what type of wood should i use for platform in swamp area 4

[delagina]

This platform will be in swamp area. Should I use PT wood to prevent wood decay?
I have ZERO wood design experience.
This is very simple on the structural analysis point of view and I can easily do that.

I'm looking for guidance for the size and type wood column, beam and floor and the connection that would be "practical/common" to use in this case. I can size the wood thru analysis but what size should I start.

 

[jayrod12]

What's the plan for foundation? Driven wood piles?

I would likely be specifying PWF material which provides better preservation than P.T. material.

 

[delagina]

I think it's a driven wood pile that will also act as a column or platform support. Can you be more specific with pwf. Pwf is only for the piles? The beams and flooring would be what? Also what connection would you recommend.

I'm googling pwf, that's a good start for me thanks. This looks very simple but I have no wood design exp. I need to know the practical sizes and type of wood to use. I have a wood design book but it's more about analysis.

 

[jayrod12]

The wood piles will have their own preservative rating. I'm not familiar enough with them to discuss the specifics.

The rest of the platform wood I would be using PWF material (Preserved Wood Foundation). Without dimensions and proposed loads I doubt anyone here would even take a stab at rough sizing. Although that existing platform appears to be framed with some pretty hefty timber.

 

[RockEngineer]

Here is some basic info on AWPA use categories and types of preservatives currently approved for use in USA.

http://preservedwood.org/TheStory/PreservativeUseCategories.aspx

 

[delagina]

If I use 8"x8"xlength' Southern Yellow Pine, Treated, for the timber pile,

would the geotech soil report give me the capacity of the pile?

Also I plan to use SYP, treated lumber/timber for all joist, deck, pile or you recommend another type of wood?

for the flooring, I plant on using 1"x6" or you recommend 2"x6"?

 

[jayrod12]

1x6 decking works great for residential. I would not use it for commercial purposes. 2x6 at a minimum. Timber piles have different treatment requirements than your standard home depot treated 8x8. Please do some more research into timber piling.

Use whatever lumber you can get around there with the treatment you want. Where I am all the treated lumber (or most) is SPF. But so is all of the other lumber. We don't use SYP for anything because it's not readily available.

 

[boo1]

Consider treating the structure for a marine environment
Piles Creosote or CCA •2.5 pcf treatment
Structure CCA •2.5 pcf
Fasteners 316 or galvanized hardware that meets ASTM A 153 or better standards

Check environmental requirements

http://www.woodpreservers.com/faq.php

 

[delagina]

I think I got this figured out. I will be using Simpson strong-tie for the connections, is this ok or I should use something else?

Also nobody answered yet, if this is driven wood piles then it's geotech scope to give me the wood pile capacity, right?

 

[Leftwow]

Treated Yellow Pine sha!

 

[andriver]

A geotech tells you the soil properties, not the structural capacities. You are on your own on this one.

 

[SlideRuleEra]

delagina - The platform in the photos is designed for heavy industrial use... see the marked up photo for the clues:

Note the closely spaced, heavy stringers.
Decking that appears to be a nominal 4" thick.
Pile bracing.

Get the geotech working on this project first thing. The piles are likely friction (not end bearing) with significant embedment length in the poor soils often present in swampy areas. Based on the apparent size of the decking, stringers, and probable long length, nominal 8" piles are probably undersized.

Establish a realistic live load rating, if the client can't provide one, reverse engineer the existing platform superstructure (that won't be hard) to come up with one. IMHO, it probably in the 150 lb/ft[sup]2[/sup] (or higher) class (no live load reduction).

Simpson does not offer hardware suitable for this type construction. Plan on heavy bolted connections.

I agree with boo1 on the 2.5 pcf CCA treatment and hot dip galvanized fasteners. If creosote is used, specify 12 pcf retention.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[LittleInch]

I built a structure in a shallow marine environment a few years ago for a water pump and filter for an oil field development using "green" i.e. fresh cut Oak piles, 12" square, hammered in until refusal and then just chain sawed them off. We were going to use hardwood, but getting the "sustainability" certificate proved too difficult.

some simple googling gives a few good results though

http://www.theconstructioncivil.org/timber-piles/

http://www.forestry.gov.uk/pdf/Timb...Timber-piles-and-foundations_DG479-217144.pdf

http://www.woodworks.org/wp-content/uploads/Rollins-Timber-Piling.pdf

https://www.fema.gov/media-library-data/20130726-1538-20490-9880/fema499_3_2.pdf

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[JoshPlumSE]

I'm not really a "wood guy", so I can't offer any sage advice of my own.

I am surprised that no one specifically recommended some type of engineered wood products. I've been following this thread because I was hoping someone would. Then I could look them up and learn some more about them. Instead, I will ask the question, why not?

There are engineered wood products that combine plastics and wood to make strong, dense products. I would have thought would be less prone to moisture problems than traditional wood. Am I mistaken? Or, is there a reason why these products would not be good for an application such as this?

 

[delagina]

Why can't I use Simpson strong-tie hot-dipped galvanized connection?
I think the loadings here are very minimal. This is just a simple maintenance platform.

I think the existing wood platform (picture) was overdesigned.

 

[jayrod12]

"Most" of the engineered wood products I've seen actually have disclaimers about not being used in exterior type exposures. There are some Glu-lam beams that receive treatment quite well but none of the LSL, PSL and LVL stuff I've seen allows for this level of exposure to the elements.

 

[SlideRuleEra]

JoshPlum - Agree with jayrod12. Another reason that comes to mind is that engineered wood is optimized to make the best use material for specific loading conditions. For industrial applications loading is less predictable. The bulky size an resiliency of sawn lumber is actually an advantage. Say one the heavy flanged valves (perhaps a few hundred pounds) is "plopped" down during maintenance, putting a point, impact load on the decking. Sawn lumber will deflect, without breaking, thereby sharing the load with adjacent members. Another situation could be a workboat slamming into the platform during docking.

delagina - You know more about the client's needs than we do... but you did ask the questions, and they are good ones. The cost of the substructure for this type platform will be substantial (driven piling in a swamp). Would be a shame to put a "cheap" superstructure on top of it. Besides, this is obviously an industrial application - not in the same league with Simpson's residential and commercial construction focus.

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[boo1]

no need for Engineered wood.
Round piles with 4x (SYP if east coast) decking/beams with heavy galv connections.
Low risk, available and cheap

 

[BUGGAR]

We use a lot of plastic lumber for the Navy but primarily for blocking, curbing, and semi-structural stuff like that. It's too flexible compared with wood and the plastic with reinforcing is not cost competitive with wood.

 

[delagina]

just want to confirm. timber pile capacity should be on geotech report, right? I don't think I can calculate the skin friction of the timber pile if it's not in the report.