detached pier

...It consists mainly of piers made of wood, steel, and reinforced concrete piles, and a bridge that connects the deck supported by the piers and the revetment on land, and is different from a pier or wharf, which directly supports the ground behind it and makes the coast side a vertical surface so that ships can be docked. A pier that is parallel to the shore is called a shore-bridge, and if the bridge of a shore-bridge is long, it is called a detached pier. Unlike a pier, a pier is not directly subjected to the earth pressure of the ground behind it, so it is not subjected to large horizontal external forces during earthquakes. Also, since it is only necessary to make the piers long even on soft ground made of clay layers, there are fewer restrictions on the bearing capacity of the foundation ground as with piers and wharves, making it an economical structure in deep water.

*Some of the terminology that mentions "detached pier" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…主として，木材，鋼材，鉄筋コンクリート製の杭で作られる脚柱と，これで支えられた床版および陸岸の護岸とを結びつける渡橋とからなり，直接背後の地盤を支え，海岸側を垂直面にして船を接岸できるようにした岸壁や物揚場とは異なる。桟橋のうち陸岸に平行なものを横桟橋shore‐bridgeといい，横桟橋の渡橋が長い場合にはデタッチトピアdetached pierと呼ぶ。　桟橋は岸壁と異なり直接背後の地盤の土圧を受けないから，地震の際にも大きな水平外力を受けることがなく，また，粘土層からなる軟弱地盤においても脚柱を長くすればよいので，岸壁，物揚場のように基礎地盤の支持力についての制約は少なく，大水深のところで経済的構造物となる。…

※「detached pier」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報