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（中國建筑設(shè)計(jì)研究院， 北京 100044）
［摘要］以中鐵青島世界博覽城十字展廊工程為背景，對高矢跨比索拱結(jié)構(gòu)的力學(xué)性能進(jìn)行了研究，發(fā)現(xiàn)索拱結(jié)構(gòu)可有效改善高矢跨比純拱結(jié)構(gòu)的力學(xué)性能，尤其是風(fēng)荷載作用下水平向抗側(cè)剛度得以顯著的提高。采用三角形剛性撐桿的索拱結(jié)構(gòu)力學(xué)性能改善最為顯著，但張拉構(gòu)造措施較為復(fù)雜，且必然存在一定的預(yù)應(yīng)力損失，于是提出了采用三角形柔性撐桿的弦撐式索拱結(jié)構(gòu)，并進(jìn)一步探討了影響此結(jié)構(gòu)形式力學(xué)性能的多個關(guān)鍵因素。通過對索桁架頂部結(jié)構(gòu)高度取值研究，發(fā)現(xiàn)該值在一定區(qū)間變化時(shí)，其中起控制作用的性能目標(biāo)并無顯著影響。通過對上弦梁分格數(shù)量和尺寸研究，發(fā)現(xiàn)隨著網(wǎng)格數(shù)量不斷增加，上弦梁構(gòu)件應(yīng)力比逐漸降低。當(dāng)上弦梁拱腳根部以上區(qū)域分格數(shù)量超過8時(shí)，構(gòu)件應(yīng)力比趨于穩(wěn)定。對拱腳支座水平剛度進(jìn)行研究，結(jié)果表明高矢跨比索拱結(jié)構(gòu)對其邊界水平向剛度的要求較低，支座剛度對索拱結(jié)構(gòu)力學(xué)性能的影響，實(shí)際工程中多數(shù)情況下可以忽略。通過對支座是否允許滑動和不同的滑動時(shí)機(jī)分析，發(fā)現(xiàn)索拱結(jié)構(gòu)支座允許滑動，將導(dǎo)致外部荷載作用下支座滑移幅度過大，支座節(jié)點(diǎn)難以處理。下弦索可施加的索力有限，無法滿足腹索索力始終不松弛的性能目標(biāo)。最后建議索拱結(jié)構(gòu)兩側(cè)均采用不可滑動的鉸接支座，并對下部支撐結(jié)構(gòu)進(jìn)行必要的施工階段承載力驗(yàn)算，從而保證索拱結(jié)構(gòu)的安全。
［關(guān)鍵詞］索拱結(jié)構(gòu)；高矢跨比；柔性撐桿；拱腳支座；水平向抗側(cè)剛度
中圖分類號：TU378-6文獻(xiàn)標(biāo)識碼：A文章編號：1002-848X(2021)03-0040-07
Design and research of high rise-span ratio cable arch structural system
DONG Yue, XU Shan, SUN Hailin, LU Ying, SUN Qingtang
(China Architecture Design Group, Beijing 100044, China)
Abstract:Taking the Qingdao World Expo City Cross Gallery Project by China Railway Engineering Group as the background, the mechanical properties of the high rise-span ratio cable arch structure were studied, and it was found that the cable arch structure can effectively improve the mechanical properties of the high rise-span ratio cable arch structure, especially the lateral stiffness of the horizontal direction under the wind load. The mechanical properties of the cable arch structure with triangular rigid struts were improved most significantly, but the tensioning structure measures were complicated and there was a certain loss of prestress. Therefore a chord-supported cable arch structure with triangular flexible struts was innovatively proposed, and a number of key factors affecting the mechanical properties of this structure were further discussed. Through the study of the value of the top structure of the cable truss, it is found that when the value changes in a certain interval, there is no significant influence on the performance objectives of the control function. Through the research on the grid size and scale of the upper string beam, it is found that as the number of grids continues to increase, the stress ratio of the upper string beam member gradually decreases. When the number of grids in the area above the root of the upper chord beam arch foot exceeds 8, the member stress ratio tends to be stable. Research on the horizontal stiffness of the arch foot support shows that the high rise-span ratio cable arch structure requires lower boundary horizontal stiffness. The impact of the support stiffness on the mechanical properties of the cable arch structure can be ignored in most cases in actual engineering. Through the analysis of whether the bearing is allowed to slide and the different sliding timings, it is found that the cable arch structure bearing is allowed to slide, which causes the bearing to slide excessively under the action of external load, and the bearing node is difficult to handle. The cable force that can be applied by the lower chord cable is limited, which cannot meet the performance goal of not slackening the abdominal cable force. Finally, it is suggested that non-sliding hinged supports should be used on both sides of the cable arch structure, and the necessary construction stage bearing capacity of the lower supporting structure should be checked to ensure the safety of the cable arch structure.
Keywords:cable arch structure;high rise-span ratio;flexible strut;arch foot suppot;horizontal stiffness
作者簡介：董越，碩士，高級工程師，一級注冊結(jié)構(gòu)工程師，Email：dongyue729@163.com。
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