北京五環(huán)路京山立交橋鋼箱梁架設(shè)施工方案.doc

北京五環(huán)路京山立交橋鋼箱梁架設(shè)施工

　　北京五環(huán)路是北京市2003年度重點工程建設(shè)項目，它是一條截流、疏導(dǎo)過境交通，連接市區(qū)邊緣集團的一條重要交通干線。由中鐵十九局集團第三工程有限公司負(fù)責(zé)施工的五環(huán)四期第五合同段在K9+155.178處上跨京山鐵路，該橋全長824 米，分左右兩幅，全寬28.5m，位于R=1050m的平曲線及R=10000m的豎曲線上，其中跨越京山鐵路的第7～9孔采用 48m+72m+48m米的鋼混組合連續(xù)箱梁的結(jié)構(gòu)型式，單幅分3軸，共6軸，由于在交叉處主線與京山鐵路斜交（交角32°），為了保證鋼梁拼接處的臨時支墩與鐵路平行，每軸分7個節(jié)段，全橋共42個預(yù)制拼接段，梁高2.5m，最大長度為35m，最大吊裝重量為59t。
　　該橋上跨京山上行、下行，京津三線，豐西四線共四條鐵路正線，運輸十分繁忙，晝夜通行客貨列車298趟，平均每5 分鐘就有一列火車通過，由于跨線作業(yè)，既不能危及行車安全又要保障運營時間，因此架設(shè)鋼梁的安全性和可行性便顯得尤為重要。在施工之前我們除了協(xié)調(diào)與鐵路運營部門的關(guān)系申請要點外，同時對架設(shè)方案進行了深入細(xì)致的研究，確保架設(shè)的安全性和可行性。
　　根據(jù)現(xiàn)場地形情況，充分考慮到鐵路行車限界的要求，我們選擇采用在梁段拼接點平行于鐵路行車方向搭設(shè)臨時支墩，同時沿主線兩側(cè)切線方向搭設(shè)架梁軌道梁，采用鄭州大方DF40m/100型架橋機進行架梁作業(yè)的梁體架設(shè)方案（見后附圖）。具體施工方案及施工驗算如下：
　　——鋼箱梁臨時支墩施工：
　　地基處理：由于該處地基承載力較低，實測地基承載力 150Kpa,而臨時墩的荷載為110t,受鐵路限界的影響，基礎(chǔ)又不能無限擴大，因此為了保證地基承載力滿足施工要求，我們采用了12%的石灰土對地基進行處理，使地基承載力達到200Kpa以上。
　　基礎(chǔ)施工：為了提高地基土的水穩(wěn)性，保證地基整體受力，減小地基不均勻沉降的影響，在處理完的地基上我們施做了一層80cm厚的C25混凝土基礎(chǔ)。每個
Beijing Jingshan Fifth Ring Road overpass steel box girder erection

Fifth Ring Road of Beijing, Beijing 2003 is the key construction projects, it is a closure, to ease cross-border traffic, connecting the urban fringe groups an important transport route. Central Railway 19 Bureau Group Third Engineering Co., Ltd. for construction of the fifth contract segment rings 4 Department on the cross in the K9 +155.178 Jingshan railway bridge length 824 meters, about 2 minutes, the whole width of 28.5m, at R = 1050m flat curve and R = 10000m of vertical curve, which Jingshan railway across the first 7 to 9 holes with 48m +72 m +48 m m composite continuous steel-concrete box beam type, sub-3 Single-axis, 6-axis, as in the Main Line and the intersection of Jingshan Railway Skew (angle 32 °), in order to ensure the temporary supporting steel beams and Stitching the railway parallel to the axis points of each segment 7, a total of 42 prefabricated full-bridge connection section , high beam 2.5m, maximum length of 35m, the maximum lifting weight of 59t.
The bridge across Jingshan uplink, downlink, Beijing and Tianjin three lines, four lines of four abundance West Main Line railway, transport very heavy passenger and freight trains pass 298 times a day and night, every 5 minutes there is a train passed, since cross-line operations, can not endanger traffic safety and also protect the hours of operation, so setting up the safety and feasibility of beam it is very important. Before the construction of our addition to coordinating the relationship with the railway operations for points, the same time, set up an intensive program of study, to ensure the safety and feasibility of setting up.
According to the site topography, and fully take into account the requirements of railway traffic bound, we choose to use the Beam splice point the direction parallel to the erection of temporary supporting rail traffic, while the main line on both sides of the tangent direction along the erection of girder beam, with Zhengzhou generous DF40m / 100 machine girder bridge beam erection operations program (see below photo). Checking the specific construction plan and construction are as follows:
- Construction of temporary supporting steel box girder:
Ground handling: because of the low bearing capacity, the measured bearing capacity 150Kpa, load the temporary pier for the 110t, by the railway gauge the impact of base can not be indefinitely expanded, so in order to ensure the bearing capacity to meet the construction requirements, we use 12% of the limestone soil on the ground for processing, the foundation bearing capacity to 200Kpa above.
Foundation Construction: To improve the water stability of soil to ensure that the whole force foundation, reducing the differential settlement of foundation, finished with the foundation we have done applied a layer of 80cm thick C25 concrete foundation. Each
 

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