橋墩樁基礎(chǔ)設(shè)計計算書..

1、基礎(chǔ)工程課程設(shè)計一設(shè)計題目：某橋橋墩樁基礎(chǔ)設(shè)計計算二設(shè)計資料：某橋梁上部構(gòu)造采用預(yù)應(yīng)力箱梁。標(biāo)準(zhǔn)跨徑30m，梁長29.9m，計算跨徑29.5m,橋面寬13m(10+2x1.5),墩上縱向設(shè)兩排支座，一排固定，一排滑動，下部結(jié)構(gòu)為樁柱式橋墩和鉆孔灌注樁基礎(chǔ)。1、水文地質(zhì)條件：河面常水位標(biāo)高25.000m，河床標(biāo)高為22.000m，般沖刷線標(biāo)高20.000m，最大沖刷線標(biāo)高18.000m處，一般沖刷線以下的地質(zhì)情況如下:(1)地質(zhì)情況c(城軌)：序號名稱層厚土層描述天然重度Y比例系數(shù)m推薦容許承載力“極限摩阻力T1淤泥質(zhì)土4.6m軟塑16kN/m標(biāo)準(zhǔn)荷載:(1) 恒載橋面自重：N=1500kN+8

2、x10kN=1580KN;箱梁自重：N2=5000kN+8x50Kn=5400KN;墩帽自重：N3=800kN;橋墩自重：N4=975kN；扣除浮重：10*2*3*2.5=150KN(2) 活載跨活載反力：N5=2835.75kN，在順橋向引起的彎矩：M廠3334.3kMf;兩跨活載反力：N6=5030.04kN+8x100kN；(3) 水平力制動力：H廠300kN，對承臺頂力矩6.5m;風(fēng)力：H2=2.7kN對承臺頂力矩4.75m主要材料6MN/m承臺采用C30混凝土，重度Y=25kN/n3>y45kN/m3浮容重)，樁基采用C30混凝土，HRB335級鋼筋；50kPa20kPa2粘土

3、3.8m灰黃色，硬塑17kN/m315MN/m4240kPa50kPa3碎石>50m黃色，密實20kN/m355MN/m4550kPa240kPa4、墩身、承臺及樁的尺寸墩身采用C30混凝土，尺寸:長寬高=3仏6.5皿3。承臺平面尺寸:長寬=7熔.5皿2,厚度初定2.5m，承臺底標(biāo)高20.000m。擬采用4根鉆孔灌注樁，設(shè)計直徑1.0m，成孔直徑1.1m，設(shè)計要求樁底沉渣厚度小于300mm。5、其它參數(shù)結(jié)構(gòu)重要性系數(shù)Yo=1.1荷載組合系數(shù)年10,恒載分項系數(shù)Y=1.2活載分項系數(shù)Y=1.46、設(shè)計荷載（1）樁、承臺尺寸與材料承臺尺寸：7.0mx4.5mx2.5m初步擬定采用四根樁，設(shè)計

4、直徑1m,成孔直徑1.1m。樁身及承臺混凝土用30號，其受壓彈性模量Eh=3x104MPa。（2）荷載情況上部為等跨30m的預(yù)應(yīng)力箱梁橋，混凝土橋墩，作用在承臺底面中心的荷載為:恒載及一孔活載時:N1.2（1580540080097515074.52.515）1.42835.7515713.55KNH1.4（3002.7）423.78KNM3334.3300（2.56.（5）2.7）4.752.51K.N4恒載及二孔活載時:N1.2（1580540080097515074.52.515）+1.45830.04=19905.556KN樁（直徑1m）自重每延米為:n12q=V1511.781KN/

5、m（已扣除浮力）三、計算1、根據(jù)公路橋涵地基與基礎(chǔ)設(shè)計規(guī)范反算樁長根據(jù)公路橋涵地基與基礎(chǔ)設(shè)計規(guī)范中確定單樁容許承載力的經(jīng)驗公式，初步反算樁的長度，設(shè)該樁埋入最大沖刷線以下深度為h，般沖刷線以下深度為h2，則:It2mAaii00ky(h3)222樁的設(shè)計樁徑lm，沖抓錐成孔直徑為1.1m，樁周長和面積為U=nxl.l=3.456m,盲10.785n2,假定樁長20m取久=0.70t/d0.取m°=0.80查表得K2=6.0已知=550KPa2019905.556ql0.5qh405058.8565.891h土換算加權(quán)重度2164.6173.8(h24.63.8)20h2101029.

6、8h2NP1ulT2mA°ky(h3)0.53.456h2ii002224.6203.850(h24.63.8)2400.70.80.7855506(1029.hf)(h1)h12(441.096h21147.916h3829.416)令NhP得4h23h5舍去負(fù)值.)現(xiàn)取h=17m20m,滿足取久=0.70,貝山樁低標(biāo)高為1.00m2.單樁豎向允許承載力代入數(shù)據(jù)h=17m得h2P丄UT2mA°ky(h3)5480.67KN2ii0022229.829.8加權(quán)重度10二10二8.432KN/ma2h21723、樁的平面布置圖25.00m常水位；70022.00m河床20.0

7、0m般沖刷線18.00m最大沖刷線n505000承臺平面布置圖1.00m樁底標(biāo)高10.040010050100150承臺橫橋向立面圖承臺縱橋向立面圖4、樁的內(nèi)力及位移計算(1)確定樁的計算寬度blbKKKd0.9(d1)k，沿水平力H作用方向上裝間凈距1f01b'LL1.5m0.6h0.63(d1)*3.6m，Kb'10.767m,b1.381m，110.6h11滿足nb2.762B'14.5取一排裝兩邊外側(cè)邊緣距離B'3.5m12)計算樁-土變形系數(shù)地面或最大沖刷線下的影響深度h2(d1)4m范圍內(nèi)有兩層土。mmh2m(2hh)hm112120h2m62.61

8、5(22.61.4)1.4/4211197.5KN/m40.67E0.673107h2.°1107Kn/m2,Id4o.。49嘰0.436mi,hh7.4122.5，滿足按彈性樁計算3)樁頂剛度系數(shù)1、2、3、4的計算l20182m,h17m,0.5Ad20.785n204mh011197.5171.904105KN/m3,A042.54.91m2(按樁中心距計算)11Ihf-9AECAh0020.5170.7853107111.9041054.916.601050.670EI已知hh查表得：Q3EI27.4124),取用，l000.4839,50.6491,6MM0.040E1I,

9、2EIQ3M0.43620.872m1.253570.1234EI,EI4M0.5466EI(4)計算承臺地面遠(yuǎn)點O處位移0、b0、單孔活載+恒載+制動力)N15713.555863.26b0n40.670EIEI1n4n2mx21mi140.5466EI0.67EI41.25240.0401EI0.1604EI,n36.3739EI40.1234EI0.4936EI,n20.2436(EI)2nx2HnM41i3i4nn24nMc2ix21ii1nH3n23mnnx2241ii1(n)236.3739EI423.780.4936EI8475.4250.1604EI6.3739EI0.0.24

10、36El)20.1604EI8475.4250.4936EI8475.4250.1604EI6.3739EI0.0.2436El)28840.31EI2014.24Ei(5)計算作用在每根樁頂上的作用力Pi、Qi、Mi豎向力pibx10i00.670EI5863.26El1.2叩5615.31KN2241.46KN水平力Qi彎矩Mi20400.0401EI8840.310.1234EI2014.24105.94KN30EIEI2014.248840.31-a0.5466EI0.1234EI10.09KNm30EIEI校核:nQ4105.94KN423.76KNH423.78KNii1ni1xp

11、iinpInM2(5615.312241.46)1.254i2(5615.312241.46)15713.54KN10.098474.985KNmMp15713.55KN,校核正確8475.425KNm(6)計算最大沖刷線處樁身彎矩M。，水平力Q0及軸向力P0MMQl10.09105.942221.97KNm0ii0QQ105.94KN,P5615.310.7852155641.86KN0i0(7)最大彎矩Mmax及最大彎矩位置Zmax的計算M0.436221.97C-0-0.9135QQ0105.94Z-0.97838查表得：ZZ0.97838,Z2.244mmax0.436可查表(線性內(nèi)插

12、)得KM1.666MMK221.971.463369.80KNm0.436m1,h7.4124(取4)max0M(8)樁頂縱向水平位移驗算樁在最大沖刷線處水平位移xo和轉(zhuǎn)角(p。的計算查表得：Ax2.44066，Bx1.62100，A1.62100，BQM105.94221.97XoAoB2.44066O3EIx2EIx0.4363EI0.4362EI1.750581.621003.21103m3.21mm6mm，符合規(guī)范要求Q7EIEI105.94221.97(山問+亦(1-75058)1-82103rad樁頂縱向水平位移MeiB黑“盼需"75058）1-82103radQl3Ml

13、2m3-211°3（1-821°3）23EI2EI（6-850'31）103m7血水平位移容許值=0.525=2.5cm=25mm符合規(guī)范要求。5、按m法計算樁身入土段任一深度處的彎矩和樁側(cè)橫向土抗力(并作已經(jīng)算出b1.38m,11Z曲線，zMz/、zF曲線）221.97KNm0.436m1,Q105.94KN,M2M0b1ZX00ZZZAxBxZAbx12M0ZBbx1ZX002.440661.6210000.2293580.12.278731.450947.6216682314.43320207612.054870.4587160.22.117791.29088

14、14.166744437.88830950422.055050.9174310.41.802731.0006424.1183641212.2294218236.347791.3761470.61.502680.7498130.1560827813.7458168443.90191.8348620.81.22370.5372732.7432751213.1325980645.875872.29357810.970410.3611932.4573032711.0357992643.49313.4403671.50.466140.0628823.386476872.8818532826.268334

15、.58715620.146960.075729.830742244.627097765.2036445.9633032.6-0.039860.111363.4663132928.84648294412.31286.88073430.087410.094718.770806818.6813080217.45218.0275233.50.104950.0569812.285919286.0933842218.37939.17431240.107880.0148714.433049441.8173519216.25041曲線，ZXVZAx丁ZBx，2MZ”曲線，MzQ-AmM0Bm111xZZZAM

16、BMQAMMB0MMZ00010221.97221.970.2293580.10.09960.9997424.200808221.9122878246.11310.4587160.20.196960.9980647.8573408221.5393782269.39670.9174310.40.377390.9861791.6982222218.9001549310.59841.6055050.70.592280.93817143.9121944208.2455949352.15782.064220.90.689260.88407167.4763948196.2370179363.71342.5

17、229361.10.747140.8141181.5400772180.705777362.24593.2110091.40.764980.68694185.8748404152.4800718338.35493.6697251.60.737340.59373179.1588732131.7902481310.94915.0458722.20.53160.32025129.16816871.0858925200.25415.9633032.60.354580.1754686.155848438.9468562125.10276.88073430.193050.0759546.90728916.

18、858621563.76591&0275233.50.050810.0135412.34581383.005473815.351299.17431240.000050.000090.0121490.01997730.0321266、樁身界面配筋計算（1）配筋的計算最大彎矩發(fā)生在Z=2.082m處,此處設(shè)計最大彎矩為M了369-80<Nm最大設(shè)計豎向力為P0.5qZ0.5UZ5641.860.50M-j66.3mm，又hh7.412(4)Nj11.7810.5，計算長度202.0820.5(23.4565580.718KN4頁）5倔74.4故需要考慮縱向彎曲對偏心距的影響系數(shù)Mj6

19、6.ftm，又hNj1lh7.41(24)計算長度p4°.j65.5874.4e1400h0r500s0)2h10.950075.1mm,r0.22.71e0,1.150.01h20950mm，h1000mm，代入得：10.血,C30混凝土1RB鋼筋Ra17.5Mp,Rgl-0h1而l05.5871.0841取1，0.364,2340MP，偏心距系數(shù)e0rr.1320.13222322.87,彎矩系數(shù)NrMj2958.4r3N軸力系數(shù)N一rr2若取g=0.9,查墩臺與基礎(chǔ)附表得以下表格數(shù)據(jù)實際偏心系數(shù)E-2表中偏心系數(shù)E相應(yīng)E配筋率NrNENrEN1.1320.13440.9800.

20、00222322.87367662958.44943.20.12880.9800.004383904943.20.13570.9600.006393045334.90.13030.9600.008409275334.9當(dāng)u=0.006和u=0.008時均有N>Nr,EN>ENr,故樁身只需要按構(gòu)造配筋，取u=0.006縱筋A(yù)ur24712.39nm2現(xiàn)采用12_22,實配A'188424562mm2gg2）對截面進(jìn)行強(qiáng)度校核實際Ar24562(5000.58%0.5%取a65mm其中rss層厚度C6522T54mm50mm，縱向鋼筋間距91.9mmr435mmgs0.8混凝

21、土保護(hù)r80mm,滿足要求，布置如下圖所3)驗算垂直于彎矩作用平面內(nèi)承載力11.2N(fAfA')N(13.8103122801034562)s0uGcdhsdgu1.1413217.3KNN5580.718KN滿足要求j7、承臺設(shè)計（1）樁與承臺的連接處構(gòu)造設(shè)計承臺平面尺寸：長寬=7熔.5皿2,厚度2.5m，承臺底標(biāo)高20.000m。采用樁頂主筋伸入承臺連接。樁身嵌入承臺內(nèi)的深度為200mm；伸入承臺內(nèi)的樁頂主筋做成喇叭狀，夾角15度。伸入承臺內(nèi)的主筋豎向高度為100cm35*2.2=77cm，不設(shè)彎鉤的帶肋鋼筋?？箯濅摻畈贾迷诔信_內(nèi)上下兩排并且不截斷穿過樁身。箍筋設(shè)20箍_10,間

22、距200mm,構(gòu)造鋼筋前后兩端各18根_10，抗裂鋼筋前后兩端各8根_12下設(shè)相同的鋼筋網(wǎng)具體配筋圖見附圖B。（2）樁頂局部受壓驗算樁頂局部受壓時按右式計算PARj/式中P.承臺內(nèi)基樁承受計算軸向力，jcamjPN5580.718KN,jj1,A120.785mm2,橋梁C30混凝土Rj20.1MP,系數(shù)1.54c4amARj/cam10.78520.1103/1.5410245.78KNN5580.718KN,滿足要求，可按構(gòu)造配筋j(3)承臺受沖切驗算承臺有效高度h0=250-20-4=276cm,跨比樁邊沖切，相關(guān)參數(shù)見樁平面布置圖B，計算沖0x0x502260.840.20x0.221

23、，1.995a0yh00.8425總0.111,計算沖切系數(shù):2260y0.22.701，h25002000,0.9hp0y1.390MP，則2C30混凝土HRB鋼筋取ft2.701(2.50.5)0.91390(ba)0xc0y(h0yc1.995(10.25)a)ox2.2459389.3KNC1C2150cma1x50cm,a25cm,計算沖切系數(shù)1y1x0.560.2fht05615.31KN滿足要求0.56hp0.2210.21.3301y1.801，0.9Nj1x(c0.5a)(c0.5a)hpj1x21y1y11x0.913902.2414888.3KN5615.31KN滿足要求(4)抗剪承載力驗算fhhpt01.330(1.50.50.25)1.801(1.50.50.5)0.221