橋梁工程PPT(姚林森第二版)第2篇 第6章

1、第二篇 鋼筋混凝土和預應力混凝土簡支梁橋第6章 梁式橋的支座武漢理工大學交通學院道路橋梁工程系Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology本章內(nèi)容 1.1 概述 Summary 1.2 支座的類型和構(gòu)造 The type and structure of support 1.3 支座的設(shè)計與計算 Design and calculation of bearing武漢理工大學交通學院道路橋梁工程系Dept of Road & Bridge En

2、gineering, School of Transportation, Wuhan University of Technologya.傳遞上部結(jié)構(gòu)的支承反力；b.保障結(jié)構(gòu)在活載、溫度變化、混凝土收縮和徐變等因素作用下的自由變形， 以使上、下部結(jié)構(gòu)的實際受力情況符合結(jié)構(gòu)的靜力圖示。 1.1 概述(1)支座的作用 武漢理工大學交通學院道路橋梁工程系Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology知識點：梁橋支座的作用及布置，開始講解這個知識點(2)支座的

3、合理布置 1.1 概述a.較大縱坡的橋武漢理工大學交通學院道路橋梁工程系Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyb.連續(xù)梁橋知識點：梁橋支座的作用及布置，講解結(jié)束本章內(nèi)容 1.1 概述 Summary 1.2 支座的類型和構(gòu)造 The type and structure of support 1.3 支座的設(shè)計與計算 Design and calculation of bearing武漢理工大學交通學院道路橋梁工程系Dept of Road &

4、amp; Bridge Engineering, School of Transportation, Wuhan University of Technology武漢理工大學交通學院 制作：陳小佳a.簡易墊層支座b.橡膠支座c.弧形鋼板支座（目前很少采用）d.鋼筋混凝土擺柱式支座（目前很少采用） 1.2 支座的類型和構(gòu)造Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology知識點：支座類型，開始講解這個知識點a.適用于標準跨徑小于10m的簡支板、梁橋；b.采用

5、若干層油毛氈或石棉做成， 壓縮后的厚度不小于1cm；c.該種支座變形性能較差，容易引起附加的內(nèi)力。 SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN1. 簡易墊層支座 簡易墊層支座的特點：武漢理工大學交通學院道路橋梁工程系Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1cm板、梁橋上部結(jié)構(gòu)1.2 支座的類型和構(gòu)造橡膠支座的優(yōu)點構(gòu)造簡單加工方便造價低結(jié)構(gòu)高度小安裝方便使用性能良好橡膠支座的分類板式橡膠支

6、座a.盆式橡膠支座SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN2.橡膠支座 Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造板式橡膠支座 SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan

7、 University of Technology1.2 支座的類型和構(gòu)造 a.變形機理l 轉(zhuǎn)動變形：利用橡膠的不均勻彈性壓縮實現(xiàn)l 水平位移：利用橡膠的剪切變形實現(xiàn)顯然橡膠支座水平位移和轉(zhuǎn)動變形的大小與支座的厚度有關(guān)。SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN板式橡膠支座的構(gòu)造 Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造薄鋼片mm內(nèi)橡膠層5mm外橡膠層2.5mm圓形

8、矩形tdS40)(2batabSSCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN矩形支座的常見尺寸 Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造l12x14cml14x18cml15x20cm 豎向支撐反力100KN到10000kN l氯丁橡膠l天然橡膠l三元乙丙橡膠 矩形矩形支座的支承反力矩形支座的常見材料其他板式橡膠支座SCHOOL OF TRANSPORTATION,

9、WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造l聚四氟板橡膠支座 利用聚四氟板和不銹鋼板之間較低的摩擦系數(shù)，使橋梁上部結(jié)構(gòu)的水平位移不受限制l球冠圓板式橡膠支座 頂面用純橡膠制成球形表面（最大410mm),使支座傳力均勻，改善或避免支座底面產(chǎn)生偏壓、脫空等不良現(xiàn)象。適于縱橫坡較大（3%5%）的立交橋及高架橋。 SCHOOL OF TRANSPORTATION, WUT PRODUC

10、ED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology橋梁縱坡 過去對梁體縱坡為1%3%的橋梁，橡膠支座安裝使用時，在梁底與支座之間安置與橋梁縱坡一致的楔形鋼板（或楔形混凝土墊塊），或?qū)α憾说撞孔飨鄳幚恚允怪ё街?，防止垂直反作用力的分力對支座的剪切作用?現(xiàn)在可以采用新型坡型板式橡膠支座，坡度1-4%，根據(jù)特殊要求，坡度可做到6-8%。 坡形板式橡膠支座1.2 支座的類型和構(gòu)造SCHOOL OF TRANSPORTATION,

11、 WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology 板式橡膠支座注意事項1.2 支座的類型和構(gòu)造 盡可能地保證梁底與墊石頂面平行、平整，使其與橡膠支座上下面全部密貼，避免偏心受壓、脫空、不均勻受力的現(xiàn)象發(fā)生。 SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of T

12、ransportation, Wuhan University of Technology板式橡膠支座的表示1.2 支座的類型和構(gòu)造 我國交通部頒布的成品板式橡膠支座代號的表示方式，按交通部JT標準第5.1條有這樣幾項代碼組成：名稱、型式、規(guī)格及膠種。如GJZ300*400*47（CR）,表示公路橋梁矩形、平面尺寸300*400、厚度47的氯丁橡膠支座；又如GYZF4300*54（NR），表示公路橋梁圓形、直徑300、厚度54、帶聚四氟乙烯滑板的天然橡膠支座。另外，除了常用支座外，還有一些特制支座，如同濟大學橋梁工程系研制的球冠支座、抗震支座等。名稱代號（GJZ表示公路橋梁矩形支座；GYZ表示

13、公路橋梁圓形支座；TBZ表示鐵路橋梁板式支座） 形式代號（F4表示四氟滑板支座；不加代號為普通支座） 外形尺寸（矩形La*Lb*（mm）,圓形d*（mm） 橡膠分類（氯丁橡膠、天然橡膠、三元乙丙橡膠） 盆式橡膠支座工作原理SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN 盆式橡膠支座Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology 利用半封閉鋼制盆腔內(nèi)的彈性橡膠塊，在三向受力狀態(tài)下具有流體的性質(zhì)，來實現(xiàn)

14、上部結(jié)構(gòu)的轉(zhuǎn)動；同時依靠中間鋼板上的聚四氟乙烯板與上座板上的不銹鋼板之間的低磨擦系數(shù)來實現(xiàn)上部結(jié)構(gòu)的水平位移。 從實驗的數(shù)據(jù)來看，橡膠處于三向約束狀態(tài)時的抗壓彈性模量為5X104kg/cm2,比無側(cè)向約束的抗壓彈性模量增大近20倍，因而支座承載能力大大提高，解決了普通橡膠支座承載能力的局限。 所以，盆式橡膠支座能滿足大的支承反力，大的水平位移，大的轉(zhuǎn)角的要求。 1.2 支座的類型和構(gòu)造SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transpo

15、rtation, Wuhan University of Technology盆式橡膠支座的表示1.2 支座的類型和構(gòu)造名稱代號（GJZ表示公路橋梁矩形支座；GYZ表示公路橋梁圓形支座；TBZ表示鐵路橋梁板式支座） 支座設(shè)計承載力（以MN計） 使用性能分類代號SXSX、DXDX、GDGD適用溫度分類代號：F表示耐寒型，常溫型不表示 GPZ35DX：表示GPZ系列中設(shè)計承載力為35MN的單向活動的常溫型盆式支座。GPZ50GD：表示GPZ系列中設(shè)計承載力為50MN的固定的常溫型盆式支座。 盆式橡膠支座的構(gòu)造SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J

16、 CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造弧形鋼板支座SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN3.其他支座Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造鋼筋混凝土擺柱式支座SCHOOL OF

17、 TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造球形鋼支座SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.

18、2 支座的類型和構(gòu)造a.球形鋼支座通過球面?zhèn)髁Γ?不出現(xiàn)力的縮頸現(xiàn)象，作用 在混凝土上的反力比較均勻；b.球形鋼支座通過球面聚四氟乙烯板的滑動來實現(xiàn)支座的轉(zhuǎn)動過程， 轉(zhuǎn)動力矩小，而且轉(zhuǎn)動力矩只與支座球面半徑及聚四氟乙烯板的摩 擦系數(shù)有關(guān)，與支座轉(zhuǎn)角大小無關(guān)，特別適用于大轉(zhuǎn)角的要求，設(shè) 計轉(zhuǎn)角可達0.05rad；c.支座各向轉(zhuǎn)動性能一致，適用于寬橋、曲線橋；d.支座不用橡膠承壓，不存在橡膠老化對支座轉(zhuǎn)動性能的影響，特別 適用于低溫地區(qū)。拉力支座SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge E

19、ngineering, School of Transportation, Wuhan University of Technology 橋梁中有的支座在運營荷載作用下，有時會出現(xiàn)上拔拉力，需要設(shè)置拉力支座。所謂拉力支座是既能承受壓力也能承受拉力的支座。彎橋和斜交較大的某些梁位上的支座都可能需要拉力支座。 對于固定支座，則可在盆式橡膠支座中心穿一根預應力鋼筋，鋼筋套在喇叭狀的套管內(nèi)，可允許預應力筋有微小位移。此外，也可在靠近支座的兩側(cè)，上部結(jié)構(gòu)的轉(zhuǎn)動軸線上布置預應力筋，使支座能承受拉力。預應力鋼筋的預加力要按1.2倍的上拔力進行施力，使支座不會因錨桿伸長而脫開。 活動拉力支座，可以采用銷接的擺

20、動支座。當活動量不是很大時，可選用柱中心加預應力的混凝土柔性柱。柔性柱的上下端可做成固結(jié)或鉸接，柱內(nèi)需要配置受彎鋼筋。此外，活動拉力支座也可考慮選用在盆式橡膠支座的兩側(cè)設(shè)置具有活動量的預應力鋼筋。1.2 支座的類型和構(gòu)造拉力支座形式SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.2 支座的類型和構(gòu)造減震支座形式SCHOOL OF TRANSPORTAT

21、ION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology抗震球形鋼支座1.2 支座的類型和構(gòu)造知識點：支座類型，講解結(jié)束本章內(nèi)容 1.1 概述 Summary 1.2 支座的類型和構(gòu)造 The type and structure of support 1.3 支座的設(shè)計與計算 Design and calculation of bearing武漢理工大學交通學院道路橋梁工程系Dept of Road &

22、amp; Bridge Engineering, School of Transportation, Wuhan University of Technology支座的受力特點SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHEN1.3支座的設(shè)計與計算Dept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology 作用在支座上的豎向力有結(jié)構(gòu)自重的反力。在計算汽車荷載支座反力 時，應計入沖擊影響力。當支座可能出現(xiàn)上拔力時，應

23、分別計算支座 的最大豎向力和最大上拔力。 直線橋梁的支座，一般僅需計入縱向水平力。斜橋和彎橋的支座，還 需要考慮由于汽車荷載離心力或其它原因如風力等產(chǎn)生的橫向水平力。 汽車荷載產(chǎn)生的制動力，應按照公路橋涵設(shè)計規(guī)范要求，根據(jù)車道數(shù) 確定。剛性墩臺各種支座傳遞的制動力，按規(guī)范中的規(guī)定采用。其中， 規(guī)定每個活動支座傳遞的制動力不得大于其摩阻力；當采用厚度相等 的板式橡膠支座時，制動力可平均分配至各支座。 對于梁橋，地震地區(qū)橋梁支座的外力計算，應根據(jù)設(shè)計的地震烈度， 按的規(guī)定進行計算和組合。知識點：板式橡膠支座的設(shè)計計算，開始講解這個知識點一、板式橡膠支座的設(shè)計計算SCHOOL OF TRANSPOR

24、TATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology（一）支座平面尺寸 根據(jù)橡膠支座和支承墊石混凝土的壓應力不超過它們相應容許承壓應力的要求，確定支座平面面積。在一般情況下，面積由橡膠支座的強度控制設(shè)計：1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineerin

25、g, School of Transportation, Wuhan University of Technologyn 支座厚度 梁式橋的主梁由溫度變化等因素在支座處產(chǎn)生的縱向水平位移，依靠全部橡膠片的剪切變形t來實現(xiàn), 與t的關(guān)系為：tah由有1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.3支座的設(shè)計與計算G橡膠的剪切模量；

26、A橡膠支座的面積。SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology由此可得，1.3支座的設(shè)計與計算另應滿足規(guī)范要求p180： 矩形支座：a/10ta/5 圓形支座：d/10td/5加勁鋼板厚 p181SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Eng

27、ineering, School of Transportation, Wuhan University of Technology1.3支座的設(shè)計與計算（二）支座偏轉(zhuǎn)與平均壓縮變形驗算2s1sNh（二）支座偏轉(zhuǎn)與平均壓縮變形驗算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology根據(jù)下式計算：1.3支座的設(shè)計與計算若梁端轉(zhuǎn)角已知，或按公式算得，則有：得SCH

28、OOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology（三

29、）支座抗滑性驗算1.3支座的設(shè)計與計算計算實例p181知識點：板式橡膠支座的設(shè)計計算，講解結(jié)束二、弧形鋼板支座的設(shè)計計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology1.3支座的設(shè)計與計算 弧形鋼板支座的設(shè)計與計算包括確定支座的平面尺寸a和b、支座墊板的厚度h和弧形鋼板的弧面半徑r，固定支座尚須驗算齒板或稍釘?shù)目辜魪姸?。SCHOOL OF TRANSPO

30、RTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyn 確定鋼板的平面尺寸1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyn 確定鋼

31、板的厚度1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyn 確定下墊板弧面半徑1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuh

32、an University of Technologyn 驗算齒板的抗剪強度1.3支座的設(shè)計與計算SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technology三、鋼筋混凝土擺動柱式支座的計算n 確定上、下墊板（平鋼板）的平面尺寸和厚度1.3支座的設(shè)計與計算 通過鋼板與梁底和墩臺頂混凝土的局部承壓強度計算確定平面尺寸a和b，再由鋼板的抗彎計算確定厚底h。計算方法與弧形鋼

33、板支座的相同。SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyn 確定上、下弧形鋼板的弧面半徑和擺柱高度1.3支座的設(shè)計與計算 由接觸應力的強度條件確定弧面半徑r，則包括弧形鋼板在內(nèi)的擺柱全高為H=2r?；⌒武摪宓暮穸韧ǔＨ∨c墊板的相同，則鋼筋混凝土短柱的高度為H=H-2h。SCHOOL OF TRANSPORTATION, WUT PRODUCED BY

34、：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wuhan University of Technologyn 確定擺柱的平面尺寸1.3支座的設(shè)計與計算 擺柱和弧形鋼板橫橋向的長度b通常取稍小于上、下墊板的長度，以便赤板與齒槽相互匹配。對于順橋向?qū)挾萢的確定，當不計按0.5%含鋼率配置的豎向鋼筋作用時，可按下式確定：bfNckcj9 .0a0式中：Ncj按極限狀態(tài)設(shè)計的計算壓力； 0結(jié)構(gòu)的重要性系數(shù)； fck混凝土軸心抗壓值強度標準。 SCHOOL OF TRANSPORTATION, WUT PRODUCED BY：X J CHENDept of Road & Bridge Engineering, School of Transportation, Wu