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重慶建筑加固　舊橋改造加固需求促進了橋梁加固技術的發展
 
當今世界，交通運輸日趨發達，連接公路的樞紐—橋梁，對公路運輸至關重要。尤其是干線公路上的橋梁，其通過能力和承載能力直接影響公路運輸的效益。因些，對舊有橋梁承載能力的鑒定，顯得越來越重要。鑒定舊橋的承載能力要用科學的方法，即需要先進的檢測技術，一旦舊橋承載能力達不到需要的荷載標準，則需要采用必要的加固措施，使之恢復或提高承載能力。
 
近年(nian)(nian)來，這些(xie)技術在(zai)(zai)國(guo)(guo)內外有(you)(you)(you)(you)較大(da)的(de)發展。這不只是(shi)(shi)在(zai)(zai)第三世(shi)界國(guo)(guo)家中，因為資金缺乏而充(chong)分利用(yong)(yong)(yong)舊(jiu)橋(qiao)(qiao)，加以(yi)(yi)改造(zao)恢(hui)復或(huo)提(ti)高(gao)承載能力(li)，就是(shi)(shi)在(zai)(zai)發達國(guo)(guo)家中，對舊(jiu)橋(qiao)(qiao)的(de)改造(zao)利用(yong)(yong)(yong)也是(shi)(shi)很重視的(de)。如美國(guo)(guo)全國(guo)(guo)有(you)(you)(you)(you)公(gong)(gong)(gong)路(lu)橋(qiao)(qiao)梁近60萬(wan)(wan)(wan)(wan)座，約(yue)(yue)有(you)(you)(you)(you)一半(ban)是(shi)(shi)四(si)十(shi)年(nian)(nian)代(dai)以(yi)(yi)前修(xiu)(xiu)建(jian)的(de)，且其中低于(yu)現(xian)今標(biao)準的(de)占(zhan)(zhan)40%以(yi)(yi)上(shang)。州(zhou)(zhou)際公(gong)(gong)(gong)路(lu)和州(zhou)(zhou)公(gong)(gong)(gong)路(lu)有(you)(you)(you)(you)近30萬(wan)(wan)(wan)(wan)座，其中低于(yu)標(biao)準的(de)約(yue)(yue)占(zhan)(zhan)30%;市、縣(xian)、城(cheng)鎮公(gong)(gong)(gong)路(lu)橋(qiao)(qiao)有(you)(you)(you)(you)30多萬(wan)(wan)(wan)(wan)座，其中低于(yu)標(biao)準的(de)占(zhan)(zhan)50%以(yi)(yi)上(shang)。每年(nian)(nian)用(yong)(yong)(yong)于(yu)更新與(yu)修(xiu)(xiu)復現(xian)有(you)(you)(you)(you)州(zhou)(zhou)以(yi)(yi)上(shang)公(gong)(gong)(gong)路(lu)橋(qiao)(qiao)梁的(de)費(fei)用(yong)(yong)(yong)，約(yue)(yue)為500億(yi)美元(yuan)。英國(guo)(guo)公(gong)(gong)(gong)路(lu)橋(qiao)(qiao)約(yue)(yue)13萬(wan)(wan)(wan)(wan)多座，每年(nian)(nian)用(yong)(yong)(yong)于(yu)混(hun)凝土橋(qiao)(qiao)梁的(de)養護、維修(xiu)(xiu)費(fei)用(yong)(yong)(yong)約(yue)(yue)為9200萬(wan)(wan)(wan)(wan)美元(yuan)，檢查(cha)費(fei)用(yong)(yong)(yong)約(yue)(yue)為900萬(wan)(wan)(wan)(wan)美元(yuan)。要(yao)修(xiu)(xiu)復所(suo)有(you)(you)(you)(you)被損壞的(de)橋(qiao)(qiao)梁約(yue)(yue)需要(yao)幾十(shi)億(yi)美元(yuan)。日本全國(guo)(guo)約(yue)(yue)有(you)(you)(you)(you)112.8萬(wan)(wan)(wan)(wan)公(gong)(gong)(gong)里(li)(li)(li)公(gong)(gong)(gong)路(lu)，市町村級以(yi)(yi)上(shang)的(de)公(gong)(gong)(gong)路(lu)橋(qiao)(qiao)，橋(qiao)(qiao)長(chang)(chang)在(zai)(zai)15米以(yi)(yi)上(shang)者總(zong)計約(yue)(yue)12萬(wan)(wan)(wan)(wan)座（有(you)(you)(you)(you)6400公(gong)(gong)(gong)里(li)(li)(li)長(chang)(chang)）。在(zai)(zai)高(gao)速公(gong)(gong)(gong)路(lu)中橋(qiao)(qiao)梁里(li)(li)(li)程占(zhan)(zhan)的(de)比例最大(da)，約(yue)(yue)12.2%，且其維修(xiu)(xiu)、養護總(zong)投資大(da)約(yue)(yue)需3050萬(wan)(wan)(wan)(wan)美元(yuan)。由此(ci)可(ke)見，舊(jiu)橋(qiao)(qiao)改造(zao)利用(yong)(yong)(yong)在(zai)(zai)世(shi)界范圍(wei)內都(dou)是(shi)(shi)一條挖潛節資的(de)途徑(jing)。