抄録：しもきた克雪ドーム(仮称)の風荷重検討

しもきた克雪ドーム(仮称)の風荷重検討

相原知子・細澤治・浅見豊・水谷太朗・寺崎浩・吉川優
しもきた克雪ドームは１辺が108.3mの曲面形状の屋根を有する多目的ドームである．ドーム棟の屋根はＳ造の骨組の外側と内側に膜材を張った２重膜構造を採用している．ドーム棟の外装材用及び構造骨組用風荷重を検討する為に風洞実験を行った．　ドーム棟の外圧は風圧実験により求め，内圧については，換気口の開閉状況あるいは１階のガラスが強風時に破損した場合の様々なケースを想定し，圧力の応答計算によって求めた．　外装材用風荷重の最大値は内圧を建築基準法に従った閉鎖型の建物とした場合に較べて，開口部やガラスの破損を考慮した場合には1.24倍となった．構造骨組用風荷重は，風上に開口がある時に最も大きくなり，その時の内圧係数は＋0.275，ガスト影響係数は2.22であった．　ドーム棟では開口の偏在，ガラスの破損時にも耐える設計となっている．
キーワード：	ドーム，風荷重，平均化時間，内圧係数，開口，応答解析

Wind Load Investigation of Shimokita Dome (tentative name)

Tomoko AIHARA, Osamu HOSOZAWA, Yutaka ASAMI, Taro MIZUTANI, Hiroshi TERAZAKI and Masaru YOSHIKAWA
Shimokita Dome is a multipurpose dome with 108.3m length plan and curved shape roof. Double membrane located both sides of steel frame were adopted as dome roof system. To evaluate design wind loads of dome such as structural wind load and wind load of membrane, wind tunnel tests were performed. External pressure distributions of dome were determined using wind tunnel test result, directly. Otherwise, internal pressure states of dome were calculated by pressure response analyses assuming location/state of ventilation openings, or assuming location/number of breaking at first floor window glass under severe wind. Considering internal pressure derived from openings, the maximum wind load value for components and cladding is 1.24 times of value by Japanese Standard Cords which assumed close type buildings. As for structural wind load, the maximum wind load occurred in case of locating openings at windward wall with internal pressure coefficient value +0.275 and gust loading factor 2.22. Through these investigations, this dome design can endure conditions of uneven locations of openings and breaking of window glass.
keywords:	Dome, Wind Load, Averaging Time, Internal Pressure Coefficient, Openings, Response Analysis