【正文】 design seismic load for the project was developed on the basis of a probabilistic seismic hazard assessment that considered the conditions at the an assessment establishes the return period for a given earthquake and the corresponding intensity of ground shaking in the horizontal directtion in terms of an acceleration response PSHA determined two dominant seismic sources: a subduction source zone associated with the North Panama Deformed Belt capable of producing a seimic event as strong as ,and the Rio Gatun Fault, capable of producing an event as strong as . The NPDB event was used as the safety evluation earthquake,that is,the maximum earthquake that could strike without putting the bridge out of damage to the bridge would be minor but would require some closures of the Gatun Fault event was used as the foundational evaluation earthquake,a lowerlevel temblor that would cause minimal damage to the bridge and would not require the FEE load case,the SEE loading was scaled back by FEE is assumed to have a peak acceleration of and a return period of 500 years。 A design that would adhere to the American Association of State Highway and Transportation Official standard for a 100year service life and offer HS25 truck loading。 A roadway wide enough to carry six lanes of traffic, three in each direction。中文 4735 字 畢業(yè)設(shè)計 外文翻譯 題 目 跨 越 世 紀 之 橋 專 業(yè) 土木工程（橋梁） 2020 年 6 月 A Bridge For All Centuries An extremely longand record settingmain span was designed for the second bridge to across the Panama Canal in order to meet the owner’s requirement that no piers be placed in the no disruption of canal traffic was permitted at any time,the cablestayed bridge of castinplace cancrete was carefully constructed using the balancedcantilever method. In 1962 ,the Bridge of Americas(Puente de las America) opened to traffic,serving as the only fixed link across the Panama Canal .The bridge was designed to carry 60,000 vehicles per day on four lanes, but it has beenoperating above its capacity for many bottlenecks on the route that the bridge carries over the canalthe PanAmerican Highway(InterAmerican Highway)and promotegrowth on the western side of Panama,the country’s Ministry of Public Works(Ministerio de Obras Publicas,or MOP )decided to build a new highway systerm linking the northern part of Panama City,on the eastern side of the canal, to the town of Arraijan,located on the western side of the Centennial Bridge –named to memorate 100 years of Panamanian independencehas noe been constructed and, when opend, will carry six lanes of traffic. This cablestayed bridge of castinplace cancrete features a main span of 420m,the longest such span for this type of bridge in the Western Hemisphere. In 200 the MOP invited international bridge design firms to pete for the design of the crossing, requesting a twopackage proposal:one techinical, the other financial. A total of eight proposals were received by December 2020 from established bridge design firms all over the world. After shortlisting three firms on the basis of the technical merits of their proposals, the MOP selected International, of San Francisco, to prepare the bridge design and provide field construction support based on the firm’s financial package. The Centennial Bridge desige process was unique and aggressive,incorporating concepts from the traditional design/build/bid method, the design/build method , and the sacalled fasttrack design plete the construction on timethat is ,within just 27 monthsthe design of the bridge was carried out to a level of 30 percent before construction bidding began, in December selected contractorthe Wiesbaden,Germany,office of Bilfinger Berger,AGwas brought on board immediately after being selected by the MOP ,just as would be the case in a fasttrack approach. The desige of the bridge was then pleted in conjunction with construction , a process that id similan to desige/build. The design selected by the client features two singlemast towers,each supporting two sets of stay cables that align in one vertical was used to construct both the towers and the box girder deck,as well as the approach structures. The MOP , in conjunction with the Panama Canal Authority,established the following requirements for the bridge design : A 420m,the minimum length for the main span to acmodate the recently widened Gaillard Cut,a narrow portion of the canal crossing the Continental Divide that was straightened and widened to 275m in 2020。 A navigational envelope consisting of 80m of vertical clearance and 70m of horizontal clearance to acmodate the safe passage of a crane of World War 11 vintagea gift from the that is used by the Panama Canal Authority to maintain the canal gates and facilities。 A deck able to acmodate a wide pedestrian walkway。 A structure that could carry two diaer water lines。 the probability that it will be exceeded within 50 years is 10 pencent and within 100 years,18 SEE is assumed to have a peak acceleration of and a return period of 2,500 years。 the expansion joints are located at the abutments only. Deck movements on the order of 400 mm are expected at these modular expansion joints Multidirectional pot bearings are used at the piers and at the a