本文選題：矮塔斜拉橋　切入點：索梁活載比　出處：《長安大學》2016年博士論文　論文類型：學位論文

【摘要】：矮塔斜拉橋作為一種具有競爭力的組合橋型,該橋型的力學性能介于連續(xù)體系梁橋和常規(guī)斜拉橋之間,具有良好的經(jīng)濟性能和美學效果。開展矮塔斜拉橋結(jié)構(gòu)體系方面的研究具有重要的現(xiàn)實意義。本文從結(jié)構(gòu)分析角度分析了矮塔斜拉橋中設計理論中存在問題,所做的主要研究工作和取得研究成果有:(1)文中首先簡要介紹了矮塔斜拉的起源及發(fā)展現(xiàn)狀,指出索梁活載比可在本質(zhì)上反映矮塔斜拉橋在車道荷載作用下的結(jié)構(gòu)效應。本文采用比擬梁法,推導了車道荷載作用下的單塔、雙塔及多塔矮塔斜拉橋的索梁活載比計算公式。研究了索梁活載比與結(jié)構(gòu)參數(shù)之間關系,進一步指出索梁活載比可從力學本質(zhì)上反映了矮塔斜拉橋索梁塔及支承條件等結(jié)構(gòu)特性,以此可方便設計人員從宏觀上把握矮塔斜拉橋的結(jié)構(gòu)性能,在概念設計階段選擇合理的結(jié)構(gòu)參數(shù)。(2)基于荷載平衡理論、索膜理論推導了恒載作用下的主梁的彎矩、軸力及主塔的軸力;基于彈性支承連續(xù)梁理論推導了活載作用下的主梁、主塔的彎矩和撓度;在推導主梁的豎向位移計算表達式時,本文考慮了拉索的彈性變形、主塔的偏位及彈性壓縮變形等因素(3)為方便計算矮塔斜拉橋的自振頻率,分別基于雙塔塔梁固結(jié)、墩支承的矮塔斜拉橋和高墩固結(jié)體系矮塔斜拉橋,應用Rayleigh法,推導了其一階對稱和反對稱豎彎振動頻率公式及縱向漂浮基頻估算公式,并提出了名義單位質(zhì)量的抗彎剛度的概念,最后對此公式的可行性進行了算例驗證,并討論了該公式的應用對象。研究結(jié)果表明:支承條件對矮塔斜拉體系的基頻影響較大,進行頻率計算時應準確考慮支承條件;給出的能量法得到的基頻計算值與有限元值誤差能滿足概念設計階段的要求;該公式適用于雙塔塔梁固結(jié)、墩支承的矮塔斜拉結(jié)構(gòu)和高墩固結(jié)體系矮塔斜拉橋,并指出抗風設計規(guī)范中的豎彎基頻公式不適用于雙塔塔梁固結(jié)、墩支承的矮塔斜拉結(jié)構(gòu)。(4)為研究多塔矮塔斜拉橋的中塔縱向剛度,將拉索對橋塔的約束等效為彈簧單元。在推導中采用能量守恒原理,忽略了主塔的彈性壓縮。在活載作用下橋塔發(fā)生縱向變形,并引起主塔的縱向彎曲、主梁的豎向彎曲及拉索彈性伸長,在此過程中拉索的水平向做功等于主梁的重力勢能增量與斜拉索的彈性勢能增量之和,據(jù)此推導出了拉索對中塔縱向約束剛度表達式。研究表明:等效彈簧剛度與斜拉索線剛度成線性關系;與斜拉索水平角存在一定關系,并不與等效彈簧剛度成線性關系;此公式具有較高的計算精度,可供概念設計階段選取合理的結(jié)構(gòu)參數(shù)使用。(5)為研究多塔矮塔斜拉體系的在活載作用下的主梁的豎向撓度,將斜拉體系等效為多跨彈性支承連續(xù)梁�；诙嗨崩w系的結(jié)構(gòu)力學本質(zhì),推導了單位荷載作用下的邊中跨拉索彈性支承剛度系數(shù)的計算表達式。并對其進行了參數(shù)研究,最后對斜拉體系的塔梁剛度進行討論。(6)針對預應力混凝土矮塔斜拉橋的特點,提出了基于索梁權(quán)矩陣的索力優(yōu)化方法。該方法的思路是以主梁截面上下緣的正應力為控制條件,給出主梁截面恒載應力可行域和彎矩可行域,即將《公路橋規(guī)》中規(guī)定的設計強度值減去活載作用在主梁截面活載應力包絡值,使其落在主梁截面應力可行域內(nèi);并提出單位荷載法,采用最小二乘法原理,以索梁權(quán)矩陣為優(yōu)化目標,來解決優(yōu)化索力和預應力優(yōu)化配置問題,使主梁上下緣的正應力位于上述可行域內(nèi)。采用編程實現(xiàn)了這一方法并進行了實橋算例驗證(7)收集國內(nèi)外連續(xù)體系梁橋、常規(guī)斜拉橋及矮塔斜拉橋的資料,統(tǒng)計了混凝土、普通鋼筋及拉索(或預應力筋)用量指標,以此擬合上述三種橋型的經(jīng)濟跨徑;從結(jié)構(gòu)體系措施、構(gòu)件措施及材料措施等角度分析指出,改善大跨度矮塔斜拉橋力學性能的措施;最后根據(jù)本文所推導的近似估算公式,從力學性能角度分析了矮塔斜拉橋極限跨徑。論文對推導的近似計算式,均獲得了有限元解的驗證。
[Abstract]:As a competitive bridge low tower cable-stayed bridge, the mechanical properties of the bridge system between continuous girder bridge and conventional cable-stayed bridge, which has good economic performance and aesthetic effect. It is of great significance to research the extradosed cable-stayed bridge structure system. This paper from the angle of structure analysis the problems of the design theory of the extradosed cable-stayed bridge, the main research work and research achievements are: (1) this paper briefly introduces the origin and development status of Extradosed cable girder, pointed out that in essence the live load ratio reflects the structure effect of extradosed cable-stayed bridge in lane loads the paper used the beam analogy method, deduces the single tower under Lane loads, the Twin Towers and the tower of the extradosed cable-stayed bridge cable beam live load ratio. The calculation formula of cable beam live load ratio and the relationship between structure parameters, further pointed out the cable beam The live load ratio from the mechanical essence of extradosed cable-stayed bridge cable tower and beam condition of supporting structure characteristics, which can be used to facilitate the designers to grasp the structural performance of the extradosed cable-stayed bridge from the macro view, select the reasonable structure parameters in the conceptual design stage. (2) the load balance based on the theory of membrane theory the main beam under the action of dead load bending moment, axial force and axial force of tower; based on the theory of elastic bearing continuous beam girder under live load, the main tower of the bending moment and deflection in vertical displacement is derived; calculation formulas of girder, considering the cable's elastic deformation, deflection and elastic main tower of compression deformation and other factors (3) to facilitate the calculation of the natural frequency of the extradosed cable-stayed bridge, based on the Twin Towers tower pier beam consolidation respectively, supporting the extradosed cable-stayed bridge and high pier consolidation system of extradosed cable-stayed bridge, using the Rayleigh method to deduce the first-order symmetric and anti symmetric 绔栧集鎸姩棰戠巼鍏紡鍙婄旱鍚戞紓嫻熀棰戜及綆楀叕寮，

本文編號：1580959