CN111914458B - Method for controlling line shape of arch ring of reinforced concrete arch bridge - Google Patents
Method for controlling line shape of arch ring of reinforced concrete arch bridge Download PDFInfo
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- 239000011150 reinforced concrete Substances 0.000 title claims abstract description 40
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- 238000005266 casting Methods 0.000 claims abstract description 46
- 238000009434 installation Methods 0.000 claims abstract description 17
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Abstract
本发明公开了一种钢筋混凝土拱桥拱圈线形控制方法,包括:S1、获取钢筋混凝土拱桥拱设计参数;S2、基于钢筋混凝土拱桥拱设计参数完成第1号悬臂浇筑节段的施工,设i=2;S3、计算第i号悬臂浇筑节段的立模标高,基于第i号悬臂浇筑节段的立模标高完成第i号悬臂浇筑节段的浇筑;S4、若i=N,将i的值加1后执行步骤S5,若i<N,将i的值加1后返回步骤S3;S5、计算第i号劲性骨架节段的安装标高,基于第i号劲性骨架节段的安装标高完成第i号劲性骨架节段的施工;S6、若i=M,结束,若i<M,将i的值加1后返回步骤S5。本发明能够精确控制斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥的拱圈节段线形。
The invention discloses a method for linear control of the arch circle of a reinforced concrete arch bridge. 2; S3. Calculate the vertical formwork elevation of the i-th cantilever pouring segment, and complete the pouring of the i-th cantilever pouring segment based on the vertical formwork elevation of the i-th cantilever pouring segment; S4. If i=N, set the Step S5 is executed after adding 1 to the value, if i<N, add 1 to the value of i and return to step S3; S5, calculate the installation elevation of the i-th stiff skeleton segment, based on the installation of the i-th stiff skeleton segment The construction of the ith rigid frame segment is completed at the elevation; S6, if i=M, end, if i<M, add 1 to the value of i and return to step S5. The invention can precisely control the segment line shape of the arch ring of the reinforced concrete arch bridge constructed by the cable-stayed buckle and the cantilever casting combined with the rigid skeleton.
Description
技术领域technical field
本发明涉及拱桥施工领域,具体涉及一种钢筋混凝土拱桥拱圈线形控制方法。The invention relates to the field of arch bridge construction, in particular to a linear control method for an arch circle of a reinforced concrete arch bridge.
背景技术Background technique
斜拉扣挂悬臂浇筑钢筋混凝土箱型拱桥作为拱桥施工的一种新工艺,具有结构整体性好、造价低、后期养护少、施工稳定性高、跨越能力强等优点,中国西部地区多高山峡谷地形,非常适合悬浇拱的修建,因此该工艺在我国西部地区具有较大的竞争力。As a new technology of arch bridge construction, cable-stayed cantilever cast reinforced concrete box arch bridge has the advantages of good structural integrity, low cost, less maintenance, high construction stability, and strong spanning ability. The terrain is very suitable for the construction of cantilevered arches, so this process has great competitiveness in the western region of my country.
斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥由于其悬浇节段较长,施工难度大。随着悬臂浇筑长度及重量的加大,挂篮等施工临时结构易出现杆件应力偏大、悬臂端下挠过大等情况,难以满足悬臂浇筑要求,导致拱圈节段线形控制难度相应增大。而作为一种新的拱桥施工工艺,现有技术中,并没有能够精确控制斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥的拱圈节段线形的方法。The construction of reinforced concrete arch bridges with cable-stayed cantilever casting combined with rigid skeletons is difficult because of its long cantilevered sections. With the increase of the length and weight of cantilever casting, temporary structures such as hanging baskets are prone to excessive stress on the rods and excessive downward deflection of the cantilever end. big. As a new construction technique of arch bridges, in the prior art, there is no method that can precisely control the segmental alignment of the arch ring of the reinforced concrete arch bridge constructed by the cable-stayed cantilever casting combined with the rigid skeleton.
因此,如何精确控制斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥的拱圈节段线形成为了本领域技术人员急需解决的问题。Therefore, how to precisely control the formation of the segmental line of the arch ring of the reinforced concrete arch bridge constructed by the cantilever casting of the cable-stayed buckle and the cantilever combined with the rigid skeleton is an urgent problem to be solved by those skilled in the art.
发明内容SUMMARY OF THE INVENTION
针对上述现有技术的不足,本发明实际解决的技术问题是:精确控制斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥的拱圈节段线形。Aiming at the above-mentioned deficiencies of the prior art, the technical problem actually solved by the present invention is to precisely control the segmental line shape of the arch ring of the reinforced concrete arch bridge constructed by the cable-stayed suspension cantilever casting combined with the rigid skeleton.
一种钢筋混凝土拱桥拱圈线形控制方法,本方法适用于斜拉扣挂悬臂浇筑结合劲性骨架施工的钢筋混凝土拱桥,所述钢筋混凝土拱桥的拱圈的中部为外包混凝土的劲性骨架节段,两侧为悬臂浇筑节段,悬臂浇筑节段由拱脚向中间方向的编号依次为1至N,劲性骨架节段由拱脚向中间方向的编号依次为N+1至M;所述钢筋混凝土拱桥拱圈线形控制方法包括:A reinforced concrete arch bridge arch ring linear control method, the method is suitable for a reinforced concrete arch bridge constructed by cable-stayed cantilever casting combined with a rigid skeleton, and the middle part of the arch ring of the reinforced concrete arch bridge is a rigid skeleton segment covered with concrete , the two sides are cantilever pouring sections, the cantilever pouring sections are numbered from 1 to N from the arch foot to the middle direction, and the rigid skeleton sections are sequentially numbered from the arch foot to the middle direction. N+1 to M; The linear control method of the arch circle of the reinforced concrete arch bridge includes:
S1、获取钢筋混凝土拱桥拱设计参数;S1. Obtain the arch design parameters of the reinforced concrete arch bridge;
S2、基于钢筋混凝土拱桥拱设计参数完成第1号悬臂浇筑节段的施工,设i=2;S2. Complete the construction of the No. 1 cantilever pouring segment based on the arch design parameters of the reinforced concrete arch bridge, and set i=2;
S3、计算第i号悬臂浇筑节段的立模标高,基于第i号悬臂浇筑节段的立模标高完成第i号悬臂浇筑节段的浇筑;S3. Calculate the vertical formwork elevation of the i-th cantilever pouring segment, and complete the pouring of the i-th cantilever pouring segment based on the vertical formwork elevation of the i-th cantilever pouring segment;
S4、若i=N,将i的值加1后执行步骤S5,若i<N,将i的值加1后返回步骤S3;S4. If i=N, add 1 to the value of i and execute step S5; if i<N, add 1 to the value of i and return to step S3;
S5、计算第i号劲性骨架节段的安装标高,基于第i号劲性骨架节段的安装标高完成第i号劲性骨架节段的施工;S5. Calculate the installation elevation of the i-th stiff frame segment, and complete the construction of the i-th stiff frame segment based on the installation elevation of the i-th stiff frame segment;
S6、若i=M,结束,若i<M,将i的值加1后返回步骤S5。S6. If i=M, end, if i<M, add 1 to the value of i and return to step S5.
优选地,步骤S3中,第i号悬臂浇筑节段的立模标高按下式计算:Preferably, in step S3, the vertical form elevation of the i-th cantilever casting segment Calculate as follows:
式中,表示第i号悬臂浇筑节段悬臂端的拱圈截面形心设计标高,表示第i号悬臂浇筑节段悬臂端拱圈截面的设计预拱度值,表示浇筑第i号悬臂浇筑节段时的主拱圈变形修正值,表示浇筑第i号悬臂浇筑节段时的挂篮变形值,h表示主拱圈高度,表示第i号悬臂浇筑节段悬臂端拱圈拱轴线水平倾角。In the formula, Represents the design elevation of the centroid of the arch ring section at the cantilever end of the i-th cantilever casting segment, Represents the design pre-camber value of the cantilever end arch ring section of the i-th cantilever casting segment, Represents the deformation correction value of the main arch ring when pouring the i-th cantilever pouring segment, represents the deformation value of the hanging basket when pouring the i-th cantilever pouring segment, h represents the height of the main arch ring, Represents the horizontal inclination angle of the arch axis of the cantilever end arch ring of the i-th cantilever casting segment.
优选地,钢筋混凝土拱桥的设计预拱度值获取方法包括:Preferably, the method for obtaining the design pre-camber value of a reinforced concrete arch bridge includes:
建立Midas/civil模型,求取拱圈跨中设计预拱度值,拱圈其余位置设计预拱度值按拱脚水平推力影响线成比例分布。A Midas/civil model is established to obtain the mid-span design pre-camber value of the arch ring, and the design pre-camber value of the rest of the arch ring is proportionally distributed according to the horizontal thrust influence line of the arch foot.
优选地,包括浇筑第i号悬臂浇筑节段时主拱圈变形混凝土时变效应修正值和浇筑第i号悬臂浇筑节段时现场实测温度修正值 Preferably, Including the correction value of the time-varying effect of the deformed concrete of the main arch ring when pouring the No. i cantilever pouring segment and the correction value of the field measured temperature when pouring the No. i cantilever pouring segment
优选地,表示基于挂篮预压荷载试验结果得到的第i号悬臂浇筑节段的挂篮变形预测值,表示浇筑拱圈第i号悬臂浇筑节段工况下挂篮有限元仿真结果值,表示第i-1号悬臂浇筑节段的挂篮实测变形值;Preferably, represents the predicted value of the hanging basket deformation of the i-th cantilever pouring segment based on the preloading load test results of the hanging basket, represents the value of the finite element simulation result of the hanging basket under the condition of the i-th cantilever pouring segment of the pouring arch ring, Indicates the measured deformation value of the hanging basket of No. i-1 cantilever pouring segment;
基于挂篮预压荷载试验结果,记录各分级荷载下挂篮实测变形值,获取分级荷载与挂篮变形映射关系,采用线形拟合即可获得第i号悬臂浇筑节段的挂篮变形预测值 其中,a和b均为常数项,G2表示拱圈第2号悬臂浇筑节段的重量,Gi表示第i号悬臂浇筑节段拱圈的重量;Based on the test results of the preloading load of the hanging basket, the measured deformation value of the hanging basket under each graded load is recorded, and the mapping relationship between the graded load and the hanging basket deformation is obtained, and the predicted value of the hanging basket deformation of the i-th cantilever pouring segment can be obtained by linear fitting. Among them, a and b are both constant terms, G 2 represents the weight of the No. 2 cantilever pouring segment of the arch ring, and G i represents the weight of the arch ring of the No. i cantilever pouring segment;
建立浇筑第i号悬臂浇筑节段工况下挂篮有限元仿真模型,第i号悬臂浇筑节段拱圈混凝土湿重荷载采用线荷载模拟,拱圈横隔板采用集中力进行模拟,可得 The finite element simulation model of the hanging basket under the condition of the No. i cantilever pouring section is established. The wet weight load of the arch ring of the No. i cantilever pouring section is simulated by line load, and the diaphragm of the arch ring is simulated by concentrated force.
采用第i-1号悬臂浇筑节段的挂篮实测变形值作为 The measured deformation value of the hanging basket of the No. i-1 cantilever pouring segment as
优选地,步骤S5中,第i号劲性骨架节段的安装标高按下式计算:Preferably, in step S5, the installation elevation of the i-th rigid frame segment Calculate as follows:
式中,表示第i号劲性骨架节段悬臂端的拱圈截面形心设计标高,表示第i号劲性骨架节段悬臂端拱圈截面的设计预拱度值,表示安装第i号劲性骨架节段时现场实测温度修正值,h'表示型钢劲性骨架节段桁高,表示第i号劲性骨架节段悬臂端拱圈拱轴线水平倾角,δ'阶段/步骤实际总位移表示主拱圈分阶段施工有限元仿真模型中安装第i号劲性骨架节段施工阶段劲性骨架节段悬臂端控制点的阶段/步骤实际总位移值。In the formula, Represents the design elevation of the centroid of the arch ring section at the cantilever end of the i-th stiff skeleton segment, represents the design pre-camber value of the cantilever end arch ring section of the i-th stiffness skeleton segment, Represents the correction value of the temperature measured on site when the No. ith stiff frame segment is installed, h' represents the girder height of the section steel stiff frame segment, Represents the horizontal inclination of the arch axis of the arch ring at the cantilever end of the stiff skeleton segment No. i, and the actual total displacement of the δ' stage/step represents the construction stage of the installation of the stiff skeleton segment No. i in the finite element simulation model of the staged construction of the main arch ring. Phase/step actual total displacement value for the cantilever end control points of the skeleton segment.
综上所述,本发明公开了一种钢筋混凝土拱桥拱圈线形控制方法,本方法适用于斜拉扣挂悬臂浇筑结合劲性骨架施工的钢筋混凝土拱桥,所述钢筋混凝土拱桥的拱圈的中部为外包混凝土的劲性骨架节段,两侧为悬臂浇筑节段,悬臂浇筑节段由拱脚向中间方向的编号依次为1至N,劲性骨架节段由拱脚向中间方向的编号依次为N+1至M;所述钢筋混凝土拱桥拱圈线形控制方法包括:S1、获取钢筋混凝土拱桥拱设计参数;S2、基于钢筋混凝土拱桥拱设计参数完成第1号悬臂浇筑节段的施工,设i=2;S3、计算第i号悬臂浇筑节段的立模标高,基于第i号悬臂浇筑节段的立模标高完成第i号悬臂浇筑节段的浇筑;S4、若i=N,将i的值加1后执行步骤S5,若i<N,将i的值加1后返回步骤S3;S5、计算第i号劲性骨架节段的安装标高,基于第i号劲性骨架节段的安装标高完成第i号劲性骨架节段的施工;S6、若i=M,结束,若i<M,将i的值加1后返回步骤S5。本发明能够精确控制斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥的拱圈节段线形。In summary, the present invention discloses a method for controlling the linear shape of the arch ring of a reinforced concrete arch bridge. The method is suitable for a reinforced concrete arch bridge constructed by cable-stayed cantilever casting combined with a rigid skeleton. The middle part of the arch ring of the reinforced concrete arch bridge is It is the rigid skeleton segment of the outer concrete, and the two sides are cantilever pouring segments. The cantilever pouring segments are numbered from 1 to N from the arch foot to the middle direction, and the rigid skeleton segments are numbered from the arch foot to the middle direction. is N+1 to M; the linear control method for the arch circle of the reinforced concrete arch bridge includes: S1, obtaining the arch design parameters of the reinforced concrete arch bridge; S2, completing the construction of the No. 1 cantilever pouring section based on the arch design parameters of the reinforced concrete arch bridge, setting i=2; S3. Calculate the vertical formwork elevation of the i-th cantilever pouring segment, and complete the pouring of the i-th cantilever pouring segment based on the vertical formwork elevation of the i-th cantilever pouring segment; S4. If i=N, set the Step S5 is executed after adding 1 to the value of i. If i<N, add 1 to the value of i and return to step S3; S5, calculate the installation elevation of the i-th stiff skeleton segment, based on the i-th stiff skeleton segment Complete the construction of the i-th stiff skeleton segment at the installation elevation of 1; S6, if i=M, end, if i<M, add 1 to the value of i and return to step S5. The invention can precisely control the segment line shape of the arch ring of the reinforced concrete arch bridge constructed by the cable-stayed buckle and the cantilever casting combined with the rigid skeleton.
附图说明Description of drawings
为了使发明的目的、技术方案和优点更加清楚,下面将结合附图对本发明作进一步的详细描述,其中:In order to make the purpose, technical solutions and advantages of the invention clearer, the present invention will be described in further detail below in conjunction with the accompanying drawings, wherein:
图1为本发明公开的一种钢筋混凝土拱桥拱圈线形控制方法的流程图;Fig. 1 is the flow chart of a kind of reinforced concrete arch bridge arch loop linear control method disclosed by the present invention;
图2为本发明中一具体实例的拱桥的结构示意图;Fig. 2 is the structural representation of the arch bridge of a specific example in the present invention;
图3为图2中拱桥对应的拱脚截面图;Fig. 3 is the sectional view of the arch foot corresponding to the arch bridge in Fig. 2;
图4为图2中拱桥对应的标准截面图;Fig. 4 is the standard sectional view corresponding to the arch bridge in Fig. 2;
图5为图2中拱桥对应的合龙段拱圈纵向浇筑顺序图;Fig. 5 is the longitudinal pouring sequence diagram of the arch ring of the closing section corresponding to the arch bridge in Fig. 2;
图6和图7为图2中拱桥对应的合龙段拱圈横向浇筑顺序图;Fig. 6 and Fig. 7 are the horizontal pouring sequence diagrams of the arch ring of the closing section corresponding to the arch bridge in Fig. 2;
图8为新型三角桁架挂篮正视图;Figure 8 is a front view of the new triangular truss hanging basket;
图9为新型三角桁架挂篮侧视图;Figure 9 is a side view of the new triangular truss hanging basket;
图10为本发明中拱圈坐标计算坐标系的示意图;Fig. 10 is the schematic diagram of the coordinate system of arch circle coordinate calculation in the present invention;
图11为反力-位移互等定理示意图;Figure 11 is a schematic diagram of the reaction force-displacement reciprocal theorem;
图12为挂篮荷载试验锚固端布置图;Figure 12 is the layout diagram of the anchor end of the hanging basket load test;
图13为浇筑第i号悬臂浇筑节段工况下挂篮有限元仿真模型示意图;Figure 13 is a schematic diagram of the finite element simulation model of the hanging basket under the condition of pouring the No. i cantilever pouring segment;
图14为采用本发明的方法对图2中的拱桥进行线性控制,松索成拱后主拱圈线形的理论值和实测值的对比图;Figure 14 is a comparison diagram of the theoretical value and the measured value of the linear shape of the main arch after the method of the present invention is used to linearly control the arch bridge in Figure 2, and the loose cable is formed into an arch;
图15为主拱圈局部坐标系及各参数示意图。Figure 15 is a schematic diagram of the local coordinate system and parameters of the main arch ring.
具体实施方式Detailed ways
下面结合附图对本发明作进一步的详细说明。The present invention will be further described in detail below in conjunction with the accompanying drawings.
如图1所示,本发明公开了一种钢筋混凝土拱桥拱圈线形控制方法,本方法适用于斜拉扣挂悬臂浇筑结合劲性骨架施工的钢筋混凝土拱桥,所述钢筋混凝土拱桥的拱圈的中部为外包混凝土的劲性骨架节段,两侧为悬臂浇筑节段,悬臂浇筑节段由拱脚向中间方向的编号依次为1至N,劲性骨架节段由拱脚向中间方向的编号依次为N+1至M;所述钢筋混凝土拱桥拱圈线形控制方法包括:As shown in FIG. 1 , the present invention discloses a method for controlling the linear shape of the arch ring of a reinforced concrete arch bridge. This method is suitable for a reinforced concrete arch bridge constructed by cable-stayed cantilever casting combined with a rigid skeleton. The middle part is the rigid skeleton segment covered with concrete, and the two sides are cantilever pouring segments. The cantilever pouring segments are numbered from 1 to N from the arch foot to the middle direction, and the rigid skeleton segment is numbered from the arch foot to the middle direction. The sequence is N+1 to M; the reinforced concrete arch bridge arch circle linear control method includes:
S1、获取钢筋混凝土拱桥拱设计参数;S1. Obtain the arch design parameters of the reinforced concrete arch bridge;
S2、基于钢筋混凝土拱桥拱设计参数完成第1号悬臂浇筑节段的施工,设i=2;S2. Complete the construction of the No. 1 cantilever pouring segment based on the arch design parameters of the reinforced concrete arch bridge, and set i=2;
S3、计算第i号悬臂浇筑节段的立模标高,基于第i号悬臂浇筑节段的立模标高完成第i号悬臂浇筑节段的浇筑;S3. Calculate the vertical formwork elevation of the i-th cantilever pouring segment, and complete the pouring of the i-th cantilever pouring segment based on the vertical formwork elevation of the i-th cantilever pouring segment;
S4、若i=N,将i的值加1后执行步骤S5,若i<N,将i的值加1后返回步骤S3;S4. If i=N, add 1 to the value of i and execute step S5; if i<N, add 1 to the value of i and return to step S3;
S5、计算第i号劲性骨架节段的安装标高,基于第i号劲性骨架节段的安装标高完成第i号劲性骨架节段的施工;S5. Calculate the installation elevation of the i-th stiff frame segment, and complete the construction of the i-th stiff frame segment based on the installation elevation of the i-th stiff frame segment;
S6、若i=M,结束,若i<M,将i的值加1后返回步骤S5。S6. If i=M, end, if i<M, add 1 to the value of i and return to step S5.
以图2所示的拱桥为例,桥跨布置为2×30+17×13.2(主跨210m)+3×30m,桥梁全长为391.4m。主桥为净跨径210m的上承式钢筋混凝土箱型拱桥,净矢高42m,净矢跨比1/5,拱轴线采用悬链线,拱轴系数m=1.67。一侧引桥为2×30m预应力混凝土先简支后结构连续T梁,另一侧引桥为3×30预应力混凝土先简支后结构连续T梁。主桥平面位于直线上,主桥纵面位于i=±0.5%,R=25445.380m的凸曲线上。Taking the arch bridge shown in Figure 2 as an example, the span arrangement is 2×30+17×13.2 (main span 210m)+3×30m, and the total length of the bridge is 391.4m. The main bridge is a top-loaded reinforced concrete box arch bridge with a net span of 210m, a net sag height of 42m, a net sag-span ratio of 1/5, and the arch axis adopts a catenary, and the arch axis coefficient m=1.67. One side of the approach bridge is a 2×30m prestressed concrete simply supported and then structurally continuous T beam, and the other side approach is a 3×30 prestressed concrete first simply supported and then structurally continuous T beam. The plane of the main bridge is located on a straight line, and the longitudinal plane of the main bridge is located on a convex curve with i=±0.5% and R=25445.380m.
拱上排架处对应拱圈箱梁横隔板除1、14号立柱位置采用双25cm厚外,其余位置均采用35cm;排架立柱间横隔板均采用25cm,为排泄施工养护水和保持箱内干燥,在箱内拱脚处、横隔板与底板倒角处以及横隔板底部设置φ5cm排水孔;在腹板顶板设置φ5cm通气孔。Except for the positions of No. 1 and No. 14 columns, the transverse partitions of the corresponding arch ring box girder are 35 cm thick, and the other positions are 35 cm; the transverse partitions between the bent columns are all 25 cm. Dry in the box, set φ5cm drainage holes at the arches in the box, at the chamfers of the diaphragm and the bottom plate, and at the bottom of the diaphragm; set φ5cm ventilation holes on the top plate of the web.
拱圈施工扣索设置在每个节段的端部横隔板位置,锚具采用固定端圆P锚。主拱圈施工完毕后应将扣索截断,对索孔注浆填充。The construction buckle cable of the arch ring is set at the position of the diaphragm at the end of each segment, and the anchoring device adopts the fixed end round P anchor. After the construction of the main arch ring, the buckle cable should be cut off, and the cable hole should be filled with grouting.
如图3及图4所示,拱圈为单箱单室截面,宽7.0m,高3.5m。拱脚支架现浇段顶、底板厚度由80cm渐变至40cm,腹板厚度由80cm渐变至50cm。拱圈其它节段顶底板后40cm,腹板厚度为50cm。As shown in Figure 3 and Figure 4, the arch ring is a single box and single chamber section, with a width of 7.0m and a height of 3.5m. The thickness of the top and bottom plate of the cast-in-place section of the arch foot bracket is gradually changed from 80cm to 40cm, and the thickness of the web plate is gradually changed from 80cm to 50cm. The other segments of the arch ring are 40cm behind the top and bottom plates, and the web thickness is 50cm.
主拱圈采用悬臂浇筑与劲性骨架组合法施工。拱圈1号节段采用满堂支架现浇,拱圈2~14号节段采用斜拉扣挂悬臂浇筑,跨中HZ合龙段施工将劲性骨架拱与悬浇钢筋混凝土拱结合,先采用斜拉扣挂悬臂浇筑施工到14号节段,剩下24.65m合龙段采用钢结构组成钢桁拱,不再增设扣锚索,最后对钢桁拱外包混凝土完成大桥主拱圈合龙。合龙劲性骨架共分3节段,第1节段预埋到14号拱圈混凝土,第2、3节段整体吊装拼接。2~14节段施工过程为:The main arch ring is constructed by the combination method of cantilever casting and rigid skeleton. The No. 1 segment of the arch ring is cast in place with full-height brackets, and the No. 2 to No. 14 segments of the arch ring are cast by cantilevered cantilevers. The buckle and hanging cantilever was poured to the No. 14 section, and the remaining 24.65m closed section used steel structure to form a steel truss arch, and no additional anchor cables were added. Finally, the steel truss arch was outsourced with concrete to complete the closure of the main arch of the bridge. The Helong strength skeleton is divided into 3 sections, the first section is pre-buried in the concrete of No. 14 arch ring, and the second and third sections are hoisted and spliced as a whole. The construction process of
①当第n节段混凝土达到设计强度后,张拉第n组扣、锚索;①When the concrete of the nth segment reaches the design strength, tension the nth group of buckles and anchor cables;
②移动挂篮到第n+1节段浇筑位置;② Move the hanging basket to the pouring position of the n+1th segment;
③浇筑第n+1节段。③Pour the n+1th segment.
考虑到现有施工能力及施工便利性,外包混凝土的浇筑采用如下方案:低温分环浇筑拱圈合龙段,分两个工作面同步对称浇筑拱箱底板及1/2腹板混凝土,待其达到强度后,再分两个工作面对称浇筑拱箱顶板及1/2腹板混凝土。合龙段拱圈混凝土纵、横向浇筑顺序图如图5、图6及图7所示。Taking into account the existing construction capacity and convenience of construction, the pouring of the outsourcing concrete adopts the following scheme: low-temperature sub-ring pouring the arch ring closing section, and two working faces are simultaneously and symmetrically pouring the arch box bottom plate and 1/2 web concrete. After the strength, the arch box roof and 1/2 web concrete are poured symmetrically in two working planes. Figure 5, Figure 6 and Figure 7 show the vertical and horizontal concrete pouring sequence diagrams of the arch ring in the Helong section.
为适用本工程施工过程中面临的节段长、重量大等问题,特提出一种新型三角桁架式挂篮(如图8、图9所示),主要包括主桁承重系统,主桁承重系统中部左右两侧各设置有1副C型挂钩,C型挂钩顶部连接有行走装置,行走装置底部位于已浇节段的拱箱顶部的行走轨道上,C型挂钩上设置有连接板,连接板左右两侧各通过多根斜拉吊带与位于主桁承重系统前篮和后篮侧面的拉座连接,在后篮上设置有反滚轮装置,在主桁承重系统上设置有提升承重锚吊杆。挂篮上下弦杆由型钢构成的桁架组成,通过钢吊带与挂钩销轴连接,挂钩是由钢板焊接箱型断面,挂钩仅在挂篮行走时受力,拱箱混凝土浇筑时挂篮自重及混凝土湿重由锚吊杆承担。In order to meet the problems of length and weight in the construction of this project, a new type of triangular truss hanging basket (as shown in Figure 8 and Figure 9) is proposed, which mainly includes the main truss load-bearing system and the main truss load-bearing system. A pair of C-shaped hooks are arranged on the left and right sides of the middle part. The top of the C-shaped hook is connected with a walking device. The bottom of the walking device is located on the walking track on the top of the arch box of the poured segment. The C-shaped hook is provided with a connecting plate. The connecting plate The left and right sides are connected with the pull seats located on the sides of the front basket and the rear basket of the main truss load-bearing system through a plurality of cable-stayed slings. The rear basket is provided with an anti-roller device, and the main truss load-bearing system is provided with a lifting load-bearing anchor boom. . The upper and lower chords of the hanging basket are composed of trusses made of profiled steel, which are connected to the hook pins through steel slings. The hooks are welded box-shaped sections of steel plates. The hooks are only stressed when the hanging basket is walking. The wet weight is borne by the anchor boom.
与悬浇钢筋混凝土拱桥所用传统的挂篮相比,新型三角挂篮能将悬浇长度扩展到前所未有的8m,实现最大39.6°的倾角,承受188t的悬浇重量,具有强度高、刚度大、装置简单、受力明确、结构高效等优点。此外,现有挂篮锚吊杆通常锚固在拱圈悬臂端底板,为改善拱圈节段悬臂处受力性能,新型三角桁架挂篮将锚吊杆锚固位置从拱圈底板移至拱圈顶板。混凝土湿重等各种荷载也通过挂篮锚吊杆传递至拱圈顶板处,实现拱圈节段腹板处受拉向拱圈顶板处受压的转变,拱圈节段局部受力明显改善,拱圈主拉应力显著降低。新型三角桁架挂篮用于拱圈节段悬浇施工新技术,保证了拱圈悬臂施工中的线形光滑圆顺,保障了拱桥施工安全与建设质量。Compared with the traditional hanging baskets used in overhanging reinforced concrete arch bridges, the new triangular hanging baskets can extend the length of overhanging to an unprecedented 8m, achieve a maximum inclination angle of 39.6°, and bear the weight of overhanging 188t. The device is simple, the force is clear, and the structure is efficient. In addition, the existing hanging basket anchor rod is usually anchored on the bottom plate of the cantilever end of the arch ring. In order to improve the mechanical performance of the cantilever of the arch ring segment, the new triangular truss hanging basket moves the anchoring position of the anchor hanger from the bottom plate of the arch ring to the top plate of the arch ring . Various loads such as concrete wet weight are also transmitted to the top plate of the arch ring through the hanging basket anchor rod, realizing the transformation from the tension at the web of the arch ring segment to the compression at the top plate of the arch ring, and the local stress of the arch ring segment is significantly improved. , the main tensile stress of the arch ring is significantly reduced. The new triangular truss hanging basket is used for the new technology of the cantilevered construction of the arch ring segment, which ensures the smoothness and smoothness of the line in the cantilever construction of the arch ring, and ensures the construction safety and construction quality of the arch bridge.
对于等高度箱形拱桥,主拱圈任意截面高程可以按其拱轴线方程、截面高度、拱圈截面倾角进行计算。For a box-arch bridge of equal height, the elevation of any section of the main arch ring can be calculated according to its arch axis equation, section height, and section inclination angle of the arch ring.
建立如图10所示的xoy坐标系,设拱圈拱轴线方程为:Establish the xoy coordinate system as shown in Figure 10, and set the arch axis equation of the arch ring as:
式中:m表示拱轴系数;k为计算系数,f表示计算矢高;ξ为计算系数,L表示计算跨径。In the formula: m is the arch axis coefficient; k is the calculation coefficient, f represents the calculated vector height; ξ is the calculation coefficient, L represents the calculation span.
在距离拱顶x位置的水平倾角计算公式为:The formula for calculating the horizontal inclination angle at the position x from the vault is:
设主拱圈高度为h,当拱圈截面等高度时,拱背高度y上为:Let the height of the main arch ring be h, when the cross section of the arch ring has the same height, the height of the back of the arch y is :
相应的x坐标为:The corresponding x-coordinates are:
然而,施工图设计和桥梁施工时,常将坐标系原点建立在拱脚截面中心位置,见图10中的XOY坐标系,此时距离X位置的拱轴线坐标为:However, during construction drawing design and bridge construction, the origin of the coordinate system is often established at the center of the arch foot section, as shown in the XOY coordinate system in Figure 10. At this time, the coordinate of the arch axis from the X position is:
具体实施时,对建立在XOY坐标系中的拱圈,第i号悬臂浇筑节段拱圈悬臂端截面形心的立模标高为:In specific implementation, for the arch ring established in the XOY coordinate system, the vertical mold elevation of the centroid of the cantilever end section of the arch ring of the i-th cantilever casting segment is:
然而,在实际悬浇施工过程中,拱圈节段混凝土立模定位时,常以拱圈悬臂端箱梁截面底缘高程进行控制,因此,步骤S3中,对于XOY坐标系,第i号悬臂浇筑节段的立模标高按下式计算:However, in the actual cantilevered construction process, when the concrete vertical form of the arch ring segment is positioned, it is often controlled by the bottom edge elevation of the box girder section at the cantilever end of the arch ring. Therefore, in step S3, for the XOY coordinate system, the ith cantilever Elevation of vertical formwork for pouring segment Calculate as follows:
式中,式中,表示第i号悬臂浇筑节段悬臂端的拱圈截面形心设计标高,表示第i号悬臂浇筑节段悬臂端拱圈截面的设计预拱度值,表示浇筑第i号悬臂浇筑节段时的主拱圈变形修正值,表示浇筑第i号悬臂浇筑节段时的挂篮变形值,h表示主拱圈高度,表示第i号悬臂浇筑节段悬臂端拱圈拱轴线水平倾角。In the formula, in the formula, Represents the design elevation of the centroid of the arch ring section at the cantilever end of the i-th cantilever casting segment, Represents the design pre-camber value of the cantilever end arch ring section of the i-th cantilever casting segment, Represents the deformation correction value of the main arch ring when pouring the i-th cantilever pouring segment, represents the deformation value of the hanging basket when pouring the i-th cantilever pouring segment, h represents the height of the main arch ring, Represents the horizontal inclination angle of the arch axis of the cantilever end arch ring of the i-th cantilever casting segment.
距拱脚截面中心的拱圈底缘距离为:The distance from the bottom edge of the arch ring to the center of the arch foot section is:
以下为计算立模标高的具体过程:The following is the specific process of calculating the vertical mold elevation:
(1)依据设计施工图获取主拱圈净跨径Lo、净矢高f0、拱轴系数m、拱圈高度H、型钢劲性骨架节段桁高h'、起拱线标高h0;(1) According to the design and construction drawings, obtain the main arch ring net span L o , net sag height f 0 , arch axis coefficient m, arch ring height H, section truss height h' of section steel stiffening skeleton, and elevation h 0 of the arching line;
(2)依据公式获取计算系数k;(2) According to the formula Get the calculation coefficient k;
(3)令第i号悬臂浇筑节段悬臂端拱圈拱轴线水平倾角主拱圈计算跨径主拱圈计算矢高主拱圈拱脚截面水平倾角如果则令重新计算,直至退出循环;(3) Make the horizontal inclination angle of the arch axis of the cantilever end arch ring of the No. i cantilever casting segment Calculated span of main arch ring Calculate the sag height of the main arch ring The horizontal inclination angle of the arch foot section of the main arch ring if order recalculate until exit the loop;
(4)主拱圈计算跨径主拱圈计算矢高 (4) Calculated span of main arch ring Calculate the sag height of the main arch ring
(5)如图15所示,以拱脚起拱线位置为原点,以向大里程方向为X轴正向,以竖直向上为Y轴正向,建立局部坐标系。输入拱圈i节段悬臂端拱轴线位置处x坐标值X0Ceni,那么 (5) As shown in Figure 15, take the position of the arching line of the arch as the origin, take the direction of the large mileage as the positive direction of the X axis, and take the vertical upward direction as the positive direction of the Y axis to establish a local coordinate system. Enter the x-coordinate value X0Ceni at the axis position of the cantilever end arch of the i segment of the arch ring, then
(6)拱圈悬浇节段立模标高为 (6) The vertical formwork elevation of the cantilevered segment of the arch ring is
具体实施时,需由施工监控单位进行复核确认。通常拱桥设计预拱度值由3部分组成:拱圈自重、拱上建筑及桥面板、二期铺装等恒载下拱圈变形,10年收缩、徐变作用后拱圈变形及二分之一静活载下拱圈最大下挠值。通过建立Midas/civil模型,求取拱圈跨中设计预拱度值,拱圈其余位置设计预拱度值则按拱脚水平推力影响线成比例分布。When implemented, It needs to be reviewed and confirmed by the construction monitoring unit. Usually the arch bridge design pre-camber value is composed of three parts: the self-weight of the arch ring, the building on the arch and the bridge deck, the deformation of the arch ring under constant load such as the second-stage pavement, the deformation of the arch ring after 10 years of shrinkage and creep, and the half of the arch ring. The maximum deflection value of the arch ring under a static live load. By establishing the Midas/civil model, the design pre-camber value at the mid-span of the arch ring is obtained, and the design pre-camber value at the rest of the arch ring is proportionally distributed according to the horizontal thrust influence line of the arch foot.
拱脚水平推力影响线通常有2种获取方式:There are usually two ways to obtain the horizontal thrust influence line of the arch foot:
1)按结构力学影响线的定义,通过采用一个单位力P=1,令它通过桥面上的每个点(如果使用有限元法,则是逐个作用在桥面上的各个节点处),依次计算出所要求的那个要素(内力、位移、反力等),就得到影响线了。假设桥面有n个节点,就需要进行n次加载并计算n次。此种方法效率较低。1) According to the definition of the influence line of structural mechanics, by using a unit force P=1, let it pass through each point on the bridge deck (if the finite element method is used, it will act on each node on the bridge deck one by one), The required element (internal force, displacement, reaction force, etc.) is calculated in turn, and the influence line is obtained. Assuming that the bridge deck has n nodes, n loads and n calculations are required. This method is less efficient.
2)利用反力—位移互等定理计算支座反力影响线。如图11所示,设桥面有n个节点,m(m=1,2,3,…,n)是其中的任意一个节点。根据反力—位移互等定理,作用在m点处的单位力P=1引起的支座k的反力Rkm,等于支座k发生顺Rkm方向单位位移Δk=1在P=1方向上引起的位移(以顺Rkm方向为正)。2) Use the reaction force-displacement reciprocal theorem to calculate the influence line of the support reaction force. As shown in FIG. 11 , it is assumed that the bridge deck has n nodes, and m (m=1, 2, 3, . . . , n) is any one of the nodes. According to the reaction force-displacement reciprocal theorem, the reaction force Rkm of the support k caused by the unit force P=1 acting at the m point is equal to the unit displacement Δk=1 of the support k in the direction of Rkm caused by the direction P=1. The displacement (in the direction along Rkm is positive).
根据影响线的定义,作用在m点处的单位力P=1引起的支座k的反力Rkm,就是支座反力Rk的影响线在m处的值。因m是桥面上的任意一个节点,所以,反力Rk的影响线在各点处的值就是Δk=1所引起的桥面各点挠度δmk,即According to the definition of the influence line, the reaction force Rkm of the support k caused by the unit force P=1 acting at the m point is the value of the influence line of the support reaction force Rk at m. Since m is any node on the bridge deck, the value of the influence line of the reaction force Rk at each point is the deflection δmk at each point of the bridge deck caused by Δk=1, that is,
Rkm(m=1,2,3,…,n)=δmk(m=1,2,3,…,n)Rkm(m=1,2,3,...,n)=δmk(m=1,2,3,...,n)
于是,利用反力-位移互等定理,求反力影响线问题变成了求支座单位位移引起的挠度问题。Therefore, using the reaction force-displacement reciprocal theorem, the problem of finding the influence line of the reaction force becomes the problem of finding the deflection caused by the unit displacement of the support.
建立裸拱有限元模型,使拱脚产生纵桥向单位强制位移,获取此时模型中拱圈各节点的竖向挠度值,即为拱脚水平推力影响线数值。A finite element model of bare arch is established, so that the arch foot has a forced displacement of the longitudinal bridge unit, and the vertical deflection value of each node of the arch ring in the model is obtained at this time, which is the value of the horizontal thrust influence line value of the arch foot.
具体实施时,包括浇筑第i号悬臂浇筑节段时主拱圈变形混凝土时变效应修正值和浇筑第i号悬臂浇筑节段时现场实测温度修正值 When implemented, Including the correction value of the time-varying effect of the deformed concrete of the main arch ring when pouring the No. i cantilever pouring segment and the correction value of the field measured temperature when pouring the No. i cantilever pouring segment
为分阶段施工拱圈节段有限元仿真模型拆除所有扣、锚索工况下各控制点(拱圈各节段悬臂端)累计位移值(考虑混凝土时变效应)与拱圈一次成拱时各控制点位移值(无法考虑混凝土时变效应)的差值。斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥由于施工历时较长,混凝土时变效应显著,主拱圈分阶段施工过程中,在采用应力、线形双控情况下,难以保证松索成拱线形与一次成拱线形吻合,因此需要对主拱圈节段施工高程进行混凝土时变效应修正。 In order to construct the finite element simulation model of the arch ring segment in stages, the cumulative displacement value of each control point (cantilever end of each segment of the arch ring) under the condition of removing all buckles and anchor cables (considering the time-varying effect of concrete) is the same as the time when the arch ring is once arched. The difference between the displacement values of each control point (the time-varying effect of concrete cannot be considered). Due to the long construction time and the significant time-varying effect of concrete, the cable-stayed cantilever pouring combined with the rigid skeleton construction of the reinforced concrete arch bridge is difficult to ensure the formation of the loose cable during the staged construction of the main arch ring. The arch line shape is consistent with the primary arch line shape, so it is necessary to correct the concrete time-varying effect on the construction elevation of the main arch ring segment.
获取的方法包括:基于已经建立的分阶段施工拱圈节段有限元仿真模型,选择浇筑拱圈第i号悬浇节段施工阶段,保存当前施工阶段有限元仿真模型为一个单独静力模型,对主拱圈进行升温/降温处理(温度改变量为任意的单位变化量),获取温度改变与拱圈第i号悬浇节段控制点(节段悬臂端)位移变化映射关系。在浇筑拱圈第i号悬浇节段混凝土前,开展拱圈第i-1号悬浇节段位置现场温度测量,基于单位温度改变与拱圈第i号悬浇节段控制点(悬臂端位置)位移变化映射关系,获取主拱圈变形温度修正值。Obtain The method includes: based on the established finite element simulation model of the staged construction of the arch ring segment, selecting the construction stage of the i-th cantilevered segment of the pouring arch ring, saving the finite element simulation model of the current construction stage as a separate static model, The main arch ring is heated/cooled (the temperature change is an arbitrary unit change), and the mapping relationship between the temperature change and the displacement change of the control point (cantilever end of the segment) of the i-th cantilevered segment of the arch ring is obtained. Before pouring the concrete of the i-th cantilevered segment of the arch ring, carry out the on-site temperature measurement at the position of the i-1 cantilevered segment of the arch ring. position) displacement change mapping relationship to obtain the deformation temperature correction value of the main arch ring.
具体实施时,表示基于挂篮预压荷载试验结果得到的第i号悬臂浇筑节段的挂篮变形预测值,表示浇筑拱圈第i号悬臂浇筑节段工况下挂篮有限元仿真结果值,表示第i-1号悬臂浇筑节段的挂篮实测变形值;When implemented, represents the predicted value of the hanging basket deformation of the i-th cantilever pouring segment based on the preloading load test results of the hanging basket, represents the value of the finite element simulation result of the hanging basket under the condition of the i-th cantilever pouring segment of the pouring arch ring, Indicates the measured deformation value of the hanging basket of No. i-1 cantilever pouring segment;
基于挂篮预压荷载试验结果,记录各分级荷载下挂篮实测变形值,获取分级荷载与挂篮变形映射关系,采用线形拟合即可获得第i号悬臂浇筑节段的挂篮变形预测值 其中,a和b均为常数项,G2表示拱圈第2号悬臂浇筑节段的重量,Gi表示第i号悬臂浇筑节段拱圈的重量;Based on the test results of the preloading load of the hanging basket, the measured deformation value of the hanging basket under each graded load is recorded, and the mapping relationship between the graded load and the hanging basket deformation is obtained, and the predicted value of the hanging basket deformation of the i-th cantilever pouring segment can be obtained by linear fitting. Among them, a and b are both constant terms, G 2 represents the weight of the No. 2 cantilever pouring segment of the arch ring, and G i represents the weight of the arch ring of the No. i cantilever pouring segment;
挂篮在拱圈1#节段上拼装完成后,为保证施工质量和安全,下道工序施工前必须对挂篮进行加载预压试验,以检验挂篮承载能力是否满足设计要求,验证挂篮设计的合理性,同时预压试验可消除挂篮的非弹性变形以及获得分级加载的弹性变形值。以图2所示的拱桥为例,荷载试验具体操作步骤如下:After the hanging basket is assembled on the 1# segment of the arch ring, in order to ensure the construction quality and safety, the preloading test must be carried out on the hanging basket before the construction of the next process to check whether the carrying capacity of the hanging basket meets the design requirements and verify the hanging basket. The rationality of the design, and the preload test can eliminate the inelastic deformation of the hanging basket and obtain the elastic deformation value of graded loading. Taking the arch bridge shown in Figure 2 as an example, the specific operation steps of the load test are as follows:
(1)试验采用在原地面设置竖向锚索,钢绞线反拉挂篮的方式进行,挂篮拼装后,以2#节段荷载进行试验。(1) The test is carried out by setting vertical anchor cables on the original ground, and the steel strands pull the hanging basket in reverse. After the hanging basket is assembled, the test is carried out with the 2# segment load.
(2)待1#节段浇筑完成后,如图12所示,在底横梁两端分别施工4根竖向锚索(单根锚索采用6φj15.24mm钢绞线),锚索长度为17m、19m,且锚入岩石长度不得小于10m,在张拉锚索时,在原地面浇筑50×50×30cm的混凝土基座,并在基座顶面安装2I40b工字钢箱,在工字钢箱上张拉锚索,并对锚索孔进行压浆。(2) After the 1# segment is poured, as shown in Figure 12, construct 4 vertical anchor cables (single anchor cable adopts 6φj15.24mm steel strand) at both ends of the bottom beam, and the length of the anchor cable is 17m , 19m, and the length of anchoring into the rock shall not be less than 10m. When the anchor cable is tensioned, a concrete base of 50 × 50 × 30 cm is poured on the original ground, and a 2I40b I-beam box is installed on the top surface of the base. Tension the anchor cable and grouting the anchor cable hole.
(3)1#节段扣索张拉后,拆除1#现浇段支架,拼装挂篮(底模不安装),在挂篮悬臂端顶面安装2根2I40b的工字钢箱作为反拉纵梁,并在纵梁顶面相应位置焊接调平钢箱,共设置4个调平钢箱。(3) After the 1# segment is tensioned, remove the 1# cast-in-place bracket, assemble the hanging basket (the bottom mold is not installed), and install two 2I40b I-beam boxes on the top surface of the cantilever end of the hanging basket as a reverse pull Longitudinal beams, and leveling steel boxes are welded at the corresponding positions on the top surface of the longitudinal beams, and a total of 4 leveling steel boxes are arranged.
(4)安装荷载试验竖向钢束,单根竖向钢束采用4φj15.24mm钢绞线制作,下端为固定端,锚固于基座顶面的钢箱上,上端为张拉端,锚固于挂篮顶面纵梁上的调平钢箱上。(4) Vertical steel bundle for installation load test, a single vertical steel bundle is made of 4φj15.24mm steel strand, the lower end is the fixed end, which is anchored on the steel box on the top surface of the base, and the upper end is the tensioning end, which is anchored in On the leveling steel box on the top side rail of the hanging basket.
(5)2#节段重1886KN,每根竖向钢束按30%→70%→100%→110%→120%的加载顺序(141.5kN→330.1kN→471.5kN→585.8kN)进行,每加至分级荷载处,观测挂篮前端沉降值,检查挂篮各结构之间的连接处有无异常,检查无问题后,停顿10分钟,记录一次数据,再停顿25分钟,记录数据后,再进行下一级的张拉,最终张拉至120%后,再次检查挂篮有无异常,观测挂篮前端沉降,停顿60分钟,无异常后开始卸载。(5) The weight of the 2# segment is 1886KN. Add to the graded load, observe the settlement value of the front end of the hanging basket, and check whether there is any abnormality in the connection between the structures of the hanging basket. Carry out the next level of tensioning, and after the final tensioning reaches 120%, check again whether the hanging basket is abnormal, observe the settlement of the front end of the hanging basket, pause for 60 minutes, and start unloading after no abnormality.
如图13所示,建立浇筑第i号悬臂浇筑节段工况下挂篮有限元仿真模型,第i号悬臂浇筑节段拱圈混凝土湿重荷载采用线荷载模拟,拱圈横隔板采用集中力进行模拟,可得 As shown in Figure 13, the finite element simulation model of the hanging basket under the condition of pouring the No. i cantilever pouring segment is established. Force simulation, we can get
采用第i-1号悬臂浇筑节段的挂篮实测变形值作为 The measured deformation value of the hanging basket of the No. i-1 cantilever pouring segment as
挂篮实际变形量应根据节段混凝土浇筑前与浇筑后的测点高程之差进行计算,即The actual deformation of the hanging basket should be calculated according to the difference between the elevations of the measuring points before and after the concrete is poured, that is,
式中,H浇筑前、H浇筑后分别为拱圈节段混凝土浇筑前、后同一测点位置的高程。In the formula, H before pouring and H after pouring are the elevations of the same measuring point before and after the concrete pouring of the arch ring segment.
因式中采用浇筑前减去浇筑后的变形计算方法,所以得到的挂篮实际变形为正值。In the formula, the calculation method of the deformation before pouring minus after pouring is adopted, so the actual deformation of the obtained hanging basket is a positive value.
拱圈节段混凝土浇筑前、后高程测量需注意以下几点:The following points should be paid attention to in the elevation measurement before and after the concrete pouring of the arch ring segment:
1)要得到挂篮的实际变形值,必须对拱圈节段混凝土浇筑前、浇筑后分别进行高程测量。测量应选择在气温相对稳定、拱圈截面温度场相对稳定的时段进行,即在早晨太阳出来前进行。当为阴天天气时,因温差变化相对较小,可灵活选择时段开展测量。1) To obtain the actual deformation value of the hanging basket, the elevation measurement must be carried out before and after the concrete of the arch ring segment is poured. The measurement should be carried out in a period when the air temperature is relatively stable and the temperature field of the cross section of the arch ring is relatively stable, that is, before the sun comes out in the morning. When the weather is cloudy, due to the relatively small change in temperature difference, the time period can be flexibly selected to carry out the measurement.
2)由于悬臂浇筑混凝土拱桥采用拱脚固接的施工方法,再加上拱圈截面刚度大,因此,在前几个节段施工时,挂篮变形值相对较小。为减小测量仪器引起的误差,应优先采用精密水准仪进行测量。2) Since the cantilever poured concrete arch bridge adopts the construction method of fixed arch foot, and the rigidity of the section of the arch ring is large, the deformation value of the hanging basket is relatively small during the construction of the first few sections. In order to reduce the error caused by the measuring instrument, the precision level should be preferred for measurement.
3)随着节段混凝土浇筑的增加,拱圈变形量相应增大,此时,仍以水准仪测量优先,在测量困难时,可考虑采用全站仪测量。3) With the increase of segmental concrete pouring, the deformation of the arch ring increases correspondingly. At this time, the level measurement is still preferred. When the measurement is difficult, the total station measurement can be considered.
具体实施时,由于斜拉扣挂悬臂浇筑结合劲性骨架施工钢筋混凝土拱桥跨中一定长度范围内为型钢劲性骨架,由于其为钢材,没有混凝土时变效应,因此劲性骨架实际施工过程中,为切线拼装、焊接,不存在挂篮施工,因此因此,步骤S5中,第i号劲性骨架节段的安装标高按下式计算:In the specific implementation, since the reinforced concrete arch bridge is constructed with a rigid skeleton in a certain length in the middle of the span of the cable-stayed cantilever casting combined with the rigid skeleton, and because it is made of steel, there is no time-varying effect of concrete, so In the actual construction process of the rigid skeleton, it is tangentially assembled and welded, and there is no hanging basket construction, so Therefore, in step S5, the installation elevation of the i-th rigid frame segment Calculate as follows:
式中,表示第i号劲性骨架节段悬臂端的拱圈截面形心设计标高,表示第i号劲性骨架节段悬臂端拱圈截面的设计预拱度值,表示安装第i号劲性骨架节段时现场实测温度修正值,h'表示型钢劲性骨架节段桁高,表示第i号劲性骨架节段悬臂端拱圈拱轴线水平倾角,δ'阶段/步骤实际总位移表示主拱圈分阶段施工有限元仿真模型中安装第i号劲性骨架节段施工阶段劲性骨架节段悬臂端控制点的阶段/步骤实际总位移值。In the formula, Represents the design elevation of the centroid of the arch ring section at the cantilever end of the i-th stiff skeleton segment, represents the design pre-camber value of the cantilever end arch ring section of the i-th stiffness skeleton segment, Represents the correction value of the temperature measured on site when the No. ith stiff frame segment is installed, h' represents the girder height of the section steel stiff frame segment, Represents the horizontal inclination of the arch axis of the arch ring at the cantilever end of the stiff skeleton segment No. i, and the actual total displacement of the δ' stage/step represents the construction stage of the installation of the stiff skeleton segment No. i in the finite element simulation model of the staged construction of the main arch ring. Phase/step actual total displacement value for the cantilever end control points of the skeleton segment.
根据立模标高的具体计算过程中的(1)至(5)可知,拱圈跨中劲性骨架节段控制点(节段悬臂端顶缘)安装标高可表示为:According to (1) to (5) in the specific calculation process of the vertical formwork elevation, the installation elevation of the segmental control point (the top edge of the segment cantilever end) of the mid-span stiff skeleton of the arch ring can be expressed as:
以图2所示的拱桥为例,采用本发明公开的方法,在拱圈线形方面,主拱圈合龙拆除扣锚索后对全桥进行通测,测点布置在每个节段顶板外侧、中间及内侧。实测值与理论值最大差仅为2.5cm,满足规范要求,证明主拱圈线形控制良好,未出现“马鞍形”。松索成拱后主拱圈线形如图14所示。Taking the arch bridge shown in FIG. 2 as an example, using the method disclosed in the present invention, in terms of the shape of the arch ring, the whole bridge is tested after the main arch ring is closed and the anchor cable is removed. Middle and inside. The maximum difference between the measured value and the theoretical value is only 2.5cm, which meets the requirements of the specification, which proves that the linear shape of the main arch ring is well controlled and there is no "saddle shape". Figure 14 shows the line shape of the main arch after the loose cable is arched.
此外,在本发明中,当每一悬臂浇筑节段浇筑完成后,还可以通过其浇筑完成后的高程以及扣、锚索张拉后的高程对浇筑完成的节段进行检验。In addition, in the present invention, after the pouring of each cantilever pouring segment is completed, the poured segment can also be inspected by its height after pouring and the height after tensioning of buckles and anchor cables.
拱圈混凝土浇筑后,受到节段混凝土湿重作用,挂篮将发生下挠变形,设第i号悬臂浇筑节段的混凝土浇筑后的挂篮实际变形为则第i号悬臂浇筑节段的混凝土浇筑完成后的拱圈顶缘高程为:After the concrete of the arch ring is poured, under the action of the wet weight of the concrete of the segment, the hanging basket will be deformed downward. The actual deformation of the hanging basket after the concrete pouring of the i-th cantilever pouring segment is: Then the top edge elevation of the arch ring after the concrete pouring of the i-th cantilever pouring segment is:
从式可以看出:It can be seen from the formula:
当时,即挂篮理论变形与挂篮实测变形一致,此时,拱圈顶缘测点高程可简化为when , that is, the theoretical deformation of the hanging basket is consistent with the measured deformation of the hanging basket. At this time, the elevation of the measuring point at the top edge of the arch ring can be simplified as
一般情况下,挂篮理论变形与挂篮实测变形不相等,即设两者的差值为In general, the theoretical deformation of the hanging basket is not equal to the measured deformation of the hanging basket, that is, Let the difference between the two be
当时,Δf挂篮变形>0,表示挂篮理论变形值偏大;when When Δf hanging basket deformation > 0, it means that the theoretical deformation value of hanging basket is too large;
当时,Δf挂篮变形<0,表示挂篮理论变形值偏小。when When Δf hanging basket deformation is less than 0, it means that the theoretical deformation value of hanging basket is too small.
但上述两种情形都可以用式表达,即此时第i号悬臂浇筑节段拱圈顶缘的测点高程为:However, the above two situations can be expressed by the formula, that is, the elevation of the measuring point at the top edge of the arch ring of the i-th cantilever pouring segment is:
每次测量挂篮变形值是十分重要的工作,随着节段数的增加,节段倾斜度逐渐减小,因节段倾斜分解到前一节的湿重也相应减小,湿重接近于竖直(重力)方向施加在挂篮上。It is very important to measure the deformation value of the hanging basket every time. With the increase of the number of segments, the inclination of the segment gradually decreases, and the wet weight of the previous segment also decreases due to the inclination of the segment, and the wet weight is close to the vertical. The straight (gravity) direction is applied to the basket.
在拱圈混凝土达到设计强度后,即可按照监控计算出的扣索力与锚索力进行对称、分级、同步张拉。由于扣索力的作用,拱圈节段将发生上挠。根据变形关系,张拉完毕后的第i号节段顶缘高程计算公式为:After the concrete of the arch ring reaches the design strength, it can be tensioned symmetrically, graded and synchronously according to the buckled cable force and the anchor cable force calculated by monitoring. Due to the action of the buckle force, the segment of the arch ring will deflect upward. According to the deformation relationship, the calculation formula of the top edge elevation of the i-th segment after the tension is completed is:
式中:where:
Δf张拉变形为扣索张拉后与张拉前的变形差(位移)。The Δf tension deformation is the difference (displacement) of the deformation between the buckle cable after tension and before tension.
有限元软件模型仿真计算时,对现浇法施工的拱圈,应提取节段的“累计位移”,其值用δ累计位移表示,扣索张拉后的节段高程计算公式可表示为:During the simulation calculation of the finite element software model, the "cumulative displacement" of the segment should be extracted for the arch ring constructed by the cast-in-place method, and its value is represented by the cumulative displacement of δ.
受到系统误差、偶然误差、环境误差和测量误差的共同作用,实际测量高程往往与理论计算高程发生差异。Due to the combined action of systematic errors, accidental errors, environmental errors and measurement errors, the actual measured elevation often differs from the theoretically calculated elevation.
为解决因前后两次测点不一造成的测量误差,应在拱圈上设置固定测点,并做好明显标记。每次测量时,始终固定在该测点上,由此来解决测点不一的问题。In order to solve the measurement error caused by the difference between the two measuring points before and after, fixed measuring points should be set on the arch ring, and obvious marks should be made. Every time you measure, it is always fixed on the measuring point, thereby solving the problem of different measuring points.
由于悬浇节段在立模时,都将高程测点放在拱圈底板的底模上,一旦浇筑完成后,需要将高程测点转移到拱背顶缘,同样需要在拱圈上设立固定测点。Since the elevation measuring point is placed on the bottom mold of the arch ring base plate when the cantilevered section is in the vertical form, once the pouring is completed, the elevation measuring point needs to be transferred to the top edge of the arch back, and a fixed point on the arch ring needs to be set up. Measuring point.
最后说明的是,以上实施例仅用以说明本发明的技术方案而非限制,尽管通过参照本发明的优选实施例已经对本发明进行了描述,但本领域的普通技术人员应当理解,可以在形式上和细节上对其作出各种各样的改变,而不偏离所附权利要求书所限定的本发明的精神和范围。Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described with reference to the preferred embodiments of the present invention, those of ordinary skill in the art should Various changes in the above and in the details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.
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CN114741925B (en) * | 2022-04-15 | 2023-12-29 | 中铁大桥勘测设计院集团有限公司 | Method, device and equipment for calculating rod expansion and contraction amount and readable storage medium |
CN119577920B (en) * | 2025-01-24 | 2025-05-06 | 贵州省交通规划勘察设计研究院股份有限公司 | Main arch ring design method for quickly constructing large-span cantilever pouring arch bridge |
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