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（北京市建筑設(shè)計研究院有限公司， 北京 100045）
［摘要］南京揚子江國際會議中心是海峽兩岸企業(yè)家峰會永久會址，其C區(qū)單體外觀和內(nèi)部空間形態(tài)復(fù)雜多變，是具有6項不規(guī)則的超限結(jié)構(gòu)。本單體4層至5層采用單斜拉腹桿布置的跨層鋼桁架搭建懸挑12.9～14.6m的高位長懸挑空間。結(jié)構(gòu)分析發(fā)現(xiàn)：時程法計算所得豎向地震系數(shù)可能大于等效靜力法和反應(yīng)譜法，需進(jìn)行包絡(luò)設(shè)計； 在懸挑根部并沿向內(nèi)跨延伸方向的樓板拉力較大，需對樓板進(jìn)行加強(qiáng)，而改進(jìn)施工次序后的無支撐安裝法可以顯著減小樓板拉力； 懸挑側(cè)桁架構(gòu)件多由非地震工況控制，根跨構(gòu)件多由地震工況控制； 在通高桁架軸跨中部增加立柱可以增強(qiáng)懸挑桁架的空腹桁架作用，增強(qiáng)結(jié)構(gòu)的防連續(xù)倒塌能力； 合理布置TMD可以有效降低懸挑桁架的豎向振動加速度，從而滿足舒適度設(shè)計要求。
［關(guān)鍵詞］鋼結(jié)構(gòu)； 懸挑桁架； 豎向地震； 施工模擬； 性能化設(shè)計； 防連續(xù)倒塌； 舒適度
中圖分類號：TU391文獻(xiàn)標(biāo)識碼：A文章編號：1002-848X(2020)20-0023-08
Design on an out-of-code structure with large-span and high-position cantilever truss
ZHANG Yanhua, ZHEN Wei, SHENG Ping, SONG Junlin
(Beijing Institute of Architectural Design, Beijing 100045, China)
Abstract:Nanjing Yangtze River International Conference Center is the permanent site of the Cross-Strait CEO Summit. Building C of the project has a complex appearance and internal space, and is an out-of-code structure with 6 irregular items. A large-span and high-position cantilever space from the 4th to 5th floor of this building is built by a 12.9～14.6m length steel truss with tensile diagonal web members. Structural analysis indicates that: the vertical seismic coefficient taken by time history method may be larger than that taken by the equivalent static method and the response spectrum method, and envelope design was required. The slab near the root of the truss and along the force direction of the inner span needs to be strengthened because of the large tensile force, and the construction sequence of unsupported installation method is improved to significantly reduce the floor tension force. The cantilever side members of the truss are mostly controlled by non-seismic load condition, meanwhile the root span members are by seismic load condition. The vierendeel truss effect of the cantilever truss can be improved by vertical columns placed in the middle span of the through-height truss, which increases the progressive collapse prevention ability of the structure. Reasonable arrangement of TMD can effectively reduce the vertical vibration acceleration to improve the comfort of the cantilever truss.
Keywords:steel structure; cantilever truss; vertical earthquake; construction simulation; performance-based design; progressive collapse prevention; comfort
*2019年度北京市科技服務(wù)業(yè)促進(jìn)專項（Z191100003519023）。
作者簡介：張龑華，碩士，工程師，一級注冊結(jié)構(gòu)工程師，Email：zhangyh06@tsinghua.org.cn。
