航機偏移於機場剛性鋪面設計影響之探討

Effect of Aircraft Wandering on Airport Rigid Pavement Design

王詩瑩(Shih-Ying Wang)

指導教授 ： 周家蓓

國立臺灣大學/工學院/土木工程學研究所/博士(2008年)

https://doi.org/10.6342/NTU.2008.01390

摘要

臺灣大學鋪面研究小組於民國91年1月在台灣桃園國際機場(Taiwan Taoyuan International Airport, TTIA)之N1滑行道進行一個為期三年之監測計畫，以探討機場剛性鋪面於航機及環境效應下之變化情形。在該計畫中使用鼻輪定位計針對航機於N1滑行道之側向分佈型態進行觀察。經分析得知，N1滑行道上航機之側向分佈近似常態分佈，且其標準差為50cm。此一標準差小於美國聯邦飛航總署(Federal Aviation Administration, FAA)於1974年所量得之數值，亦小於FAA設計法中所採用之標準差數值－77cm。因為較小之標準差數值代表航機路徑較為集中，並可能對某特定位置造成較大之損傷。因此，本研究將探討不同航機偏移型態，特別是不同標準差數值對於機場剛性鋪面設計之影響。
將FAA AC 150/5320-6D 中之標準差數值替換為50cm，並針對通過數及覆蓋數之比值(pass-to-coverage ratio)以及相對厚度因子(relative thickness factor, RH)進行探討發現，此一較小之標準差數值對於所需之版塊厚度影響並不大。但50cm係在單一機場且單一滑行道量測而得，並無法代表大多數之情形，因此，後續假設其餘小於77cm之標準差數值進行討論，並探討不同情形下實際產生的覆蓋數會大於設計之覆蓋數之機率、不同標準差設定下版塊厚度變化的情形，以及航機偏移、航機主輪配置、與版塊縱向間距間之相互關係。
經分析發現，若現地航機側向分佈之標準差為50cm但卻以77cm進行設計，則實際產生的覆蓋數會大於設計之覆蓋數之機率為65%，即有65%的機會實際產生的覆蓋數大過鋪面可容許的數量。而且，現地的標準差與設計用之標準差之間的差距越大，則上述機率則越高。因此，為避免實際產生的覆蓋數大過鋪面可容許的數量並產生額外的破壞，則設計所採用的數值需接近現地之數值，以維持設計之可靠度。
若針對20年以及30年兩種不同之設計年限進行比較，則發現當設計年限設定為30年，則該設計可以達到較高的可靠度，並且只需要較20年之設計增加1cm之厚度。除此之外，在同一個設計年限之設定下，增加1cm亦可增加設計之可靠度，並降低實際產生的覆蓋數大於設計之覆蓋數產生之機率。
除上述外，針對航機偏移與版塊縱向間距之設計進行討論，並採用標準差10cm至100cm以及縱向間距3m至7m進行分析。選取寬體且載重較大以及輪軸配置形式較為特別的航機，配合N1滑行道上該航機實際通過次數進行討論。觀察數據得知，比較不同縱向間距之設定，當航機偏移之標準差為10cm至60cm時，距中心線6m之接縫其航機通過數較其他位置之接縫要大；當航機偏移之標準差為70cm至100cm時，則以距中心線5m之接縫其航機通過數最大。因此，在此一情形下，需避免上述接縫位置之產生。建議機場管理單位採用本研究之方法找尋合適之版塊間距，以降低在接縫處航機通過的次數。此外，並可藉由改變跑道及滑行道中心線劃設位置以達到上述目的。

關鍵字

航機偏移 ； 監測計畫 ； 機場剛性鋪面設計 ； 版塊厚度 ； 版塊縱向間距

並列摘要

Several types of sensors, including position gauges, H-bar strain gauges, dowel-bar strain gauges, temperature sensors, moisture sensors, and optical fiber sensors, were embedded in concrete slabs in Taxiway N1 of Taiwan Taoyuan International Airport (TTIA) during scheduled maintenance in January 2002. Piezoelectric position gauges were used to observe the aircraft lateral distribution pattern. It was found that aircraft mainly moved along the centerline (center lights), and the number of passes decreased on the both sides as a bell-shaped distribution. Moreover, all flights tended to have a shift to the left of center point and the standard deviation of the wandering pattern was 50 cm.
This standard deviation value is much smaller than what was found in the monitoring project conducted by Federal Aviation Administration (FAA) in 1974. Furthermore, this value is also smaller than the standard deviation value, 77 cm, used in the FAA design methods. The standard deviation value would influence the pass-to-coverage (p/c) ratios of different aircraft types, the converted coverages, and the required thickness. However, it was found that the effect of the smaller standard deviation value on required slab thickness is minor based on the FAA’s design concept. Thus, other standard deviation values were assumed for analysis, and the “over capacity probability” was defined.
It was found that the over capacity probability of using 77 cm rather than the observed value 50 cm was 65%, and the over capacity probability got higher when the difference of observed and assumed values increased. Thus, the assumed value should be as close to the observed value as possible to maintain the reliability of pavement design. As for the design life settings of 20 years and 30 years, the reliability could be retained for more years under the design life setting of 30 years but only result in the derived thickness need for 1.0 cm. Further, the increase of 1.0 cm under the design life settings of 20 years can also lift the reliability. In addition to the change of required slab thicknesses, the interaction between the aircraft wandering and the slab size was also examined. Standard deviation values 10 to 100 cm, and slab sizes, 3 to 7 m are assumed for the analysis. By using the real aircraft mix at the TTIA, it could be seen that the min accumulation among the max accumulations happen at the joint of 7m, and the max accumulation happen at the joint of 6m for standard deviations 10 cm to 60 cm as well as at the joint of 5 m for standard deviations 70 cm to 100 cm. Therefore, the airport authorities could follow the analysis procedure in this study to find the appropriate slab size setting. Further, the location of the centerlines could also be changed for prevent the maximum accumulation at the joint.

並列關鍵字

aircraft wandering ； monitoring project ； airport rigid pavement design ； required slab thickness ； longitudinal joint spacing

參考文獻

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