桥梁工程毕业设计外文翻译(箱梁).docx

西南交通大学
本科毕业设计(论文)
外文资料翻译
年级:
学号:
姓名:
专业:
指导老师:
2013年 6 月
外文资料原文:
13
Box girders
General
The box girder is the most flexible bridge deck form. It can cover a range of spans from 25 m up to the largest non-suspended concrete decks built, of the order of 300 m. Single box girders may also carry decks up to 30 m wide. For the longer span beams, beyond about 50 m, they are practically the only feasible deck section. For the shorter spans they are petition with most of the other deck types discussed in this book.
The advantages of the box form are principally its high structural efficiency (), which minimises the prestress force required to resist a given bending moment, and its great torsional strength with the capacity this gives to re-centre eccentric live loads, minimising the prestress required to carry them.
The box form lends itself to many of the highly productive methods of bridge construction that have been progressively refined over the last 50 years, such as precast segmental construction with or without epoxy resin in the joints, balanced cantilever erection either cast in-situ or coupled with precast segmental construction, and incremental launching (Chapter 15).
Cast-in-situ construction of boxes
General
One of the main disadvantages of box decks is that they are difficult to cast in-situ due to the essibility of the bottom slab and the need to extract the internal shutter. Either the box has to be designed so that the entire cross section may be cast in one continuous pour, or the cross section has to be cast in stages.
Casting the deck cross section in stages
The mon method of building box decks in situ is to cast the cross section in stages. Either, the bottom slab is cast first with the webs and top slab cast in a second phase, or the webs and bottom slab constitute the first phase, completed by the top slab.
When the bottom slab is cast first, the construction joint is usually located just above the slab, giving