中桥旧桥利用验算书

PAGE中桥(旧桥利用)验算书（一）、设计资料1、提高后设计荷载公路—Ⅱ级，安全等级取二级，人群荷载取3.5KN/m22、跨径及桥宽圆弧拱跨径L0=25m，净矢高f0=8.333m，f0/l0=1/3，拱圈宽6.8m，厚1.0m，为浆砌料石实腹拱。加宽后桥面净宽为7（车行道）+2×0.75m（人行道）=8.5m3、标准、规范采用《公路工程技术标准》JTGB01—2003，《公路桥涵设计通用规范》JTGD60—2004，《公路钢筋混凝土及预应力混凝土桥涵设计规范》JTGD62—2004，《公路砖石及混凝土设计规范》JTG022—85（二）、材料参数确定主拱圈按7.5号砂浆砌40号粗料石采用，材料容重γ1=24KN/m3，抗压极限强度R=7.5Mpa,砌体弹性模量E=800R=800×7.5×103=6×106Kpa，直接抗剪R=2.64Mpa,弯曲抗拉R=0.75Mpa拱顶填料厚按50cm计算，拱上填料与拱上侧墙的平均容重取γ2=21KN/m3，桥面，栏杆、人行道构件平均容重取γ3=25KN/m3（三）、验算采用平面杆系有限元建模计算结构内力。计算跨径L=25.9m，计算矢高f=8.64m。根据《公路钢筋混凝土及预应力混凝土桥涵设计规范》JTGD62—2004及《公路砖石及混凝土设计规范》JTG022—85，中小跨径验算拱脚、拱跨3/8和拱顶三个截面即可。1、拱脚、拱跨3/8和拱顶三个截面内力影响线。拱脚、拱跨3/8和拱顶三个截面内力影响线竖标值表表1X坐标(m)拱脚拱跨3/8拱顶轴力剪力弯矩轴力剪力弯矩轴力剪力弯矩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、拱脚、拱跨3/8和拱顶三个截面内力计算：根据《公路砖石及混凝土设计规范》JTG022—85，对于跨径不大于25m的砖、石、砼预制块砌体拱桥，当矢跨比等于或大于1/5时，可不计算温度变化影响力。由于为旧桥利用，不计收缩影响力。拱顶填料厚已达50cm，不计汽车冲击影响力，活载按平均分布计算。拱圈计算不考虑台的位移对拱圈受力影响（因桥台基础为岩石地基，稳固可靠）。本桥为中小跨径桥，只列表计算拱脚、拱跨3/8和拱顶三个截面内力，内力值见表2。拱脚、拱跨3/8和拱顶三个截面内力表表2项目恒载汽车MaxM结果::汽车MinM结果::人群MaxM结果::轴力弯矩轴力弯矩轴力弯矩轴力弯矩拱脚9084.000433.30332.40794.90492.70-608.80041.1276.823L/84627.000280.80223.30757.10358.00-420.80023.4536.42拱顶4315.000-76.70371.00721.60185.20-148.80031.8633.443、承载能力极限状态荷载组合（基本组合）按《公路桥涵设计通用规范》JTGD60—2004第4.1.6条进行荷载组合，计算由车道荷载引起的拱桥的正弯时，拱顶，拱跨1/4乘以系数0.7，拱脚乘以0.9，中间各个截面的正弯矩折减系数，用直线插入法确定（JTGD62-20044.3.1）。列表计算如下：承载能力极限状态荷载效应组合（基本组合）表表3项目拱脚3L/8拱顶N(KN)M(KN·M))N(KN)M(KN·M))N(KN)M(KN·M))恒载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组合汽max11399.0061582.9995883.7881108.0555722.899641.88汽min11623.448-400.8996072.366-307.2665462.777-273.6114、荷载效应组合对应偏心距设计值及正截面强度计算结构（主拱圈）抗力效应的设计值为：RN=aA其中：a=，e=，===0.289m根据《公路砖石及混凝土设计规范》JTG022—85表3.0.1-2，取=1.92承载能力极限状态荷载效应组合（基本组合）设计值表表4项目N(KN)M(KN·M))偏心矩e偏心影响系数效应抗力拱脚汽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拱顶汽max5722.899641.880.1120.869123085.224汽min5462.777-273.611-0.0500.970825787.994由表4比较，表明结构抗力效应的设计值RN均大于荷载效应组合设计值Nj。5、主拱圈容许偏心距验算本桥主拱为等截面圬工拱，根据《公路砖石及混凝土设计规范》JTG022—85表3.0.2-1，主拱圈正截面上的容许偏心距为Y下=0.6y=0.6×0.5=0.3m，Y上=0.6y=0.6×0.5=0.3m。由容许偏心距数值与表４比较，主拱正截面上纵向力的偏心距ej均小于规范规定的容许偏心距［e0］。6、主拱圈的稳定性验算（1）、纵向稳定性验算Nj≤RN=/，式中：==0.002=0.36s=0.36×33.03=11.89m===11.89==0.289m计算结果见表6主拱圈稳定性抗力效应的设计值表5项目轴力N(KN)效应抗力RN拱脚汽max11399.00621578.9980.783499916907.111汽min11623.44826189.4490.822766821547.8893L/8汽max5883.78818637.6610.751422914004.884汽min6072.36625772.4430.819655621124.553拱顶汽max5722.89923085.2240.797600518412.990汽min5462.77725787.9940.819777321140.227由表6比较，表明结构抗力效应的设计值RN均大于荷载效应组合设计值Nj，即纵向稳定性满足要求。（2）、横向稳定性验算根据《公路钢筋混凝土及预应力混凝土桥涵设计规范》JTGD62—2004第4.3.8对主拱宽度大于计算跨径的1/20时，可不做拱圈的横向稳定验算。在此本桥可不做横向稳定性验算。8、正截面受剪强度验算取μ=0.7,Qj≤RQ=A+μ×Nj，其