Currently I have designed a back yard that consists of a pool with flagstone coping and exposed aggregate concrete surrounding the coping for the remainder of the decking. I also have a separate area that will house a large outdoor fireplace. This masonry fireplace will be stucco and have flagstone benches, along with an exposed aggregate concrete decking. The masonry BBQ will also have a stucco finish with a flagstone surface. The BBQ area is a different area from the pool and Fireplace, but will still have a large aggregate patio that steps down to the pool. I also have many different areas within the yard that have stucco benches with flagstone surfaces. My intention was also to have some flagstone pavers meandering through the landscape and connecting to a lawn area, along with another access point to the pool. I will be performing all of the work with exception to the pool and aggregate decking.
I live in Arizona and all of this will be desert landscape with cacti, palo verde trees, succulents, natural flowers, etc.
Now with that said, and hopefully you have some form of a picture in your mind regarding the materials used, I have one area that I am still trying to work out. In between the pool and the Fireplace area, I will have a river which will be cut into the ground and will move runoff when it rains. The creek will likely be about 3 ft, so I am estimating the bridge will be approximately 5 ft or 6ft across, and a max of 36” wide.
Searching online, I find those wooden bridges which would seem quite easy to build, however I do not feel the look would go with my current plan and expect it would stand out like a sore thumb. My though was to match the flagstone and or aggregate and stucco. Though I feel this has potential to really add a bit of character to the yard, I do not want it to stand out, or look massive, and plan on softening the edges by adding some vegetation.
I have contemplated a concrete formed bridge that I could make. The form I believe would be easy enough, however I am stuck on the design. I like the arched design of the wood, but am unsure that that would look good, though expect it would provide a benefit of strength considering it will be quite heavy, especially if I put a couple 2 ft masonry/stucco walls on each side. I have contemplated an aggregate surface, and a 16” or 24” masonry/stucco wall on each side spanning the distance. In theory, to save weight, I could even frame these walls using 2x6 material, and stucco the outside just like homes in the area are made, but would only contemplate that if weight truly is an issue and prefer masonry. I also thought about doing the same exact configuration, with the only difference being rather than having an aggregate surface, I would lay flagstone matching the informal paths I have.
Though I have searched online for bridges, I have found absolutely nothing on small
concrete bridges. My questions are as follows…
1- Structure: Regardless of if the bridge has a small arch or is flat, my thought was to build in a footer on each end of the bridge, maybe 8 additional inches, spanning the width of the bridge an extending an additional 12” or so. I have also contemplated a standard 4” thickness for the platform and potentially adding 2 to 4” on the sides, where the masonry will be above forming the walls. Obviously there will be plenty of rebar. Do you see any issues with this logic, or a better way?
2- Structure: Keeping in mind that the bridge will have nothing supporting it in the center and that it will span likely 4’ before it makes contact to the footers, is a 4” surface adequate? Again, I assume that arched will add considerable strength.
3- Forming: It is clear that if I have an arch, farming the arch could pose an issue even though it would be quite gentle, maybe at a 6” grade between center and ege. Will I need to mix the concrete a bit drier to hold the form on top without spilling out, or will that compromise the strength of the cement?
4- Comments on strengthening the cement? As stated, I will have considerable rebar, but should I put some form of additive into the mix?
5- Pictures or links to any websites with a landscape bridge made of concrete would be great as regardless of design, I am sure it will assist me in my plan. I do not want this to look bad, or just wrong.
Any other comments would be great including design ideas. I believe this can work and would look great if proportional and done properly. Originally I had planned to just drape a piece of flagstone across the stream, however believe it will not look good at all and just feel like it will always look a bit off or like an afterthought where it was just tossed there to resolve an issue of access. I see this type of thing often in quick/cheap do it yourself projects.
Hopefully you made it through this book. Any help would be incredible!