中橋舊橋利用驗(yàn)算書

PAGE中橋(舊橋利用)驗(yàn)算書（一）、設(shè)計(jì)資料1、提高后設(shè)計(jì)荷載公路—Ⅱ級(jí)，安全等級(jí)取二級(jí)，人群荷載取3.5KN/m22、跨徑及橋?qū)拡A弧拱跨徑L0=25m，凈矢高f0=8.333m，f0/l0=1/3，拱圈寬6.8m，厚1.0m，為漿砌料石實(shí)腹拱。加寬后橋面凈寬為7（車行道）+2×0.75m（人行道）=8.5m3、標(biāo)準(zhǔn)、規(guī)范采用《公路工程技術(shù)標(biāo)準(zhǔn)》JTGB01—2003，《公路橋涵設(shè)計(jì)通用規(guī)范》JTGD60—2004，《公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范》JTGD62—2004，《公路磚石及混凝土設(shè)計(jì)規(guī)范》JTG022—85（二）、材料參數(shù)確定主拱圈按7.5號(hào)砂漿砌40號(hào)粗料石采用，材料容重γ1=24KN/m3，抗壓極限強(qiáng)度R=7.5Mpa,砌體彈性模量E=800R=800×7.5×103=6×106Kpa，直接抗剪R=2.64Mpa,彎曲抗拉R=0.75Mpa拱頂填料厚按50cm計(jì)算，拱上填料與拱上側(cè)墻的平均容重取γ2=21KN/m3，橋面，欄桿、人行道構(gòu)件平均容重取γ3=25KN/m3（三）、驗(yàn)算采用平面桿系有限元建模計(jì)算結(jié)構(gòu)內(nèi)力。計(jì)算跨徑L=25.9m，計(jì)算矢高f=8.64m。根據(jù)《公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范》JTGD62—2004及《公路磚石及混凝土設(shè)計(jì)規(guī)范》JTG022—85，中小跨徑驗(yàn)算拱腳、拱跨3/8和拱頂三個(gè)截面即可。1、拱腳、拱跨3/8和拱頂三個(gè)截面內(nèi)力影響線。拱腳、拱跨3/8和拱頂三個(gè)截面內(nèi)力影響線豎標(biāo)值表表1X坐標(biāo)(m)拱腳拱跨3/8拱頂軸力剪力彎矩軸力剪力彎矩軸力剪力彎矩00000000000.540.90630.4181-0.461110.00692270.0038118-0.00355140.00762220.0021112-0.0127781.080.910.3975-0.787550.0251770.014133-0.00988540.0277550.0079227-0.0443381.620.91470.3679-1.0110.0510440.0294-0.0129970.0564660.016799-0.0853352.160.91980.3317-1.1540.0821330.048566-0.00899240.0911330.028244-0.129552.70.92470.2908-1.2320.11670.0708880.00506680.12990.041955-0.172333.240.92910.2467-1.2560.15340.0957440.0310990.17140.057655-0.210333.780.93250.2004-1.2360.19120.12270.0707440.21440.0751-0.2414.320.93480.1528-1.1810.22930.15130.12530.25810.094133-0.2624.860.93580.1046-1.0970.26710.18130.19580.30170.1146-0.271775.40.93540.056555-0.988880.30380.21230.2830.34470.1363-0.268555.940.93340.0090772-0.862330.3390.24420.38770.38630.1591-0.251116.480.9298-0.037334-0.721440.37240.27660.51030.42630.1829-0.218557.020.9244-0.082331-0.569990.40360.30940.65130.46430.2076-0.169887.560.9173-0.12555-0.411110.43230.34250.81120.49980.2332-0.104118.10.9083-0.16655-0.248110.45820.37560.990.53260.2594-0.0207768.640.8975-0.20522-0.0833360.48110.40861.1880.56260.28620.08089.180.8849-0.241440.0806330.50080.44141.4060.58930.31360.20119.720.8704-0.274770.24180.7672-0.494331.6430.61280.34140.340510.30.854-0.305220.39810.7802-0.462331.360.63280.36950.499510.80.8358-0.332550.5480.7896-0.430881.0960.64930.3980.678211.30.8158-0.356660.68980.7954-0.40.85180.6620.42660.87711.90.7939-0.377550.82220.7975-0.369990.62710.6710.45541.09612.40.7704-0.394990.94380.7959-0.340660.42180.67620.48431.335130.7451-0.408991.0540.7905-0.312330.23570.6968-0.486771.59513.50.7182-0.419551.1510.7815-0.284880.0685220.6943-0.457991.335140.6898-0.426551.2340.7687-0.25844-0.0798870.688-0.429331.09614.60.6598-0.431.3040.7523-0.23311-0.209880.6779-0.400990.87715.10.6284-0.430111.3580.7323-0.20899-0.321660.6641-0.372770.678215.70.5958-0.426771.3970.7088-0.186-0.415770.6466-0.344990.499516.20.5619-0.419991.420.682-0.16422-0.492550.6255-0.317660.340516.70.5269-0.409991.4280.6519-0.14377-0.552440.601-0.290770.201117.30.491-0.396661.4190.6188-0.12466-0.596110.5732-0.264440.080817.80.4543-0.380221.3950.5827-0.10688-0.624220.5422-0.23877-0.02077618.40.417-0.3611.3550.5441-0.090334-0.637220.5084-0.21388-0.1041118.90.3792-0.3391.30.503-0.07533-0.636110.4719-0.18966-0.1698819.40.3411-0.314551.2310.4598-0.061667-0.621660.4331-0.16644-0.21855200.303-0.287771.1480.4149-0.049446-0.594990.3922-0.14411-0.2511120.50.2651-0.2591.0520.3686-0.038667-0.556880.3496-0.12299-0.2685521.10.2278-0.228660.94470.3214-0.02933-0.508990.3059-0.10299-0.2717721.60.1913-0.197220.8280.2739-0.021333-0.452440.2616-0.084113-0.26222.10.1561-0.165110.70410.2267-0.014774-0.389110.2172-0.06688-0.24122.70.1226-0.132990.57550.1806-0.009449-0.3210.1735-0.051001-0.2103323.20.091366-0.101550.44570.1364-0.0055512-0.250550.1314-0.036993-0.1723323.80.063-0.0716650.31920.095377-0.0027725-0.180550.092155-0.024772-0.1295524.30.038388-0.0446680.20170.058899-0.0010006-0.114770.057066-0.01466-0.08533524.80.018577-0.022110.10090.028866-0.0001180-0.0577750.028044-0.0068854-0.04433825.40.005044-0.00600950.0279550.00790090.0000114-0.0162240.0076997-0.0018817-0.01277825.90000000002、拱腳、拱跨3/8和拱頂三個(gè)截面內(nèi)力計(jì)算：根據(jù)《公路磚石及混凝土設(shè)計(jì)規(guī)范》JTG022—85，對(duì)于跨徑不大于25m的磚、石、砼預(yù)制塊砌體拱橋，當(dāng)矢跨比等于或大于1/5時(shí)，可不計(jì)算溫度變化影響力。由于為舊橋利用，不計(jì)收縮影響力。拱頂填料厚已達(dá)50cm，不計(jì)汽車沖擊影響力，活載按平均分布計(jì)算。拱圈計(jì)算不考慮臺(tái)的位移對(duì)拱圈受力影響（因橋臺(tái)基礎(chǔ)為巖石地基，穩(wěn)固可靠）。本橋?yàn)橹行】鐝綐?，只列表?jì)算拱腳、拱跨3/8和拱頂三個(gè)截面內(nèi)力，內(nèi)力值見表2。拱腳、拱跨3/8和拱頂三個(gè)截面內(nèi)力表表2項(xiàng)目恒載汽車MaxM結(jié)果::汽車MinM結(jié)果::人群MaxM結(jié)果::軸力彎矩軸力彎矩軸力彎矩軸力彎矩拱腳9084.000433.30332.40794.90492.70-608.80041.1276.823L/84627.000280.80223.30757.10358.00-420.80023.4536.42拱頂4315.000-76.70371.00721.60185.20-148.80031.8633.443、承載能力極限狀態(tài)荷載組合（基本組合）按《公路橋涵設(shè)計(jì)通用規(guī)范》JTGD60—2004第4.1.6條進(jìn)行荷載組合，計(jì)算由車道荷載引起的拱橋的正彎時(shí)，拱頂，拱跨1/4乘以系數(shù)0.7，拱腳乘以0.9，中間各個(gè)截面的正彎矩折減系數(shù)，用直線插入法確定（JTGD62-20044.3.1）。列表計(jì)算如下：承載能力極限狀態(tài)荷載效應(yīng)組合（基本組合）表表3項(xiàng)目拱腳3L/8拱頂N(KN)M(KN·M))N(KN)M(KN·M))N(KN)M(KN·M))恒載9084.000433.304627.0000280.804315.000-76.70汽MAX332.40794.90223.3000757.10371.00721.60汽MIN492.70-608.800358.0000-420.800185.20-148.800人群41.1276.8223.45036.4231.8633.44組合汽max11399.0061582.9995883.7881108.0555722.899641.88汽min11623.448-400.8996072.366-307.2665462.777-273.6114、荷載效應(yīng)組合對(duì)應(yīng)偏心距設(shè)計(jì)值及正截面強(qiáng)度計(jì)算結(jié)構(gòu)（主拱圈）抗力效應(yīng)的設(shè)計(jì)值為：RN=aA其中：a=，e=，===0.289m根據(jù)《公路磚石及混凝土設(shè)計(jì)規(guī)范》JTG022—85表3.0.1-2，取=1.92承載能力極限狀態(tài)荷載效應(yīng)組合（基本組合）設(shè)計(jì)值表表4項(xiàng)目N(KN)M(KN·M))偏心矩e偏心影響系數(shù)效應(yīng)抗力拱腳汽max11399.0061582.9990.1390.812421578.998汽min11623.448-400.899-0.0340.986026189.4493L/8汽max5883.7881108.0550.1880.701718637.661汽min6072.366-307.266-0.0510.970325772.443拱頂汽max5722.899641.880.1120.869123085.224汽min5462.777-273.611-0.0500.970825787.994由表4比較，表明結(jié)構(gòu)抗力效應(yīng)的設(shè)計(jì)值RN均大于荷載效應(yīng)組合設(shè)計(jì)值Nj。5、主拱圈容許偏心距驗(yàn)算本橋主拱為等截面圬工拱，根據(jù)《公路磚石及混凝土設(shè)計(jì)規(guī)范》JTG022—85表3.0.2-1，主拱圈正截面上的容許偏心距為Y下=0.6y=0.6×0.5=0.3m，Y上=0.6y=0.6×0.5=0.3m。由容許偏心距數(shù)值與表４比較，主拱正截面上縱向力的偏心距ej均小于規(guī)范規(guī)定的容許偏心距［e0］。6、主拱圈的穩(wěn)定性驗(yàn)算（1）、縱向穩(wěn)定性驗(yàn)算Nj≤RN=/，式中：==0.002=0.36s=0.36×33.03=11.89m===11.89==0.289m計(jì)算結(jié)果見表6主拱圈穩(wěn)定性抗力效應(yīng)的設(shè)計(jì)值表5項(xiàng)目軸力N(KN)效應(yīng)抗力RN拱腳汽max11399.00621578.9980.783499916907.111汽min11623.44826189.4490.822766821547.8893L/8汽max5883.78818637.6610.751422914004.884汽min6072.36625772.4430.819655621124.553拱頂汽max5722.89923085.2240.797600518412.990汽min5462.77725787.9940.819777321140.227由表6比較，表明結(jié)構(gòu)抗力效應(yīng)的設(shè)計(jì)值RN均大于荷載效應(yīng)組合設(shè)計(jì)值Nj，即縱向穩(wěn)定性滿足要求。（2）、橫向穩(wěn)定性驗(yàn)算根據(jù)《公路鋼筋混凝土及預(yù)應(yīng)力混凝土橋涵設(shè)計(jì)規(guī)范》JTGD62—2004第4.3.8對(duì)主拱寬度大于計(jì)算跨徑的1/20時(shí)，可不做拱圈的橫向穩(wěn)定驗(yàn)算。在此本橋可不做橫向穩(wěn)定性驗(yàn)算。8、正截面受剪強(qiáng)度驗(yàn)算取μ=0.7,Qj≤RQ=A+μ×Nj，其