塔吊基础设计讲解.doc

塔吊基础设计讲解一、概述1.1 编制依据1 地基基础设计规范GB5000720022 塔吊起重机设计规范GB/T13752923 砼设计规范4 桩基技术规范JGJ94945 塔吊说明书1.2 塔吊基础设计要点1.2.1塔吊基础所承受的外力根据塔式起重机设计规范（GB/T13752-92），塔机设计荷载包括基本荷载-自重荷载，起升荷载，包括或不包括起升机构传动机构加速荷载，坡度荷载附加荷载-工作状态的风荷载特殊荷载-非匀速提升重物荷载，非工作状态风载，动或静态试验荷载，碰撞荷载，突然停机荷载。上述各项荷载和荷载组合往往以塔吊作用于基础顶面的，分为非工作状态和工作状态的竖向力，水平力和弯矩表示。但仅限于塔吊自由高度时的外力，附墙后外力如何变化说明书中未作说明，依据力学分析可知附墙后再增加塔吊高度时垂直荷载有所增加但弯矩和水平力大为减少有利于塔吊的安全。1.2.2依据说明书选择塔吊基础存在的问题当前塔吊基础的选型或基础外力仅与塔吊吊钩的高度有关，其中存在如下问题：1）未反映不同地域风载的不同：基本风压在内陆约0.30.4KN/m2，在沿海约0.9KN/m2二者相差三倍左右。影响风载的高度变化系数，距地面40m为1.56距地面100m为2.09，二者相差约30%。而风载值在很大程度上决定塔吊的水平力与部分弯矩。2）若干塔吊说明书提供的塔吊对基础的作用力仅示有压力和拉力，未说明是何种情况下的外力；也未说明作用在单肢上抑或双肢上；也未提供计算必不可少的水平作用力；以此为据设计基础条件不足。3）说明书中的基础构造不合理：说明书提供的基础块配筋既不合理又偏大，以H3/36B为例选M169N，基础尺寸为6.456.451.7m，双层双向配5525钢筋Ag=455490=107800mm2而按砼规范计算Ag=26416=12832mm2二者相差甚远。1.2.3塔吊基础设计内容：塔吊对基础的基本要求是：塔吊通过基础或承台传递的作用力不大于天然（人工）地基承载力特征值或桩的承载力，以及塔吊在各种工况下均能保持其稳定性。1）确定基础外力：根据施工项目特点选择塔吊型号，臂长，初始立塔高度，极限高度，附墙道数，标高和具体立塔位置。塔吊供应厂家根据上述条件提供初始立塔高度及顶升附墙后的，非工作状态及工作状态时，作用在基础顶面的竖向力N，水平力H和弯矩M。厂家尚应提供附墙装置类型、塔吊中心与附墙点的距离和作用力；提出予埋节（件）的位置和埋深等资料。2）确定基础型式：塔吊基础应在基坑方案确定以后进行选型和计算。塔吊基础型式与基坑边坡有关：当塔吊座落于基坑内，可在天然地基或人工地基上作独立的塔吊基础；若塔吊在基础底板完成后安装，且有安装条件时也可利用或部分利用建物底板作塔吊基础。当塔吊位于基坑侧壁以上：灌注桩护坡时，可部分利用护坡桩支承塔吊，被利用的护坡桩应具有支护和支承双重功能。边坡为自然放坡时，可采用独立式塔吊基础，地基应有足够的承载力和稳定性。采用土钉墙护坡除地基应有足够的承载力外，土钉应保证塔基的稳定性。3）计算基础对地基的压力：理论上应计算塔吊最大自由高度及附墙后最大高度时非工作与工作状态，四种情况下对地基的压力，取其中最大值。塔吊基础设计，可以只计算非工作状态下最大自由高度时，作用力沿塔吊基础对角线时的基础对地基的作用力，满足此种要求则同时满足了其它要求。4）核算地基承载力：采用天然地基时可依据地基的物理，力学指标确定地基的容许承载力，或用其他方法确定地基容许承载力并进行修正后以核算是否满足基础的要求。当使用桩基则需进行桩基设计5）基础或承台强度计算：各种基础均需核算冲切受剪是否满足要求，并计算配筋。对于承受拉力的桩尚应核算桩的承拉力以及承台在反向作用力时的强度与配筋。6）基础稳定性核算：基础稳定性计算包括滑移和倾覆均需具有足够的安全度。1.3塔吊对基础的作用力1.3.1型式I（图1-1）提供条件为 竖向力N（ KN） 水平力H （KN） 弯矩M(KN.m)作用于基底的竖向力：N+G=N+25A2h（KN）式中G为基础重：25-砼单位重量（KN/m3） A-方形基础之边长（m） h-基础或承台高（m）弯矩：M=M+Hh（KN.m）1.3.2型式II（图1-2）提供条件为竖向力F1 F2水平力HF1 F2为塔吊起重臂与塔吊之对称轴呈450方向时单肢的作用力，若需反算弯矩和垂直力，可近似取N=（F1-F2）2M=（F1+F2）0.707A 式中F1 F2均取绝对值1.3.3常用塔吊的计算参数FO/23B （塔身2m2m）工作状态非工作状态吊钩高重量N弯矩M水平力H支座反力重量N弯矩M水平力H支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg8.854130993761831237255079044130727604628162463831111.8557101038501989250085286345710727605133158513870614.8572901087992147264685511347290727605638154563910117.8587701140712295280755746048770727606862150863947120.8602501197862443298485997350250727607335147163984123.8617301259462591317876265251730727607809143464021126.8632101325502739338936549853210727608460139764058129.8646901395972887361656851054690980369111230835042832.86617014708830343860471089561701259139762331656125035.867650155023318241209750345765015574210413439797280438.869130163402333043981785465913018752511063555258509041.870610172225347846918922236061022126111714678039810844.8720701814913626500238606862090256949123658081411185047.8735701912013774532939007863570294591130169455612634150.87505020135639225673094255650503341851366710903114155653.87653021195440706033498599665303757321431812423815750356.878010222996421864104103109680104192331496914017817418359.8794902344814366680401077856949046468515520156849191594FO/23C （塔身1.6m1.6m）工作状态非工作状态吊钩高重量N弯矩M水平力H支座反力重量N弯矩M水平力H支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg8.851200985961631337405934041200727603988240454464511.8523501028421764354576163242350727604413237574493214.8535001074861897373626411243500727604838234704522017.8546501125292030394556678044650727606013231824550720.8558001179702162417366963645800727606438228954579523.8567701235712284441377252246770727606827226524603726.8577401295372406467117558147740727607362224104628029.8587101358682527494577881248710844787897276995205432.85968014256326495237482214496801088528432389626380235.86065014962327705546485789506501348328967509827630738.86162015704728925872789537516201624159502637608957041.8625901648373013621619345652590191603100367729510359044.86356017299031356576797547535602223951057191588118369H3/36B （塔身2m2m）工作状态非工作状态起升高度N自重M最大力矩H剪切力支座反力N自重M最大力矩H剪切力支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg9.77041515572520754078175989662321849845050527978591312.77218516096722434230478396680021849845587523548635515.77395516671324114401680993697721849846125519128679818.77572517296425794591783779715421849847548514698724021.77749517971827474800786754733121849848085510278768324.77926518697629155028589918750821849848623505848812527.78103519473930835275393271768521849849362501428856830.782805203005325155787971897862218498410102496998901033.7845752117763419595871018758039718498410841492578945336.7863452210513587635101066828216218498411580488148984539.7881152308293755675531166118393218498412320483729033842.7898852411123923717181166618570218498413059479299078045.7916552518994091760051218328747219747813748521719590148.79342526319042598041312712589248240592145386189311251451.795195274985442784942132540910122859251527784447129953ST60/14 （1.6m1.6m）工作状态非工作状态吊钩高N自重M弯矩H剪力支座反力N自重M弯矩H剪力支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg8.851200985961631337405934041200727603988240454464511.8523501028421764354576163242350727604413237574493214.8535001074861897373626411243500727604838234704522017.8546501125292030394556678044650727606013231824550720.8558001179702162417366963645800727606438228954579523.856770123571228444377252246770727606827226524603726.8577401295372406467117558147740727607362224104628029.8587101358682527494577881248710844787897276995205432.85968014256326495237482214496801088528432389626380235.86065014962327705546485789506501348328967509827630738.86162015704728925872789537516201624159502637608957041.8625901648373013621619345652590191603100367729510359044.86356017299031356576797547535602223951057191588118363ST60/14 （2m2m）工作状态非工作状态吊钩高N自重M弯矩H剪力支座反力N自重M弯矩H剪力支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg8.854130993761831237255079044130727604628162463831111.8557101038501989250085286345710727605133158513870614.8572901087992147264685511347290727605638154563910117.8587701140712295280755746048770727606862150863947120.8602501197862443298485997350250727607335147163984123.8617301259462591317876265251730727607809143464021126.8632101325502759338936549853210727608460139764058129.8646901395972887361656851054690980369111230835042832.86617014708830343860471689561701259139762331656125035.867650155023318241209750345765015574210413439797280438.869130163402333043981785465913019752511063555258509041.870610172225347846918822236061022126111714678039810844.8720901814913626500238606862090256949123658081411185947.8735701912013774532939007863570294591130169455612634150.87505020135639225673094255650503341851366710903114155653.87653021195440706033498599665303757321431812423815750356.878010222996421864104103109680104192331496914017817418359.8794902344814366680401077856949046468515620156849191594P16A （1.6m1.6m）工作状态非工作状态吊钩下高度N自重M力矩H剪切力支座反力N自重M力矩H剪切力支座反力拉力压力拉力压力mkgmkgkgkgkgkgmkgkgkgkg8.0053559677501748191994597947559559704848150333881211.0054154699081805200894716648154559705033148843896114.0055344745141921220074967949344559705402145863925817.0055939776531979233685133749939559705587144383940720.0057129856582094269215548651129559706599141403970523.0058319944682210308626002152319610937273163074246726.00595091039992325351496490353509838757781269685372329.006069911418524413975170100546991083548290384466579532.006129411950624984216272809552941212308544444917213835.006248413057926144719078432564841482569052571938543538.006367414219627295248184318576741769789560707129954941.00648641543282845580209045258864207398100688504711447944.00654591605812903608789360859459223244103229252112225147.00666491734473018667701000946064925621010830108081138406256HC （2m2m）节身吊钩高度(m)工作状态非工作状态M(kN.m)H(KN)N(KN)M(kN.m)H(KN)N(KN)臂长60m12.419701863717333359616.620481965919694261920.721322168222855164124.822232270525505666429.023212472828926468733.124242575132187071037.325352777335667573341.426593279639378175545.528415481943318677849.7295556842440387801臂长65m12.419331767216743363716.620101969519104266020.720932171822265168324.821832274124915670529.022792476428336472833.123822578631597075137.324935180935077577441.426555283238788179745.528395585542728681949.7295757873434487842臂长70m12.418291770716273367716.619041973018634270020.719862075321795172324.820752277624445674629.021702379827876476833.122895082131127079137.324475284434607581441.426335586738318183745.528295689042258686049.72954589134297878831.4常用塔吊说明书推荐基础尺寸与对地基承载力的要求：基础的型号与构造示于图1-3与相应表内型号边长A(mm)高度h(mm)体积(m3)直径根数直径根数M52N400013502024108821.6M64N445013502024108826.73M74N480013502028148831.1M81N50001350203014101033.8M101N56001350253316111142.3M126N62501350255216141452.8M142N59401700253816121259.2M169N64501700255520131370.7型号中数字表示基础重（T）地基承载力kg/cm2(105N/m2)Fo/23C 1.6m1.6mFo/23B 2m2m吊钩高m基础型号吊钩高m基础型号M64NM74NM81NM101NM81NM101NM142NM126NM169N8.81.611.341.220.978.81.240.991.070.900.8611.81.681.381.261.0011.81.281.021.080.860.8814.81.751.431.301.0214.81.331.041.040.860.9017.81.831.491.351.0517.81.371.071.070.880.9220.81.921.541.401.0920.81.431.111.090.900.9423.82.021.611.451.1223.81.491.151.120.931.0226.82.121.691.511.1526.81.551.191.160.961.0729.82.241.761.571.1929.81.621.231.190.991.0232.82.371.851.641.2332.81.701.281.231.021.0535.82.521.951.721.2835.81.911.371.301.061.0938.82.352.001.4038.82.391.611.461.201.2041.82.501.6441.81.921.651.311.3344.81.9544.82.341.901.671.4847.82.892.201.831.6650.82.592.161.8753.82.1356.82.4659.82.85地基承载力kg/m2(105N/m2)M3/36B 2m2m吊钩高mM101NM142NM126NM169N9.71.491.371.141.1512.71.491.371.151.1615.71.491.381.151.1618.71.491.381.151.1621.71.501.401.161.1824.71.551.431.191.2027.71.601.471.231.2330.71.661.521.271.2633.71.731.571.311.3036.71.801.621.351.3339.71.881.671.401.3742.71.961.731.451.4145.72.061.791.501.4548.72.161.861.551.5054.72.562.131.761.66ST60/14的基底压力 kg/cm2(105N/m2)1.6m1.6m2m2m吊钩高mM64NM74NM81NM101N吊钩高mM81NM101NM142NM126NM169N8.81.611.341.220.978.81.240.991.070.900.8611.81.681.381.261.0011.81.281.021.080.860.8814.81.751.431.301.0214.81.331.041.040.860.9017.81.831.491.351.0517.81.371.071.070.880.9220.81.921.541.401.0920.81.431.111.090.900.9423.82.021.611.451.1223.81.491.151.120.931.0226.82.121.691.511.1526.81.551.191.160.961.0729.82.241.761.571.1929.81.621.231.199.991.0232.82.371.851.641.2332.81.701.281.231.021.0535.82.521.951.721.2835.81.911.371.301.061.0938.82.352.001.4038.82.391.611.461.201.2041.82.501.6441.81.921.851.371.3544.81.9544.82.341.901.671.4847.82.892.201.831.6650.82.592.161.8753.82.1356.82.4659.82.85P16A的基底压力 kg/cm2(105N/m2)吊钩下高度M52NM64NM74NM81NM101NM126N8.001.611.271.091.010.830.7011.001.651.301.111.030.840.7114.001.731.351.151.070.930.7317.001.781.381.171.090.970.7420.001.891.451.231.130.920.7723.002.071.551.301.200.960.8026.002.281.681.391.271.020.9229.002.721.901.531.381.080.9032.00*2.131.681.501.140.9335.00*2.732.061.801.311.0338.00*2.582.201.521.1441.00*2.741.771.2844.00*1.931.3747.00*2.321.56256HC塔基边长（m）安装高度（m）地基承载力（KN/m2）臂长10013016019022025012.46.25.55.24.94.84.755.0m/60.0m radius16.66.35.65.35.04.94.920.76.65.95.55.35.15.124.86.86.15.65.55.35.329.07.16.36.05.75.65.633.17.36.66.25.95.85.837.37.56.86.46.16.06.041.47.87.06.66.36.26.245.58.07.26.86.56.56.549.78.07.26.86.56.56.512.46.25.55.14.84.64.565.0m/70.0m radius16.66.35.65.24.94.74.620.76.55.85.45.15.04.824.86.76.05.65.35.15.129.07.06.25.85.65.55.533.17.26.56.05.85.65.637.37.56.76.26.05.85.841.47.76.96.56.26.06.045.58.07.16.76.46.36.349.78.07.16.76.46.36.312.46.35.65.25.04.84.831.7/36.7/43.3/48.3m adius16.66.55.85.45.25.05.020.76.76.05.75.45.35.324.86.96.25.95.65.55.529.07.26.56.15.95.85.833.17.46.76.36.16.06.037.37.66.96.56.36.26.241.47.97.16.76.56.46.445.58.17.36.96.66.66.649.78.27.36.96.76.66.6注：基础高度1.4m二、天然地基独立基础计算2.1基底压力计算：按承载力计算地基应符合下式要求Pfa (2-1)式中P-基底平均压力（104N/m2）fa-修正后地基承载力特征值（104N/m2）见2.2受偏心荷载作用时除需符合式2-1外尚应满足Pmax1.2fa (2-2)式中Pmax-基底最大边缘压力2.1.1轴心或单向偏