In our country, most of bridges were built in 1960s or 1970s, which were based on that time traffic discharge and development planning, so design criterion of these bridges were very lower. in addition, it was inevitable to bring about cracks > concrete rupture, steel rust ^ honeycomb and water proof layer failure, because some established bridges were built by poor construction and maintenance during the course of operating period. all above mentioned lead to durability and bearing capacity could n ' t gain to design standard
由於我國很多橋梁建於上個世紀六、
七十年代，基於當時的車流量和各方面的發展規劃，橋梁設計等級普遍偏低；另外，某些既有橋梁由於施工質量差和運營期間維護不到位，不可避免地會產生裂縫、混凝土破損、鋼
筋銹蝕、蜂窩及防水層失效等缺陷，從而導致耐久性及承載力達不到設計要求。
As the reinforced concrete highway bridge built in 1960s ? 70s in china, the load - bearing capacity of xingtan bridge is insufficient clue to the increasing traffic and the overloading of trailers and container vehicles. on the other hand, the bridge was wore out and damaged. so, a perfect retrofit scheme needs to be carried out in order to meet both safe and economical demands
同我國六
七十年代建造的鋼
筋砼公路橋梁一樣，普遍存在因交通量增大、拖掛運輸車、集裝箱車輛超載運輸等原因造成橋梁承載力不足。加之橋梁老化、破損，迫切需要對舊橋進行技術改造，採用加固補強使其達到既能安全行駛，又節省投資。
It worked and worked faster : i felt the pulses throb in my head and temples ; but for nearly an hour it worked in chaos ; and no result came of its efforts
我動著腦筋，越動越快。我感到我的腦袋和太陽穴在搏動著。但將近一個小時，我的腦子亂七八糟，一切努力毫無結果。
