橋梁設(shè)計(jì)大賽計(jì)算書(共21頁)

1、橋梁結(jié)構(gòu)設(shè)計(jì)理論方案 作品名稱 參賽學(xué)校 參賽隊(duì)員、專業(yè)名稱 指導(dǎo)教師 大慶市大學(xué)生結(jié)構(gòu)創(chuàng)新設(shè)計(jì)競(jìng)賽組委會(huì)二一一年目錄1設(shè)計(jì)說明根據(jù)本次大賽要求及所提供材料，本組成員秉承“安全、節(jié)省、承載力高、美觀”原則，設(shè)計(jì)此橋梁“步步精心”結(jié)構(gòu)模型。橋梁以桁架結(jié)構(gòu)為主體，盡量做到受力均勻，拉桿和壓桿合理分布。其中“桿件承載力充分利用和橋身自重輕”為此設(shè)計(jì)最大亮點(diǎn)。1.1設(shè)計(jì)構(gòu)思在接到比賽要求最初，本組成員經(jīng)過分析得出“材料本身承載力強(qiáng)、材質(zhì)輕、只適合粘結(jié)”的結(jié)論，初步確定以“平面結(jié)構(gòu)，主梁主要承力，桁架結(jié)構(gòu)”為大體思路。為減輕橋梁自重，我們決定盡量多用拉桿，但在模擬加載過程中，發(fā)現(xiàn)此想法難以實(shí)現(xiàn)。遂改用另

2、一種減重方式，即盡量使每根桿都受力均勻，所受最大拉（壓）力和最小拉（壓）力差值最小。1.2結(jié)構(gòu)選型在確定“平面結(jié)構(gòu)、主梁主要承力、桁架結(jié)構(gòu)”為大體思路后，設(shè)計(jì)步驟如下：根據(jù)大賽尺寸要求，初步確定橋梁的跨度、高度和寬度；根據(jù)以往經(jīng)驗(yàn)和資料分析，設(shè)計(jì)出橋梁大體模型；以實(shí)際情況為準(zhǔn)，提取計(jì)算簡圖；利用結(jié)構(gòu)力學(xué)求解器軟件對(duì)結(jié)構(gòu)進(jìn)行模擬加載，計(jì)算出各桿所承受軸力及彎矩，以確定橋梁各單元桿件截面尺寸；結(jié)合桿件密度，取最優(yōu)荷重比。1.3詳細(xì)計(jì)算1.3.1設(shè)計(jì)資料根據(jù)大賽要求，可以確定橋梁跨度L=1300mm，凈跨L0=1200mm，橋?qū)払=185mm，由經(jīng)驗(yàn)和資料初步確定橋高H=150mm，豎向腹桿間距由比

3、賽小車車輪中心軸距離確定，選為120mm。1.3.2橋梁形式、尺寸及支撐布置根據(jù)上述原則，最終確定橋梁如圖1-1,1-2圖1-1正視圖圖1-2俯視圖1.3.3基本假定節(jié)點(diǎn)粘結(jié)處按照鉸接計(jì)算；支座簡支；荷載取為豎直集中靜荷載，分別作用在結(jié)點(diǎn)和單元上考慮動(dòng)荷載影響，計(jì)算荷載取為實(shí)際荷載1.2倍；忽略橋本身自重，材料材質(zhì)均勻。定義桿件單元和結(jié)點(diǎn)碼，下文提到單元和結(jié)點(diǎn)碼皆基于此定義圖1-4 1.3.4荷載模擬橋面板近似為均布荷載q=mg/l0=3×10/1300=0.0125N/mm一輛小車加砝碼P=120N，考慮動(dòng)荷載影響P=1.2P=144N一輛小車在兩榀桁架上荷載分配的原則如圖1-5圖

4、1-5P1=0.25P=36NP2=0.75P=108N考慮每輛小車輪距，將一輛小車及砝碼的荷載簡化為兩集中力Q1和Q2Q1=0.5P2=18NQ2=0.5P1=54N則橋梁計(jì)算簡圖如圖1-6圖1-6按照?qǐng)D1-6將計(jì)算簡圖輸入結(jié)構(gòu)力學(xué)求解器，將集中荷載依次作用在各單元中間位置，得出各桿件所受最大軸力和彎矩值，依次列在附表1-5，再將集中荷載依次作用在各結(jié)點(diǎn)位置，同樣得出各桿件所受最大軸力和彎矩值，依次列在附表6-9，此數(shù)據(jù)作為設(shè)計(jì)最終依據(jù)。1.3.5計(jì)算示例材料性質(zhì)：木材 E=Mpa，抗拉強(qiáng)度ft=30MPa 查閱有關(guān)資料可知：木材抗壓強(qiáng)度fc=30MPa，抗彎強(qiáng)度fm=20MPa，抗剪強(qiáng)度f

5、v=2Mpa從表1-9可知，桿件單元共分為三類。一、受拉構(gòu)件；二、受壓構(gòu)件；三、壓彎構(gòu)件。以下每類桿件均舉例說明計(jì)算過程，其余不再列出。另在結(jié)構(gòu)中還存在拉彎和受剪構(gòu)件，因其對(duì)結(jié)構(gòu)影響較小，在此忽略不計(jì)。一 受拉構(gòu)件，以單元1為例A>=8.5mm2選截面2×6mm的桿件二 受壓構(gòu)件，以單元23為例試選5×6桿件i=62.5/30=2.1=192/2.1=133.02>75=3000/2=0.17A>N/fc=19.7mm2選5×6桿件合適。三 壓彎構(gòu)件，以單元10為例試選如圖1-7截面圖1-7由圖1-7知：A=52mm2，Ix=497.33mm4，

6、ix=3.093mm，Iy=169.33mm4，iy=1.81mm，Wx=99.47由圖1-1知：Lox=l0y=120mm強(qiáng)度驗(yàn)算：=0.98<1強(qiáng)度滿足要求剛度驗(yàn)算：x=Ix/ix=120/0.093=38.8<=120y=ly/iy=120/1.81=66.3<=120剛度滿足要求穩(wěn)定性驗(yàn)算：A平面內(nèi)K=0.489m=（1-K）2=0.261=1/1(/80)2=0.81N/(mA)=25.71N/mm2<fc=30 N/mm2B平面外N/(yAfc)+M/(lNfm)2=0.4<1滿足穩(wěn)定性要求圖1-7截面適合。其余各桿件算法與此相同，不再一一列出，以上公

7、式皆取自木結(jié)構(gòu)設(shè)計(jì)規(guī)范GB500052003。最終各單元截面選擇見附表10、11。2節(jié)點(diǎn)設(shè)計(jì)2.1節(jié)點(diǎn)構(gòu)思經(jīng)過實(shí)驗(yàn)，膠水粘結(jié)可以承受的力比材料本身的只強(qiáng)不弱，但考慮到構(gòu)件用膠水粘結(jié)時(shí)，接觸面積較小，為增加構(gòu)件之間粘結(jié)強(qiáng)度，用1×55 mm木板做成墊片，輔助粘結(jié)。同樣原理，細(xì)桿與其他桿件連接時(shí)，不用正面粘結(jié)，而用側(cè)面。且為增加膠結(jié)強(qiáng)度，特別對(duì)結(jié)點(diǎn)粘結(jié)處進(jìn)行砂紙打磨處理，以增加其摩擦力。并對(duì)于多結(jié)點(diǎn)交接處，滴加更多膠水，以增加粘結(jié)力。2.2節(jié)點(diǎn)詳圖圖2-1節(jié)點(diǎn)1實(shí)際詳圖圖2-2節(jié)點(diǎn)2實(shí)際詳圖圖2-3節(jié)點(diǎn)6實(shí)際詳圖3設(shè)計(jì)總結(jié)結(jié)構(gòu)整體采用桁架結(jié)構(gòu)，既滿足受力均勻的要求，同時(shí)又保證了計(jì)算、施工

8、的方便；計(jì)算過程利用結(jié)構(gòu)力學(xué)求解器軟件，使結(jié)果更準(zhǔn)確，為設(shè)計(jì)提供了有效依據(jù)；交點(diǎn)多的節(jié)點(diǎn)，采用1×55mm薄片做墊片，既充分利用了材料，又使節(jié)點(diǎn)承載力有了顯著提高；橋梁中只承受拉力的單元做到了足夠多，此設(shè)計(jì)較多的減少了橋身自重；施工精細(xì)，節(jié)點(diǎn)、桿件處理分毫不差，每根桿件都根據(jù)連接做出相應(yīng)角度坡口，真正地詮釋了橋梁的名字“步步精心”。4破壞分析動(dòng)荷載影響可能估計(jì)不足，實(shí)際加載過程中，可能因此破壞；節(jié)點(diǎn)膠水過少，或者因溫度變化開裂，造成粘結(jié)強(qiáng)度降低；木材本身有結(jié)點(diǎn)，截面削弱，蟲眼等因素；結(jié)構(gòu)不對(duì)稱，加載時(shí)整體失穩(wěn)，發(fā)生脆性破壞。附 錄附表1 Q1作用在單元13和14，Q2作用在單元5和6

9、（見圖附-1）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm177.490.000.0077.490.000.30266.000.000.3066.000.000.00382.110.010.0082.110.011.604108.95-0.011.60108.95-0.010.005-100.56-8.790.00-100.5610.71115.626-100.56-9.94115.62-100.569.5692.447-58.76-1.4292.44-58.760.0812.478-58.76-1.1512.47-58.760.35-36.099-72.75-0.25-

10、36.09-72.751.2523.5410-72.75-1.2823.54-72.750.22-40.6011-81.44-0.76-40.60-81.440.74-41.8812-81.442.64-41.88-81.444.14365.5013-203.18-26.66365.50-203.1828.84496.3314-203.18-31.89496.33-203.1823.610.0015220.120.030.00220.120.033.3616141.22-0.013.36141.22-0.010.0017-60.730.000.00-60.730.000.001878.890.

11、000.0078.890.000.0019-78.310.000.00-78.310.000.00206.330.000.006.330.000.0021-7.580.000.00-7.580.000.002210.820.000.0010.820.000.0023-11.580.000.00-11.580.000.0024-27.270.000.00-27.270.000.002526.830.000.0026.830.000.0026-20.660.000.00-20.660.000.0027-1.240.000.00-1.240.000.0028-2.530.000.00-2.530.0

12、00.00291.910.000.001.910.000.00附表2 Q1作用在單元12和13，Q2作用在單元6和7（見圖附-2）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1139.720.000.00139.720.000.542117.260.000.54117.260.000.003137.210.010.00137.210.012.044145.53-0.022.04145.53-0.020.005-134.33-1.910.00-134.33-0.41-139.456-134.33-6.83-139.45-134.3312.67210.637-106.04-9

13、.91210.63-106.049.59191.868-106.04-3.37191.86-106.04-1.87-122.999-130.670.87-122.99-130.672.3771.4810-130.67-3.0971.48-130.67-1.59-209.3111-153.854.76-209.31-153.856.26452.1612-153.85-24.77452.16-153.8530.73809.4613-237.73-35.76809.46-237.7319.74-151.6414-237.730.51-151.64-237.732.010.0015257.560.03

14、0.00257.560.033.7016232.60-0.013.70232.60-0.010.0017-19.230.000.00-19.230.000.001824.940.000.0024.940.000.0019-97.430.000.00-97.430.000.002022.620.000.0022.620.000.0021-14.490.000.00-14.490.000.002221.470.000.0021.470.000.0023-17.960.000.00-17.960.000.0024-33.000.000.00-33.000.000.00258.310.000.008.

15、310.000.0026-6.420.000.00-6.420.000.0027-12.970.000.00-12.970.000.0028-5.460.000.00-5.460.000.0029-31.030.000.00-31.030.000.00附表3 Q1作用在單元11和12，Q2作用在單元7和8（見圖附-3）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1205.960.000.00205.960.000.802170.050.000.80170.050.000.003164.870.010.00164.870.012.174161.26-0.022.17161.

16、26-0.020.005-148.85-3.060.00-148.85-1.56-277.456-148.851.19-277.45-148.852.69-44.287-146.31-6.05-44.28-146.3113.45400.138-146.31-12.92400.13-146.316.5819.949-187.32-1.5119.94-187.32-0.01-71.1610-187.321.70-71.16-187.323.20222.8211-205.39-20.82222.82-205.3934.681054.4212-205.39-35.461054.42-205.3920.

17、04129.4113-214.55-5.56129.41-214.55-4.06-447.4514-214.552.98-447.45-214.554.480.0015232.440.020.00232.440.023.1416241.62-0.013.14241.62-0.010.00177.040.000.007.040.000.0018-9.200.000.00-9.200.000.0019-28.250.000.00-28.250.000.0020-0.920.000.00-0.920.000.0021-29.840.000.00-29.840.000.002227.650.000.0

18、027.650.000.0023-38.010.000.00-38.010.000.0024-9.410.000.00-9.410.000.0025-3.620.000.00-3.620.000.00262.760.000.002.760.000.0027-26.370.000.00-26.370.000.00281.710.000.001.710.000.0029-70.140.000.00-70.140.000.00附表4 Q1作用在單元10和11，Q2作用在單元8和9（見圖附-4）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1251.430.000.00251.43

19、0.001.172215.190.001.17215.190.000.003181.610.010.00181.610.012.414180.03-0.022.41180.03-0.020.005-166.18-3.040.00-166.18-1.54-274.766-166.18-0.34-274.76-166.181.16-226.157-169.723.13-226.15-169.724.63239.538-169.72-10.95239.53-169.728.5595.719-248.74-6.3795.71-248.7413.13501.7510-248.74-25.43501.75

20、-248.7430.07779.7811-205.82-30.33779.78-205.8225.17470.6612-205.82-7.29470.66-205.82-5.79-314.2013-199.73-0.84-314.20-199.730.66-324.6914-199.731.96-324.69-199.733.460.0015216.380.020.00216.380.022.8916218.10-0.012.89218.10-0.010.00171.290.000.001.290.000.0018-1.730.000.00-1.730.000.00197.190.000.00

21、7.190.000.0020-73.020.000.00-73.020.000.0021-4.320.000.00-4.320.000.002253.700.000.0053.700.000.0023-72.800.000.00-72.800.000.00243.310.000.003.310.000.0025-1.590.000.00-1.590.000.00261.190.000.001.190.000.0027-15.580.000.00-15.580.000.0028-38.570.000.00-38.570.000.0029-32.460.000.00-32.460.000.00附表

22、5 Q1+Q2作用在單元9和10（見圖附-5）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1247.100.010.00247.100.011.392247.10-0.011.39247.10-0.010.003200.690.010.00200.690.012.654197.87-0.022.65197.87-0.020.005-182.64-3.380.00-182.64-1.88-315.226-182.640.27-315.22-182.641.77-192.937-185.340.78-192.93-185.342.28-9.168-185.342.20-9.1

23、6-185.343.70345.209-282.64-29.06345.20-282.6444.441267.6410-282.64-44.441267.64-282.6429.06345.2011-185.34-3.70345.20-185.34-2.20-9.1612-185.34-2.28-9.16-185.34-0.78-192.9313-182.64-1.77-192.93-182.64-0.27-315.2214-182.641.88-315.22-182.643.380.0015197.870.020.00197.870.022.6516200.69-0.012.65200.69

24、-0.010.00172.150.000.002.150.000.0018-2.830.000.00-2.830.000.00190.130.000.000.130.000.0020-98.860.000.00-98.860.000.002156.900.000.0056.900.000.002256.900.000.0056.900.000.0023-98.860.000.00-98.860.000.00240.130.000.000.130.000.0025-2.830.000.00-2.830.000.00262.150.000.002.150.000.0027-0.080.000.00

25、-0.080.000.0028-88.870.000.00-88.870.000.0029-0.080.000.00-0.080.000.00附表6 Q1作用在結(jié)點(diǎn)12和13，Q2作用在結(jié)點(diǎn)5和6（見圖附-6）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1108.770.000.00108.770.000.42291.690.000.4291.690.000.003112.970.010.00112.970.011.924133.21-0.011.92133.21-0.010.005-122.96-3.050.00-122.96-1.55-276.176-122.960.

26、86-276.17-122.962.36-82.547-82.140.46-82.54-82.141.9662.738-82.14-1.8562.73-82.14-0.35-69.839-101.660.16-69.83-101.661.6639.4610-101.66-1.9139.46-101.66-0.41-99.5711-116.870.81-99.57-116.872.3187.7612-116.87-2.4487.76-116.87-0.94-114.9413-237.00-4.96-114.94-237.00-3.46-620.3814-237.004.42-620.38-237

27、.005.920.0015256.760.030.00256.760.033.8216196.85-0.013.82196.85-0.010.0017-46.120.000.00-46.120.000.001859.890.000.0059.890.000.0019-103.800.000.00-103.800.000.002012.950.000.0012.950.000.0021-11.390.000.00-11.390.000.002215.960.000.0015.960.000.0023-15.300.000.00-15.300.000.0024-35.450.000.00-35.4

28、50.000.002520.230.000.0020.230.000.0026-15.580.000.00-15.580.000.0027-3.820.000.00-3.820.000.0028-3.570.000.00-3.570.000.0029-4.750.000.00-4.750.000.00附表7 Q1作用在結(jié)點(diǎn)11和12，Q2作用在結(jié)點(diǎn)6和7（見圖附-7）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1172.010.000.00172.010.000.662143.340.000.66143.340.000.003154.210.010.00154.210.0

29、12.094152.79-0.022.09152.79-0.020.005-141.03-2.720.00-141.03-1.22-236.526-141.03-0.15-236.52-141.031.35-164.107-128.211.13-164.10-128.212.6361.668-128.21-2.0961.66-128.21-0.59-99.339-159.260.41-99.33-159.261.9139.8010-159.26-2.0739.80-159.26-0.57-118.2311-185.710.62-118.23-185.712.1245.8112-185.71-3

30、.3945.81-185.71-1.89-271.4213-224.45-1.69-271.42-224.45-0.19-383.9414-224.452.45-383.94-224.453.950.0015243.170.030.00243.170.033.3716246.64-0.013.37246.64-0.010.00172.640.000.002.640.000.0018-3.480.000.00-3.480.000.0019-67.170.000.00-67.170.000.002021.920.000.0021.920.000.0021-20.410.000.00-20.410.

31、000.002225.490.000.0025.490.000.0023-24.210.000.00-24.210.000.0024-22.630.000.00-22.630.000.0025-1.430.000.00-1.430.000.00261.070.000.001.070.000.0027-22.720.000.00-22.720.000.0028-3.980.000.00-3.980.000.0029-59.510.000.00-59.510.000.00附表8 Q1作用在結(jié)點(diǎn)10和11，Q2作用在結(jié)點(diǎn)7和8（見圖附-8）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N

32、.mm1234.780.000.00234.780.000.972194.800.000.97194.800.000.003172.840.010.00172.840.012.294170.81-0.022.29170.81-0.020.005-157.66-2.990.00-157.66-1.49-268.736-157.660.06-268.73-157.661.56-172.017-159.981.30-172.01-159.982.8074.318-159.98-2.6674.31-159.98-1.16-155.249-217.011.06-155.24-217.012.5662.0

33、410-217.01-2.9862.04-217.01-1.48-205.9211-211.601.32-205.92-211.602.8242.5512-211.60-2.8242.55-211.60-1.32-206.4013-207.60-2.06-206.40-207.60-0.56-363.2014-207.602.28-363.20-207.603.780.0015224.910.020.00224.910.023.0116228.62-0.013.01228.62-0.010.00172.830.000.002.830.000.0018-3.730.000.00-3.730.00

34、0.00190.900.000.000.900.000.0020-37.110.000.00-37.110.000.0021-28.460.000.00-28.460.000.002235.550.000.0035.550.000.0023-55.750.000.00-55.750.000.00240.680.000.000.680.000.0025-2.050.000.00-2.050.000.00261.550.000.001.550.000.0027-23.470.000.00-23.470.000.0028-5.540.000.00-5.540.000.0029-59.650.000.

35、00-59.650.000.00附表9 Q1作用在結(jié)點(diǎn)9和10，Q2作用在結(jié)點(diǎn)8和9（見圖附-9）單元碼桿端1桿端2軸力N剪力N彎矩N.mm軸力N剪力N彎矩N.mm1255.040.010.00255.040.011.332232.37-0.011.33232.37-0.010.003191.170.010.00191.170.012.534188.94-0.022.53188.94-0.020.005-174.40-3.210.00-174.40-1.71-295.326-174.40-0.02-295.32-174.401.48-207.927-177.461.86-207.92-177.

36、463.36105.138-177.46-2.75105.13-177.46-1.25-135.469-273.70-0.23-135.46-273.701.27-73.3010-273.70-1.73-73.30-273.70-0.23-191.0011-194.871.88-191.00-194.873.38124.0812-194.87-3.72124.08-194.87-2.22-232.0013-191.10-1.52-232.00-191.10-0.02-324.2814-191.101.95-324.28-191.103.450.0015207.030.020.00207.030.022.7716209.63-0.012.77209.63-0.010.00171.970.000.001.970.000.0018-2.610.000.00-2.610.000.00192.180.000.002.180.000.0