無背索曲塔曲梁斜拉橋參數(shù)敏感性分析

1、無背索曲塔曲梁斜拉橋參數(shù)敏感性分析劉世明1,2 劉永健1 （1.長(zhǎng)安大學(xué) 橋梁與隧道陜西省重點(diǎn)實(shí)驗(yàn)室，陜西西安 710064；2.華北水利水電學(xué)院 土木與交通學(xué)院，鄭州450011；）摘 要：為研究無背索曲塔曲梁斜拉橋施工中各參數(shù)變化的影響，對(duì)橋梁施工過程進(jìn)行預(yù)控和參數(shù)誤差識(shí)別，確保成橋時(shí)主梁變形、塔頂位移、主梁應(yīng)力、塔底應(yīng)力和拉索索力達(dá)到設(shè)計(jì)狀態(tài)，以無背索曲塔曲梁斜拉橋東莞水道橋?yàn)楣こ瘫尘?，采用MIDAS/CIVIL空間有限元分析軟件，考慮結(jié)構(gòu)容重、混凝土彈性模量、拉索彈性模量、溫度作用等參數(shù)變化的影響，進(jìn)行了各參數(shù)的敏感性分析。結(jié)果表明：主梁在y方向上變形的敏感參數(shù)為整體溫度作用，主梁在z

2、方向上變形、主梁應(yīng)力、塔頂位移、塔底應(yīng)力以及拉索索力的敏感參數(shù)是整體溫度作用和容重；整體降溫時(shí)，主梁z方向最大位移增量為-12.2mm，位于主跨1/4跨徑附近，梁截面應(yīng)力增量在上、下緣的左右側(cè)相差較大，主梁的扭轉(zhuǎn)明顯，引起塔頂x、y、z方向的位移增量最值分別為7.4mm、3.2mm和-21.3mm，在塔底截面上、下緣均產(chǎn)生拉應(yīng)力增量，拉應(yīng)力增量最大值為7.28MPa，發(fā)生在左側(cè)塔底部截面左下緣；整體降溫和容重增加引起的索力增量最值分別為23.24kN和18.11kN，其中，整體降溫時(shí)左、右側(cè)對(duì)應(yīng)拉索的索力增量表現(xiàn)出較大的差異，對(duì)應(yīng)拉索的索力增量差值最大達(dá)6.05kN。關(guān)鍵詞：橋梁工程；斜拉橋參

3、數(shù)敏感性分析；有限元分析；無背索；曲塔；鋼-混組合梁中圖分類號(hào)：U448.22 文獻(xiàn)標(biāo)識(shí)碼：A Sensitivity Analysis of Parameters for Curved-pylon and Curved-girder Cable-stayed Bridge without Back-staysLIU Shiming，LIU Yongjian（1.Key Laboratory for Bridge and Tunnel of Shaanxi Province, Changan University, Xian 710064,china;2.North China Institu

4、te of Water Conservancy and Hydroelectric Power, Zhengzhou 450011, China;）Abstract：In order to study the influence of parameters for curved-pylon and curved-girder cable-stayed bridge without back-stays during construction, to precontrol the construction process and identify the parameter error, to

5、be sure the deformation of the beam and the top of the pylon, stress of beam and the pylon bottom, cable force of the stay cable which be corresponding to the design value at the completion of the bridge construction, according to the construction of Dongguanshuidao bridge, which is a curved-pylon a

6、nd curved-girder cable-stayed bridge, the analytical model is founded through the finite element analysis software MIDAS/CIVIL, and the parameters change such as structural unit weight and concrete elasticity modulus and cable elasticity modulus and temperature action are considered, sensitivity ana

7、lysis of the parameters are carried out. The results show that the sensitive parameter of the deformation of the beam at the direction of y axis is temperature, and the sensitive parameters of the deformation of the beam at the direction of z axis and stress of the beam and the deformation of the to

8、p pylon and the stress of the pylon bottom are temperature and structural self-weight; the maximum deformation increment at the direction of z axis of the beam is -12.2mm caused by temperature drop, which is located at 1/4 point of the main span; temperature drop can cause the stress increment of th

9、e upper and lower beam and the stress differences of the left side and right side of upper and lower beam section are greater, torsion is obvious, the deformation increment caused by temperature drop of the top pylon at the direction of x axis, y axis and z axis are 7.4mm, 3.2mm and -21.3mm respecti

10、vely, the tensile stress is occurrence at the upper and lower edge of pylon bottom section when temperature drop, the maximum tensile stress increment is 7.78MPa at the location lower edge of left pylon bottom section; the cable force increment caused by temperature drop and unit weight increment ar

11、e 23.24kN and 18.11kN respectively, the force differences of the same number cable between the left and right are lager, the maximum difference of cable force increment is 6.05kN. Key words: bridge engineering; sensitivity analysis of parameters of cable-stayed bridge; finite element analysis; witho

12、ut back-stays; curved-pylon; curved-girder; steel-concrete composite beam引言無背索斜拉橋通過塔柱傾角來平衡橋面恒載和活載，不設(shè)背索，結(jié)構(gòu)獨(dú)特，造型優(yōu)美，近年來在我國(guó)得到一定程度的發(fā)展1，目前已建成10余座。斜拉橋施工過程的影響因素比較多，黃燦2等采用幾何控制法的基本原理，對(duì)幾何尺寸、剛度和荷載變化對(duì)超大跨徑鋼箱斜拉橋的影響進(jìn)行了系統(tǒng)的分析，為施工階段誤差確定、修正、控制提供依據(jù)；何祖發(fā)3等對(duì)獨(dú)柱斜塔混合梁斜拉橋的施工控制進(jìn)行了研究；其他學(xué)者也對(duì)斜拉橋參數(shù)敏感性進(jìn)行了相關(guān)研究 4-8，然而，尚未見無背索曲塔曲梁斜拉橋施工控

13、制及參數(shù)敏感性研究文獻(xiàn)，類似橋梁的建設(shè)經(jīng)驗(yàn)和研究資料較少，為確保橋梁施工的順利實(shí)施，鑒于橋梁施工過程中影響因素多，結(jié)合東莞水道橋的施工監(jiān)測(cè)監(jiān)控工作，進(jìn)行橋梁結(jié)構(gòu)容重、混凝土彈性模量、拉索彈性模量、溫度作用等參數(shù)的敏感性分析具有重要的理論價(jià)值和工程實(shí)用價(jià)值8-10。1 橋梁結(jié)構(gòu)分析建模1.1橋梁概況東莞水道橋平面位于半徑為800m圓曲線上，左、右側(cè)縱坡分別為1.68和-4.00，豎曲線半徑為2000m。結(jié)構(gòu)采用無背索曲塔曲梁矮塔斜拉橋，塔梁墩固結(jié)體系，跨徑布置為51.5m+138m+55m。橋面寬度為29.2m37.2m，橋梁的立面、平面、主塔處橫斷面如圖1、2、3所示。主梁采用單箱四室箱型斷面

14、，頂板橫向?qū)ΨQ于箱梁中心線設(shè)置向外2%的雙向橫坡，中心線處高度為2.3m4.705m，沿縱向分為混凝土部分和鋼梁部分，其中混凝土部分采用C60混凝土，布置三向預(yù)應(yīng)力，左右兩側(cè)長(zhǎng)度分別為23.25m、19.25m，鋼主梁部分長(zhǎng)度為95.5m，采用Q345鋼材。主塔采用鋼殼混凝土曲塔結(jié)構(gòu)，與水平線夾角為58，塔身截面縱橋向?qū)挾葹?m7m，橫橋向3m4.5m。斜拉索采用環(huán)氧噴涂鋼絞線索，共有3s15.2、25s15.2和27s15.2三種規(guī)格，斜拉索布置在中央分隔帶處。橋梁中跨沿縱橋向兩側(cè)無索區(qū)長(zhǎng)度分別為29m、28m。梁上索距為9m，塔上索距為4.742m，為確保塔身的穩(wěn)定性，在兩橋塔間布置2根水平拉索，全橋共有22根斜拉索。圖1 橋梁立面圖（單位：cm）Fig.1 Longitudinal view of the bridge (unit: cm)圖2 橋梁平面圖（單位：cm）Fig.2 Plan view of the bridge (unit: cm)圖3 橋塔處