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1) GROUNDWORKS TO STEEL REINFORCEMENT: Method Statement
2) CONSTRUCTION SHUTTERING: Method Statement
3) STEEL RE-INFORCEMENT: Method Statement
4) CONCRETING WORKS: Method Statement
5) QUALITY MANAGEMENT: Systems in place
THE ABOVE INCLUDE SUPPORTING IMAGES
When constructing our Bespoke Concrete Skateparks there is a general protocol to follow once we are on site, have completed all risk assessments, method statements, permit to dig etc.
This would be: 1: Set out site to dimensions 2: Strip Site 3: Dig in all drainage channels 4: Mark all Excavations 5: Compact/Teram sub base 6: Begin Stone work The depth of an excavation depends a number of factors, is the park above ground? What are the results of the Site Investigation? Soil types? CBR rating? Water table? Etc. When we have reached the desired level for excavation (using machine with operator, dumper with operator \& banks men) to adequate subsoil level we then begin to compact the ground with a 'roller' (size to fit spec), we then lay a layer of Teram 1000 mg this will stop any fines washing out of the structural fill over time. We would then lay and compact the specified granular fill to specification compaction, then this has more Teram laid on it \& we begin to build up the stone levels by laying 250 mm layers that are compacted with roller every 250 mm \& have Teram layers every 3 layers of 250 mm so the Teram layers are 750 mm apart in the fill, this greatly increases structural integrity and allows us better manipulation of the stone for our purposes.
When all desired levels are reached \& checked by engineer with a laser level to ensure compliance with design drawings we then begin installing steel coping and any raised area shuttering, when this is complete we then install all relevant reinforcement to tie between platform slabs \& transition or banked faces. After this is done we would then start to trim \& excavate all sculpted stonework to accommodate transition faces.
For any 'tombstone' or 'extension' areas these would be built upon the stone with a C40 concrete foundation with 'L' bar reinforcement to tie into blinding concrete placed above for complete structural integrity. With this method we can install reinforcing 'starter bars' which protrude the blinding surface \& allow us to tie into any reinforcing steel required by tombstone/extension. When this is complete the final concrete surface (C50-60) is poured onto this.
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For ourselves we have seen many methods of skatepark construction over the years, timber shutter, steel frame, modular concrete, brick shuttering etc. Although what we (and many of our foreign peers) have found is that timber shuttering works the best, it is more tangible to work with \& it also works well with the concrete when you prepare it well.
All our shuttering work is carried out by highly experienced personnel \& is worked to a tolerance of 2 mm over 10 m , this ensures that accurate installation of shuttering is present and that drainage will work in accordance with the Engineers levels.
All our 'facing' timber shuttering is from milled timber to give a smooth \& blemish free surface of the visible edges after all screeding \& vibrating has taken place, this also ensures that any 'movement joint' will work freely as well.
All shuttering work is held together with screws as opposed to nails, the use of screws, high quality impact drivers and good timber give a solid construction that will hold the concrete placed in it without movement.
The use of screws means that any repair or improvement works can be done to the shuttering without decreasing any of its structural integrity as the screws can be easily drawn out as they are driven in.
Shuttering constructed with screws will not weaken \& loosen as a nailed structure may. The use of screws allows shuttering to be easily taken apart allowing the recycling of timber and giving us a sustainable system to work with.
Any vertically shuttered wall pour would also be reinforced with the use of screwed bar throughout the pour.
The use of Steel Re-inforcing bar \& Steel Mesh sheets in bespoke skatepark construction is very important as it is with any other form of concrete construction, it increases the strength of the concrete, the load it can withstand \& most important it prevents any slab misalignment due to ground movement issue, i.e. Tectonic movement, ground swelling, frost heave etc. Now these forces may only move the slabs a matter of millimetres when issue has subsided and ground has settled but a skatepark slab which has misaligned a matter of 4 B 5 mm can cause a major safety issue as there will be a 'lip' at the bottom of the transition and this can cause users to fall into the transition at speeds of up to 25 mph . This type of accident can be very severe especially with small children.
We recommend using A252 steel fabric mesh in every pour that we do in a skatepark, this will sit equidistant of the stone level \& the surface, so 75 mm from each supported on plastic chairs that are for the purpose. The mesh is also tied with steel wire or sometimes welded to 12 mm re-inforcing 'L' bars that connect raised platform areas with transition face areas, also at the toe of every transition we have 600 mm long 25 mm dia steel dowels placed at 400 mm centres (to correspond with mesh squares) these are tied with steel wire \& connected to the flat bottom mesh.
We also use fibre mesh re-inforcement in our bespoke concrete coping to increase strength \& to combat shrinkage, this works very well. We would not recommend using it in the 'running surface' areas as it will protrude the surface in places encouraging surface wear \& also the wrong fibres used i.e. glass fibre can cause the user severe rashes when falling onto the surface. We understand that it decreases shrinkage cracking but it will not eliminate them \& I would not be confident of it maintaining the same structural integrity as rebar when a 'coping line' crack occurred.
We also are aware of concrete expansion \& contraction due to temperature variations and bear this in mind when constructing our parks. Our concrete knowledge tells us that any expanse of concrete of over 3 m in any direction is at risk of cracking if you do not allow free movement between pours, this is why we think carefully about our pour lines \& have our engineer specify movement joints (not expansion joints, movement only) where required \& eliminate square corners that cracks will form from.
In a skatepark we will generally find one or two minor movement/shrinkage cracks and these can be filled with epoxy resin 6 months after pouring \& settlement has taken place.
All of these methods \& techniques have been accumulated over many years of working with professional skatepark \& swimming pool builders from around the world. Basically a wise use of movement joints \& clever pouring plans will virtually eliminate all potential cracking issues.
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This is information regarding how \& why we apply our bespoke concrete in skateparks. The concrete we use is a very specialist mix designed specifically for use in skateparks, this has been designed from years of experience. We use a P400-P450 cement content mix with a specific blend of soft \& sharp sand with 10 mm aggregates, the cement content in the mix depends on seasonal weather conditions as this affects the rate of curing in the concrete \& this is a very important factor for us to control. We also use hardeners, additives \& plasticisers as required by each stage of the process. Our mix also has a specific amount of air entrainment to combat freeze/thaw degradation. We understand that the quicker the 'early-set' time of the concrete then the stronger that concrete will be, with this we also understand that the slower the time it takes for the surface to dry out/cure then the stronger that this will be also. So we use water. The concrete is designed to give a high compression strength (as required by BS EN14974:2006). It is generally C50-60 \& above when compression tested \& this is above BS requirements but we believe the stronger the better.
The method in which we apply the concrete determines the longevity, smoothness \& surface strength of the concrete, therefore ensuring quality product that will last the test of time. First we apply the concrete to the area required under pressure to ensure adhesion, then it is allowed to slightly set (to ensure strength) before it is shaped by screeding off with wooden formers or by the use of wooden shaping tools. This is then allowed to set a little more before we fill all the low spots and compact the high spots with use of resin tools, then this is all compacted with resin tools before being allowed to set some more (the timing of this is weather specific \& can only be assessed by very experienced personnel, of whom we are). The resin tooling process is applied to all the surface area as many times as required to ensure a flat running surface with no undulations or bumps. When the time is right we then move onto steel trowels to compact the surface even more \& create a very smooth running surface, this will be done 2 or 3 more times at specific intervals (determined by the curing rate of the concrete on that day), this really ensures that we achieve the surface smoothness that we require.
We also fully understand the benefits of using edging tools on our concrete works, this is done in various ways \& for many reasons. The type of edging tools that we use depends on the application of the pour that we are doing i.e. edge of floor slab would have a 10 mm radius edging tool applied to the edge of the pour at various intervals through the concrete curing process, this along with the use of hardening agents ensures a strong edge which is far more resistant to chipping. We also 3 mm edge all pour joins to ensure a long life of the join without chipping and cracking appearing due to minor frost heave.
Now when we are pouring next to metal work i.e. coping, ledge steel etc we use a smaller radius edging tool of 3 mm , this then eliminates any feather edging that is very prone to chipping,
cracking and will therefore be susceptible to frost heave which increases the problem every winter. The use of a micro edger here will allow any moisture which is sitting between the metalwork \& the concrete slab edge to simply freeze \& pop out causing no damage at all to the slab. The same applies to our pour lines between features, we would micro edge them \& would also recommend that this is done between floor slab pours as well but this can be a choice of the client. It is a proven method to greatly alleviate the damage caused by frost heave \& is widely used in Europe \& the Americas for aforementioned reasons. After all this is complete we then apply a water based sealer which allows the surface to cure at a consistent rate \& not to dry out to rapidly which will greatly affect strength.
With this process in certain seasonal conditions we use hessian sheets that have been dampened to cover the concrete surface \& allow a slower more consistent curing of the surface which again increases strength. We then allow the concrete to cure for 2-3 weeks (again dependent on seasonal weather conditions) before applying an acrylic based chemical sealer which greatly protects the smooth surface of the compacted concrete against weather, dusting, wear \& tear. This also slightly increases strength in the final surface of the concrete and ensures that the running surface of the concrete will stay consistent \& not become too slippery or too grippy \& ensures a fantastic surface for the users for years to come.
I must also add that being park users ourselves we are greatly aware of the 'finite' details that can make or break a skatepark, the most relevant of these in regards to concrete works is that the coping tolerances are adhered to and exceeded. If the clearance or 'bonk' as we call it is too much or too little then it really affects the riding experience \& greatly detracts from the enjoyment of the skatepark not to mention can be dangerous, especially for younger users. We work to a tolerance of $7-9 \mathrm{~mm} \&$ this is from the surface of the radius, it must be, there is nothing worse than when the top $100-200 \mathrm{~mm}$ of the transition is pushed back to create a 'false' clearance. This is really unappealing to ride \& something that you will never get with a Concrete Skatepark.
One more note on edging, where the use of the park is predominantly scooters or there are a high number of scooters using the facility we can install steel edging at the concrete pour joins i.e. at the top of a bank, edge of a hip etc. This will protect the concrete edges from the damage that a scooter base can cause with constant 'grounding out' as they pass over it. This will greatly increase the lifespan of the concrete skatepark.
I hope that this information is adequate for your engineers/architect to determine our knowledge \& experience of the skatepark construction concreting process.
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