, contractors, and skilled artisans to work by a set matrix...if you demand it.

As an expert, can you give us a rough number how much such a roofed wooden bridge (28’ span length, 8’ wide, 5000 pound live load) would cost (including material and fundaments) in your area, if all the work is done by a contractor?

That is a far questions, and to make it of some benefit for Jerry, I will give a "rough estimate" for Southeast Michigan. If Jerry is still reading the thread, he can confirm or adjust these numbers accordingly.

Green Rough Lumber for his region will cost about $0.40 to $0.65 per board foot depending on grade and species.

The simple timber frame will cost between $25 and $45 per square foot of bridge. This is most likely to be a simple "king" or "queen" post design with two trusses on either side of a joist deck assembly, though there are several applicable designs for such a simple span.

The roof and enclosure will either be separate or part of the package dependant on design and Bridgewright doing the work. Good roofers charge between $200 to $400 per square (100 square feet) including materials. Siding and bridge deck cost for installation labor between $3 to $5 per square foot with the owner or GC providing materials.

The the volume of abutments (foundation) will be dependant on soil types. So you are most likely looking at between $100 and $200 dollars for either gabion or formed concrete work per cubic yard installed.

Not being a "public" and only part time agricultural/forestry bridge a PE is not warranted (but recommend) in this case. This fee would cost between $2000 and $6000 dollars dependant of PE hired. I have one I have known and worked with for over 20 years that would be in the low range of this amount and is a founding member of the Timber Framers Guild.

Without inspecting the specific sight, dialing in a more solid cost amount would be difficult (and misleading on my part to be more specific) yet this can leave Jerry with a good idea of cost should he choose to contract for work outside of himself. Again I stress, that this is a challenging project, but not outside the scope of most "industrious individuals" whether he builds a simple timber frame truss assembly or simply "hardens" the banks - stream bead with gabion and gravel. The cost could swing wildly dependant of his involvement and the contractor(s) he would choose to hire.


Regards,

j

They are called “Zimmermann” here.
A “Schreiner” is a woodworker specialized on smaller things like furniture, doors, windows etc.
And I sure did not want to express they are less qualified. It simple is a different approach for the same target. Not worse, not better, just different.
Before you can call yourself a Zimmermann here, you have to go through a 3 year formal apprenticeship. It starts with a year of full time school for theory and basic practical education, followed by two years of working with a company under direction of a qualified master and in between some more weeks of school for further theory.
After finishing your apprenticeship and two years practice as a journeyman you can take part in a master course that takes one more year fulltime.
Until 2004 only masters had been allowed to start their own company. Than the law was modified due to EU regulations. Now journeymen with at least 6 years of experience (at least 4 years in leading position) are also allowed to start a business.
As far as I know, you do not have any formal qualification system comparable to this?

The bridge you are talking about is a construction like this,



just bigger, and with a roof like this



on top, to protect the wooden construction against moisture?

What is PE? The statcis calculation and building plans? You need these here for building permission.

So we have 28 x 8 x 32.5$ = 7280 $ for the frame.
For the roof let us say 30 x 10 / 100 * 300 $ = 900 $ (Sounds really cheap to me. Bitumen shingles?)
I guess the platform for the shingles is not included?
So I add 300 ft2 of boards for the roof.
220 ft2 of boads for the deck.
450 ft2 of boards for the siding.
If a 5’ board costs 0,525 $ per foot that is
(300+220+450) x (12/5 x 0.525 $ for material + 4$ for work) = 5100 $
For the fundations 2 x 3 yd x 1 yd x 1,5 yd x 200 $ /yd3 = 1800 $
Plus 4000 $ PE (not sure what this is)
= 19080 $ = 13700 Euro
Not that far from what I estimated?

Hi Manfred,

Thank you for the "German" translation. Over the years I have had several conversations on this subject of translating "Timberwright" into modern German, from the "Dutch" old order Amish speak, and some of my "Swiss" and other Eastern European contacts and their understanding. "Zimmermann" would seem to mean both 'Carpenter' and/or 'Timberwright.' Do you know any other translation for Timberwright or Timber Framer? I would love to know you understanding of this.

As far as I know, you do not have any formal qualification system comparable to this?

You are most correct, as both Germany, and France have much better appreciation of these crafts than does most of North America in general. Anyone that has traveled or read about the German Timber-Frame Road (German: Deutsche Fachwerkstraße) would recognize that. Most places with an ancient wood or timber framing culture like Japan Korea, China, and much of Europe , has a superior understanding and training system in many ways. We do have a Timber Framers Guild, and many fine Timberwrights, but the experience levels are vastly divergent amoug the members, and not as standardized as you would find in other timber framing cultures.

The Bridge in the first photo is a perfect example. Thanks for posting that so Jerry could see it. Such a bridge is rather easy to design, joint and assemble with a little guidance.

What is PE? The statistics calculation and building plans? You need these here for building permission.

PE stands for "Professional Engineer" and you understood the meaning of it perfectly. For a "private bridge" Jerry may not need a PE stamp and/or only limited approval from authorities. It is different from region to region, state to state. Europe tends to be more restrictive that way any many portions of it.

We may have lost some in the pricing translation...

From Jerry's photo of the potential crossing spot, I was thinking of a 10 foot wide bridge 24 feet long which would give a 240 square foot multiplier. This would equate to $6000 @ $25/ft2 to $10,800 @ $45/ft2.

Lumber for siding, decking, and sheathing @ $0.40 to $0.60 @ approximately 3500 board feet would cost $1400 to $2100.

The roof with a 12/12 pitch and metal standing seem would be about 5 roof squares costing approximately $1000 to $2500. This price is average for both standing seam metal or Cedar Shingle.

With approximately 1200 ft 2 of siding and decking to lay-hang at $3 to $5 /ft2 that labor price would be $3600 to $6000, but can be brought down depending on method use, hardware attachment choice and skill level of applicant. Here hourly unskilled labor (well supervised) could lower the cost.

I could (would not go into foundation) approximate cost without seeing the location first.

As for our pricing being about the same, that was never really the issue (sorry if I seemed to make it seem so.) I had concerns that Jerry and other readers maybe intimidated by such a project or though "hourly wage" (time and material? was the only way to get the work contracted. Additionally what Jerry could do as choices since most of this work he could do himself, thereby saving quite a bit, was also a consideration I wanted him to focus on. I would also suggest that a less experienced Timberwright from his region could/would be willing to do the project for a lower fee, just to gain experience, yet still a satisfactory job of it all with Jerry's help. Much to consider...harden stream bed and banks, or build a nice little covered bridge.

Regards,

j

Hey,

I read through all the ideas just to make sure that I was not repeating any. I spent years traveling in a 40 ft travel trailer that had a load bearing weight of around 10,000 lbs on the trailer frame. If you found an old travel trailer and placed a concrete slab on each side to support it. For as little as you cross it it should not be an issue. I have driven over logs tied together on a section of my old property that I put down to cross a boggy area. If you don't want to put permanent concrete down or a permanent structure leave the wheels on the trailer and place a large cable in your concrete slab so you can hook on with your tractor and move it. This option would not stand up to heavy traffic but occasional crossing would work fine. Old travel trailers are fairly cheap. Check with a dealer they sometimes take in trade in and then just toss them in a yard. They are usually happy to unload them. You can also try Craig's list. Another option is to use the steel beams that are used to support load bearing walls in houses. Use 2 of them for a frame and then metal studs as cross beams spaced apart to form a grid you can drive over. if you are good at welding you could attach an axle and wheels like a boat trailer, with a tow bar you could have a temporary bridge and just remove it when you aren't using it. Hey my boat trailer that I had for my pontoon boat carried the weight of my boat which also was about 10,000 lbs. That could be another option you could weld a metal grid to that or make wood slates to drive over.. To place your temporary bridge you could use a winch on the opposite shore to winch it in place. That way you can get around the powers to be since you are not building a permanent structure and it would cause minimal damage to the area. The advantage would be that you could easily set it up at multiple location depending on where you are working. You could throw up a pole barn to house your bridge or just cover in a tarp. I hope this helps.

@Jay:
The Japanese seem to be a class of their own, taking the quality of joinery a good furniture Schreiner could do to the scale of a Zimmermann´s work. I can hardly imagine anyone can pay for this quality of work in a high wage country like Japan nowadays. Guess most of the building work there is done by more western standards now.

Zimmermann (for the big stuff) and Schreiner (for the small woodworks) are the two most common occupations. In both you can get a Master.
A synonym for Schreiner is Tischler (table maker).
I do not know any synonym for Zimmermann, except of Zimmerer which is the same thing, depending on the local dialect.
There are some more specialized occupations that have different names.
A Drechsler is a wood turner.
A Stellmacher is wheelwright. Nowadays they most of them are building special vehicles, working with all kinds of material.
A Böttcher (cooper?) makes barrels etc.
A Holzinstrumentenbauer (wooden instrument make) builds violins, guitars etc.

Regarding further education there is an occupation called Holztechniker (wood engineer). This is a 2 year qualification you can do alternatively to a master course. As entry requirement you need a Realschul-Abschluss (~junior high exam) plus an apprenticeship in one of the above occupations plus at least 1 year of experience. Holztechniker can specialize for example in industrial wood processing like chipboard production or large scale furniture production or they are working as structural draftsman and designing engineers.

And you can get a university degree in woodworking. There are different areas of expertise offering bachelor and master degrees. A German specialty is the Diplomingenieur degree. This was the common name for university degrees in engineering before the Bachelor and Master degrees were introduced here, too. Many universities still offer these grades in combination with the new ones.
There used to be the Diplomingenieur (FH) who did a 4 year training at an university of applied sciences (Fachhochschule) and the Diplomingenier (without the FH added) who did 5 years at a university with more theoretic focus.

If I apply the same logic one would use when trying to go off grid with photo-voltaic's (reduce your load as much as possible) I could use a smaller (lighter) tractor which would reduce my bridge needs. I do happen to have another tractor which weighs in around 2,500. Also I could get by with 8' wide bridge as the wheel base of my tractor is a little less than 6'. The other thing to consider is to look for an area where the stream narrows to bring the span length down.

Is there any "tipping point" for sizes that save me money? I believe 8' long material is more common than 10' so would going with an 8' wider bridge save me more than the simple 20% less surface area?

I LOVE the look of an old fashion covered bridge, but justifying the expense even if I built it my self is going to be tough.

I do know where there is a place that scraps out house trailers so I'm going to go by there and see what a frame would cost.

Hello All,

I really would like to take the time to thank everyone for sharing their ideas and concepts. Jerry has provided us with a great exchange!


Hi Manfred,

I really would like to give a special thanks to you for a wonderful discourse and would like to stay in touch. Your background and knowledge is grand, and should I get back to Germany, I would love to contact, or perhaps reference students-colleagues to you for your opinion on certain matters. Please PM me.

The Japanese seem to be a class of their own...

Of this there is no debate. With the oldest standing timber frame in continuous use and the oldest sustain wood and timber framing culture in the world still going strong (with the Swiss a near second for continuous use and rustic simplicity.) I have learned more from studying these modalities (Chinese, Korean, and Japanese) than any other timber framing forms. They are the pinnacle of the craft in so many ways.

Thank you very much for the translations. Germany and France are two countries that still has maintained a high regard and professional status for wood working in the world. Others could do so much better to follow this lead.

I can hardly imagine anyone can pay for this quality of work in a high wage country like Japan nowadays. Guess most of the building work there is done by more western standards now.

There was a time just after WWII that things became very bleak in Japan arts and crafts. Now there is a strong resurgent among many young folk to learn traditional crafts (though not as strong as many would like to see.) Cities with its modern forms of architecture is the primary focus for major metropolitan areas like Tokyo, yet there are many working Diaku - 大工 (Carpenters) of several styles that ply their trades as well. Many new homes each year area mix of traditional and modern. Some are even taking old homes (400 years plus) and converting them to contemporary dwellings. I correspond with several of them and I currently have a 400 year old Minka Farm house - 民家 I am looking to export that one of my Japanese collaborators found for us. The interest in traditional wood architecture and building methods is growing each year in Japan, as well as in China and Korea).

Common domestic home outside Tokyo by a contact Diaku of mine.

Close up of front enterance.

Close up of mail box.

View from living room. Note hand tooling on major timbers are all done with a Chouna - 釿 (type of hand adze.) Walls inside and out are often plastered with a traditional cobb or lime plaster of there own making depending on prefecture (region.) His family has been active Diaku for over 100 generations (~1000 years) with a recent pasting of his Grandfather at 87.

Hello Becky,

You suggestion falls in line with some of the others that suggest salvaging some form or "metal scaffold" frame from a trailer or the related. The issue with this is they are designed for "distributed loads" not the often dyanmic "point loads" that bridges must endure. This alone will often negate them from such use as bridges, and to this the rapid degradation do to oxidation and you loose all your work of a bridge really quick. I have seen this time and again with folks getting them just for foot bridges, doing all the work (even painting them which traps the rusting rot) and only to lose the bridge in a few years. Metal and concrete bridges are not as enduring as folks often think, and seldom do "reclaimed trailers" work for more than foot bridges.

Hi Jerry,

Glad to see your still following along. Hope you find some of this of interest of use to you.

Hmmmm...tipping point, well from 8' to 12' yes, but not to much from 8' to 10'. However, if you can make do servicing the other side and taking logs or firewood out with an 8' wide bridge then do so, as this will be less work for you to build. The funny part about this type of "king post" bridge, as once you have studied them, made a few plan and elevation drawings, you begin to see the simplicity of them. After building one, you begin to see many other possibilities that would have otherwise seemed daunting, yet really are not. The first time I saw students in their teens build one, I was very taken back and what hand power can accomplish, soon followed my time with the Amish Barnwrights.

Keep the questions coming, with whatever you choose to do.

Regards,

j

@Jay:
A really beautiful piece of work your Japanese friend created there!
I will PM you my address data. I am always glad to help with information.

Sorry for going off topic:
You have already mentioned the Fachwerkhaus Tradition.
But there are other traditional techniques, which might be interesting for you, too.

For example Bundwerk:
http://www.maier-holzbau.com/referenzen/bundwerk/
This type of woodwork has its origin in the northeastern alpine region.

Or different block home variations:

Here a company that is building block homes from used wood in the traditional style of the Bavarian alpine upland:
http://www.zimmerei-koller.at/altholzbau.php

Have a look at this little duck house:

I was told their junior director made it as the practical part of his Master course exam.

In my region almost all really old houses are block homes, too. Only rich people could afford to build of stone here. But you cannot see the wood, as the houses are covered with slate from the outside to protect them against the moist climate, and with lime plaster from the inside to make them windproof and brighter.
A picture of such a traditional farm house from my area:


Or the Umgebindehaus. The name refers to the arched construction with the beams on the outside at the first floor. The upper floor is often made of Fachwerk.
These houses have their origin in Saxony and parts of Thuringia.

Hm…
I cannot find the private massage function?
Could you give me a hint?

Manfred,
Click on Jays name in one of his posts. Another page will pop up. In the bottom left corner you will see a Purple moosage line with a small graphic. Click on that. Another page will pop up where you can write to Jay.

Thank you! PM is on its way.


Two examples of German wood builders at their best:

Wooden roof. Size 16.000 m2. Built for the Expo 2000 in Hannover by Herzog & Partner, Munich:




Plaza de la Encarnacion, Sevilla, Spain
Built by J.MAYER.H, Berlin

I heard a story once (so it must be true) about a guy that build a bridge by getting a big stack of pressure treated wood (2x4's maybe) and basically built his own laminated arch's by bending each layer and glued and screwed it together. These arches went into a poured concrete thing that held them up but also prevented them from spreading.

The two culture with some of the oldest and also most modern "wood architecture," that keeps the rest of the world playing "catchup" is Germany and Japan. Thank you Manfred for sharing those photos...very inspiring!

Regards,

j

P.S. Yes Jerry, I have seen several "home made" laminar beams as you described...time consuming, but very doable, even with smaller pieces-sections of wood.

Jay C. I'm now considering going much lighter for load and getting something like the DR PowerWagon to get firewood out of the area behing the creek. This would reduce the load down to something like 1,000 lbs. I've also decided there are some trees that need to go. I believe they are cottenwood but are in the 18"-24" diameter. If I dropped three of them across the creek and got them close together what do you think? I assume they would last longer if I de-bark them and rais them off the ground.

Thanks
Jerry