預應力混凝土連續梁橋畢業論文(已修改)

　

【正文】 預應力混凝土連續梁橋畢業論文1． 擇優推薦方案。2． 進行推薦方案上部結構內力分析，截面設計。3． 進行推薦方案的施工驗算。一． 設計原始資料（實驗、研究方案）1． 橋位地址剖面圖2． 3． 平曲線半徑R=∞4． 縱坡i=05． 單向橫坡i=2%二． 主要技術指標1． 設計荷載：汽——超20級。2． 橋面凈寬：++++3． 橋位氣溫：℃，最高+℃4． 地震烈度：7度三． 設計完成后提交的文件和圖表（論文完成后提交的文件）1． 計算說明書部分：1） 設計指導思想、重點、難點2） 各個方案的特點，推薦方案的被選理由3） 推薦方案上部結構的結構計算書、截面設計計算書4） 推薦方案施工驗算書5） 施工中注意事項6） 設計小結2． 圖紙部分：1） 方案比較圖2） 推薦方案整體布置圖3） 推薦方案施工示意圖4） 推薦方案上部結構配筋構造圖5） 細部構造圖四． 主要參考資料1.《公路工程技術標準》JTGB0120032．《橋規》3．教材：《橋梁工程》、《結構設計原理》、《基礎工程》、《橋梁電算》4．與推薦方案相類似的手算實例。The Design of LuoXi Bridge,GuangdongGeneralThe LuoXi bridge,Guangdong,now under construction is a four lane highway bridge downstream of ZhuJiang main bridge is designed jointly by Highway Planning and Design Institute,MOC and Highway Surveying,Planning and Design Institute, whole bridge is constructed by Construction Division,Department of Communication,Guangdong bridge is at south part of Guangzhou city,across the ZhuJiang width of the river is 461m,average depth of water ,average velocity of water ,clay and weathered sandstone etc.,average thickness bedrock is brown sandstone which has an average pressive strength flow is steady and scouring of river bed is not boats are 5000～7000t,navigation width 120m,height the navigation is not closed at construction period,any construction equipment enter the navigation channel is not permitted.Three alternatives were considered in selecting the type of are:continuous rigid frame bridge with main span of 180m,continuous grider bridge with mian span of 150m and cable stayed bridge with 2 pylons with mian span of the persent trend is to eliminate expansion joints as well as bearings in the design of long bridges,after technical and economical parison,the scheme of 65+125+180+110m continuous rigid frame is finally adopted in the main bridge is 480m long with expansion joints provided only at its junctions with approaches,and the superstructure of the mian structure is pletely integral with the piers to form a rigid frame.Single box is used for superstructure of main of box is 4m at bearing of pier,and 10m at bearing of and pier,and 3m at the closure section of the of the two main piers in the river supporting the superstructure is posed of two reinforced concrete legs with dimension ,placed on pile cap immersed in water.The pier is supported by a group of cast in situ reinforced concrete bored pier rests on 12 bored piles each long,and 、 piers rest on 24 piles with average length of and prevent damage of main pier due to ship collision double wall circular steel cofferdam with diameter of 28m at top and 23m at bottom are used around and pier serving as encircling structure of artificial island.Pot rubber bearings which allow only longitudinal displacement are provided at the end piers of main bridges to transmit lateral shear general layout of whole bridge is shown in .ConcreteConcrete with 28 days strength of 50MPa is used for superstructure and 、 pier walls,and concrete with strength of 30MPa is used for 、 pier walls and pile caps,and concrete with strength of 25MPa is used for test mixes of concrete are required to find the suitable consistency to facilitate the casting of concrete at deep bottom parts of box section in which the reinforced steel and prestressed tendon are densely distributed. Durability, appearance and watertightness of concrete shall conform to the appropriate requirements, and the requirement to remove the form one day after casting of concrete and to take load after three days of casting shall also be tests shall be undertaken before construction to ascertain the modulus of elasticity as well as creep and shrinkage characteristic of concrete.Post tensioned tendon and prestressing systemPost tensioned tendon of superstructure is posed of wire strands and high strength 1 gives the characteristic of the pretressed seven wire strand is supplied by VSL HongKong,and high strength bars domestic product.Table 1. Characteristies of Prestressing SteelItemsSeven wire strandsHigh strength barsNominal diameter (mm)32Nominal cross section(mm2)99804Ultimate strength(N/mm2)18651028Yield strength(N/mm2)1665765Relaxation(1000/h,20℃,initial stress is ultimate strength)7%5%All the longitudinal pretressing tendons are or strands,anchored at one end by EC519 or EC531 VSL anchor respectively,which has ultimate tensile strength 3496kN and 5704kN respectively,and the tensile force adopted is 75% of ultimate tensile loss is rather small due to relative straightness of duct,hence the strands having length less than 70m are prestressed only at one end,and prestressed at both ends for longer longest continuous tendon of main span exceeds 190m,which is the longest prestressed tendons used in our country.EC531 VSL anchor is used for transverse prestresssing, prestressed alternatively at distance center to center or doubleφ32 finish rolled,deformed high strength bars ,spaced at 50cm used as vertical prestressed tendons of webs.Three way of prestress is used in this bridge,The domesticφ32 finish rolled,deformed high strength bars are used as vertical prestresssing bars,and VSL prestressing systems are used as longitudinal and transverse prestresssing kinds of strands are used,which are strand at top slab,strand at bottom slab ,draped strand ,continuous strand ,post strengthening strand ,and temporary strand .Table 2 shows kinds and quantities of strands used at different locations.Table 2. Types、Kinds and Quantities of Strands at Different LocationsItems65m mid spanTop of pier125m mid spanTop of 、 pier180m mid span110m mid spanStrand at top slab (EC531)2262Draped strand(EC531)88Continuous Strand (EC531)444444Strand at bottom slab (EC519)26304026Post streng – thening strand(EC519)4444Temporary strand (E