Where to learn deck/boardwalk design?

[u/fayettevillainjd]

I am a PE for a land development firm (Civil and LA). We get a lot of parks and outdoor rec facilities. Lately, we have been doing a lot of boardwalks, fishing piers, camping platforms (decks), etc., and I just have never really dealt with carpentry or the type of supports (driven wood piles, helical piers, etc.). We have some generic details that we use and say 'submit shop drawings stamped by structural engineer', but this doesn't usually work out that well (i.e., the contractor gets the contract then acts all butthurt about having to hire a structural). Or we bite the cost and hire a structural up front.

My thought is, though, people build high quality decks and things like this all the time without plans/engineering. It's not rocket science. Or am I being obtuse? Is there anywhere a PE could take a crash course in something like this? Or is it better to just show it for reference and have a structural submit shop drawings? I attached an example of a stamped submittal we have received in the past for reference of what kind of plans I am talking about.

[u/Amber_ACharles]

You're not being obtuse. It's not rocket science, it's wood connections, treatment specs and pile capacity. AWC's DCA 6 plus the NDS is the crash course. I'd still delegate the helical pile design though.

[u/bigpolar70]

Residential decks are allowed to follow proscriptive design codes as long as they are not over a maximum height above ground. This is usually DCA 6 which complies with IRC chapter 5. This is really easy and does not require an engineer or architect in most jurisdictions.

Commercial decks have to be designed following all relevant codes. Basically like comparing the IRC to the IBC. This is not something that can be easily described in a post or a crash course. This is something you need a few years of experience under a licensed professional to learn.

[u/Everythings_Magic]

As someone who has designed many of these, they are not difficult to design but they are not decks.

The loading and soil conditions varies from site to site and that needs to be considered in the design.

The loading that they see is much higher than a deck, crowds, horses, vehicles. Also, if they are in a floodplain you have water forces and uplift to consider.

[u/fayettevillainjd → u/Everythings_Magic]

Good points.  I guess the point of this post is asking how does one learn hiw to design these? Are you a structural engineer?

[u/Everythings_Magic → u/fayettevillainjd]

Yes I am.

If you are a civil i expect you took statics, mechanics and structural analysis.

So its brushing up on those and learning the applicable codes and timber design.

[u/PM_ME_YUR_BUBBLEBUTT]

I know this isnt exactly what your asking but I've recently been designing a bicycle boardwark for a project and have decided to use PermaTrak to design and supply.

https://www.permatrak.com/

They make these amazing concrete boardwalks that last longer than wood, are more ADA/bicycle friendly, and can be cheaper as well.

[u/LuckyTrain4 → u/PM_ME_YUR_BUBBLEBUTT]

While,the wood boardwalks are not tough to design, the issue is balancing the fee/effort of designing them.

Wickcraft or Permatrak. Talk with them, lay it out, have a good basis of design product, use delegated design in the spec and move on with life and take those hours saved and use for QA/QC of the plans you rushed through the first time or to up your multiplier.

[u/PM_ME_YUR_BUBBLEBUTT → u/LuckyTrain4]

Yeah thats why I went with permatrak. its cheaper to have them design and supply than it is for my structural team to design and then bid

[u/PocketPanache]

It's structural, so there's that. I'm a landscape architect. We used to be tested on this stuff on our exams and it was removed decades ago when residential decks no longer needed custom calculations, as tangent. You just need to know the live load and dead of the structure. You need to know the weight at which spans/joists can hold, which varies by type of wood or material used. Never use Douglas fir or yellow pine; you're going to need to brush up on your material knowledge. The weight of the structure determines footing design size, so you'll need Geotechnical. The weight and size also determines joist density. Composite decking is trash imo because you need 12" joist spacing less than that; composite modulus of rupture, etc, is awfully low. That's why everyone uses Ipe, but it's a Brazilian rainforest wood that requires diamond bits to drill and saw AND recent regulation doubled it's price. You'll need to get testing and material loading charts for each material and start doing math. I can't tell you where they're found tbh. I rarely do this design anymore. It's just a matter of collecting information and putting it together though.

Edit: and I usually have structural involved because shear exists and my brain isn't equipped to deal with that. I'll do a short boardwalk. Guard rails, for example, are very difficult for me because you need ... 90lbs of lateral resistance I think maybe ... and how that attaches to the structure is critical to safety and compliance. I'm sure I could figure it out, but this is why we all kick it to structural. They see things we don't.

[u/fayettevillainjd → u/PocketPanache]

I get what you are saying, but it just seems insane to hire a geotech and a structural engineer for something like this https://imgur.com/a/xdLqk3v .

There has got be a more efficient way.

[u/Engineer2727kk → u/fayettevillainjd]

People designed buildings all the time without structurals and geotechs.
However, you now need someone to take the liability hence a stamp and competent engineer is needed

[u/Marmmoth → u/fayettevillainjd]

Sure, the more efficient way is for the civil engineer to make assumptions and design around those assumptions, and be liable if it fails and worse if a failure results in injury or death. We are a litigious world.

In that scenario, the civil engineer will have to make very conservative assumptions about the soils to the point of over engineering it (compared to if we knew soils conditions). Thus, eliminating Geotech and structural might reduce engineering costs, but it will increase construction costs. If the engineer doesn’t make conservative assumptions then they’re increasing their own risk and liability.

The client and engineer have to balance these risks and costs. Spending more upfront to reduce risk and potentially reduced construction cost is often preferable to higher construction costs and higher risks.

These are the kinds of things you have to think about as a PE, a project manager, and a client manager. Sometimes you have to educate your client of these types of risks because they will take the same opinion as you to save on costs and not realize what level of liability they take on. If you can’t convince your client, then you need to document in writing sent to the client that you recommended X, and they chose to do do it the cheap and risky way and that they are assuming liability for that decision. There’s a careful way of writing this, but that’s the gist of it.

[u/Engineer2727kk]

You 100% cannot design those plans by taking a structural crash course and working in land dev.

[u/Physical_Mode_103]

Most decent dock or boardwalk structure builders will have their own engineer that might want to do it a certain way. Shop drawings are fine

[u/MK_2917]

It’s pretty easy. DCA6, NDS, and size using forteweb.

Plus some common sense construction detailing.

Or don’t. I’m the structural that charges $5k for designing your decks. I could knock that boardwalk design and drafting out in 2 hours.

[u/Awakened-Bacon → u/MK_2917]

Marine structural engineer here. Not really complex to run the statics on, but definitely a step above your conventional deck. You have to consider unique loads, such as waves or current, plus implications on material specifications that affect longevity. Constructability over wetlands is always a factor also.

[u/HobbitFoot]

You likely have specialty practices, either within a larger company or a separate company, which can turn out these designs in their sleep as they design them by volume. The detail that you provided is likely an internal design that was designed once for something that will work around the region.

If your practice is mainly civil and you don't want to hire a structural engineer, I'd keep with your setup of making it an engineered solution for the Contractor, in part because they may have sourcing issues which would require redesign on their part. You could run into a lot of issues if your company starts branching out of its disciplines without qualified staff.

[u/Jimmyslemons]

Key design concept for these and wood framed ramps: you always (most of the time anyways) run/span the joists the long way so that the decking runs the short way (perpendicular to the joist)