预应力混凝土箱梁长距离顶推工法

1、.For ensure two learn a do learning education made effectiveness, promote all members consciously respected Constitution, and comply with party rules, with XI General Secretary series important speech spirit armed mind, and guide practice, and promoted work, do qualified Communist, according to Comm

2、unist 2016 city education information work special self-examination report XX City Bureau, and XX city government education steering mission: according to XX Province Government Education Steering Committee Office on carried out province education information work special Steering check of notificat

3、ion ( Teach SC letter x 20164) documents, about quickly organized in our city Education Bureau Department in charge of the supervision standards for learning and study of informatization of education in charge of primary and middle schools in the city led by specialized training, issued a notice of

4、meeting, special supervision and school self-assessment form. The school at the time of preparation, special organizational self-assessment. City Bureau organization about personnel in school since assessment of based Shang for has summary and self-examination, now will situation reported following:

5、 a, and led attention according to Ministry of education on issued Liu Deputy Prime Minister in second times national education information work videophone Conference Shang speech of notification (taught technical 20156,) of file spirit, I City Government is in charge of led and education administra

6、tive sector main head height attention, learning convey has central led in first international education information Assembly speech spirit, Learning to communicate the spirit of the second National Conference on videophone education information and instructed relevant departments according to the d

7、ocument, has developed the education development plan of the city. Second, overall management, coordination, establish management systems and propulsion mechanisms XX education started in the proceedings of the XX Party 200311 working arrangements, XX municipal party Committee Municipal Government a

8、ttach great importance to education information, education information development into the citys overall planning, education as a breakthrough in the construction of educational modernization in advance XX, city leaders often goes into the front line of education guide education work and financiall

9、y guaranteed. Equipment improvement, application is the power education development. To tube easy good information technology equipment, XX City used layered is responsible for, and unison of strategy initiatives: that Bureau established information work led group, urged city education information m

10、anagement and application work, education information and equipment Center is responsible for equipment maintenance, built information work platform, guarantee platform normal run; will electronic Chief, and personnel, and results, and student, and Senate, and assets, management field of information

11、 application decomposition to Bureau Office, and personnel section, and manages, and education section, and meter fiscal section, functions Department, To drive forward e-Government as a breakthrough in the informatization of education, education administrators into full play in the education of inf

12、ormation guidance and example, and take this opportunity to point to gradually expand the scope of education application of information technology. Formed Department personnel grasp business and educational information development and application; application and预应力混凝土箱梁长距离顶推工法(TLEJGF-93-18)铁道部大桥工程局

13、一、前言1989年由铁道部大桥工程局设计并施工的钱塘江第二大桥铁路引桥采用了顶推工法，使用新的顶推设备和能整体脱模、就位的预制台，对长达288m的九跨连续双线铁路预应力混凝土箱梁进行了长距离(799.4m)接力单点顶推。经过施工实践，证明此工法是桥梁施工的一种简捷 、方便、安全有效的工法。二、工法特点预应力混凝土平弦连续箱梁顶推工法的特点是：在固定的台座上用固定式的模板分段灌注混凝土；有节奏地重复同样工作；施工材料运输距离短；梁体是没有薄弱接缝的连续梁整体式结构；采用拉杆法顶推，用较少的机械设备就能完成混凝土连续梁施工任务；施工时不受气候和洪水的影响。三、适用范围本工法适于在城市江河、山区地域

14、修建预应力混凝土连续梁桥，特别是在桥址周围施工场地狭窄，或者是桥下净空不能满足需要，须降低梁高的情况下建桥，更显优越。四、工艺原理预应力混凝土平弦箱梁进行接力单点顶推，就是将每联梁分节段在置于引桥开始的桥台处桥中线上的预制台座上预制(预制时全箱型梁断面一次灌注混凝土)，然后将制好的梁段用聚四氟乙烯橡胶组合板作为支座顶面的滑板，以设在每个墩上的四台大行程水平穿心式千斤顶为动力，以传力拉杆传力，逐段顶推，全悬臂向前推进，将整联梁滑移到位。五、施工方法1.施工准备桥跨为32m，根据连续梁的恒载弯矩曲线，反弯点在距支点约1/4跨径处，为使恒载作用下的最大正负弯矩处无接缝，将梁体预制节段长度确定为每联梁

15、两端头各8m，其余均为16m。(1)制梁台座和钢模板(图1)图1 制梁台座和钢模板制梁台座是预制梁和顶推梁的基地，长约18m，设在引桥开始的桥台处，底部是不允许沉陷的桩基承台，其上面搁着制梁的钢模底盘，台座构造布置的原则是保证梁体制造精度。钢模板为固定式，分为两节，各8m长，外侧模由钢支撑固定，大螺杆调整侧面坡度，钢模底盘浮搁在特制的YS100200型垂直螺纹千斤顶(顶力1000kN，行程200mm)上，千斤顶按纵向6台横向4台布置，底盘平面位置靠前后四个角落的定位钢垛固定，在每节钢模中部的两侧下角做成小块L形可抽式活动外钢模，在梁体顶推前抽出，在支座顶板上放上滑板作为后滑动支座。内钢模分为顶

16、、侧两种：n形钢顶模可利用轮子纵向移动，片状内侧模靠内外模间的对拉螺栓及与顶模的栓接固定位置。(2)纵向牵引设备(图2)图2 牵引设备纵向牵引是整个顶推的操作重心，牵引设备主要包括穿心式千斤顶和牵引拉杆，穿心式千斤顶(YC75-1000，牵引力750kN，行程1000mm)安在制动墩前进方向托架上，靠液压泵站驱动； 牵引拉杆是用32高强度螺纹钢筋制成，每根长约8m(半个节段)分三段，中间以连接器串接(以利拆装使用)，通过在梁体顶、底板预留孔内插入的钢锚柱，与伸出梁体底板处的钢横梁锚固。当液压泵站向千斤顶充油时，千斤顶活塞杆伸长牵引梁体前进，回油时，即将顶座处拉杆上的止退螺母随时拧紧，千斤顶活塞

17、杆收回，重复上述动作直至梁体顶推至指定的位置 。由于梁体位于4的上坡道上，拆接节段拉杆或水平千斤顶时，为防止梁体纵向下移，应准备木板随时塞在制动架顶和梁底面间。(3)横向导向设备整个梁体在顶推过程中的方向控制是靠每个墩顶两侧的导向架实现的，在顶推过程中有专人在两者空隙间不断填塞四氟板，以防梁体在前进时偏离中线，从而保证梁体前进中位置准确。(4)梁底滑动设备(图3)图3 梁底滑动设备梁底滑动设备包括滑板和滑道。滑板就是填塞在梁底与各墩临时支座顶面的四氟板。四氟板以长40cm左右为宜。滑道即墩顶的临时支座。为使其表面光滑，用不锈钢钢板包裹，与四氟板间的滑动摩擦因数不得大于0.05；在临时支座的顶面

18、可随连续梁梁体作微小转动，临时支座分可调整式和不可调式两种，可调式采用2台矮千斤顶(YS20030，每台顶力2000kN，行程30mm)的组合结构，不可调式用钢垫块代替矮顶。(5)钢导梁(见图1)钢导梁按图在工厂制造，预拼后，运到工地安装，每联混凝土箱梁的前后端都用钢导梁连接，以减少混凝土梁两个端跨在顶推悬臂时的梁体内力，使混凝土箱梁的端跨在到达或脱离桥墩墩顶时比较平顺。导梁在每联端跨节段灌注前就位，两者之间用预应力高强粗筋张 拉连接，剪力由设在导梁上的剪力梁承受，剪力梁同样以预应力粗筋与混凝土箱梁作竖向刚性连接。在梁体顶推即将到位，导梁与前端另一联混凝土梁相妨碍时，导梁就需转到混凝土箱梁顶面

19、，这时导梁与混凝土箱梁顶的钢连接梁用高强度螺栓联结。(6)接引千斤顶设备(图4)图4 接引顶梁体顶推前，在前方墩顶两边设置好接引千斤顶，用来接引顶推到达的钢导梁，使其顺利过渡到临时支座上。(7)纵向预应力粗筋的张拉设备纵向预应力粗筋设置在混凝土梁上、下底板内，每节段混凝土梁间的连接，按照顶推步骤在后端截面上间隔张拉50%数量的预应力粗筋(而在每联灌注完第三节即8+16+16m即弯矩最大时 ，才张拉100%的粗筋)张拉及未张拉的粗筋末端均用连接器与下节段粗筋连接，两者错开长度1.2m。2.节段成梁工艺立底模外模扎底板腹板钢筋预埋底板腹板制孔波纹管立内侧模顶模扎顶板钢筋预埋顶板制孔波纹管灌注箱梁混

20、凝土养生张拉灌浆拆模顶推。(1)每次灌注的节段混凝土养生达到设计强度的80%后，按梁体设计要求张拉纵向预应力粗钢筋并在其套管内压浆。(2)内模脱下顺序为：先脱内侧模，后脱内顶模由支架滚轮运出。(3)外模脱下顺序：先落下后滑动支座处的千斤顶，抽出此处的L形活动模板；在千斤顶顶部垫上四氟板并顶紧梁底成为支承点，滑动导向架侧面也填塞四氟板；将钢底盘下的24个千 斤顶同时落下15cm，使外模脱下，即可进行顶推。为克服顶推时各支座上的静摩擦，可采用试推法：先顶拉出几cm，再松顶、回油、检查各配件的使用和接触情况，这样进行23次后，再正式开始顶推。3.顶推工艺流程(见图5)图5 钱塘江二桥铁路引桥预应力混

21、凝土箱梁顶推工艺流程4.顶推步骤(图6)图6 顶推步骤对图6中几个主要顶推步骤说明如下：(1)步骤：将第一节段梁向前顶推约7m至图示位置后停止，然后顶起钢底盘及外模并调到设计尺寸。第二节段的内模就位，此内模前端有一小段是插进第一节梁体内，使新老混凝土连接整齐。(2)节段梁顶推到步骤位置时，前导梁悬臂最大，前端挠度也最大，是倾覆稳定的控制阶段，前方墩要用接引千斤顶接引导梁。在第三节段梁体混凝土灌注并养生到设计强度后，该节段后端的预应力纵筋需全部张拉至设计吨位。(3)步骤第二、三节段间的弯矩最大，必须使全部纵向预应力粗筋发挥作用。(4)当灌注到第十二节段梁时(即步骤)，牵引设备需从025#墩倒换至

22、020#墩。(5)继续灌注节段梁顶推至步骤，灌注第一联最后一节段梁，并安装后导梁。(6)第一联顶推到最后一孔，如步骤时，将钢剪力梁转90横放作为垫梁，在其上装上钢连接梁，张拉竖向连接高强粗筋。拆下前导梁，向上提起安装在钢连接梁上，此时前导梁的前端底面标高已高出前方墩现浇梁梁顶标高，因此前导梁即在前方梁体顶面被接引、支承和滑动，可继续向前顶推，如步骤。(7)第一联顶推到位如步骤时，吊拆前后导梁，在梁两端补穿钢绞线束，张拉、封端。(8)在第二联及第三联快顶推到位时暂停顶推，进行步骤、工作，如步骤。(9)完成步骤后，所有临时支座再次按设计标高进行调整，然后再顶推到设计位置。(10)灌注横隔墙，达设计

23、强度后作为支顶处，将临时支座换成正式支座，落梁就位，顶推完成。六、机具设备本工法就Pp=32m的9孔连续梁所需机具设备分述如下。1. 顶推梁施工临时设施及设备数量 预制台座(含底、侧钢模板) 1座钢导梁(含垫梁) 2组(按一联计)导梁连接梁 1组(按一联计)水平千斤顶托架 2副(按一联计)制动架 4副(按一联计)拉杆锚柱 2对(按一联计)32(40Si2MnM0V)螺纹钢筋拉杆 8根/16m(按一联计)75t水平千斤顶(行程1000mm) 8台(按一联计)200t矮油压千斤顶(带保险) 30台(按一联计)100t垂直油压千斤顶(带保险) 32台812t千斤顶 4台(按一联计)台座后临时膺架 1

24、座梁体中线监察台 1座(及测量工具)墩顶钢垫块临时支座 10个聚四氟乙烯板 若干m2.预制梁临时设施及设备8t塔吊(含轨道) 1台800L拌合机 12台11.5m3混凝土斗(含水平车及轨道) 2只附着式震动器，插入式震动器 若干钢筋加工、木模制造、预埋件制造设备 各1间试验设备及设施 1间七、劳动组织按工序(钢模板安拆、钢筋及预埋件制安、混凝土生产、灌注、顶推)分工操作，在项目负责人统一指挥下，相互支援。其中四大工种(吊装、木工、混凝土工、钢筋工)约75人，配合工种(电、钳、焊、司机、试验)约14人(不包括拌合司机、测量、铆工)，技术及行政4人，共计约96人。八、质量要求顶推梁(铁路桥梁)除应

25、符合铁路桥涵施工规范、铁路混凝土及砌石工程施工规范中的有关规定外，对下述工序应予控制：（一）梁体外形尺寸1.底模中心线与桥梁设计中心线偏差不得大于1mm。2.底模顶的纵坡高程偏差1mm。3.支座预埋板的锚固螺栓应垂直，中心位置偏差不大于1mm(含对角线)。（二）预留压缩量顶推梁为多孔连续梁，应根据实际情况修正设计预留压缩量，保证梁体支座预留孔与桥墩支座位置相一致。（三）顶推施工1.中线 2mm2.相邻两跨临时滑动支座同侧纵向顶面高程 1mm3.每个墩上的临时滑动支座横向顶面高程 1mm4.制梁台座各临时滑动支座和底模顶高程 1mm5.梁顶高程 2mm6.导梁中线 2mm7.导梁纵横向底面高程(

26、包括接头处) 1mm8.梁段尾部的梁端面不垂直度 1/1000梁高九、安全措施除应遵照铁路桥涵施工技术安全规则(TBJ40397)和国家有关安全规定外，还应注意如下事项：1.顶推用全螺纹拉杆应经常检查，防止顶推中拉杆突然断裂后飞出伤人。2.应细心检查预应力粗筋扎丝与螺帽的紧配合，以免张拉时螺帽滑脱后飞出伤人。3.为了顶推位置的准确及安全，每墩顶两旁均应安装导向架。十、效益分析钱塘江第二大桥采用了长距离顶推工法，由于桥下净空要求，从设计上降低了梁高，减少了引桥长度、节省了部分制梁台座和全部存梁台座，节省制梁及架梁龙门吊机8台，合计节约40万元。十一、工程实例1.钱塘江第二大桥两岸共48孔32m铁

27、路引桥采用本工法施工，质量优良，该桥已于1992年4月1日正式通车。2.南昌赣江公路大桥跨度48m的西引桥也采用本工法施工，进展顺利。 ( 执笔：吴丹桂)#；demonstration of information work is education, promotion and development of education information managers. Turns out, this working party . Ming Associate Professor several times to XX chuanjingsongbao. May 2014 XX recei

28、ved State Council expert group to the City County acceptance of balanced development of compulsory education in the country, the Group of experts on XX education informatization on the balanced development of education give full recognition to the role. On October 9, 2014, the CPPCC inspections XX i

29、n XX city education information and XX education highly. On April 20, 2016, the XX as a unit of the first experimental informatization passed inspection. In acceptance of the conclusion of the expert group, wrote: 1. the project around the construction of pilot objectives, tasks and main content, sc

30、ientific formulation and implementation of programmes, and promotes the balanced development of urban and rural education based on information technology, completing various tasks of the pilot project. 2. adjusting measures to local conditions, innovative institutional mechanisms, by exploring the i

31、nvestment protection mechanism, system security mechanisms, the task to lead the mechanism, mechanism and application integration mechanisms, operation and maintenance of departmental interaction mechanisms , developed educational information resources sharing, promoting fair education, improve the

32、quality of education, promoting the reform of education and teaching, distinctive effective patterns and operating mechanism. 3. through the implementation of the pilot project, building a nationwide network of high quality educational resources sharing environment, construction and application of b

33、oth cloud platform, the e-learning space through education and public service platform of educational resources, promote the integration of information and depth of education, and progressive education application of information technology to become the norm. Popularization and application of the re

34、sults of project pilot has better value to promoting informatization of education in the County with a demonstration . February 24, 2014, in Education Department Office on education information pilot units work progress situation of informed (taught technical office letter (2014) 13th,) in the, XX province XX City Bureau introduc