【正文】
行于懸臂板跨徑的車輪著地尺寸的外援,通過鋪裝層45176。分布線的外邊線支付版外邊緣的距離,;作用于橋面板頂面得均布荷載集度為:(kN)懸臂板根部可變作用效應(yīng)為:(kNm)(kN)承載能力極限狀態(tài)基本組合:(kNm) 懸臂板可變荷載圖(單位:cm) (kN)當(dāng)主梁間現(xiàn)就部分完工后,橋面板與梁肋之間的連接可視為一系列彈性支承上的多跨連續(xù)板。在計算彎矩時,可先計算出相同跨度簡支板的跨中荷載彎矩,在乘以偏安全的修正系數(shù)加以修正,以求得支點處和跨中截面的設(shè)計彎矩。而在計算剪力時,可不考慮板和主梁的彈性固結(jié),認為簡支板的支剪力即為連續(xù)板的支剪力。1)主梁架設(shè)完畢時,橋面板可視為單線懸臂板,,分別為Mg1=(kNm)Vg1=(kN)2)成橋之后先計算簡支板的跨中彎矩和支點剪力, 連續(xù)板永久荷載圖(單位:cm)梁肋間板的計算跨徑(m);圖中g(shù)1為濕接縫的自重,;g2為橋面鋪裝層的自重,;計算得簡支板跨中二期恒載作用效應(yīng)為(kNm)(kN)考率梁肋彈性固結(jié)效應(yīng)后,則支點二期恒載作用效應(yīng)(kNm)跨中二期恒載作用效應(yīng)(kNm)3)永久荷載效應(yīng)支點永久荷載彎矩(kN)支點永久荷載剪力(kN)跨中永久荷載彎矩(kNm)以車輛荷載進行橋梁結(jié)構(gòu)的局部計算,汽車后輪著地寬度和長度分別為,;平行于板的跨徑方向的荷載分布寬度為:(m)1)車輪在板跨中部時,垂直于板跨徑方向的的荷載分布寬度為:(m)(m)取=,兩后輪有效分布寬度發(fā)生重疊,應(yīng)求兩個車輪荷載有效分布寬度:(m);2)車輪在板的支承處時,垂直于板的跨徑方向的荷載分布寬度為:=++=(m)3)車輪在板的支承附近,距支點距離為x時,垂直于板的跨徑方向荷載有效分布寬度為:=+將重車后輪作用于板的中央,求出簡支板跨中最大可變作用的彎矩為:(kNm)計算剪力時,將可變作用布置于靠近梁肋的位置,考慮了相應(yīng)的有效寬度后。其中, 連續(xù)板可變荷載圖(單位:cm)所以,連續(xù)板可變作用效應(yīng)支點截面彎矩(kNm)跨中截面彎矩(kNm)支點截面剪力kN承載能力極限狀態(tài)作用基本組合支點彎矩(kNm)支點剪力(kN)跨中彎矩(kNm),配筋與承載力驗算懸臂板及連續(xù)板支點負彎矩處采用相同的抗彎鋼筋,股指虛按其最不利荷載效應(yīng)進行配筋,即。連接處高度為h=26cm,保護層厚度c=3cm,采用Φ12HRB335鋼筋,有效高度為(cm);根據(jù)解得x=,滿足規(guī)范要求。其中。受拉鋼筋面積(mm2)采用Φ12@18HRB335鋼筋,單位長度行車道板所含鋼筋面積As=628mm2。驗算截面承載力(m) 則截面承載力 (kNm)(kNm)承載力滿足。由計算得連續(xù)板跨中處最不利彎矩,截面高度h=16cm,保護層c=3cm,選用HRB335鋼筋,有效高度(cm)。根據(jù),;解得x=,滿足規(guī)范要求。所需鋼筋面積(mm2),采用Φ12@18HRB335鋼筋,單位長度行車道板鋼筋面積As=628mm2,驗算截面承載力(m)(kNm) (kNm)承載力滿足要求。矩形截面受彎構(gòu)件截面尺寸應(yīng)符合下式的要求即(kN)滿足最小抗剪尺寸要求;當(dāng)截面滿足以下條件時可不需進行斜截面抗剪強度計算。即(kN)故橋面板按構(gòu)造配筋即可。結(jié) 論混凝土T型簡支梁設(shè)計首先對主梁進行內(nèi)力計算,計算荷載橫向分布系數(shù),在橋梁設(shè)計中,為使荷載橫向分布的計算能更好的適應(yīng)各類型的結(jié)構(gòu)特征,就需要按照不同的橫向結(jié)構(gòu)簡化模型擬定出相應(yīng)的計算方法。目前常用的荷載橫向分布計算方法為杠桿原理法,偏心壓力法。還要進行荷載內(nèi)力的計算,在確定計算恒載時,為了簡化起見,習(xí)慣上往往將沿橋跨分散作用的橫隔梁重量、沿橋橫向不等分布的鋪裝層重量以及作用于兩側(cè)的人行道和欄桿等重量均勻的分攤給各主梁承受。因此對于等截面橋梁的主梁,其計算恒載是簡單的均布荷載。有時為了精確起見,也可根據(jù)施工安裝的情況,將人行道、欄桿、燈柱和管道等重量象活載計算那樣,按荷載橫向分布的規(guī)律對各主梁進行分配。計算在確定后可利用內(nèi)力影響線求得恒載內(nèi)力。還要進行活載內(nèi)力的計算,以及內(nèi)力組合。然后進行持久狀況承載能力極限狀態(tài)下截面設(shè)計、配筋與驗算。進行主筋的配置和箍筋的配置,以及斜截面抗剪承載能力驗算。然后進行持久狀況斜截面抗彎極限承載能力狀態(tài)的驗算和裂縫寬度驗算,撓度驗算,進行校核,看是否滿足要求。經(jīng)過驗算,各項設(shè)計均符合要求。參 考 文 獻[1] 姜福香,雷俊卿.橋梁工程[M].北京:機械工業(yè)出版社,2010.[2] 向海帆,沈足炎等. 土木工程概論[M]. 北京:人民交通出版社,2007.[3] 中國公路學(xué)會橋梁與結(jié)構(gòu)工程學(xué)會.中國公路學(xué)會橋梁與結(jié)構(gòu)工程學(xué)會論文集[C].北京:人民交通出版社,2002.[4] 孔祥福,符立國,張珂.近代以來中外橋梁發(fā)展概述[J].山東交通學(xué)院學(xué)報,2003,11(2):55~58.[5] 張克林.高速公路路基施工技術(shù)發(fā)展淺析[J].現(xiàn)代公路,2008(3):15~17..[6] 劉暉.公路路基施工技術(shù)[J].科技信息,2008(5):33~36.[7] 李愛波.淺談對公路橋梁發(fā)展趨勢的看法[J].黑龍江科技信息,2008(12):187.[8] 蘇昆.梁式橋的發(fā)展趨勢分析[J].中國集體經(jīng)濟,2004(4):156.[9] 項海帆.我國公路橋梁建設(shè)的成就與不足[J].中國交通報,2003(5):20~21.[10] 黃儀深.橋梁改造加固設(shè)計[A].中國公路學(xué)會全國公路橋梁維修與加固技術(shù)研討會論文集[C].2001.[11] Neville . 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Leighty2004,6Evolvement of bridge Engineering,brief reviewAmong the early documented reviews of construction materials and structure types are the books of Marcus Vitruvios Pollio in the first century basic principles of statics were developed by the Greeks , and were exemplified in works and applications by Leonardo da Vinci,Cardeno,and the fifteenth and sixteenth century, engineers seemed to be unaware of this record , and relied solely on experience and tradition for building bridges and aqueducts .The state of the art changed rapidly toward the end of the seventeenth century when Leibnitz, Newton, and Bernoulli introduced mathematical formulations. Published works by Lahire (1695)and Belidor (1792) about the theoretical analysis of structures provided the basis in the field of mechanics of materials .Kuzmanovic(1977) focuses on stone and wood as the first bridgebuilding materials. Iron was introduced during the transitional period from wood to steel .According to recent records , concrete was used in France as early as 1840 for a bridge 39 feet (12 m) long to span the Garoyne Canal at Grisoles, but reinforced concrete was not introduced in bridge construction until the beginning of this century . Prestressed concrete was first used in 1927.Stone bridges of the arch type (integrated superstructure and substructure) were constructed in Rome and other European cities in the middle ages . These arches were halfcircular , with flat arches beginning to dominate bridge work during the Renaissance period. This concept was markedly improved at the end of the eighteenth century and found structurally adequate to acmodate future railroad loads . In terms of analysis and use of materials , stone bridges have not changed much ,but the theoretical treatment was improved by introducing the pressureline concept in the early 1670s(Lahire, 1695) . The arch theory was documented in model tests where typical failure modes were considered (Frezier,1739).Culmann(1851) introduced the elastic center method for fixedend arches, and showed that three redundant parameters can be found by the use of three equations of coMPatibility.Wooden trusses were used in bridges during the sixteenth century when Palladio built triangular frames for bridge spans 10 feet long . This effort also focused on the three basic principles og bridge design : convenience(serviceability) ,appearance , and endurance(strength) . several timber truss bridges were con