大跨度馬鞍形體育場屋蓋預應力鋼索結構專項施工方案

廈門體育中心建設項目體育場屋蓋大跨度馬鞍形體育場屋蓋預應力鋼索結構專項施工方案編制：審核：審批：中國建筑第八工程局有限公司二O二二年二月大跨度馬鞍形體育場屋蓋預應力鋼索結構專項施工方案上徑向索錨固工況分析鋼斜撐安裝完成后，繼續(xù)同步牽引上徑向索直至錨固到位，位形和索力如下圖所示。工況3-0索桿系位形（mm）工況3-0徑向索內力（N）工況3-0環(huán)索內力（N）上徑向索索力（kN）軸線12345678910索力616.3633.4663.5613.8458.8372.2249.8533.5558.8584.8軸線11121314151617181920索力637.7582.7531.7440.6133.4346.6464.9559.5616.5620.0軸線21222324252627282930索力635.7586.7612.3571.1441.3345.5114.5349.0383.6446.1軸線31323334353637383940索力454.4427.0409.2401.2248.4344.9479.9615.8629.5610.9環(huán)索索力（kN）軸線12345678910索力2768278127932796279027852788278127712762軸線11121314151617181920索力2756275527532749272727172704267626412614軸線21222324252627282930索力2604261426352656266526722704271227102699軸線31323334353637383940索力2691269226992706270827202738275027512754鋼斜撐軸力（kN）軸線789101112131415軸力90.8-214.5-232.5-259.5-307.7-268.3-223.4-135.1218.2軸線272829303132333435軸力282.2-35.2-99.4-219.1-259.4-213.3-156.9-120.8113.0上徑向索錨固后，徑向索索力和鋼斜撐軸力如上表所示，可知，上徑向索錨固后最大索力為663.5kN，在上徑向索錨固后，已經(jīng)形成穩(wěn)定的索網(wǎng)結構體系，此時，鋼斜撐由于環(huán)索預張后部分軸線對應的鋼斜撐受到一定的拉力作用。張拉工況分析事實上，鋼斜撐安裝完成后，結構已經(jīng)具有一定的初內力，此時結構除下掛的鋼撐桿和下徑向索外，可視為穩(wěn)定的結構體系。牽引下徑向索錨固并進行同步張拉，張拉過程中分為四級同步張拉，分別為25%—50%—75%—105%。最終得到張拉力如下表6-7所示，表中與設計索力的誤差主要是由于索夾重量產生的。張拉完成態(tài)的位移和內力如下圖所示。張拉力值（單位：kN）軸線編號第一級第二級第三級第四級設計索力誤差/%36225.1450.2675.4900.5866.8-3.937240.0480.0720.0959.9917.2-4.738343.4686.91030.31373.71310.8-4.839310.6621.3931.91242.61180.7-5.240293.2586.3879.51172.71124.3-4.31277.0554.0831.01107.91064.6-4.12323.1646.2969.31292.41242.5-4.03343.8687.61031.51375.31313.7-4.74353.2706.31059.51412.61353.8-4.35240.1480.3720.4960.6919.4-4.56171.9343.8515.7687.6652.2-5.416154.3308.5462.8617.1585.9-5.317228.7457.4686.2914.9879.3-4.018277.8555.7833.51111.41065.9-4.319304.4608.7913.11217.51165.3-4.520282.6565.3847.91130.51082.5-4.421286.4572.8859.11145.51108.2-3.422268.5537.0805.51074.01032.3-4.023286.9573.7860.61147.51092.6-5.024287.9575.8863.71151.61103.8-4.325233.1466.2699.3932.3898.7-3.726172.1344.2516.4688.5660.6-4.2張拉完成態(tài)鋼構等效應力變化/MPa張拉完成態(tài)結構豎向位移/mm張拉完成態(tài)鋼斜撐內力/N張拉完成態(tài)環(huán)索內力/N張拉完成態(tài)上徑向索內力/N張拉完成態(tài)下徑向索內力/N結論（1）提升階段最大徑向索力為206.3kN，出現(xiàn)在體育場?軸線，整個提升過程中的提升力在31.2~206.3kN。上徑向索錨固階段最大索力為663.5kN，在上徑向索錨固后，已經(jīng)形成穩(wěn)定的索網(wǎng)結構體系，此時，鋼斜撐由于環(huán)索預張后部分軸線對應的鋼斜撐受到一定的拉力作用。（2）鋼斜撐安裝階段最大提升力為176.5kN，發(fā)生在安裝鋼斜撐?時，提升高度為1550mm，絕對標高為+64.157m；鋼斜撐?絕對標高最大為+70.193m，此時提升力為111.6kN，提升高度為750mm。（3）張拉階段最大張拉力為1412.6kN，張拉完成后鋼構最大等效應力變化為106.9MPa，最大豎向位移為70.9mm。張拉完成后各位置索力與設計索力對比如下：上徑向索內力/kN軸線編號設計索力/kN完成態(tài)索力/kN誤差/%11103.71073.0-2.821054.41016.1-3.631117.81067.7-4.54988.3939.2-5.05844.0807.8-4.36784.1750.1-4.371594.71554.3-2.581624.11585.7-2.491726.41691.0-2.0101832.01799.2-1.8112014.61983.0-1.6121832.11799.8-1.8131627.01592.9-2.1141347.21312.9-2.5151230.41193.9-3.016748.5718.3-4.017931.9900.1-3.4181096.81057.9-3.5191121.51077.3-3.9201124.41084.6-3.5211088.01059.3-2.6221051.61017.6-3.2231149.91103.9-4.0241096.41056.6-3.625882.0853.6-3.226791.6766.7-3.227977.9953.3-2.5281081.31061.1-1.9291220.21204.0-1.3301431.71416.7-1.0311477.51465.0-0.8321383.11370.5-0.9331314.81299.5-1.2341277.41257.2-1.6351458.61434.5-1.636586.1558.3-4.737937.9903.8-3.6381043.8992.8-4.9391130.81081.0-4.4401091.41054.7-3.4下徑向索（桿）內力/kN軸線編號設計索力/kN完成態(tài)索力/kN誤差/%11064.61107.9-4.121242.51292.4-431313.71375.3-4.741353.81412.6-4.35919.4960.6-4.56652.2687.6-5.416585.9617.1-5.317879.3914.9-4181065.91111.4-4.3191165.31217.5-4.5201082.51130.5-4.4211108.21145.5-3.4221032.31074-4231092.61147.5-5241103.81151.6-4.325898.7932.3-3.726660.6688.5-4.236866.8900.5-3.937917.2959.9-4.7381310.81373.7-4.8391180.71242.6-5.2401124.31172.7-4.3環(huán)索索力/kN軸線編號設計索力/kN完成態(tài)索力/kN誤差/%19978.610003.80.329981.810006.60.239964.99989.80.249895.99921.00.359788.39813.10.369726.39750.50.279663.29686.70.289603.79626.00.299548.49569.10.2109507.09526.30.2119487.09505.90.2129496.09515.50.2139512.69532.70.2149533.69554.80.2159548.59570.80.2169527.59549.60.2179545.69567.60.2189511.59532.70.2199435.79456.10.2209381.39401.50.2219348.39368.40.2229351.79371.70.2239377.29397.80.2249390.99412.20.2259376.19397.90.2269384.39406.20.2279394.09414.30.2289392.39412.00.2299364.49384.20.2309321.09341.20.2319299.19320.10.2329324.19346.20.2339376.39399.60.2349440.09464.20.3359533.89559.80.3369597.39623.10.3379721.09746.30.3389826.79851.30.3399885.29910.00.3409931.49956.60.3環(huán)索索夾位置位移/mm軸線編號UXUYUZ1-1.9-35.55.72-1.9-32.83.93-1.0-25.6-1.941.3-17.2-9.054.1-12.0-13.367.3-8.0-16.6710.4-4.6-20.8811.8-2.6-25.0913.2-0.7-30.61013.80.2-35.51113.60.4-37.81214.80.3-37.41314.60.6-34.71413.91.5-31.31513.23.0-26.61610.16.2-21.7176.99.8-17.9183.315.3-13.319-0.323.9-7.120-2.032.1-1.221-22-23-3.628.7-5.524-6.521.8-11.825-9.217.4-17.026-12.713.4-22.127-17.59.1-28.528-18.46.5-38.329-20.34.4-47.430-21.63.7-53.331-23.03.6-57.732-22.83.5-56.033-20.32.0-50.034-16.8-0.9-42.435-14.2-4.4-34.836-11.0-9.2-27.237-7.6-14.6-20.038-5.2-20.8-11.339-3.1-28.3-1.940-2.0-33.94.1Max-23.0-35.5-57.7

鋼構件長度誤差影響分析本工程索網(wǎng)結構的徑向索均設置可調端，環(huán)索可通過對接螺桿調節(jié)，因此本方案只考慮鋼斜撐的長度誤差。首先以單根鋼斜撐為研究對象，研究結構預應力分布及環(huán)索節(jié)點位形（環(huán)索節(jié)點位形一定程度上表征了結構的剛度）對不同位置處單根鋼斜撐的索長誤差的敏感性；然后以單根鋼斜撐為研究對象，施加不同的長度誤差，以引起的索力偏差不超過設計成形態(tài)預應力值的5%為要求，制定單根鋼斜撐的長度誤差限值；最后，以得到的誤差限值作為鋼斜撐最大允許長度誤差，生成若干組正態(tài)分布的隨機誤差樣本，通過MATLAB完成蒙特卡羅法抽取滿足上述正態(tài)分布的隨機索長誤差樣本。將隨機抽取的18組索長誤差樣本采用施加溫度荷載的方法引入有限元模型進行分析，同時編寫APDL程序得到張拉成形態(tài)結構索力及位形響應，并對數(shù)值計算結果進行數(shù)據(jù)統(tǒng)計，其程序流程如圖7-1所示。根據(jù)結果對鋼斜撐長度誤差限值的合理性進行評價，并為施工驗收標準提供建議。隨機誤差影響分析流程圖9.2.1誤差敏感性研究采用有限元軟件ANSYS建立與實際工程一致的計算模型，其中周邊鋼結構采用Beam188單元，鋼斜撐和豎桿采用Link8單元，拉索采用Link10單元，通過施加初應變的方法模擬初始預拉力。圖7-2為上徑向索、下徑向索、鋼斜撐、環(huán)索四類拉索（桿）的分類編號及環(huán)索節(jié)點編號，其中SJS、XJS、GXC、HS分別表示上徑向索、下徑向索、鋼斜撐、環(huán)索。依次取一根鋼斜撐，通過施加溫度荷載模擬長度誤差，計算其本身及附近其他主索索力相對于設計成形態(tài)預應力的變化量，該相對變化量為［(Fi'-Fi)/Fi］×100%其中，F(xiàn)i為設計成形態(tài)下的主索索力；Fi'為誤差狀態(tài)下的主索索力。計算附近環(huán)索節(jié)點位形相對于設計成形態(tài)位形的變化量［|di'-di|/di］×100%其中，di為設計成形態(tài)下各環(huán)索節(jié)點(i=1～40)相對于結構無應力時的安裝位形狀態(tài)的位移；di'為誤差狀態(tài)下各環(huán)索節(jié)點相對于結構無應力態(tài)的位移。上徑向索和環(huán)索編號下徑向索和節(jié)點編號構件編號圖為研究結構預應力分布及環(huán)索節(jié)點位形對單根鋼斜撐長度誤差的敏感性，分別使鋼斜撐縮短其自身長度的1/250，以東西兩側中間處的GXC05和GXC14為例，分別縮短20.2mm和26.1mm，計算主要構件內力相對變化量及環(huán)索節(jié)點位形相對變化量，如表所示。內力相對變化/kN編號理想模型GXC05誤差/%GXC14誤差/%GXC01-438.6-438.30.06-438.20.08GXC02-277.5-277.30.07-277.20.10GXC03-409.7-409.40.08-409.20.11GXC04-600.7-619.33.09-600.00.12GXC05-760.5-716.25.84-759.60.12GXC06-612.4-632.23.23-611.70.12GXC07-219.4-219.30.05-219.20.10GXC089.19.01.059.01.11GXC0981.881.60.2781.50.30GXC10-521.4-521.10.05-521.00.08GXC11-561.9-561.50.07-561.50.07GXC12-646.9-646.40.08-647.80.14GXC13-730.3-729.60.08-784.67.45GXC14-900.3-899.50.08-782.213.11GXC15-764.8-764.20.08-818.16.98GXC16-598.2-597.70.08-599.00.14GXC17-305.9-305.70.06-305.70.06GXC18-230.4-230.30.02-230.30.01HS019939.79929.90.109925.90.14HS029895.29885.40.109881.60.14HS039842.19832.30.109828.60.14HS049741.59731.70.109728.20.14HS059623.29613.40.109610.10.14HS069566.09556.20.109553.00.14HS079480.39470.60.109467.50.14HS089423.69413.80.109410.90.13HS099379.39369.50.109366.70.13HS109359.49349.40.119346.80.13HS119382.79372.30.119370.10.13HS129424.39414.80.109411.60.13HS139446.19436.70.109433.40.13HS149443.49434.00.109430.60.13HS159433.19423.80.109420.30.14HS169419.49410.10.109406.60.14HS179431.29422.00.109418.30.14HS189414.09404.90.109401.10.14HS199383.79374.70.109370.80.14HS209375.79366.70.109362.70.14HS219407.49398.50.109394.30.14HS229464.59455.50.109451.20.14HS239543.59534.50.099530.10.14HS249581.19572.00.099567.50.14HS259563.49554.40.099549.80.14HS269587.49578.40.099573.60.14HS279574.09565.00.099560.20.14HS289554.19545.20.099540.30.14HS299538.29529.30.099524.30.15HS309529.99521.00.099515.60.15HS319549.59540.50.099534.90.15HS329589.59580.50.099575.60.14HS339643.89634.80.099629.90.14HS349701.69692.50.099687.70.14HS359756.19746.90.099742.20.14HS369812.99803.60.099799.00.14HS379916.29906.70.109902.20.14HS389981.19971.50.109967.10.14HS399994.79985.00.109980.70.14HS409988.69978.80.109974.70.14XJS01672.0671.30.10671.00.15XJS02930.1929.10.11928.70.15XJS031406.71405.20.111404.60.15XJS041378.81377.40.101376.70.15XJS051301.51300.20.101299.70.14XJS061105.01103.80.111103.30.15XJS071195.01193.80.101193.30.15XJS081250.01248.70.111248.10.15XJS091384.41383.00.101382.40.15XJS10944.7943.60.11943.10.16XJS11913.2912.30.10911.90.14XJS12716.2715.50.10715.10.15XJS13943.3942.40.10941.90.15XJS141167.11165.80.111165.30.15XJS151172.01170.70.111170.20.15XJS161105.91104.80.101104.20.15XJS171159.31158.20.101157.60.15XJS181158.51157.30.101156.70.15XJS191248.11246.80.101246.20.15XJS201140.81139.50.111139.00.16XJS21945.6944.60.10944.20.14XJS22643.6643.00.10642.60.16SJS01766.5765.80.09765.50.13SJS02845.1844.40.08844.00.13SJS03930.4929.60.09929.20.13SJS041041.61040.60.091040.20.13SJS05992.8991.90.10991.50.14SJS061065.81064.90.091064.50.13SJS071042.61041.60.101041.30.13SJS081045.21044.20.091043.90.13SJS09963.6962.70.09962.30.13SJS10910.2909.40.09909.20.11SJS11575.1574.50.10574.30.14SJS121461.01459.60.091459.20.12SJS131293.01291.70.101291.30.13SJS141330.81329.60.101329.10.13SJS151401.71406.40.331399.90.13SJS161500.91487.40.901499.00.13SJS171447.41454.10.461445.50.13SJS181234.91233.80.091233.30.13SJS191099.81098.80.091098.40.13SJS201000.2999.30.09999.00.12SJS21779.1778.40.09778.10.12SJS22838.2837.40.09837.10.12SJS231030.51029.60.091029.20.12SJS241059.31058.40.091057.90.13SJS25983.0982.10.09981.70.13SJS261055.41054.40.091054.00.13SJS271060.11059.20.091058.80.13SJS281032.01031.10.091030.70.12SJS291022.81021.90.081021.50.12SJS30820.4819.70.08819.30.14SJS31754.6753.90.09753.60.13SJS321246.51245.50.081245.00.12SJS331370.71369.60.091369.00.12SJS341663.51662.10.091663.00.03SJS351845.71844.10.091882.21.97SJS362032.82031.00.091946.84.23SJS371844.91843.30.091883.62.10SJS381770.01768.40.091769.60.02SJS391669.51668.00.091667.50.12SJS401552.91551.70.081551.00.12豎向位移相對變化/mm編號理想模型GXC05誤差/%GXC14誤差/%01-121.8-122.00.11-121.40.3802-125.0-125.20.13-124.60.3403-116.2-116.40.16-115.80.3004-107.7-107.90.18-107.40.2405-101.2-101.30.18-101.00.1206-102.2-102.30.16-102.10.0807-92.2-92.30.11-92.30.0808-85.4-85.50.11-85.50.0809-81.1-81.20.10-81.20.0910-78.1-78.20.12-78.20.1511-77.3-96.625.03-77.40.2312-79.5-79.50.06-79.70.2813-82.0-82.00.01-82.30.3214-81.1-81.10.00-81.40.3815-81.4-81.50.03-81.80.4516-99.9-100.00.07-100.30.4317-113.1-113.20.08-113.70.5218-131.8-131.90.08-133.41.2019-148.9-149.00.07-154.63.7820-161.1-161.20.06-175.48.8921-166.2-166.20.06-197.618.9122-164.9-164.90.04-178.98.5423-156.3-156.30.02-161.73.4924-144.1-144.10.01-145.91.2625-128.7-128.60.04-129.60.7026-117.1-117.00.05-117.80.5727-103.3-103.20.09-104.00.6528-96.0-95.90.10-96.60.6329-88.8-88.70.11-89.30.6030-91.8-91.70.11-92.20.4731-88.0-87.90.12-88.30.3832-81.2-81.10.14-81.40.2833-67.5-67.30.19-67.60.2334-68.0-67.90.21-68.10.1635-84.5-84.40.18-84.60.0536-71.3-71.20.16-71.10.2237-74.0-73.90.14-73.70.3538-88.2-88.10.05-87.80.4239-102.8-102.80.03-102.30.4340-114.8-114.90.07-114.30.42通過以上分析，可以看出鋼斜撐長度僅對其自身及相鄰桿件的軸力有較大影響，而對其余主索的索力影響甚微，豎向位移也呈現(xiàn)一樣的規(guī)律。由此可見，鋼斜撐是典型的局部敏感性構件。相對來說，索力與內環(huán)節(jié)點豎向位移對西側鋼斜撐的敏感性要比東側高。誤差限值研究對于預應力整體張拉結構，為確保結構張拉成形態(tài)具有足夠的剛度并符合設計位形，一般規(guī)定拉索的索力容許偏差最大為設計值的5%。因此需要在施工過程中，控制每根拉索的索長誤差在某一限值范圍內，以滿足上述要求；若超過誤差限值，應及時采取減小拉索安裝偏差、重焊耳板等措施，以保證施工質量。由圖7-3和表7-3可知，東西兩側中間部位的鋼斜撐誤差限值較大，特別是東側中間部位的鋼斜撐對索力誤差影響較小，而與下弦索接近部位的鋼斜撐誤差對索力影響較大，其誤差限值要小一些，也即中間部位的鋼斜撐誤差敏感性較低，邊緣部位的鋼斜撐誤差敏感性較高。鋼斜撐誤差限值鋼斜撐誤差限值/mm編號最小值/mm最大值/mmGXC01-24.724.7GXC02-30.530.5GXC03-24.924.9GXC04-22.922.9GXC05-113.8113.8GXC06-75.675.6GXC07-67.567.5GXC08-35.735.7GXC09-22.622.6GXC10-12.912.9GXC11-14.714.7GXC12-20.120.1GXC13-25.825.8GXC14-30.530.5GXC15-26.326.3GXC16-19.819.8GXC17-15.815.8GXC18-14.014.0鋼斜撐隨機誤差對結構成形態(tài)索力偏差的影響圖7-4-圖7-6為考慮隨機索長誤差影響后，結構成形態(tài)下主索索力相對于設計預應力的變化量的統(tǒng)計數(shù)據(jù)。圖中各點數(shù)據(jù)表示的是100組計算結果中各主索索力相對變化量的最大值與最小值。由圖可知，不同拉索的預應力最值都在不同程度上偏離了設計成形態(tài)預應力，其中圖7-4可見環(huán)索索力相對變化量絕對值均不超過0.8%，鋼斜撐長度誤差對環(huán)索索力影響較小，圖7-5可見下弦索索力相對變化量絕對值不超過6%，圖7-6可見上弦索索力相對變化量絕對值不超過8%，均滿足《索結構技術規(guī)程》(JGJ257-2012)中拉索張拉力允許偏差10%這一要求。受隨機索長誤差影響程度由大到小依次為上弦索、下弦索和環(huán)索。其中上弦索較敏感的是與鋼斜撐對應區(qū)域，下弦索較敏感的是與鋼斜撐相鄰區(qū)域，環(huán)索索力整體對鋼斜撐長度誤差不敏感。環(huán)索索力偏差下弦索索力偏差上弦索索力偏差結論不同拉索的預應力最值都在不同程度上偏離了設計成形態(tài)預應力，環(huán)索索力相對變化量絕對值均不超過0.8%，鋼斜撐長度誤差對環(huán)索索力影響較小，下弦索索力相對變化量絕對值不超過6%，上弦索索力相對變化量絕對值不超過8%，均滿足《索結構技術規(guī)程》(JGJ257-2012)中拉索張拉力允許偏差10%這一要求。受隨機索長誤差影響程度由大到小依次為上弦索、下弦索和環(huán)索。其中上弦索較敏感的是與鋼斜撐對應區(qū)域，下弦索較敏感的是與鋼斜撐相鄰區(qū)域，環(huán)索索力整體對鋼斜撐長度誤差不敏感。張拉工裝計算書計算方法本工程針對受力較大且處于重要位置的張拉工裝，采用有限元分析軟件ANSYS2020R2進行分析，為保證有限元分析的穩(wěn)定性，開孔處網(wǎng)格劃分加密且平滑，無畸形單元出現(xiàn)影響分析結果。有限元模型根據(jù)張拉工裝受力特點及ANSYS單元的基本特征和適用范圍，在連接件（LJJ）上端銷軸處采用圓柱面約束（軸向徑向固定，切向自由），下端在內徑32mm外徑50mm的圓環(huán)區(qū)域內施加沿y軸負半軸方向375kN的面荷載；在反力架（FLJ）上蓋板端采用內徑80mm外徑145mm的圓環(huán)面固定約束，下蓋板端在直徑214mm的圓形中空區(qū)域內施加沿z軸負半軸方向750kN的面荷載。單元尺寸為10mm，有限元模型和邊界條件及荷載施加如下圖所示。材料應力-應變模型采用三折線模型，屈服準則為Von-Mises準則。材料彈性應力狀態(tài)下的彈性模量E=2.06×105N/mm2；屈服后的彈性模量取初始彈性模量的3%，即E′=6180N/mm2；泊松比μ=0.3；構件的屈服強度根據(jù)《鋼結構設計標準》(GB50017-2017)取值345MPa，極限強度取值510MPa，剪切模量7.9×104MPa。LJJ-75-1有限元模型LJJ-75-1邊界條件及荷載施加FLJ-75-2有限元模型FLJ-75-2邊界條件及荷載施加模型分析結果下圖分別為張拉工裝在最不利工況作用下的等效應變云圖和等效應力云圖。LJJ-75-1等效應變云圖LJJ-75-1等效應力云圖FLJ-75-2等效應變云圖FLJ-75-2等效應力云圖除去孔徑邊緣處的應力集中，其余區(qū)域應力均小于345MPa，滿足設計要求。

環(huán)索胎架計算書結合現(xiàn)場實際情況，體育場環(huán)索胎架采用普通扣件式鋼管腳手架搭設，胎架高度1.2m，平面寬度為1.6m×1.8m。具體搭設參數(shù)：（1）立桿設置立桿縱向間距800mm，橫向間距600mm。（2）水平桿設置步高500mm，掃地桿離地高度不超過200mm。（3）構配件設置腳手板：腳手架底部用30~50mm腳手板墊著分攤平均壓力。木方：腳手架平臺上方縱向放置兩根200mm高度的木枋用來協(xié)助安裝索夾。安全繩和護欄：高于4m的需要設置防護欄和安全繩懸掛點。（4）剪刀撐胎架四周均設置剪刀撐，并應采用不少于2個旋轉扣件固定。相交于立桿上，至中心節(jié)點距離不大于150mm。根據(jù)搭設方案，取最重環(huán)索索夾3236kg計算，并考慮兩側拉索最大重量2303kg，胎架上部荷載最大為5539kg。每根立桿承受荷載為：按算，鋼管截面特性：，。承載力驗算：穩(wěn)定驗算：按《建筑施工扣件式鋼管腳手架安全技術規(guī)范》計算。計算長度：，查表得；立桿穩(wěn)定性：，滿足要求。圖9.4-1環(huán)索胎架結構圖本工程體育場的環(huán)索胎架布置與40個軸線對應，根據(jù)環(huán)索放樣態(tài)曲線確定，如下圖所示。圖9.4-2類似工程環(huán)索胎架操作平臺計算書操作平臺技術參數(shù)（1）根據(jù)提升張拉設備重量、工裝重量、作業(yè)人員數(shù)量以及設備和工裝的幾何尺寸，制作拉索作業(yè)平臺。平臺尺寸大小為4.0mx0.75m，考慮最多同時上5人和一些零星工器具及設備，總承重取1200kg，利用在鋼構件作為支承，懸挑來實現(xiàn)。平臺安裝于耳板兩側，平臺上部掛鉤和立桿采用螺栓連接，短立桿均有4個螺栓孔，長立桿均有6個螺栓孔（每個立桿上至少有2個螺栓固定），可根據(jù)兩個懸挑支撐件的水平高低差來調節(jié)立桿長