金匱(kui)大橋(qiao)(qiao)(qiao)(qiao),簡稱金匱(kui)橋(qiao)(qiao)(qiao)(qiao)。現有(you)金匱(kui)橋(qiao)(qiao)(qiao)(qiao)位于無錫市中心城區(qu)南長區(qu),為(wei)城市主干道(dao)太(tai)湖大道(dao)跨(kua)越京(jing)杭(hang)運(yun)河的一座(zuo)橋(qiao)(qiao)(qiao)(qiao)梁。原(yuan)金匱(kui)橋(qiao)(qiao)(qiao)(qiao)為(wei)鋼筋混凝土剛架拱橋(qiao)(qiao)(qiao)(qiao),由于拱趾沉(chen)降不(bu)均勻,現已(yi)限載通行。根(gen)據城市規劃,擬在舊橋(qiao)(qiao)(qiao)(qiao)原(yuan)址上(shang)重建本項目。改(gai)建后金匱(kui)橋(qiao)(qiao)(qiao)(qiao)采用55m+105m+55m鋼桁架鋼箱梁橋(qiao)(qiao)(qiao)(qiao),橋(qiao)(qiao)(qiao)(qiao)寬46m,主跨(kua)跨(kua)越京(jing)杭(hang)大運(yun)河,邊跨(kua)跨(kua)越運(yun)河東路(lu)和運(yun)河西路(lu)。
金匱橋地處(chu)太(tai)湖廣場,景觀要求高,因此需要大橋具有較強的標志性。大橋橋面較寬(kuan),既要滿足通航及運(yun)河(he)東路凈空(kong)要求,又需盡早落地進(jin)入兩端(duan)連接的隧道,故(gu)梁體高度應盡可能小(xiao)。
在比選了各種(zhong)橋型方(fang)案后(hou),對于(yu)主跨為100m左右(you),橋寬(kuan)46m的(de)橋梁(liang),采用(yong)下承式(shi)鋼(gang)(gang)桁梁(liang)可謂最佳(jia)選擇。設計(ji)中(zhong)創新地將懸索(suo)橋造型與傳(chuan)統鋼(gang)(gang)桁梁(liang)有機地結合,利用(yong)主桁富于(yu)變化的(de)曲線,塑造出風格獨特的(de)鋼(gang)(gang)桁梁(liang)橋。
主(zhu)梁(liang)采(cai)(cai)用(yong)(yong)(yong)開(kai)口(kou)式主(zhu)桁(heng)(heng)(heng)與鋼(gang)(gang)箱梁(liang)相(xiang)結合,此類結構在(zai)國內應(ying)用(yong)(yong)(yong)較少(shao)。開(kai)口(kou)式主(zhu)桁(heng)(heng)(heng)由于沒有橫(heng)聯與平(ping)聯,橋(qiao)面視線更開(kai)闊,景觀效果更好。但在(zai)汽車活(huo)載作用(yong)(yong)(yong)下,主(zhu)桁(heng)(heng)(heng)上弦跨(kua)中(zhong)桿件受壓,容(rong)易發生(sheng)整(zheng)體(ti)失穩,對于跨(kua)度不大、桁(heng)(heng)(heng)高(gao)不高(gao)的(de)(de)鋼(gang)(gang)桁(heng)(heng)(heng)梁(liang),通過控制主(zhu)桁(heng)(heng)(heng)上弦跨(kua)中(zhong)桿件應(ying)力水平(ping),能有效地(di)解決主(zhu)桁(heng)(heng)(heng)的(de)(de)整(zheng)體(ti)失穩問題。對主(zhu)桁(heng)(heng)(heng)桁(heng)(heng)(heng)數(shu)的(de)(de)選擇,可采(cai)(cai)用(yong)(yong)(yong)3片(pian)(pian)主(zhu)桁(heng)(heng)(heng),橋(qiao)面系(xi)采(cai)(cai)用(yong)(yong)(yong)縱、橫(heng)肋加固的(de)(de)正交異性鋼(gang)(gang)橋(qiao)板面體(ti)系(xi);也可采(cai)(cai)用(yong)(yong)(yong)2片(pian)(pian)主(zhu)桁(heng)(heng)(heng),橋(qiao)面系(xi)采(cai)(cai)用(yong)(yong)(yong)正交異性板鋼(gang)(gang)箱梁(liang)體(ti)系(xi),這(zhe)兩種(zhong)均能滿足通航凈空(kong)要求(qiu)。經多(duo)方面比較,采(cai)(cai)用(yong)(yong)(yong)2片(pian)(pian)主(zhu)桁(heng)(heng)(heng)、橋(qiao)面系(xi)為正交異性板鋼(gang)(gang)箱梁(liang)體(ti)系(xi)。