桥梁改建可以减少首要开拓商的早期投资本钱（席卷吊销资本，土建成本等），缩短工期，体现更高的经济价值。今朝，桥梁加固设计与总计的研讨还绝对滞后。在某些方面，乃至无法使用公认的算法，这使设计职员难以上手。除了耐心的专业常识，桥梁加固设计职员还应当具有丰硕的设计教训与丰富的施工指点。残破的设计施工图更加合理，可靠，传神，施工质量容易包管，几近不有窜改和更动。 ，资源合理，加固成果好。它不仅可以治愈“暂且”，而且可以只管即便地对待“根”。
假设只有施工经验，则生成的加固方案与施工图可能缺乏对布局的琐细应力综合以及对疾病成因与趋势的综合。通常，加固的零件不有取得足够的加固，或者过量的加固，不需要加固的地域也获得加固，组成更多的终于。费钱后，加固成果不佳。许多设计师在加固材料的数量上绝对随意。有得多人按照经验和见识使用质料。不论是华侈原料还是不有到达可慧的加固成就，它们对自身都不熟识，业主也不知道，而且大多数人都不有做任何事项。对于钢筋计算，一些高素质的设计单元只对钢筋加固前的组织进行一些从新查抄，而对付钢筋加固后的承载力至少进行算计。可是远近闻名，因素的疾病通常表当时畸形使用阶段。承载才略主要抒发组件是否保险。可以保险使用的组件并非不有疾病。于是，必须共计每种质料在截面上的应力强度以反映部件。可否有疾病，有若干好多及其进行趋势。
“应力强度的计较是反映组件疾病的必要底子，而承载力的较量争论则是安全使用组件的最终保障。”两者都是必不可少的。在现实的钢筋总计中，通常似乎承载力的最终形状满足要求，但部件中确实具备许多疾病。是以，一种门径是增加车辆的设计负荷，以使承载伎俩不克不及满足申请，然则缺乏靠得住的过载数据。另外一种方法是依据各种疾病与水准，通过一些算法获得各种折减系数，并对承载力进行折减以剖明该组件不满足承载力要求。组件加固后，将填补大于或便是减小的承载能耐的承载技能花样。尽管该方法具有一定的科学依据，但也具备许多酬劳的果决因素，这些因素也不能反映管制部件上种种物料的工作前提。
如何加强差异类型的桥梁？
（1）通常在中跨四面从底部到顶部有多个垂直bug，动态漏洞的宽度可能跨越规格极限值，偶然会在中跨泛起挠曲，标明抗弯强度不足。
（2）通常状况下，平板的底部在中跨附近可能会涌现多个纵向裂纹，而且某些动静裂纹的宽度将超越规格申请。这多是因为设计图采纳了预制的规范图钢筋，但在施工进程中使用了它。现浇将单向板转变为一体的双向板，从而改变了板的受力内容，从而导致板底部的横向钢筋老火短缺，并导致底部的纵向漏洞板在横向弯矩劝化下的应力。
2.混凝土预制组件简支板桥
（2）可能还会有支撑空隙。由于每个平板的每一个收尾都有2个撑持，于是每个桥都有更多支撑。假定在施工过程中撑持垫石的高度不正确，或者在安设历程中预制板的翘曲或墩台的不平均沉降将导致某些撑持物变空；
（3）在中跨四面的钢筋混凝土板底部左近，从底部到顶部有垂直缝隙，而且接缝的宽度可能跨越规则的申请，或者中跨可能有向下的挠曲，何况耐笔直性不足。
（4）纵向裂纹涌那时平板的底部。大少数预应力混凝土制成的简支平板桥凡是经由过程预应力构造的。若是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破绽。钢筋。
（5）平凡空心板在支撑端左近没有剪切斜马脚。然而，比年来，一些桥梁采纳了宽度为1.5米或更大的大型空心板，这确实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发明歪斜的漏洞。
可选的加固办法是：
（1）关于在板底部孕育发生的纵向与横向裂纹，当裂纹的宽度跨越规格限定时，可以经由粘贴钢板法或粘贴纤维复合质料法进行加固。然则它不能无效整治跨跨挠度题目。
（2）预应力加固法子，将多条平行的预应力细钢丝锚定在板的底部，此后在张紧后用不凡混凝土掩饰笼罩（将多条预应力钢丝锚固在板的底部），或设置转向支架与而后将折线形的钢束拉紧拉力，将预应力钢缆经由过程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）更改机关系统法子，譬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四周添加桥墩或斜撑。请寄望，在中间支点的负弯矩周边中，应云散桥面板的重修添加足够的抗拉钢筋。以上两种门径对筹算中跨挠度有较好的成绩。
（4）锚定喷射混凝土加固法子，将钢网锚定在板的底部，此后放射混凝土覆盖。实质上是要在板的底部增加钢筋，这类似于“在板的底部锚定多条预应力钢丝”的暗示图，一致之处在于在板的底部添加了普通钢网。
（5）只能通过对桥面的改造，如增长桥面横筋的布置，增厚铺路层等，才能图谋桥面铰接处的纵向漏洞。
（6）平板桥架的空闲情景可以经由过程更换，增进钢背板，楔紧等办法打点。
钢筋混凝土和预应力混凝土连续平板桥
钢筋混凝土与预应力混凝土陆续平板桥通常采取实心平板或空心平板截面，况且大少数为现浇结构。跨度小于20米。预应力混凝土延续板跨度较大。通常，采用后张法。那些高度相等，而高度可变。立交桥与人行天桥在都会桥梁中有更多的运用。钢筋混凝土延续板有更多的使用。
思空见贯标题：
（1）在钢筋混凝土连气儿平板桥的每个跨度的中间相近，平板底部周围从底部到顶部有多个垂直bug，这些漏洞可能会在横向方向上浸透，这是笔直bug，剖明抗弯强度不足；
（2）钢筋混凝土延续平板桥各墩顶部的桥面开裂，桥下的渗水一样平常水平渗入。如图所示，可能具备一个或多个裂纹，这多是由于活荷载或桥墩沉降不均匀引起的，这批注负弯矩很大，而且支点截面的抗弯本事不足。
（3）纵向马脚涌当时每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漏洞”。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受到预应力。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）中跨挠度要么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缝隙过量且太宽，招致刚度消沉与挠度增大。
可选的加固方式是：
（3）预应力加固办法，将转向支架放在板的底部，并遵照折叠的线形束将其拉伸。这类办法有益于用力组成的各类疾病。
（4）改变构造体系门径，比方在跨度中间或附近添加斜支撑，以整治跨度中间过分向下挠曲或预应力不足的题目，类似于下图，但拉力为支撑一小部分的负弯矩周边应增强钢筋。
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哄骗中桥数量至少的梁桥，其横截面形式通常蕴含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一样平常是16至50米，此中少数是较大的。大少数施工门径采取预制组装，少数接纳现浇施工。由于具有肋形横截面，是以自重更轻，蜿蜒手段与跨度比平板桥大，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笔挺裂纹的数量随跨度的添加而增加。静载荷裂纹的宽度可能会逾越指定的极限值，况且某些裂纹会在中跨度中发作过大的下偏角；
（2）凑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引起的剪切病，如图所示：
（3）梁腹板上的垂直马脚大局部位于薄腹板的中间。中间两头宽而细。它们不会向上或向下皱褶。大一小块混凝土维护不善，或者腹板上的温度或水平肋骨太少。其他启事引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，桥面板上沿翼缘板毗邻处的纵向漏洞更为常见。这类疾病会惹起恶性轮回，加剧单束其他疾病的程度。
（5）由于其他施工缘故原由引起的缝隙，这些裂痕可以在工程实现前缔造。
如果是依照B型预应力混凝土构件的一部份设计的简支梁，则可能存在钢筋混凝土简支梁的某些病害，但水平不合，于是不再赘述。然则它也有一些常见的疾病，即彻底预应力混凝土简支梁。关于彻底预应力和局部预应力的A类混凝土构件，在正常使用条件下不核准泛起马脚。要是发生这种环境，无论枢纽关头的宽度如何，都应找到原由进行治疗或增强。
预应力混凝土简支梁分歧于钢筋混凝土简支梁的其他思空见贯疾病：
（1）可以经由过程粘贴钢板与粘贴纤维复合资料，或者经过增加截面门径来增加铺路层的厚度并增长厚度，来增强梁底部的笔挺裂纹与沿预应力筋的纵向裂纹。该一小部分的压缩区域。该区域无利于增进蜿蜒强度和刚度，但是高度的添加遭到制约，同时自重也增长了。假设梁底部的高度增进，则加固实践上会增进；
（2）对付腹板上的倾斜裂纹，可将钢板或纤维复合原料粘贴在与裂纹相反的标的目的上，并与水平线成可以或许45°角，即与歪斜裂纹约略正交的偏袒。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形箍和压条的形式粘贴。
（3）对付腹板上的膨胀破绽与锚固区域的漏洞，依照接缝的宽度，使用环氧胶堵住或加添接缝；
（5）关于因力惹起的上述各类疾病，可以采纳外部预应力增强方法。有许多特定的办法。该办法的设计和构造芜杂，但成果较好。
（6）对于病多，重的单根梁，在前提批准的情况下，可颠末剪断横梁来替代刚度更高的新梁，同时减少其他梁的载荷漫衍。如图所示，在大少数情况下，边际光束严沉痾变。
5.钢筋混凝土和预应力混凝土连气儿梁与悬臂梁桥
间断梁桥与悬臂梁桥的横截面一般是T形，I形和箱形。 30米以上的大少数跨度是箱形的，而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间断梁。跨度小于30米的钢筋混凝土间断梁或悬臂梁的跨度通常小于50米。这种使用大跨度钢筋混凝土资料的桥梁价钱昂贵，桥面的负弯矩地区也很容易。呈现横向破绽。高度恒定的预应力混凝土陆续梁的跨度通常在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，接连梁通常在200米以下。 ，但200多米也很思空见贯。这种类型的桥梁通经常使用于穿梭窒碍物或都市立交桥，何况无论跨度大小若何，都容易涌现种种疾病。
常见的标题是：
（1）悬臂梁牛腿的挠度太大，墩顶的桥面板每每开裂。首要是由于悬臂刚度不足，体积小，车辆超重的影响，纵向预应力消散大，施工品格差等起因组成的；
（2）如下图所示，悬臂梁的局部裂缝主要是由于钢筋不足，高度低，温度影响或吊颈与梁之间的连接不良所致，导致汽车跳动与局部过大。影响;
（3）若是悬臂梁的锚孔跨度太大，则当其尺寸过小或钢筋不足时，极可能在翼展的底部泛起中跨挠度或垂直裂痕。中跨梁
（4）将预应力筋锚固到齿形板上后泛起倾斜裂纹。对付所有预应力箱形梁，这都是一种可能的疾病。下列图所示，主要缘由是齿板相近的应力集合太大，普通钢筋的构形过小，预应力钢绞线被锚固。鸠合适量惹起的。
（5）箱形梁顶部与底部的纵向裂痕，下列图所示，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而至；板厚薄，横向钢筋不足，箱形梁的内外。温差过大会惹起温度应力等启事；
（6）箱形梁顶部与底部的纵向马脚。在箱形梁的顶部和底部，少量的预应力纵向钢绞线穿过，局部应力过大，或者以为箱形梁的正剪力滞后效应还不足。或者是由于偏疼荷载感导下箱形梁的变形与扭转而引起的腹板下端过大的局部应力而至；
（7）箱形梁腹板中间的垂直破绽通常在脱模后的2至3天内发生，况且不会向上与向下皱褶。预应力后，大少数将关闭。这主要是由于混凝土的收缩或箱形梁的表里之间的温度差或腹板的水平增强。不足或与混凝土混合物的品质有关；
（8）箱梁腹板上的斜漏洞以下图所示，通常涌现在桥墩支点与倒置点之间的梁段中。这是一个剪切裂痕，其缘由加倍冗杂，首要是纵向或垂直预应力。迷失不足或适量，箱梁外部和外部之间的温差过大，箱梁的笔直或扭转刚度不足，在偏幸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-预应力钢筋设置装备摆设不足，混凝土异化物和添加剂的影响，施工不妥，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漏洞，以下图所示，首要是由于箱形梁横向蜿蜒的空间效应和内外温差应力而至，从而在箱梁上发作较大的竖向应力。腹板的外部或外部，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原由引起的。
（10）在悬臂施工进程中，每一个节段的毗连处或封闭截面的邻接处都有缝隙，这主要是由于施工缝的处置不善组成的，这些邻接处变成柔弱虚弱的有部分，在纵向弯矩，混凝土紧缩或压缩的作用下开裂。温差应力大，或由于预制讨论不致密。桥面开裂后，接缝会渗水，钢材也会被腐蚀。
（11）当箱形梁较宽时，横向隔板或横梁中可能会泛起垂直裂缝，下列图所示。这首要是由于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）钢筋混凝土和预应力混凝土陆续梁
中跨向下太过笔挺通常陪伴着中跨梁底部的横向裂痕，桥墩顶部的桥面板上的破绽或倾斜的腹板裂痕。首要缘故原由是笔挺刚度不足，例如梁上下，腹板薄与纵向预应力。由压力不足或过分丧失引起。
其他疾病与钢筋混凝土与预应力混凝土悬臂梁相同。上述疾病的可选增强办法是：
（1）对于悬臂梁的牛腿端的偏斜，最有效的办法是增加预应力。利用可变高度梁的本性，将全长无粘结预应力电缆布置在路面层中，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）为防止托梁呈现破绽，通常在双侧粘贴块状钢板或钢带，如图3所示。如果盒内的托梁可以由人行使，请思考从外部钻一个斜孔，日后如图4所示，经由历程预应力筋将其张紧并锚固。
（3）对付一连梁中跨和悬臂梁锚固孔，底部挠度太大。最有效的法子是外部预应力加固。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和图2所示，外部预应力梁取得了加固，划一高度的间断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裂缝通常在填充讨论后用薄钢板或碳纤维等复合质料加固；
（5）对付墩顶顶部桥面的横向裂缝，可以去除路面层的混凝土，并可以在平板顶部轮廓添加平庸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。或在盒子中腹板两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）对于延续梁底部的横向漏洞或分段节理处的横向马脚，常采取纵向粘结钢板或碳纤维等复合材料加固；或使用外部预应力电缆进行加固。对于分段节中的裂痕，如果黑白应力引起的，则只要用胶水添补即可；
（7）对付箱形梁顶部与底部的纵向裂痕，通常采纳横向粘贴钢板或其他纤维复合材料或增长横向联接的方法来对其进行加固。假设顶板的底面纵向开裂，则首要是由于顶板的水平跨度太大而未设置横向预应力所致。您可以考虑在顶部平板上方的路面层上添加横向预应力筋，以下图所示，接下来联接路面层与屋顶板。在它们之间植入了大量的锚杆，以通报桥面板的预应力。
（8）对付箱形梁顶部与底部的纵向马脚和腹板的竖向裂缝，可经由进程密封，灌浆或粘贴纤维复合质料进行加固；
（9）关于腹板上的歪斜漏洞，可以将钢板或纤维复合质料粘贴到腹板上，类似于下图。或恰当增进腹板的厚度，或纵向或垂直施加预应力以增强腹板；
（10）对于腹板上的水平破绽，可在腹板上粘贴垂直钢板或纤维复合原料，或添加水平邻接，好比增多横向隔板或施加垂直预应力增强；
（11）对付箱形横梁中横隔板或横梁的竖向漏洞，可以在横隔板的双侧施加横向外部预应力，并经过箱壁锚固，如下图所示。或添加横向挡板以增强抵当横向弯曲和扭曲的能耐。
6.预应力混凝土T形刚性框架桥
T形刚性框架桥涵概具有吊挂梁或搭钮的T形刚性框架以及一连的刚性框架。其主要特征是梁和墩凝集在共同，但前者的上部布局类似于悬臂梁桥，后者的上部组织类似于陆续梁桥，分歧之处在于墩必须遭受较大的荷载。纵向弯矩。当然，仿照照旧具有力的差异，况且跨度也添加了良多。延续的刚性框架（如双薄壁墩）已抵达约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，照旧间断的刚性框架，通常使用高度可变的箱形梁，预应力悬臂梁和陆续梁桥。他们也可能有题目。 ，可选的加固方式也相斥。
区分在于带有悬挂梁的T形刚性框架具有较长的悬臂。要是施工或设计质量不佳，尤其是施工品质较差，将招致很大的预应力散失与悬臂的抗弯刚度不足。牛腿很容易出现。太甚偏斜与其他疾病。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布置在箱形梁顶面上的路面层中，并静止在两头的牛腿上。在新旧混凝土之间植入了少量的锚杆，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，可以在中间腹板的双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，此后将其锚固到腹板双侧的锚固座上方，如图所示：
7.钢筋混凝土平板拱，肋拱与箱形拱桥
所谓的平板拱，肋拱与箱形拱主要是按照主拱环的截面形式来分别的，这里主要是指船面拱桥，其跨度可以小也可以大，小则大于10米，大的可以达到箱形肋拱。它长420米，具有种种机关与款式，但许多疾病大抵相反。
思空见贯的问题是：
（1）主弓环的下边缘和正面的横向裂纹以及弓形脚的上边沿与正面的横向裂纹，如下图所示。这首要是由于这两个一部分的抗弯强度不足。起因有很多，比如尺微暇，加固不足量，拱轴不合理，桥墩沉降不均匀或向路堤滑动或旋转，车辆超重的影响，残缺性差与施工风致差所致。若是裂纹的上下边缘的地位与上述相反，则一样平常为墩沿桥孔的偏向滑动或旋转。
（2）在主弓形环（平板弓形环）或腹弓形环中呈现纵向裂纹，如下图所示。它通常陪伴着墩，平台帽或帽梁的纵向破绽。要是漏洞大体位于中间，则可能是桥墩和平台根抵的上，优雅沉降不平均组成的。假如仅仅是侧拱盒的接缝处的裂缝，那么接缝通常是不联接的。良好，残缺性差，这是由于偏幸载荷下侧拱盒的更鼎力和变形而至；
（3）混凝土的碎裂与脱还俗生在主拱环的局部，通常发生在具有低压缩应力的地方，比方拐角，等截面拱形拱的拱脚左近等。抗压强度原料不足，招致破裂或压碎，或外部钢筋生锈和膨胀；
（4）主拱圈拱趾处的径向裂纹首要是由于原料的抗剪强度不足惹起的；
（5）双曲拱桥的拱形波峰上呈现纵向裂纹，或在拱肋与拱波的邻接处涌现圆形裂纹，这主要是由于肋骨之间的横向连接强劲，完整性差，截面组合不合理以及不平均组成的。墩台的横向沉降等等
（6）拱的蜿蜒的框架，梁和柱破裂，额外是短柱的短端被破裂和压碎，墩，基台或实心腹板截面的腹弓环的拱脚与拱顶穿过侧壁到桥面板的马脚，以及侧壁。侧壁与拱形环之间的连贯以及侧壁中的其他裂缝下列图所示。首要缘由是短柱和腹弓环上不有搭钮，响应位置的侧壁和桥面板上不有变形缝，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-网站 beam 网站 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 网站 section, change the horizontal wall type web hole pier to the column type web hole pier, and change the arch type 站点 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 网站, 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 Don't 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 symmetry 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 common 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 co妹妹only 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 co妹妹on 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 component's disease phenomenon, its causes, and the reinforcement methods currently used one by one.
(1) Bridge decks: The decks of rigid frame arch bridges are co妹妹only 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 webs 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 站点, 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 网站 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 webs 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 站点 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 网站, 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 中绝交通施工时，横隔板可采取混凝土加固，即在原横隔板的基础底细上，通过植筋加厚加高横隔板。
不克不及中决绝通施工时，横隔板只有采用施工疾速、简练的钢组织加固，下列图。在原混凝土横隔板的四个角，采用粘贴和螺栓固定四根角钢，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操办任务，并点焊固定位子后，长时间中断交通，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幸受压构件，在恒载及车辆感导下，通常不发作拉应力，其内主要按构造配筋。但有的斜撑底部周围有较多由顶面而下的环形裂痕，有的开裂至截面高度一半左右。采纳有限元计算剖析可知，使用荷载下，构件不发作拉应力，但在墩、台不均匀沉降时，斜撑底部的负弯矩就尤其敏感，较小的不匀称下沉，在此处将产生较大的拉应力。实桥察看也说明斜撑底部有漏洞涌现，极可能是墩、台有不平均沉降。其余，温度下降时也容易孕育发生斜撑底部的负弯矩。
可选的加固办法有：
关于斜撑根部的破绽，可采用环形包裹粘贴纤维布，也可接纳顶面粘贴钢板或碳纤维条。也可考虑增大截面加固。
（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讲，尤为需求，以其它类型桥梁比照，刚架拱桥的混凝土铺装层是组合断面的一部份，直接染指受力，更必要的是拱片大、末节点负弯矩区的受拉钢筋都放置于现浇铺装层中。假定该地位所接受的拉应力过大，将会导致桥面横向贯穿开裂，若桥梁集团性较差，还会惹起桥面的拱片地位处纵向贯通开裂，这两类裂痕均属构造受力性裂痕，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。
可选的加固门径有：
① 凿除桥面铺装，从新浇筑铺装层混凝土，按新规范申请进步混凝土标号，加强桥面钢筋网的配筋。并额定留心钢筋网必须架起来。新浇铺装层的厚度，按照需要选择是否加厚。
② 进一步增强负弯矩区的纵向钢筋配置。
中等跨径以下的桁架拱一般采用钢筋混凝土，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，常采取预制拼装施工。上弦杆及跨中实腹段除蒙受轴力外，还遭受较大弯矩，上弦杆为偏心受压构件，腹杆有斜杆与竖杆，一样平常采纳斜拉杆式腹杆，即斜杆为偏幸受拉，竖杆为偏幸受压构件。于是跨径大时，需在上弦杆、斜杆及实腹段中施加预应力。
思空见贯题目有：
（1） 上弦杆及实腹段跨中四面底面及正面横向开裂，或下挠过大，告白杆件的无效预加应力不足，或截面高度偏小，普通钢筋设置不足；
（2）斜杆开裂，说明拉力过大，预加应力不足。
（3）下弦杆及竖杆沿杆长偏袒涌现多条缝隙或局部压碎，首要是杆件截面尺码偏小。要是出现垂直于杆长倾向的马脚，注明杆件的长细比过大或桁架片变形较大惹起较大偏心弯矩而至；
（4）各杆件节点四周开裂，由于各杆件轴线通常不会相交于一点，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）横向朋分（如横隔板、横系梁、剪刀撑等）中部泛起竖向马脚或其它裂缝，主要是桁片横向团体性差，横向分割刚度不足、尺码偏小；
（6） 由于桁架拱采用预制拼装施工，探求较多，干计议可能因焊接风致或委靡题目松脱，湿寻觅也可能因根究强度不足引起开裂；
（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。
可选的加固方式有：
（1）对上弦杆、斜杆及实腹段bug，假设不太老火可采取粘贴钢板或纤维复合材料方式加固，否则可接纳体外预应力加固，或汇集增大截面，张拉体外预应力索后用钢筋混凝土包裹；
（2）对下弦杆及竖杆的裂缝，最佳接纳增大截面法加固，要是漏洞不太老火，可采取加钢板箍或包裹纤维复合质料加固；
（3）对节点漏洞，可采取粘贴块状钢板或纤维复合资料加固；
（4）对横向豆割马脚，最好采用加大横向支解截面尺码，或增设横向肢解，或施加横向预应力加固。要是开裂程度较轻，可采取局部粘贴钢板或纤维复合资料加固；
（5）对种种施工寻觅的裂痕，可接纳补焊、灌缝、植入锚筋、粘贴钢板等门径增强。
十一、圬工拱桥
（1）拱圈呈现大面积的很有问题风化剥落、灰缝脱空。起因是砌体与砂浆的原料差，或者遭到氧化性强的水与气体的浸蚀；
（2） 主拱圈拱顶下缘呈现1～2条横向意会的bug，如果马脚两侧有明显高差，阐明墩台有不平匀下沉，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动弹，或由于拱圈承载力已不足惹起，若拱顶上拱且下缘涌现横向压碎裂纹，则可能墩台向桥孔内滑动或迁移转变；
（3）拱圈的个别拱石出现裂缝，灰缝脱落，压碎或外凸；
（4）拱圈分层砌筑时，沿砌缝涌现环向裂缝，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有关；
（5）砌体表层沿砌缝无规则的开裂，主要是砂浆标号低或沙浆不困苦；
（7）拱上侧墙沿拱圈的拱背开裂或离开，首要是墩台下沉，温度变幻或车辆作历时主拱圈与拱上建筑变形不答腔，或砌缝未处置好惹起。
其它一些病害与钢筋混凝土上承式拱桥类似。
可选的加固方法有：
（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）对由于墩台不平均下沉惹起的拱顶横向马脚，假定下沉还未执著，应先加固墩台根抵，再对bug灌水泥浆后，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。假定沉降基本终止，就只有加固拱圈，开裂不老火时，也可只灌浆封锁。对由于墩台滑动或滚动惹起的拱顶bug，如果墩台位移还没有停止，应先加固墩台，再对裂缝注浆封锁后，可从拱腹或拱背浇筑钢筋混凝土，增大截面加固。对由于承载技能花样不足惹起的拱顶横向缝隙及下沉，除可采用拱背或拱腹增大截面外，还可同时采用减轻拱上修筑自重来减少恒载，如实腹拱改空腹拱，下列图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腹式拱上修筑。对小跨径拱桥还会在拱顶上浇筑一钢筋混凝土简支板或垫板，下列图2，将原桥改为拱梁组合体系，以减轻主拱圈活载，进步承载力。以上加固中若墩台肩负增加较多，应思索墩台及根蒂的承载力及坚强是否满足加固需要。
（3）拱圈个别拱石出现的病害，可凿除压碎一小部分，视马脚宽度大小，用环氧胶、高标号水泥砂浆或环氧沙浆，灌缝或填缝，再用水泥沙浆或小石子混凝土修补。拱石老火碎裂的，要全数凿除用混凝土填补；
（4）主拱圈沿砌缝环向开裂时，采取钢板或铸件做成的楔形剪力键或抓钉竖向嵌入拱圈双侧，开裂局限大且很有问题时在拱圈上径向钻孔穿入长锚栓，切当加压后锚固，其间距布置视环向开裂水平而定，原缝隙用水泥浆灌缝封锁，图3；
（5）砌体表层砌缝开裂，可采用水泥沙浆灌缝封锁或勾缝；
（6）拱上侧墙外倾，视外倾水准，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材料，对空腹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取加厚侧墙尺码，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，照实腹式改枵腹式等，如上图1；
（7）拱上侧墙沿拱背开裂或来到，如果是根底下沉引起并未终止的，应先加固根蒂根基，再用高标号水泥浆或砂浆灌缝封锁。并搜检两拱脚上方侧墙上至桥面的伸缩缝是否统统，不然可能惹起拱上建筑与主拱圈变形不与谐。其它病害的加固门径与钢筋混凝土上承式拱桥类似。
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