土木工程建筑橋梁外文翻譯---歐洲橋梁研究-建筑結(jié)構(gòu)-資料下載頁(yè)
2025-05-12 13:58本頁(yè)面
【導(dǎo)讀】在歐洲，一個(gè)共同研究的平臺(tái)隨著歐盟的發(fā)展誕生了。為了舉例說(shuō)明歐洲的。戰(zhàn)，這是為了能使研究和實(shí)踐更好地結(jié)合，具有針對(duì)性。此外，在歐洲，不容忽。20世紀(jì)60年代的歐共體便是基于這一目的。它的成立帶有很強(qiáng)的政治動(dòng)機(jī)，但。益，直到70年代，英國(guó)才加入由歐共體轉(zhuǎn)化而來(lái)的歐洲經(jīng)濟(jì)共同體。有建立歐洲共同的貨幣體系的經(jīng)濟(jì)目標(biāo)。這緣于英國(guó)和其他的歐洲國(guó)家迥異的大學(xué)教育培養(yǎng)體制，歐洲基金計(jì)劃如。性，新的研究成果的發(fā)布受到了限制。些不以英語(yǔ)為強(qiáng)勢(shì)外語(yǔ)的歐洲國(guó)家對(duì)國(guó)際會(huì)議的參與并不積極，比如法國(guó)。英國(guó)擁有大量的石拱橋，某些地區(qū)有超過(guò)60%的公路橋?yàn)楣爬系氖皹?，?jiàn)，因?yàn)樗鼈冊(cè)诙?zhàn)中許多已被毀壞。從20世紀(jì)的50年代至70年代，在歐洲涌現(xiàn)了大量的混凝土結(jié)構(gòu)的橋梁，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)。僅是存在于法、英兩國(guó)。物理檢查、非損傷雷達(dá)檢。力筋腐蝕和完整性的檢測(cè)。然而，對(duì)出現(xiàn)問(wèn)題的嚴(yán)重性會(huì)很難做出判斷。
【正文】 ructure, a baroscopic was then used to investigate all predicted voids and in more than 60% of cases this gave a clear confirmation of the radar findings. In several other cases some evidence of honeybing in the in site stitch concrete above the duct was found. When viewing voids through the baroscopic, however, it proved impossible to determine their actual size or how far they extended along the tendon ducts although they only appeared to occupy less than the top 25% of the duct diameter. Most of these voids, in fact, were smaller than the diameter of the flexible baroscopic being used (approximately 9 mm) and were seen between the horizontal top surface of the grout and the curved upper limit of the duct. In a very few cases the tops of the prestressing strands were visible above the grout but no sign of any trapped water was seen. It was not possible, using the baroscopic, to see whether those cables were corroded. Digital radar testing The test method involved exciting the joints using radio frequency radar antenna: 1 GHz, 900 MHz and 500 MHz. The highest frequency gives the highest resolution but has shallow depth peration in the concrete. The lowest frequency gives the greatest depth peration but yields lower resolution. The data collected on the radar sweeps were recorded on a GSSI SIR System 10. This system involves radar pulsing and recording. The data from the antenna is transformed from an analogue signal to a digital signal using a 16bit analogue digital converter giving a very high resolution for subsequent data processing. The data is displayed on site on a highresolution color monitor. Following visual inspection it is then stored digitally on a tape for subsequent analysis and signal processing. The tape first of all records a ‘header’ noting the digital radar settings together with the trace number prior to recording the actual data. When the data is played back, one is able to clearly identify all the relevant settings —making for accurate and reliable data reproduction. At particular locations along the traces, the trace was marked using a marker switch on the recording unit or the antenna. All the digital records were subsequently downloaded at the University’s NDT laboratory on to a microputer.（ The raw data prior to processing consumed 35 megabytes of digital data.） Postprocessing was undertaken using sophisticated signal processing software. Techniques available for the analysis include changing the color transform and changing the scales from linear to a skewed distribution in order to highlight、突出 certain features. Also, the color transforms could be changed to highlight phase changes. In addition to these color transform facilities, sophisticated horizontal and vertical filtering procedures are available. Using a large screen monitor it is possible to display in split screens the raw data and the transformed processed data. Thus one is able to get an accurate indication of the processing which has taken place. The puter screen displays the time domain calibrations of the reflected signals on the vertical axis. A further facility of the software was the ability to display the individual radar pulses as time domain wiggle plots. This was a particularly valuable feature when looking at individual records in the vicinity of the tendons. Interpretation of findings A full analysis of findings is given elsewhere, Essentially the digitized radar plots were transformed to color line scans and where double phase shifts were identified in the joints, then voiding was diagnosed. Conclusions 1. An outline of the bridge research platform in Europe is given. 2. The use of impulse radar has contributed considerably to the level of confidence in the assessment of the Besses o’ th’ Barn Rail Bridge. 3. The radar investigations revealed extensive voiding within the posttensioned cable ducts. However, no sign of corrosion on the stressing wires had been found except for the very first investigation. 出處： 出處：天工網(wǎng)
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