t07-空心薄壁梯形变截面预应力型结构施工技术的(二).doc

Manipulator is now used as a industrial robots in use, the control objectives often appear often in industrial automation. Industrial automation technology has gradually matured, as mature a technology line has been rapid development in industrial automation as a separate subject. Manipulator application began to filter into welding, logistics, mechanical processing, and other industries. Especially at high or very low temperatures, full of poisonous gases, high radiation case, robot in similar circumstances showed great use also brings great convenience to the staff. Precisely because of this robot to get people's attention began to be a high degree of development. Labor rates, working conditions, labor intensive aspects of promoting development. Both at home and abroad to develop the PLC (programmable logic controller) is in various special circumstances and under special conditions set for mechanical devices. Now turned on the development of the microelectronics automatic control technology and the rapid development of the trains, the success of PLC hardware software and simulation control win big and successful development, now continues to develop as a factory automation standards. Because robots are good development of the technology makes a good optimization of productive capital, and robot shows this unique advantages, such as: has good compatibility, wide availability, hardware is complete, and programming that can be mastered in a short time, so in the context of industrial PLC applications became ubiquitous. Manipulator in many developed country agriculture and industry has been applied, such as the use of mechanical harvesting large areas of farmland, repeated operations on the high-speed line that uses a robotic arm, and so on. Today, the high level of automation combined with restrictions on the manipulator development level is slightly lower than the international. The design is mainly arm welding machine by PLC Automation control. This of design let designers on in school by learn of has a must of consolidation, understand has some usually didn't opportunities awareness in world range within some leading level of knowledge has has must awareness, hope designers can in yihou of design in the can success of using in this design in the proceeds of experience 1.2 manipulator in both at home and abroad of research profile automation mechanical arm research began Yu 20th century medium-term, after years with with computer and automation technology of development, Makes mechanical arm on the Grand stage of industrial automation and shine, gradually became an industrial evaluation standards, and its importance can be seen. Now original robotic arm spent most of mass production and use on the production line, which is programmed robotic arm. As the first generation of manipulator position control systems main features, although not back several generations that can detect the external environment, but can still successfully complete like welding, painting, delivery as well as for materials simple movements. Second generation mechanical arms are equipped with sensors and manipulators have the environment there is a certain amount of "sense", when the mechanical arm is to use the program as a basis. Difference is that the robot begand 桥梁施工新技术现场经验交流会 空心薄壁梯形变截面预应力V型结构施工技术空心薄壁梯形变截面预应力V型结构施工技术第二工程公司 张新内容提要：V型结构在桥梁工程中并不常用，类似潮州韩江北桥的空心薄壁梯形变截面预应力V型结构更是少见，本文结合韩江北桥工程实例，介绍截面复杂多变的V型结构的主要施工技术，对其它类似工程具有很好的参考价值。关 键 词： V型结构 平衡塔 施工1.工程概况1.1设计概况及施工环境潮州市韩江北桥位于潮州市湘子桥以北约1.73公里处（北堤桩号2+350），跨越韩江水道，标段起讫里程为K0+606.9K2+537.5，全长1930.6m，其中主桥580m，两岸引桥长1350.6m。道路等级为城市主干道，双向六车道，河道内引桥桥宽28m，河道外引桥宽25m，主桥桥宽30m。主桥施工场地均位于韩江大堤内，其中Z1、Z4、Z5、Z6墩位于沙滩上，Z2墩位于航道浅水边，这五个桥墩采用填砂石形成施工作业平台(韩基标高9.5m),Z3墩位于韩江航道中。韩江枯水期水位在7.5m左右，雨季期间水位上涨到14m左右，而且水流冲刷破坏严重。1.2结构形式主桥上部为五跨连续无风撑钢管混凝土系杆拱桥(C跨+B跨+A跨+B跨+C跨)，其跨径组合为（85m+114m+160m+114m+85m）；下部为钻孔桩基础、矩形承台、双薄壁矩形空心墩、V形结构。主桥总体结构布置如图1所示。图1 主桥总体结构布置图V型结构设计为空心薄壁梯形变截面预应力钢筋砼结构，如图2所示(以Z3墩为例)，与上部现浇箱梁形成倒三角形结构，与下部空心薄壁矩形墩固结形成。两侧V腿最底部离地面约11m高，顶部离地面约1620m高。全桥六个主墩，每主墩为两个独立的V构，总共12个V型结构。Z3(Z4)墩V型结构:往B跨的V腿斜长13.12m，底面倾角43o3454”。往A跨的V腿斜长13.39m，底面倾角43o3126”。根部厚3.12m。V腿横桥向底宽8m，顶宽4.45m，底板及顶板厚0.6m，侧墙厚0.5m，中隔墙厚1.6m。 Z2(Z5)墩V型结构:往C跨的V腿斜长10.94m，底面倾角42o394”。往B跨的V腿斜长11.46m，底面倾角42o3637”。根部厚2.459m，横桥向底宽8m，顶宽约4.5m，侧墙厚0.5m，中隔墙厚1.4m。Z1(Z6)墩V型结构:往引桥的V腿斜长8.74m，底面倾角41o3543”。往主桥C跨的V腿斜长9.15m，底面倾角41o3543”。根部厚1.89m，横桥向底宽8m，顶宽约4.6m，侧墙厚0.5m，中隔墙厚1.2m。每个V型结构均设计有斜向预应力，预应力束设在V腿的底板及顶板内，每侧V腿设12束(底板6束，每束9根；顶板6束,每束19根)。预应力束固定端在空心墩顶内，张拉端在上部箱梁内。图2 Z3墩V型结构设计图1.3 主要工程数量全桥共12个V构，主要工程数量详见表1。表1 主要工程数量表墩位C50砼II级钢筋钢绞线Z1(Z6)每个V构C50砼=193m3，四个V构合计=772 m3每个V构=22.5t四个V构合计=90t每个V构=4.2t，四个V构合计=16.8tZ2(Z5)每个V构C50砼=284m3，四个V构合计=1136 m3每个V构=29.3t，四个V构合计=117.2t每个V构=5.42t，四个V构合计=21.7tZ3(Z4)每个V构C50砼=415m3，四个V构合计=1660m3每个V构=39.8t，四个V构合计=159t每个V构=6.24t，四个V构合计=25t合计全桥合计C50=3568 m3，II级钢筋=366.2t，钢绞线=63.5t。2. V型结构总体施工方案概述2.1施工特点平衡塔斜拉施工方法是利用拉杆向上斜拉，通过中间塔平衡水平分力及抵消部分力矩，结构受力分析比较明确，充分利用型钢的轴向抗拉及抗压性能，这种方法不受桥墩高度限制，支架体系也不受桥下洪水的影响；此外，因施工支架不落地，在进行V型结构施工期间，还可以同时进行上部箱梁的基础处理及搭设部分支架，有利于加快进度。2.2施工方法采用型钢在空心墩顶上组拼为平衡塔，通过中间塔平衡水平分力及抵消部分力矩。V腿外侧利用贝雷梁组拼为斜托梁，斜托梁底部与墩顶预埋件销接，中部及顶部通过型钢斜向拉在平衡塔上。V腿砼浇筑后利用水平刚性拉杆临时固定，水平拉杆与V腿形成临时倒三角稳定结构，直至顶部箱梁施工后形成永久三角形结构。V腿为空心薄壁变截面状，结构复杂，操作空间狭小，而且混凝土方量大，为了降低施工荷载，并减少混凝土的收缩及徐变应力，将Z3(Z4)墩V腿结构分三次先后浇筑砼，第一次浇筑根部，第二次浇筑空心段，第三次浇筑顶部实心段；Z1(Z6)、 Z2(Z5)墩V腿分两次浇筑砼，第一次浇筑根部及空心段，第二次浇筑顶部实心段。2.3 主要施工步骤(以Z3为例)第一步：空心墩顶部实心段施工后，利用汽车吊或塔吊安装平衡塔、斜托梁、斜向拉杆，人工安装第一节模板，绑扎钢筋，浇筑根部砼。第二步：安装第二节模板，绑扎钢筋，调整模板至斜腿位置，凿毛砼接头并清理干净，两侧对称浇筑空心段砼。第三步：安装第三节模板，绑扎钢筋，预埋型钢水平拉杆，调整模板至斜腿位置，凿毛砼接头并清理干净，两则对称浇筑顶部砼。第四步：砼达到90%设计强度后，利用预埋的型钢水平拉杆与V腿形成临时稳定三角结构，割除斜托梁及斜向拉杆，施工上部现浇箱梁。主要施工步骤如图3所示。manipulator control mode and programmable controllers introduction 2.1 Select discussion with manipulator control 2.1.1 classification of control relays and discrete electronic circuit can control old industrial equipment, but also more common. Mainly these two relatively cheap and you can meet the old-fashioned, simple (or simple) industrial equipment. So he can see them now, however these two control modes (relay and discrete electronic circuits) are these fatal flaws: (1) cannot adapt to the complex logic control, (2) only for the current project, the lack of compatibility and (3) not reforming the system with equipment improvements. Spring for the development of China's modern industrial automation technology the substantial increase in the level of industrial automation, completed the perfect relay of the computer too much. In terms of controlling the computer showed his two great advantages: (1) each of the hardware can be installed on one or more microprocessors; (2) the official designer of the software writing content control is all about. Now in several ways in the context of industrial automation can often be seen in three ways: (1) Programmable Logical Controller (referred to as IPC); (2) Distributed Control System (DCS for short), and (3) the Programmable Logical Controller (PLC for short). 2.1.2 PLC and the IPC and DCS contrast contrast 1, each of the three technologies of origins and development requirements for fast data processing makes it invented the computer. The men brought in terms of hardware there, using a high level of standardization, can use more compatibility tools, is a rich software resources, especially the need for immediacy in operational systems. So the computer can effectively control is used to control and meet its speed, on the virtual model, real-time and in computational requirements. Distributed system started with a control system for industrial automatic instrument used to control, whereas now it is successfully developed into industrial control computer used as a central collection and distribution system and transition of distributed control system in analogue handling, loop control, has begun to reflect the use of a huge advantage. Though distributed system has great advantages in loop regulation, but only as a means of continuous process control. Optimization of PLC is the corresponding relay needs was born, its main use in the work order control, early primary is replaced relay this hulking system, focused on the switch controlling the running order of functions. Marked by the microprocessor in the early 1970 of the 20th century emerged, micro-electronics technology has developed rapidly, people soon microelectronics processing technology will be used in the Programmable Logical Controller (that is中铁十三局集团有限公司 2053. 主要施工技术3.1平衡塔施工3.1.1结构形式常规的V型结构多为实心矩形截面，平衡塔常采用万能杆件、贝雷梁、军用梁等定型构件组拼形成，但由于本桥V型结构为空心变截面，而且受预应力束干扰(平面投影为斜向，中心间距45cm)，斜向拉杆的位置受到限制，若采用上述定型构件组拼则导致定型构件局部应力过大。因此本桥的平衡塔采用槽钢、工字钢自由组拼以适应斜向拉杆的位置。平衡塔平面尺寸为2m×6m，高度1216m。每个平衡塔共813根格构柱，每个格构柱由两根25b槽钢 (Z1、Z6部分格构柱为I25b工字钢) 组拼成25cm×25cm的矩形组合截面。格构柱之间用10槽钢作水平及斜撑，将格构柱连成整体，确保有足够的强度、刚度及稳定性。如图4所示。图4 Z3墩V型结构施工平衡塔构造图3.1.2 施工方法平衡塔座落在空心墩顶上，在施工墩顶砼时按格构柱的位置在墩顶上预埋钢板，砼施工后在钢板上准确定出纵横轴线及标高。每个格构柱预先在地面加工组拼，将每四个格构柱组拼成单体空间结构，然后利用汽车吊或塔吊安装，最后在墩顶上将所有格构柱连成整体。长度超过12m的格构柱竖向分段安装，接头先用螺栓临时连接，试拼合格后解体分段吊装，最后焊成整体。吊装时用全站仪及吊线控制格构柱的垂直度，然后将格构柱与墩顶的预埋钢板焊接固定。水平撑及斜撑利用汽车吊起吊，手动葫芦辅助就位后与缀板焊接固定，将各个格构柱连成整体。平衡塔的安装如图5、图6所示。图5 平衡塔安装图(一)图6 平衡塔安装图(二)3.2 斜托梁施工3.2.1 结构型式斜托梁采用12排单层普通贝雷梁组拼，两侧为单排，中间每2排贝雷梁拼成一组，相邻两组中心间距1.21.5m，净距5070cm。在贝雷梁下弦杆的下方布置横向底托梁，横向底托梁由两根20a槽钢形成组合结构。横向底托梁间距3m6m，通过斜向拉杆将横向托梁与斜向贝雷梁连成整体。在横向底托梁的对应位置布置斜向拉杆。斜向拉杆由2*10槽钢组拼，Z1(Z6)、Z2(Z5) 轴V腿竖向设两道拉杆， Z3(Z4)轴V腿设三道拉杆，每道拉杆横桥向布置六组（每组贝雷梁对应一组拉杆）。拉杆一端与横向底托梁销接，另一端与平衡塔销接。较长拉杆用拉板焊接接长。水平刚性拉杆采用4×I25a工字钢，在最后一次砼浇筑前预埋在V腿顶部，通过水平刚性拉杆与两侧V腿形成临时稳定的倒三角结构。斜托梁构造如图7所示(以Z3为例)。图7斜托梁构造图3.2.2 施工方法斜托架采用汽车吊、塔吊安装。Z1(Z6)轴斜托架长9m，Z2(Z5)轴斜托架长12m， Z3(Z4)轴斜托架长15m(分成两段9m+6m安装)。在地面将每排贝雷梁组拼成型，用吊车单排起吊至墩顶高度，将贝雷梁的端部与墩顶预埋件销接拉住，提升到要求倾角后用钢丝绳临时固定。待各组贝雷梁均安装完后，先安装第一道横向底托梁，使底托梁与两排贝雷梁连接形成骨架，然后对应贝雷梁的位置安装两组斜向拉杆，通过手动葫芦调整横向底托梁使贝雷梁达到要求倾角后固定斜向拉杆，再将其它组贝雷梁倾斜放低与横向底托梁连接，最后安装其它对应位置的斜向拉杆。斜托梁的安装如图8、图9、图10、图11所示。图8 斜托梁安装图(一) 图9 斜托梁安装图(二)图10 斜托梁安装图(三)图11 斜托梁安装图(四)3.3 钢筋模板工程3.3.1 钢筋工程因本桥V构为空心薄壁梯形变截面状，导致V构的钢筋为变长度，即每根钢筋长度都不相同，这样给钢筋加工、存放、运输以及绑扎安装均造成很大麻烦，需要在钢筋加工场统一加工成型，每根钢筋标注型号和长度，并根据安装的先后顺序进行存放、运输，避免打乱顺序。钢筋用吊车或人工提升到工作面，按底板->腹板->顶板的顺序绑扎安装，对于每根横向闭合箍筋将其分四段，待安装完成后再焊接连成闭合钢筋。由于V腿钢筋密集而且预埋件较多，施工时注意保护，并遵循“次要避让主要”的原则，优先保证主受力筋的位置。斜向预应力钢绞线固定端位于空心墩顶上，空心墩竖向预应力钢绞线张拉端位于V腿交叉处顶部，施工时按设计要求进行预埋，并注意保护钢绞线。钢筋绑扎安装如图12、图13、图14所示。图12 钢筋绑扎安装图(一)图13 钢筋绑扎安装图(二)图14 钢筋绑扎安装图(三)3.3.2模板工程常规的V型结构多采用定型或组合钢模板施工，但因本桥的V构数量众多且结构复杂，所以采用木模板施工，其中外侧模板用光滑的黑漆板，内模用普通胶合板。模板利用吊车起吊放在操作平台上，人工搬运逐块拼装。模板支立采用底模->侧模->内模->顶模的顺序。侧模按不同部位的节段进行放样，以保证形状准确。由于侧模向内倾斜，施工时利用吊锤和角度尺控制其倾斜度。空心段底板的顶模、顶板底模和顶模部分采用小块活动模板拼装，浇砼时拆除部分模板形成工作窗口，以方便砼的卸料及振捣，浇筑后及时支上模板封堵。模板利用10×10cm方木及48mm钢管作纵横楞。底板的底模与顶板的顶模用钢筋对拉，防止内模及顶模上浮。为保证操作安全，在V腿横桥向外侧搭设悬挑脚手架。模板安装如图15、图16、图17所示。图15 模板安装图(一) 图16 模板安装图(二)图17 模板安装图(三)3.4混凝土工程V腿砼施工操作空间狭小，单次浇筑方量大（最大约为226m3），如果用起重机吊料斗下料，施工效率低，施工时间长，容易出现施工冷缝。因此采用汽运及泵送联合的输送办法：将砼泵拖放在V腿的附近地面，砼在搅拌站集中搅拌后用运输车水平运到现场，用砼泵垂直泵送，再通过滑槽送到工作面进行浇筑，这样能够减少泵送距离，将坍落度控制在14cm左右，满足泵送要求，也提高了施工效率，更加容易保证砼的质量。V腿砼掺入高效缓凝减水剂，砼初凝时间在10h左右，注意控制每次浇筑时间不超过砼的初凝时间。砼浇筑顺序：第一段(根部)：横桥向由中间往两端推进，顺桥向两侧对称进行。第二段(空心段)：由低往高逐层浇筑，横桥向从中部开始往两侧多点卸料，顺桥向两侧对称浇筑。第三段(顶部)：从中部开始，利用砼自然坡度逐层浇筑，两侧要对称进行。浇筑空心段砼时，拆除空心段部分模板形成工作窗口，以方便砼的卸料及振捣，浇筑后及时支上模板封堵。3.5预应力施工V腿斜向预应力为单端固定、单端张拉，固定端位于空心墩顶，张拉端位于上部箱梁的底板内。在施工V腿时先预埋好钢绞线，待箱梁施工完后才能张拉V腿预应力。斜向预应力钢绞线采用YCW400千斤顶张拉，张拉封锚后进行真空压浆。3.6施工监控主要是在浇筑砼过程监控平衡塔、斜托梁的变形以及V腿交叉处砼拉应力，若平衡塔变形过大将导致V腿倾角不符合设计要求、砼拉应力过大引起开裂，甚至引起平衡塔支架体系整体倾覆。为了监测平衡塔和斜托梁的变形，分别在平衡塔顶和斜托梁安装反射棱镜(如图18所示)，在砼浇筑全过程中利用全站仪实时测量各点的三维坐标，若变形超过5mm及时指导现场调整砼浇筑方向，确保两侧V腿砼浇筑基本对称。在V腿交叉处上顶面和底面预埋应变计用来监控砼应力。当发现砼拉应力超过2.5MPa时,一方面通过调整砼浇筑的方向保证对称施工，另一方面在斜向拉杆的顶端打入楔铁对拉杆施加预紧力。图18 施工监控棱镜布置图4.结束语 a.全桥12个V构施工历时六个月(包括多次洪水冲毁施工便道而影响一个月时间)，单个V型结构施工时间约为5570d。竣工后的每个V构都内实外光、表面平整光滑、棱角分明，结构尺寸均符合设计要求。竣工后的V构如图19所示。图19 竣工后的V型结构 b.V型结构施工过程中最需要注意的是砼浇筑过程中两侧V腿对称进行，强调平衡对称施工。 c.若非斜向预应力钢绞线的干扰，应尽可能采用贝雷梁、万能杆件、军用梁等定型构件组拼平衡塔，可以缩短平衡塔组拼时间。 d.若非结构复杂、操作空间狭小，每个V构应尽可能一次连续浇筑砼(同时要求砼连续浇筑时间不得超过砼初凝时间)，有利于缩短工期。 e.平衡塔体系在第一次砼浇筑过程中变形最明显(对不平衡浇筑砼最敏感)，主要是第一次浇筑砼时平衡塔与空心墩顶预埋钢板连接并非属于固结状态，当第一次砼浇筑凝固后，平衡塔与砼完全固结，而且平衡塔工作长度也变短，因此浇筑第二次、第三次砼时变形较小。f.与常规V构采用钢模板施工相比，本桥V构采用木模板施工，能够适应结构截面复杂多变的特点而方便施工，此外可以投入多套模板，实行平行流水作业，有利于加快进度，并节省投入，社会效益和经济效益明显。参考文献：1、钢结构设计规范(GB50017-2003)2、郭耀杰，钢结构稳定设计3、邹纪民，浙江东阳江大桥V形墩施工，公路,2002(12)4、刘青云，怀化舞水二桥V形墩施工技术，铁道建筑技术，2003(3)5、李立峰，邵旭东，赵化，长沙湘江南大桥V形腿设计与分析，公路，2002(11)