【正文】 常高的風(fēng)險(xiǎn)，這個(gè)基本原理已經(jīng)得到證實(shí)。 鉸接縫和支座處有關(guān)排水裝置各種的問題。箱體橫截面高 ，寬 4m。物理檢查、非損傷雷達(dá)檢測(cè)及其它的研究方法均已被用來去調(diào)查橋梁中潛在的缺陷。歐洲也有大量的使用后張法建造的混凝土橋梁，但這種橋梁中的鐵制錨索套管會(huì)妨礙雷達(dá)對(duì)橋梁的檢測(cè)。 隨著經(jīng)濟(jì)和政治的發(fā)展，土木工程，尤其是橋梁工程至今沒能形成某種統(tǒng)一陣線。為了舉例說明歐洲的研究方法已經(jīng)被這種方式所替代，一個(gè)典型的案例就是有關(guān)英國后張法橋梁被討論的事，愛丁堡大學(xué)給出了這個(gè)關(guān)于用數(shù)字化脈沖雷達(dá)鑒定后張法混凝土橋梁孔隙的資源互補(bǔ)的案例。 關(guān)于知識(shí)的傳播，目前似乎已出現(xiàn)了 2種非常不同的方式、英美主要集中于在相關(guān)期刊出版物上發(fā)表首要的研究成果，例如 ASCE、 LCE及其它期刊，而歐洲內(nèi)陸國家主要集中于在專門會(huì)議上展示其重要的研究成果，后者存在著局限性，新的研究成果的發(fā)布受到了限制。但它仍然被用于大跨徑橋梁和鐵路用橋，如今，隨著英國正在進(jìn)行的高速公路拓寬計(jì)劃的實(shí)施，這種橋梁又重新受到了人們的青睞。因?yàn)檫@ 種橋梁可能會(huì)毫無預(yù)兆地出現(xiàn)脆性斷裂，后張法鋼絞線在預(yù)制段搭接部位的防腐工作是影響這種類型橋梁長期穩(wěn)定性的主要因素。 大橋中跨和南部引橋跨徑均采用后張法裝配式預(yù)制結(jié)構(gòu)，這些后張法預(yù)制構(gòu)件構(gòu)件包括五種類型的預(yù)應(yīng)力張拉措施。 現(xiàn)澆混凝土表面大片的剝落部位和暴露在外的生銹的加強(qiáng)筋。 修理不合格防水材料和混凝土表面的瑕疵。 為了對(duì)比，選定了 10 個(gè)觀測(cè)孔，小孔是垂直向下鉆進(jìn)導(dǎo)管。在少數(shù)幾個(gè)案例中，在沙漿表面能明顯地看到預(yù)應(yīng)力鋼絞線，但沒有跡象表明有水滲透了進(jìn)去。這種轉(zhuǎn)換是使用一種 16 位的模擬信號(hào)變流器，它能使數(shù)據(jù)獲得相當(dāng)高的分辨率，以便用于后續(xù)的數(shù)據(jù)處理。除了 這些能變換顏色的設(shè)備外，還可能使用用來過濾水平線和豎直線的特殊程序。 Bridge research in Europe A brief outline is given of the development of the European Union, together with the research platform in Europe. The special case of posttensioned bridges in the UK is discussed. In order to illustrate the type of European research being undertaken, an example is given from the University of Edinburgh portfolio: relating to the identification of voids in posttensioned concrete bridges using digital impulse radar. Introduction The challenge in any research arena is to harness the findings of different research groups to identify a coherent mass of data, which enables research and practice to be better focused. A particular challenge exists with respect to Europe where language barriers are inevitably very significant. The European Community was formed in the 1960s based upon a political will within continental Europe to avoid the European civil wars, which developed into World War 2 from 1939 to 1945. The strong political motivation formed the original munity of which Britain was not a member. Many of the continental countries saw Britain’s interest as being purely economic. The 1970s saw Britain joining what was then the European Economic Community (EEC) and the 1990s has seen the widening of the munity to a European Union, EU, with certain political goals together with the objective of a mon European currency. Notwithstanding these financial and political developments, civil engineering and bridge engineering in particular have found great difficulty in forming any kind of mon thread. Indeed the educational systems for University training are quite different between Britain and the European continental countries. The formation of the EU funding schemes —. Socrates, Brite Euram and other programs have helped significantly. The Socrates scheme is based upon the exchange of students between Universities in different member states. The Brite Euram scheme has involved technical research grants given to consortia of academics and industrial partners within a number of the states— a Brite Euram bid would normally be led by an industrialist. In terms of dissemination of knowledge, two quite different strands appear to have emerged. The UK and the USA have concentrated primarily upon disseminating basic research in refereed journal publications: ASCE, ICE and other journals. Whereas the continental Europeans have frequently disseminated basic research at conferences where the circulation of the proceedings is restricted. Additionally, language barriers have proved to be very difficult to break down. In countries where English is a strong second language there has been enthusiastic participation in international conferences based within continental Europe —. Germany, Italy, Belgium, The Netherlands and Switzerland. However, countries where English is not a strong second language have been hesitant participants }—. France. European research Examples of research relating to bridges in Europe can be divided into three types of structure: Masonry arch bridges Britain has the largest stock of masonry arch bridges. In certain regions of the UK up to 60% of the road bridges are historic stone masonry arch br