柱下鋼筋混凝土條形基礎(chǔ)設(shè)計(jì)

1、圖1為某框架結(jié)構(gòu)柱網(wǎng)布置圖。已知B軸線上邊柱荷載設(shè)計(jì)值F,中柱荷載設(shè)計(jì)i值F,初選基礎(chǔ)埋深為d,地基土承載力特征值f,設(shè)計(jì)參數(shù)的值見表1,試設(shè)計(jì)B軸線上條形基礎(chǔ)JL2。irt4中I|Fj'R.Fj-sF),FibfflfiaaJUvitLMiA；J-(J-IS(fl-IS中_Li-L-"_LiL.11 '；2)®(D®(T圖1.1柱網(wǎng)平面布置圖表1.1設(shè)計(jì)參數(shù)柱荷載F(kN)柱間距L(m)基礎(chǔ)埋深d承載力特征值faF1F2L1L22m150kPa1200kN1400kN7.2m9m:、設(shè)計(jì)要求1.進(jìn)行基礎(chǔ)平面布置；2 .確定基礎(chǔ)底寬、長度、肋梁高度

2、、翼板厚度;3 .取結(jié)構(gòu)計(jì)算簡圖；4 .結(jié)構(gòu)計(jì)算，按倒梁法計(jì)算基礎(chǔ)內(nèi)力5、根據(jù)內(nèi)力進(jìn)行配筋。設(shè)計(jì)計(jì)算書1.基礎(chǔ)平面布置圖根據(jù)題目條件及表中數(shù)據(jù)，繪制基礎(chǔ)平面布置圖，如圖3.1.1所示圖3.1.12.基礎(chǔ)底面尺寸(1)確定荷載合力重心位置設(shè)合力作用點(diǎn)與邊柱A的距離為x,根據(jù)合力距定理,以A為參照點(diǎn),有:cFx14007.2140014.4140021.6140028.8120036ikiF1400412002ik確定基礎(chǔ)梁的長度和外伸尺寸18n基礎(chǔ)梁兩端外伸長度為a、a,取邊跨的0.25倍12取a0.257.21.8n1L2(xa)2(181.8)39.6mc1a39.61.87.251.8m2

3、(3)按地基持力層的承載力確定基礎(chǔ)梁的寬度bbFk1400412002L(f2(d)39.6(150202)1.83n1.8n(4)確定肋梁高度及翼板高度采用C30混凝土，f1.43N/mmt基底沿寬度b方向的凈反力pf80001122cN/4nbL1.839.6.懸臂根部剪力設(shè)計(jì)值V0.41.8112.2(0.2)78.54<N/m2翼緣板有效高度h 0.7 fl0h t78.5410378.5mm0.711.43161取h22cmm（等厚翼板）。0-11梁局取h-L-7200900Tlm818平面圖如圖3.2.1所示圖3.2.1立面圖如圖3.2.2所示圖3.2.23.基礎(chǔ)梁內(nèi)力計(jì)算（

4、倒梁法）將基礎(chǔ)倒置作為多跨連續(xù)梁，將外力荷載視為支座，將地基凈反力與柱腳的彎矩視作基礎(chǔ)梁上的荷載，作出計(jì)算簡化圖，如圖3.3.1所示圖 3.3.1(1)基礎(chǔ)沿縱向的地基凈反力F q bp =Lk1200 2 1400 4202.02kN.m39.6nj(2)計(jì)算梁內(nèi)彎矩為方便計(jì)算，將倒梁法計(jì)算簡圖圖分解為以下兩部分，如圖3.3.2所示:(a)五跨連續(xù)外伸部分受局部荷載.A.B.C.D.Ee FLbMMMMMMMMMiHiLhBBJlMMMMBmI1MHMMBMMMMMBMI202.2kN/m(b)五跨等跨連續(xù)梁受均布荷載圖3.3.21)對(duì)圖3.3.2(a),采用彎矩分配法進(jìn)行計(jì)算L8m7乙2m

5、LULLUdUJJyr/202.02kN/m0.4290.5710.50.50.50.50.571327.27327.27下163.64-93.44-46.7211.682336233611B84677293.44分配及傳遞-5.010-1.93-0.37-6.674.49-2.560.87-0.500.16>-3.338.97>-1.28>-0.250.31-14.60-29.208.974.48-2.17<-4.331.730.86-0.38<-0.740.310.16-29.20=>-14.604.17-4.330.62-0.740.118.34>

6、;-2.171.24>-0.380.22-0.05-0.11-0.13-0.13327.2786.08-86.08-17.2217.22-17.2217.2286.08根據(jù)分配繪制彎矩圖，如圖3.3.3圖3.3.32)對(duì)圖3.3.2(b),采用彎矩系數(shù)法進(jìn)行計(jì)算圖 3.3.4等跨連續(xù)梁受均布荷載，直接采用彎矩系數(shù)法公式：Mmq12，根iin據(jù)查的的數(shù)據(jù)知：rmB2"50.105rmB3m0.079故：MM0.105202.027.21099.64kNmBEMMCD跨中彎矩：1MnqL2AB8AB0.015202.027.2827.34kNm11099.640202.027.28

7、2759.27NmMBCMDC1qL28BC1qL28DCMMCB2MMDC211099.64827.34202.027.2821827.34827.34202.027.282345.60Nm481.75NmMdeMbc345.60NmMEFMAB759.27Nm繪制彎矩圖，圖3.3.45927.7591099.641099.643.3.5所示3)將兩個(gè)彎矩圖進(jìn)行疊加之后，為最終彎矩圖，如圖圖3.3.5(3)計(jì)算梁內(nèi)剪力qin01q2202.021.8363.6kNVB左1202.021013.56327.277.5631.*NMBMAl1一202.027.521013.56327.27,82

8、2.6cN7.5202.02750.7kN844.561013.567.57.5VC左1qnl21qn2MM-CBl2MMDCl1202.02844.561013.567.57.51202.027.5727.3<N2703.aN通過計(jì)算得各支座剪力如下表：1友3.3.1各支座剪力H算結(jié)果V一A，左V-A右V=B,右VC,左V一C,右VD,左V=D,右V=E,左V=F，左V=F,右363.6631.9822.6750.7703.8727.3727.3703.8750.7822.6631.9363.6(4)校核軸力對(duì)A點(diǎn)：F363.6A對(duì)B點(diǎn)：631.9995.5kNF750.7B對(duì)C點(diǎn)：822.61573.3Nfc727.3703.81431.1kNA11431.1-1400F -F100%100%2.22%C1400根據(jù)表3.3.1繪制剪力圖，如C 2F2經(jīng)驗(yàn)算誤差均小于20%故不需要進(jìn)行調(diào)整圖3.3.6所示AB單純的課本內(nèi)容，并不能滿足 學(xué)生的需要，通過補(bǔ)充，達(dá)到內(nèi)容的完善F -FF1100%100%1