That's an excellent and very practical question! The answer depends heavily on the specific bench design, your local climate, and the expected usage. Generally, most permanent park benches benefit from a proper foundation, but placement on a stable, well-prepared paver base is possible under the right conditions.
For heavy-use public or commercial benches, a concrete foundation is highly recommended. This involves digging footings below the frost line (to prevent heaving in cold climates) and setting anchor sockets or bolts into the wet concrete. Once cured, the bench legs are secured to these anchors. This method provides unmatched stability, safety, and longevity, preventing tipping, rocking, or sinking.
Now, for placing a bench directly on pavers, it is feasible if you ensure a few critical things. First, the paver patio itself must have a perfectly level, compacted base of gravel and sand to prevent any shifting or settling. The pavers must be solidly interlocked. Lightweight or smaller residential benches can often sit flat on this stable surface. However, for added security, especially in windy areas, you should use surface-mounted anchors. These are metal plates or straps that attach to the bench legs and are then screwed or bolted down into the pavers and the base below.
In summary: A special concrete foundation is the gold standard for permanent, heavy-duty installation. For a paver patio, choose a robust bench design and always anchor it down to the stable base beneath the pavers. Never just place a bench loosely on top of unsecured pavers. Checking local building codes and the bench manufacturer's instructions is always the final, crucial step.