I have always wondered what really happened to the Jurassic Park gate prop, and the "stone" archway. Does Universal Studios have the "stone" archway for their Jurassic Park ride?
His recollection is that he is quite sure that the gate was ...
"...struck and trashed after the filming..."
...and that whatever remained of the gates and materials were obliterated by the elements, notably ...
"...hurricane Iniki [which made landfall] during the end of the production on the island of Kauai, Hawaii, which probably damaged them significantly."
It's possible that pieces of the gate could be found nearby the gate site (noting that the poles that are show to tourists aren't actually part of the original since they're nearly a hundred feet ahead of the site where the gate was placed) if one were to look hard enough, but since the gate was likely made out of little more than flimsy sheets of balsawood painted brown for wood and grey for stone, they could literally have gone anywhere.
There are several YouTube videos of people going to the location of the Gate filmed in the movie.
The actually Gate was located about 300 feet past these 2 poles. There is nothing left of the gate.
The last 2 give a pretty good description of how to get there if you want to see it yourself.
Let me answer this in part.
The old gates were constructed out of a haphazardly-welded iron frame, with a mix of concrete, sand and crushed Waialeale volcanic rock used to create the facade (have a look at the helipad prop/Manawaiopuna falls stair case - these are protected original structures, although the pad is in a thousand parts now - these demonstrate the concrete composition as found at the gate location).
I do not know what came of our actual ‘wooden’ gate prop - I think that was taken away to allow access to the road again after filming, along with the park lettering, but the concrete poles that currently stand on the loop road were absolutely used in the movie to hold and add tension to the ‘electric-fence’, connected about 12 feet away from the gate and away from the road itself. These have been repositioned and erected since. The wire was originally looped through holes drilled into the iron framework on both the gate and the poles (you can still where the wires were cut in the concrete posts), with the facade added over the top.
There was a trench that ran along the length of the road up to the gate, holding potted ferns/palms etc. None of this was ever removed from the site outside of locals collecting souvenirs, and some of the plants are still on site, growing naturally in the foot-deep mud on either side of the road. The trench also still exists and is a great reference to show the road-to-gate filming location - in fact this can also be seen simply using Google earth. Hurricane Iniki destroyed both the gate prop and the Rex paddock fence, however there is still to this day chunks of concrete with volcanic rock embedded in it lying on the road and through the swamp in that area.
If you look hard enough, you will see that the fence wire was actually reused up at the ‘Rex paddock’ to stabilise a concrete dam, and the fence iron posts were cut and reused for both the water dam system nearby and the various 4wd gates through the area. There is still traces of grey paint on some of these. :)
Also… if you look hard enough you will find some of the fence mounts that were concreted to the ground. They basically look like a circle of concrete around a cut wire in the middle… this wire was used behind the fence to stabilise it and support the whole structure from falling backwards as was the case after Iniki hit the island.
With the final movie coming out shortly, hope this info helps to bring light to some of the secrets that have sat quietly for the last 30 years…. :)