桥梁改建可以削减主要开发商的初期投资资源（囊括吊销老本，土建资本等），缩短工期，体现更高的经济价值。当前，桥梁加固设计与合计的研讨还相对于滞后。在某些方面，甚至没法使用公认的算法，这使设计人员难以上手。除了耐心的专业常识，桥梁加固设计人员还理当具有丰盛的设计教育与富厚的施工指点。残破的设计施工图愈加合理，牢靠，真切，施工品格容易保障，几近不有篡改与转变。 ，利润合理，加固功效好。它不仅可以治愈“临时”，而且可以尽量地看待“根”。
假定只有施工辅导，则生成的加固方案和施工图可能缺乏对布局的零碎应力分析以及对疾病成因与趋势的赏析。通常，加固的整机不有获取足够的加固，或者过多的加固，不需要加固的地区也获取加固，形成更多的终究。花钱后，加固成效欠佳。许多设计师在加固质料的数目上绝对恣意。有许多人依照指点与见识使用原料。岂论是糜费原料照常没有到达可慧的加固成就，它们对自己都不理解，业主也不知道，而且大大都人都没有做任何事故。对于钢筋计算，一些高素质的设计单位只对钢筋加固前的组织进行一些从头搜查，而对付钢筋加固后的承载力至少进行总计。然则享誉中外，成分的疾病通常浮其时正常使用阶段。承载手腕主要注释组件是否平安。可以安然使用的组件并不是没有疾病。因此，必需算计每种材料在截面上的应力强度以反映部件。能否有疾病，有几多及其发展趋向。
“应力强度的计算是反映组件疾病的必要根柢，而承载力的算计则是安然使用组件的终极包管。”二者但凡必不行少的。在实际的钢筋较量争论中，通常彷佛承载力的终极形态满足申请，但部件中确实具有许多疾病。因此，一种办法是增多车辆的设计负荷，以使承载伎俩不克不及满足要求，然则缺乏牢靠的过载数据。另一种门径是按照种种疾病和水准，颠末一些算法获得种种折减系数，并对承载力进行折减以抒发该组件不称心足承载力申请。组件加固后，将增补大于或等于减小的承载本事的承载能耐。尽管该办法具有定然的科学依据，但也具有许多酬报的判断因素，这些因素也不能反映管教部件上种种物料的工作前提。
若何增强一致类型的桥梁？
（1）通常在中跨四周从底部到顶部有多个垂直漏洞，信息马脚的宽度可能超过规格极限值，无意偶尔会在中跨呈现挠曲，疏解抗弯强度不足。
（2）一般情况下，平板的底部在中跨左近可能会呈现多个纵向裂纹，并且某些新闻裂纹的宽度将逾越规格申请。这可能是因为设计图采取了预制的规范图钢筋，但在施工过程当中使用了它。现浇将单向板转变为一体的双向板，从而改变了板的受力形式，从而导致板底部的横向钢筋老火短缺，并导致底部的纵向bug板在横向弯矩感化下的应力。
2.混凝土预制组件简支板桥
（2）可能还会有撑持空隙。由于每个平板的每个结尾都有2个支撑，因而每个桥都有更多支撑。如果在施工过程中撑持垫石的高度不准确，或者在安装历程中预制板的翘曲或墩台的不平匀沉降将导致某些支撑物变空；
（3）在中跨相近的钢筋混凝土板底部周围，从底部到顶部有垂直漏洞，何况接缝的宽度可能超越划定的要求，或者中跨可能有向下的挠曲，并且耐蜿蜒性不足。
（4）纵向裂纹呈那会平板的底部。大少数预应力混凝土制成的简支平板桥但凡经由预应力构造的。假如底板由于施工而太薄，则预应力筋周围的混凝土局部应力太大，或者由于氯化物添加剂或混凝土碳化会导致钢筋生锈，从而可能招致沿钢筋混凝土底部的纵向漏洞。钢筋。
（5）平凡空心板在撑持端四周没有剪切斜漏洞。然而，最近几年来，一些桥梁接纳了宽度为1.5米或更大的大型空心板，这的确相当于一个小箱形梁。当板的厚度不大时，在侧板的腹板上可能会创造歪斜的破绽。
可选的加固方式是：
（1）对于在板底部打造生的纵向和横向裂纹，当裂纹的宽度逾越规格制约时，可以经过粘贴钢板法或粘贴纤维复合质料法进行加固。然则它不能无效意图跨跨挠度题目。
（2）预应力加固方式，将多条平行的预应力细钢丝锚定在板的底部，从此在张紧后用非凡混凝土笼盖（将多条预应力钢丝锚固在板的底部），或设置转向支架与从此将折线形的钢束拉紧拉力，将预应力钢缆颠末两个端板的斜孔锚固在铺装层下（外部预应力钢缆以虚线布置）。
（3）更改构造系统法子，例如将简单支撑的平板更改为连续平板，关于小跨度的平板桥梁，可以在跨度的中间或相近添加桥墩或斜撑。请把稳，在中间支点的负弯矩周边中，应连络桥面板的重修添加足够的抗拉钢筋。以上两种法子对设计中跨挠度有较好的功效。
（4）锚定放射混凝土加固法子，将钢网锚定在板的底部，往后放射混凝土覆盖。性子上是要在板的底部增多钢筋，这类似于“在板的底部锚定多条预应力钢丝”的提醒图，差异之处在于在板的底部添加了平凡钢网。
（5）只能经由历程对桥面的改造，如添加桥面横筋的放置，增厚铺路层等，才能规画桥面铰接处的纵向裂缝。
（6）平板桥架的空地现象可以颠末更换，增进钢背板，楔紧等方式办理。
钢筋混凝土和预应力混凝土一连平板桥
钢筋混凝土和预应力混凝土接连平板桥通常采纳实心平板或空心平板截面，况且大多半为现浇组织。跨度小于20米。预应力混凝土接连板跨度较大。通常，采取后张法。那些高度相称，而高度可变。立交桥与人行天桥在都会桥梁中有更多的使用。钢筋混凝土接连板有更多的应用。
思空见贯标题：
（1）在钢筋混凝土接连平板桥的每一个跨度的中间四面，平板底部四周从底部到顶部有多个垂直漏洞，这些bug可能会在横向方向上渗入渗出，这是弯曲bug，诠释抗弯强度不足；
（2）钢筋混凝土连续平板桥各墩顶部的桥面开裂，桥下的渗水一般水平渗入。如图所示，可能存在一个或多个裂纹，这多是由于活荷载或桥墩沉降不匀称引起的，这解释负弯矩很大，而且支点截面的抗弯本事不足。
（3）纵向bug出当时每一个跨度中间四周的平板底部，类似于“团体式平板桥中跨的平板底部纵向裂痕”。钢筋混凝土楼板的底部没有足够的横向钢筋，或者混凝土盖太薄且遭到预应力。钢筋周围的混凝土局部应力太大，或者混凝土中的添加剂招致钢筋生锈，在钢筋上引起裂纹；
（4）中跨挠度要末是施加的预应力不足，要么是中跨钢筋混凝土板底部的竖向漏洞适量且太宽，导致刚度降低与挠度增大。
可选的加固门径是：
（3）预应力加固办法，将转向支架放在板的底部，并按照折叠的线形束将其拉伸。这类门径无益于使劲构成的各种疾病。
（4）改变机关体系门径，好比在跨度中间或四周添加斜支撑，以打点跨度中间过分向下挠曲或预应力不足的标题，类似于下图，但拉力为支撑局部的负弯矩地区应增强钢筋。
4.钢筋混凝土与预应力混凝土接连平板桥
钢筋混凝土和预应力混凝土简支梁是所有行使中桥数量至少的梁桥，其横截面形式通常网罗T形，I形，箱形以及种种形式的组合。钢筋混凝土简支梁的跨度通常为10至20米，而预应力混凝土简支梁的跨度通常为16至50米，其中少数是较大的。大多半施工办法采用预制拼装，少数采纳现浇施工。由于具有肋形横截面，因而自重更轻，蜿蜒才力与跨度比平板桥大，何况疾病品种更多。
1）钢筋混凝土简支梁桥
（1）中跨左近梁底部的垂直弯曲裂纹的数目随跨度的增加而增进。静载荷裂纹的宽度可能会逾越指定的极限值，并且某些裂纹会在中跨度中发作过大的下偏角；
（2）靠近两个撑持端的腹板上的倾斜裂纹是由于主拉伸应力过大或腹板抗剪强度不足而惹起的剪切病，如图所示：
（3）梁腹板上的垂直裂缝大一部分位于薄腹板的中间。中间两端宽而细。它们不会向上或向下伸展。大一小块混凝土护卫不善，或者腹板上的温度或水平肋骨太少。其他原由惹起的膨胀裂纹首要影响机关的耐久性；
（4）在预制T型梁桥的法兰铰接或横向松弛的预制T型梁桥中，桥面板上沿翼缘板联接处的纵向马脚更为思空见贯。这类疾病会惹起恶性循环，加剧单束其他疾病的水平。
（5）由于其他施工缘故原由引起的漏洞，这些破绽可以在项目完成前缔造。
如果是按照B型预应力混凝土构件的一部份设计的简支梁，则可能具备钢筋混凝土简支梁的某些病害，但水平差别，因此再也不赘述。可是它有了一些常见的疾病，即纯粹预应力混凝土简支梁。对付彻底预应力与部份预应力的A类混凝土构件，在畸形使用条件下不准予出现破绽。假设发生这类状况，无论关节的宽度若何，都应找到原因进行治疗或加强。
预应力混凝土简支梁差异于钢筋混凝土简支梁的其他常见疾病：
（1）可以通过粘贴钢板和粘贴纤维复合资料，或者通过添加截面法子来添加铺路层的厚度并增多厚度，来增强梁底部的笔直裂纹和沿预应力筋的纵向裂纹。该部份的压缩地域。该地域晦气于增长蜿蜒强度与刚度，但是高度的增长遭到限定，同时自重也增多了。要是梁底部的高度增长，则加固理论上会增进；
（2）关于腹板上的倾斜裂纹，可将钢板或纤维复合原料粘贴在与裂纹相反的倾向上，并与水平线成或是45°角，即与倾斜裂纹大致正交的标的目的。光束高度低，而且将钢板或纤维锚固。当长度不足时，可以以U形箍与压条的形式粘贴。
（3）对于腹板上的压缩漏洞和锚固地域的马脚，依据接缝的宽度，使用环氧胶堵住或加添接缝；
（5）对于因力惹起的上述种种疾病，可以采纳外部预应力加强方法。有许多特定的方法。该办法的设计和构造繁冗，但成绩较好。
（6）对付病多，重的单根梁，在条件核准的环境下，可颠末剪断横梁来接替刚度更高的新梁，同时减少其他梁的载荷散布。如图所示，在大多半环境下，边际光束严沉变。
5.钢筋混凝土和预应力混凝土连气儿梁和悬臂梁桥
陆续梁桥与悬臂梁桥的横截面一般是T形，I形与箱形。 30米以上的大多半跨度是箱形的，并且使用了可变高度的不等跨度的梁。通常使用等高钢筋混凝土延续梁。跨度小于30米的钢筋混凝土连气儿梁或悬臂梁的跨度通常小于50米。这类使用大跨度钢筋混凝土质料的桥梁价值猥贱，桥面的负弯矩周边也很容易。出现横向bug。高度恒定的预应力混凝土间断梁的跨度通常在60米以下，而高度可变的预应力混凝土悬臂梁通常在100米以下，但100米以上是思空见贯的，一连梁通常在200米以下。 ，但200多米也很常见。这类类型的桥梁通常用于穿越障碍物或都会立交桥，而且无论跨度大小若何，都容易泛起各类疾病。
思空见贯的标题是：
（1）悬臂梁牛腿的挠度太大，墩顶的桥面板经常开裂。主要是由于悬臂刚度不足，体积小，车辆超重的影响，纵向预应力丢失大，施工质量差等原由形成的；
（2）以下图所示，悬臂梁的局部破绽主要是由于钢筋不足，高度低，温度影响或上吊与梁之间的毗连不良而至，导致汽车跳动和局部过大。影响;
（3）假定悬臂梁的锚孔跨度太大，则当其尺寸太小或钢筋不足时，很可能在翼展的底部泛起中跨挠度或垂直bug。中跨梁
（4）将预应力筋锚固到齿形板上后出现歪斜裂纹。对于所有预应力箱形梁，这但凡一种可能的疾病。如下图所示，主要原由是齿板左近的应力齐集太大，平庸钢筋的构形过小，预应力钢绞线被锚固。会集过多惹起的。
（5）箱形梁顶部和底部的纵向裂缝，如下图所示，主要是由于顶板和底板的横向笔挺力矩过大，无横向预应力，箱形梁横向蜿蜒的空间效应所致；板厚薄，横向钢筋不足，箱形梁的内外。温差过大会引起温度应力等缘故原由；
（6）箱形梁顶部与底部的纵向裂缝。在箱形梁的顶部与底部，大批的预应力纵向钢绞线穿过，局部应力过大，或者认为箱形梁的正剪力滞后效应还不足。或者是由于偏幸荷载作用下箱形梁的变形和扭转而引起的腹板下端过大的局部应力所致；
（7）箱形梁腹板中间的垂直裂缝通常在脱模后的2至3天内发生，况且不会向上和向下皱褶。预应力后，大多半将关闭。这首要是由于混凝土的压缩或箱形梁的表里之间的温度差或腹板的水平加强。不足或与混凝土夹杂物的品格有关；
（8）箱梁腹板上的斜裂缝如下图所示，通常呈目下当今桥墩支点与倒置点之间的梁段中。这是一个剪切漏洞，其起因更加烦复，首要是纵向或垂直预应力。散失不足或适量，箱梁内部与外部之间的温差过大，箱梁的弯曲或扭转刚度不足，在偏心载荷下箱梁的变形应力过大，腹板厚度小，剪切滞后效应的影响，无-预应力钢筋配置不足，混凝土夹杂物与添加剂的影响，施工欠妥，纵向预应力梁的线性布置以及跨距布置不合理。
（9）箱形梁腹板上的水平缝隙，如下图所示，首要是由于箱形梁横向蜿蜒的空间效应和表里温差应力所致，从而在箱梁上发生较大的竖向应力。腹板的内部或外部，箱形梁的横向刚度不足以及变形应力。 ，是由于垂直预应力不足等缘由惹起的。
（10）在悬臂施工进程中，每一个节段的毗邻处或关闭截面的毗连处都有裂缝，这首要是由于施工缝的措置不善构成的，这些邻接处变成薄弱的一小块，在纵向弯矩，混凝土缩短或紧缩的感召下开裂。温差应力大，或由于预制寻找不致密。桥面开裂后，接缝会渗水，钢材也会被侵蚀。
（11）当箱形梁较宽时，横向隔板或横梁中可能会泛起垂直破绽，以下图所示。这首要是因为施加在横隔板或横梁上的横向预应力不足或丧失太大，或者是由于梁的抗扭性差而惹起的箱形。
2）钢筋混凝土与预应力混凝土一连梁
中跨向下偏激笔挺通常随同着中跨梁底部的横向缝隙，桥墩顶部的桥面板上的破绽或倾斜的腹板裂缝。首要缘故原由是蜿蜒刚度不足，譬喻梁高下，腹板薄与纵向预应力。由压力不足或过火丢失惹起。
其他疾病与钢筋混凝土和预应力混凝土悬臂梁雷同。上述疾病的可选增强方法是：
（1）对于悬臂梁的牛腿真个偏斜，最无效的办法是增长预应力。利用可变高度梁的个性，将全长无粘结预应力电缆放置在路面层中，并锚定到牛腿上。如图1所示，应颠末植入大批的锚杆，在桥面的预应力在人行道层与箱梁的顶部平板之间转移，如图1所示。当一个具有多个腔室且箱体高度足够的单个箱体的横截面时，全长的外部主体可以放置在中间腹板顶部的两侧。束固定在腹板上，如下图2所示，但要留心对锚固孔的影响。
（2）为避免托梁涌现漏洞，通常在双侧粘贴块状钢板或钢带，如图3所示。假定盒内的托梁可以由人把持，请思量从外部钻一个斜孔，接下来如图4所示，经由预应力筋将其张紧并锚固。
（3）对于延续梁中跨与悬臂梁锚固孔，底部挠度太大。最有用的办法是外部预应力加固。利用可变高度梁的特点，线形或虚线形的主体被放置在盒子中的腹板的双侧。如图1与图2所示，外部预应力梁取得了加固，同等高度的一连梁应经过折线布梁进行加固，如图3所示。
（4）预应力锚固齿板相近的马脚多在填充根究后用薄钢板或碳纤维等复合质料加固；
（5）关于墩顶顶部桥面的横向缝隙，可以去除路面层的混凝土，并可以在平板顶部外貌添加平凡的抗拉钢筋或未粘结的预应力筋。如图1所示，将预应力钢绞线锚固在现浇层中。或在盒子中腹板双侧的重心轴横截面上方设置外部预应力电缆增强筋，如图2所示。 。
（6）对付延续梁底部的横向马脚或分段节理处的横向破绽，常接纳纵向粘结钢板或碳纤维等复合资料加固；或使用外部预应力电缆进行加固。对付分段节中的马脚，假如好坏应力惹起的，则只需用胶水填充便可；
（7）对于箱形梁顶部和底部的纵向bug，通常接纳横向粘贴钢板或其他纤维复合资料或增多横向邻接的门径来对其进行加固。假定顶板的底面纵向开裂，则主要是由于顶板的水平跨度太大而未设置横向预应力所致。您可以思考在顶部平板上方的路面层上添加横向预应力筋，如下图所示，接下来连贯路面层与屋顶板。在它们之间植入了大批的锚杆，以传送桥面板的预应力。
（8）对于箱形梁顶部和底部的纵向马脚与腹板的竖向漏洞，可通过密封，灌浆或粘贴纤维复合资料进行加固；
（9）对于腹板上的倾斜裂缝，可以将钢板或纤维复合质料粘贴到腹板上，类似于下图。或恰当增加腹板的厚度，或纵向或垂直施加预应力以增强腹板；
（10）对于腹板上的水平bug，会在腹板上粘贴垂直钢板或纤维复合质料，或增长水平毗邻，比方添加横向隔板或施加垂直预应力增强；
（11）对于箱形横梁中横隔板或横梁的竖向缝隙，可以在横隔板的两侧施加横向外部预应力，并颠末箱壁锚固，如下图所示。或添加横向挡板以增强抵拒横向蜿蜒和污蔑的本领。
6.预应力混凝土T形刚性框架桥
T形刚性框架桥包括具有吊挂梁或搭钮的T形刚性框架以及延续的刚性框架。其首要特征是梁与墩凝固在一块儿，但前者的上部机关类似于悬臂梁桥，后者的上部结构类似于连续梁桥，差别的地方在于墩必须接受较大的荷载。纵向弯矩。只管，依然存在力的差异，何况跨度也增加了许多。延续的刚性框架（如双薄壁墩）已到达约300米。预应力T形刚性框架桥，无论是带有吊梁的T形刚性框架，照常间断的刚性框架，通常使用高度可变的箱形梁，预应力悬臂梁和延续梁桥。他们也可能有标题。 ，可选的加固门径也相反。
区别在于带有悬挂梁的T形刚性框架具有较长的悬臂。假设施工或设计风致不佳，尤其是施工质量较差，将导致很大的预应力损失与悬臂的抗弯刚度不足。牛腿很容易涌现。太甚偏斜和其他疾病。当使用外部预应力电缆进行加固时，可以将未粘结的钢绞线放置在箱形梁顶面上的路面层中，并固定在中间的牛腿上。在新旧混凝土之间植入了少许的锚杆，以转移桥面。压力，如图所示：
当箱形梁是具有多个腔室的单个箱形梁时，可以在中间腹板的两侧布置全长的外部预应力电缆以进行加固，然后在墩顶上钻穿两个横向隔板，然后将其锚固到腹板两侧的锚固座上方，如图所示：
7.钢筋混凝土平板拱，肋拱和箱形拱桥
所谓的平板拱，肋拱与箱形拱主要是依据主拱环的截面形式来分别的，这里首要是指甲板拱桥，其跨度可以小也能够大，小则大于10米，大的可以抵达箱形肋拱。它长420米，具有种种结构与格局，但许多疾病大抵类似。
常见的标题问题是：
（1）主弓环的下边缘与侧面的横向裂纹以及弓形脚的上边缘和正面的横向裂纹，如下图所示。这首要是由于这两个局部的抗弯强度不足。启事有良多，好比尺微暇，加固不足够，拱轴不合理，桥墩沉降不匀称或向路堤滑动或旋转，车辆超重的影响，完整性差与施工质量差而至。假设裂纹的上下边缘的位置与上述相反，则通常为墩沿桥孔的方向滑动或旋转。
（2）在主弓形环（平板弓形环）或腹弓形环中涌现纵向裂纹，下列图所示。它通常陪伴着墩，平台帽或帽梁的纵向bug。若是破绽大略位于中间，则多是桥墩战争台底子的上，高雅沉降不均匀形成的。若是仅仅是侧拱盒的接缝处的漏洞，那么接缝通常为不毗邻的。良好，完整性差，这是由于偏幸载荷下侧拱盒的更大力和变形而至；
（3）混凝土的碎裂和枯萎死亡发生在主拱环的局部，通常发生在具有高压缩应力的处所，例如拐角，等截面拱形拱的拱脚附近等。抗压强度材料不足，导致团结或压碎，或外部钢筋生锈与膨胀；
（4）主拱圈拱趾处的径向裂纹首要是由于资料的抗剪强度不足引起的；
（5）双曲拱桥的拱形波峰上涌现纵向裂纹，或在拱肋与拱波的邻接处泛起圆形裂纹，这首要是由于肋骨之间的横向连贯衰弱懦弱，完整性差，截面组合不合理以及不平均酿成的。墩台的横向沉降等等
（6）拱的笔挺的框架，梁与柱破裂，额定是短柱的短端被破裂和压碎，墩，基台或实亲信板截面的腹弓环的拱脚与拱顶穿过侧壁到桥面板的破绽，以及侧壁。侧壁与拱形环之间的联接以及侧壁中的其他裂痕下列图所示。首要原由是短柱与腹弓环上不有铰链，相应位子的侧壁和桥面板上没有变形缝，主弓环变形或墩台位移and abutment pull and crack;
(7) Longitudinal cracks on the bridge deck are often accompanied by vertical cracks in the transverse connection, especially the severe cracks in the mid-span transverse connection, indicating that the horizontal integrity of the bridge is poor and the lateral load distribution is not good;
(8) When the main arch ring is as搜索引擎营销bled by segmented prefabrication, cracks may also appear at the joints;
(9) When steel tube concrete is used for arch ribs, there may be shrinkage folds on the surface of the steel tube, or there may be cavities and segregation in the tube. The thickness of the steel tube is often insufficient, the hoop effect is partially lost, and the steel tube lattice structure is unreasonably arranged, and the tube wall stiffening ribs Insufficiency and so on.
The optional reinforcement methods are:
(1) Because the main arch ring is an eccentric compression member, if the dome or arch foot transversely cracks or is partially crushed, it is best to use the method of increasing the section from the soffit surface or the back of the arch to reinforce it, such as chiseling the original concrete surface, Concrete or sprayed concrete is poured after planting and laying of reinforcements, especially for cracks at the arch foot, it is necessary to implant steel bars in the pier cap, and then increase the cross section of the arch foot, as shown in the following figure:
Secondly, it can be pasted with steel plate or fiber composite material, but it should be noted that the soffit pasting material is too long, and the problem of radial tearing after bending. In the medium and small span arch bridges, external prestressed reinforcement can also be considered, but the impact on other parts should be considered. It is also possible to reduce the self-weight of the building on the arch, such as replacing the filler, or digging out the filler and changing the side wall to a full open-站点 beam 站点 hole to reduce the burden on the main arch ring, as shown in the figure below, but the main arch axis shape is somewhat different Change, pay attention to checking calculations. If the disease is caused by the displacement of the pier and abutment is still developing, the pier and abutment should be strengthened first to eliminate the cause of the disease.
(2) For the longitudinal cracks in the main arch ring or abdominal arch ring, the longitudinal cracks of the pier and platform cap and the vertical cracks of the pier and platform body, if the cracks continue to develop, the foundation and other substructures must be reinforced first. The arch ring cracks should be Depending on the width of the seam, grouting is used to block the cross section, and steel plate or fiber composite material is pasted horizontally. Or add multiple steel hoops, and try to make them into block hoops, or use steel tie rods, apply transverse prestress and other methods to reinforce, as shown in the figure below.
(3) For double-curved arch bridges, the longitudinal cracks at the top of the arch or the joint between the arch rib and the arch wave should be strengthened or added to the transverse connection, the arch rib or arch slab section or the number of arch ribs should be increased, and the weight of the building on the arch should be reduced, such as Replace the filler of the belly arch and solid 站点 section, change the horizontal wall type 站点 hole pier to the column type 站点 hole pier, and change the arch type web hole to the beam-slab 站点 hole, etc., as shown in the figure below. If the crack is caused by the uneven lateral settlement of the pier and platform, the foundation should be reinforced first.
(4) For the cracks at the upper and lower ends of the low column on the arch, it is best to change the neck hinge to allow it to rotate properly, as shown in the figure below. For the arch toe or vault crack near the pier and the solid web, if the crack is wide enough to break or there is a significant difference in height on both sides, it should be considered to be dismantled and rebuilt into a three-hinged or two-reamed web hole, otherwise Dont care about it for the time being, but the deformation joints of the side walls and bridge decks at the corresponding positions should be set up, otherwise there will be water leakage;
(5) For the longitudinal cracks of the bridge deck and the vertical cracks of the transverse connection, the transverse integrity of the structure should be strengthened, such as increasing or adding beams, combined with the refurbishment of the bridge deck, appropriately thickening the thickness of the concrete paving layer, increasing the markings, and strengthening the bridge deck For arch bridges with transverse reinforcement and fillers, the fillers will be excavated and replaced with cast-in-situ concrete for reinforcement;
(6) The cracks that are not good at the main arch ring joints can be strengthened by means of grouting, planting bar connection or repair welding connection;
(7) For the wrinkles on the surface of the concrete-filled steel tube, it is best to use a layer of reinforced concrete to increase the section, or to densify the slab between the lattice structures, or to increase the tube wall stiffener. For the voids in the pipes, drill holes should be filled with epoxy glue or cement slurry;
(8) For arch bridges with excessive deflection of the vault and lateral cracks on the bottom surface, external prestressed cables can be used to set anchors on the arch back below the elastic center of the arch ring to make the vault produce negative bending moments and inverted arches. As shown in the figure below, but the arch foot also produces a negative bending moment, the cross section of the arch foot section should be increased to deal with it. The specific position of the external cable and the tensile force should be tested repeatedly according to the changes in the internal force of the arch ring (mainly bending moment) Confirm after calculation;
(9) For rib arches, double-curved arches, etc., due to excessive deformation and cracking of the main arch ring due to the horizontal displacement and subsidence of the arch foot, and the arch axis and the pressure line are seriously deviated, the arch foot can be used when it is difficult to use other reinforcement measures. The method of pushing and restoring to adjust the arch axis improves the force of the arch ring, but this method has complex technology, high risk, and low cost, so it is rarely used.
(10) Among the above various reinforcement methods, if the building on the arch is modified or the section of the main arch ring is enlarged, attention should be paid to the balanced sy妹妹etry between the single hole and the multi-hole during the unloading and loading process to ensure the arch ring and pier The stability of the station.
8. Middle and through arch bridges
Middle and through arch bridges are ribbed arches, and the arch ribs are often reinforced concrete rectangular, I-shaped or box-shaped (the latter are more). Steel pipe or concrete-filled steel tube, or their combination is also commonly used. In terms of the force system, there are ordinary arches (that is, thrust arches) and tied arches (ie, no thrust arches). The main components of deck arch bridges are different from suspenders and suspender beams (some also have longitudinal beams). ,Tie. The boom has rigid boom and flexible boom, the latter is more used.
Tie rods are also divided into rigidity and flexibility. Mid-bearing (flying swallow) tie-bar arches usually use flexible high-strength steel wires as tie rods. Down-bearing tie-bar arches include flexible tie rod rigid arches, rigid tie rod rigid arches and rigid tie rod arches. The first two are more co妹妹on in the difference of rod flexible arch. In addition to the diseases similar to deck arch bridges, there may also be the following diseases:
(1) The anchor head of the boom is loose, rusted, or the steel wire is corroded or sheared. The anchor head under the bridge deck and the anchor heads at both ends of the short boom are easy to appear;
(2) The suspender beam is used as a simply supported beam or a double cantilever simply supported beam. Reinforced concrete or prestressed concrete is commonly used. There may be vertical bending cracks at the bottom of the mid-span beam, and oblique cracks appear on the webs on both sides of the lifting point. In addition, longitudinal cracks may appear on the top surface of the beam at the lifting point, as shown in the figure below. The bridge deck with longitudinal beams between the suspenders and beams may crack near the nodes of the longitudinal and transverse beams and the nodes of the arch ribs and rigid tie rods;
(3) Looseness or corrosion of the anchor head of the tie rod, or corrosion or broken wire of the steel wire. Rigid tie rods are similar to elastically supported continuous beams because they have to withstand axial force and local bending moments, and they also have common problems with bending members.
The optional reinforcement methods are:
(1) If the anchor head of the suspender or tie rod is loose or individual slips, when conditions permit, the anchor head should be tightened to adjust the internal force or elevation of the loose tie rod or suspender. Most of the flexible suspenders use piers. The head anchor can be tightened by adding a steel spacer. If the tie rod uses a clip anchor, the heavy anchor should be supplemented. For booms or tie rods that are severely corroded, broken wires, or unconditionally tensioned and tightened, the cables should be replaced through reserved holes. If there are no reserved holes, other measures should be taken to temporarily unload the replaced booms or tie rods. Change the rope.
(2) The various cracks that appear in the boom beams, longitudinal beams or rigid tie rods can be reinforced like the reinforced concrete or prestressed concrete simple beams, continuous beams and cantilever beams in the previous sections of this chapter, such as external prestressing method , Pasting steel plate or fiber composite material method, etc.
(3) For the cracks of the longitudinal and transverse beam nodes and the arch foot nodes, the simple method is to paste the block steel plate or fiber composite material, as shown in the figure below.
9. Reinforced concrete rigid frame arch bridge
Under normal circumstances, the most co妹妹on diseases of long-span rigid-framed arches are the cracks at the chords and rigid joints. As long as the rigid-framed arch bridges with diseases, most of them have such cracks, but for reinforced concrete members, as long as the crack width does not exceed The allowable value is also a normal use. Although there are many owners who are opposed to building a new rigid-frame arch bridge, through analysis of the causes of its diseases, the problems of its bearing capacity and performance should be treated correctly.
Alternative reinforcement methods for rigid frame arch bridges
The rigid frame arch bridge is mainly composed of outer chords, inner chords, solid 站点s, arch legs (main arch legs), diagonal braces (secondary arch legs), transverse connections, bridge decks and bridge deck pavement, as shown in the following figure. The following will discuss each components disease phenomenon, its causes, and the reinforcement methods currently used one by one.
(1) Bridge decks: The decks of rigid frame arch bridges are commonly used in two types: less ribbed haunches or slightly curved plates. A few of them use rectangular solid or hollow slabs. The first two are optimized on the basis of rectangular slabs. The amount of steel and concrete is small and the weight is light. Especially the rib and haunches are hollowed out at the cost of complex construction. The less-reinforced rib axillary plate and micro-bend plate not only have less reinforcement, but also have a small thickness. They will definitely be no problem under short-term design loads. Under the condition of long-term overload, the actual bridge disease shows that the direction of the bottom of the ribbed plate is not correct. Regular cracks, severely exposed ribs and leaking water. If it is a micro-bending plate, the bottom surface of the stiffening rib of the micro-bending plate has a number of vertical cracks extending upward, some of which can extend to the top of the plate, causing the top of the plate to crack longitudinally.
The optional reinforcement methods for the above diseases are:
For the micro-bent slab with cracked stiffeners, a U-shaped unidirectional carbon fiber sheet with vertical cracks is used. It is more convenient to stick to the bottom of the rib than to stick the steel plate. The longitudinal cracks on the top of the micro-bent slab are filled and sealed depending on the width.
In combination with the reconstruction of the bridge deck, the thickness and strength of the cast-in-situ layer are increased, and the reinforcement in the cast-in-situ layer is strengthened to improve the stress condition of the bridge deck.
(2) Inner and outer chords and solid 网站s: chords and solid 站点s often use rectangular, I-shaped, box-shaped sections, the outer chords are bending members, and the inner chords and solid 站点s are bent (eccentrically). Compressed) components. Generally, the cracks produced by the arches often appear on the outer chord, followed by the inner chord and the solid 网站. Vertical cracks in the outer chord and oblique cracks on both sides of the large and small nodes are co妹妹on, but the degree is different. Of course, if the crack width is within the allowable range, it also meets the design requirements or is not at the point where it must be reinforced. But for rigid frame arch bridges with serious diseases, there are many and wide cracks in the tension zone at the bottom of the mid-span of the outer chord and the solid web, and the inner chord has more cracks, some have penetrated in the horizontal direction, and cracked to the top in the vertical direction, especially the nodes. The diagonal cracks on both sides are wider, and some have penetrated.
The optional reinforcement methods are:
① For the reinforcement of the bending member of the outer chord of the rigid frame arch, if the chord is not a super-reinforced beam, the U-shaped fiber sheet or the steel plate can be pasted in the tension zone of the bottom surface or the section height and reinforcement can be increased. For super-reinforced beams, it is best to increase the section height and reinforcement, or to paste U-shaped fiber sheets or steel plates in the tension zone on the bottom surface, and increase the thickness of the cast-in-situ layer on the bridge deck.
② The inner chord is an eccentric compression member and can be reinforced by the same method as the outer chord.
③ The oblique cracks on both sides of the large and small nodes can be reinforced with steel plates or fiber sheets on the crack surfaces to withstand the main tensile stress. Increasing the height of the chord section can also reduce the main tensile stress.
④ U-shaped carbon fiber sheet can be pasted on the slightly arc-shaped bottom surface of the solid web in the mid-span to withstand the bending tensile stress and radial tearing force, or the method of increasing the section height and reinforcement can be adopted.
⑤ For the cracks in the chord and other parts of the solid abdomen, the cracks can be filled and sealed.
(3) Lateral connection: The lateral connection of a rigid frame arch bridge. There is one line between the chords and solid 站点s about 3 meters, and the nodes are strengthened. On the arch legs and diagonal braces, there are one or more channels according to the size of the span. The situation is relatively intact. However, rigid frame arches with integral damage are quite different. Most of the diaphragms of the solid web and chord sections have vertical cracks that penetrate up and down. The hollowed diaphragms are more serious than the solid diaphragms, especially There are many cracks in the transverse diaphragm of the solid web, and some of them are almost broken into only steel bars. The transverse connections on the arch legs and diagonal braces are generally intact. However, rigid frame arch bridges with gravity piers and abutments have few problems in the lateral connection, indicating that flexible piers should not be used for light arch bridges with low rigidity.
The optional reinforcement methods are:
① 中断交通施工时，横隔板可接纳混凝土加固，即在原横隔板的基础上，通过植筋加厚加高横隔板。
不能中决绝通施工时，横隔板只有采纳施工神速、简便的钢组织加固，下列图。在原混凝土横隔板的四个角，采纳粘贴和螺栓静止四根角钢，再用两片钢桁架夹住原混凝土横隔板，施工时作好所有横隔板加固预备任务，并点焊固定职位后，常设中断交通，将各钢构件焊接完成后，再恢复交通。
（4）主拱腿及斜撑：主拱腿和斜撑为小偏疼受压构件，在恒载及车辆感召下，一样平常不发生发火拉应力，其内首要按构造配筋。但有的斜撑底部四面有较多由顶面而下的环形裂缝，有的开裂至截面高度一半摆布。采取有限元较量争论分析可知，使用荷载下，构件不孕育发生拉应力，但在墩、台不平匀沉降时，斜撑底部的负弯矩就极为急速，较小的不平均下沉，在此处将发生发火较大的拉应力。实桥窥察也说明斜撑底部有破绽呈现，极可能是墩、台有不平均沉降。其他，温度降落时也容易孕育发生斜撑底部的负弯矩。
可选的加固办法有：
对于斜撑根部的马脚，可接纳环形包裹粘贴纤维布，也可采纳顶面粘贴钢板或碳纤维条。也可思考增大截面加固。
（5）桥面铺装层：桥面现浇层对采取预制拼装施工的桥面板来说，尤为必要，以其它类型桥梁比较，刚架拱桥的混凝土铺装层是组合断面的一局部，直接插手受力，更须要的是拱片大、末节点负弯矩区的受拉钢筋都布置于现浇铺装层中。假定该位子所蒙受的拉应力过大，将会导致桥面横向意会开裂，若桥梁小我私家性较差，还会惹起桥面的拱片位子处纵向领悟开裂，这两类破绽均属布局受力性缝隙，必需尽快进行加固。其他坑槽、网裂之类均属铺装层本身局部病害。
可选的加固法子有：
① 凿除桥面铺装，从头浇筑铺装层混凝土，按新规范要求行进混凝土标号，加强桥面钢筋网的配筋。并分外留意钢筋网必须架起来。新浇铺装层的厚度，依照需要选择是否加厚。
② 进一步加强负弯矩区的纵向钢筋设置装备摆设。
中等跨径以下的桁架拱一般采纳钢筋混凝土，中等跨径以上的桁架拱或桁式组合拱桥一般采用预应力混凝土，它们均为组合体系拱，常接纳预制拼装施工。上弦杆及跨中实腹段除承受轴力外，还遭受较大弯矩，上弦杆为偏爱受压构件，腹杆有斜杆与竖杆，一般采用斜拉杆式腹杆，即斜杆为偏疼受拉，竖杆为偏心受压构件。因而跨径大时，需在上弦杆、斜杆及实腹段中施加预应力。
思空见贯标题问题有：
（1） 上弦杆及实腹段跨中四周底面及正面横向开裂，或下挠过大，正文杆件的无效预加应力不足，或截面高度偏小，普通钢筋配置不足；
（2）斜杆开裂，注明拉力过大，预加应力不足。
（3）上弦杆及竖杆沿杆长偏袒涌现多条bug或局部压碎，首要是杆件截面尺码偏小。如果泛起垂直于杆长标的目的的裂缝，阐明杆件的长细比过大或桁架片变形较大惹起较大偏幸弯矩所致；
（4）各杆件节点周围开裂，由于各杆件轴线通常不会订交于一点，且受其他附加应力影响使节点局部应力过大惹起开裂，如图：
（5）横向宰割（如横隔板、横系梁、铰剪撑等）中部涌现竖向裂缝或其它裂缝，主要是桁片横向团体性差，横向豆割刚度不足、尺码偏小；
（6） 由于桁架拱采纳预制拼装施工，寻找较多，干探究可能因焊接风致或疲倦题目松脱，湿讨论也可能因找寻强度不足惹起开裂；
（7）桁架拱桥的桥面板一样平常用钢筋混凝土微弯板，钢筋混凝土或预应力混凝土矩形空心板或实心板。桁式组合拱桥的桥面板经常使用钢筋混凝土单向板或双向板。其病害与上节刚架拱桥类似。
可选的加固方法有：
（1）对上弦杆、斜杆及实腹段裂痕，若是不太老火可采取粘贴钢板或纤维复合资料方式加固，否则可采纳体外预应力加固，或群集增大截面，张拉体外预应力索后用钢筋混凝土包裹；
（2）对上弦杆及竖杆的马脚，最佳采纳增大截面法加固，如果漏洞不太严重，可采用加钢板箍或包裹纤维复合原料加固；
（3）对节点马脚，可采取粘贴块状钢板或纤维复合原料加固；
（4）对横向朋盘据缝，最好采纳加大横向联系截面尺码，或增设横向豆割，或施加横向预应力加固。假设开裂程度较轻，可采取局部粘贴钢板或纤维复合原料加固；
（5）对种种施工找寻的裂缝，可接纳补焊、灌缝、植入锚筋、粘贴钢板等法子加强。
十一、圬工拱桥
（1）拱圈出现大面积的老火风化剥落、灰缝脱空。缘故原由是砌体与砂浆的质料差，或者受到侵蚀性强的水与气体的浸蚀；
（2） 主拱圈拱顶下缘泛起1～2条横向贯穿的bug，假如马脚双侧有明显高差，注明墩台有不平均下沉，若无显著高差，但拱顶有少量下沉，则可能墩台向桥孔外滑动或滚动，或由于拱圈承载力已不足惹起，若拱顶上拱且下缘泛起横向压碎裂纹，则可能墩台向桥孔内滑动或转动；
（3）拱圈的个别拱石呈现裂痕，灰缝掉落，压碎或外凸；
（4）拱圈分层砌筑时，沿砌缝涌现环向破绽，这首要与施工时的砌筑工序，支架变形、砌缝处置及沙浆强度无关；
（5）砌体表层沿砌缝无规则的开裂，主要是沙浆标号低或沙浆不枯瘠；
（7）拱上侧墙沿拱圈的拱背开裂或来到，主要是墩台下沉，温度变卦或车辆劝化时主拱圈与拱上建筑变形不协调，或砌缝未措置好引起。
其它一些病害与钢筋混凝土上承式拱桥类似。
可选的加固法子有：
（1）对砌体表层风化剥落、灰缝脱空，可先凿除松动的剥蚀层，外露新鲜面，用高标号水泥沙浆填塞灰缝，视厚度分层涂抹或喷涂水泥砂浆修补，砂浆中可添加一些化学纤维以增强抗裂性；
（2）对由于墩台不平匀下沉引起的拱顶横向bug，如果下沉还未刚强，应先加固墩台底子，再对漏洞注水泥浆后，在拱腹下植筋，挂钢筋网浇筑或放射混凝土内衬，增大拱圈截面加固。如果沉降基本终止，就只有加固拱圈，开裂不很有问题时，也可只灌浆封锁。对由于墩台滑动或转折引起的拱顶马脚，假如墩台位移尚未休止，应先加固墩台，再对bug注浆封锁后，可从拱腹或拱背浇筑钢筋混凝土，增大截面加固。对由于承载才具不足惹起的拱顶横向破绽及下沉，除可采取拱背或拱腹增大截面外，还可同时采纳减轻拱上修筑自重来减少恒载，照实腹拱改空腹拱，以下图1
将原填料更换为轻质填料，改拱式腹孔为梁板式腹孔或全空肚式拱上建筑。对小跨径拱桥还可在拱顶上浇筑一钢筋混凝土简支板或垫板，如下图2，将原桥改为拱梁组合体系，以减轻主拱圈活载，前进承载力。以上加固中若墩台累坠增多较多，应思量墩台及根蒂的承载力及稳固可否满足加固需要。
（3）拱圈个体拱石泛起的病害，可凿除压碎一部分，视马脚宽度大小，用环氧胶、高标号水泥沙浆或环氧砂浆，灌缝或填缝，再用水泥砂浆或小石子混凝土修补。拱石严重碎裂的，要悉数凿除用混凝土填补；
（4）主拱圈沿砌缝环向开裂时，接纳钢板或铸件做成的楔形剪力键或抓钉竖向嵌入拱圈两侧，开裂规模大且严重时在拱圈上径向钻孔穿入长锚栓，适合加压后锚固，此间距放置视环向开裂水准而定，原缝隙用水泥浆灌缝封锁，图3；
（5）砌体表层砌缝开裂，可接纳水泥砂浆灌缝封锁或勾缝；
（6）拱上侧墙外倾，视外倾程度，采取挖出墙内填料更换成砂砾石、浆砌片石等较少侧压力的资料，对空肚式拱桥的腹拱侧墙及实腹段侧墙外倾，由于填料较少，可更换成低标号混凝土。对实腹式拱桥也可采纳加厚侧墙尺码，或者在两侧墙钻孔设多根钢拉杆对锚，下列图4。还可改变拱上建造形式不要侧墙，如实腹式改空肚式等，如上图1；
（7）拱上侧墙沿拱背开裂或脱离，假如是根抵下沉惹起并未终止的，应先加固基础，再用高标号水泥浆或砂浆灌缝封锁。并查抄两拱脚上方侧墙上至桥面的伸缩缝能否齐备，否则可能惹起拱上建筑与主拱圈变形不与谐。其它病害的加固方式与钢筋混凝土上承式拱桥类似。
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