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Concrete structure reinforcement design

By Shirley Robinson,2014-04-26 04:08
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Concrete structure reinforcement design

    Concrete structure reinforcement design

    Sheyanbo? Wangchenjia?

    ? Foundation Engineering Co., Ltd. Heilongjiang Dongyu

    ? Heilongjiang Province, East Building Foundation Engineering Co., Ltd. Coal

    AbstractStructure in the long-term natural environment and under the use environment's function, its function is weaken inevitably gradually, our structural engineering's duty not just must finish the building earlier period the project work, but must be able the science appraisal structure damage objective law and the degree, and adopts the effective method guarantee structure the security use, that the structure reinforcement will become an important work. What may foresee will be the 21st century, the human building also by the concrete structure, the steel structure, the bricking-up structure and so on primarily, the present stage I will think us in the structure reinforcement this aspect research should also take this as the main breakthrough direction.

    bricking-up structure reinforcement Key word Concrete structure reinforcement

    steel structure reinforcement

    1 Concrete structure reinforcement

    Concrete structure's reinforcement divides into the direct reinforcement and reinforces two kinds indirectly, when the design may act according to the actual condition and the operation requirements choice being suitable method and the necessary technology.

    1.1 The direct reinforcement's general method

    1(Enlarges the section reinforcement law

    Adds the concretes cast-in-place level in the reinforced concrete member in bending compression zone, may increase the section effective height, the expansion cross sectional area, thus enhances the component right section anti-curved, the oblique section anti-cuts ability and the section rigidity, plays the reinforcement reinforcement the role.

    In the suitable muscle scope, the concretes change curved the component right section supporting capacity increase along with the area of reinforcement and the intensity enhance. In the original component right section ratio of reinforcement not too high situation, increases the main reinforcement area to be possible to propose the plateau component right section anti-curved supporting capacity effectively. Is pulled in the section the area to add the cast-in-place concrete jacket to increase the component section, through new Canada partial and original component joint work, but enhances the component supporting capacity effectively, improvement normal operational performance.

    Enlarges the section reinforcement law construction craft simply, compatible, and has the mature design and the construction experience; Is suitable in Liang, the

    board, the column, the wall and the general structure concretes reinforcement; But scene construction's wet operating time is long, to produces has certain influence with the life, and after reinforcing the building clearance has certain reduction.

    2) Replacement concretes reinforcement law

    This law's merit with enlarges the method of sections to be close, and after reinforcing, does not affect building's clearance, but similar existence construction wet operating time long shortcoming; Is suitable somewhat low or has concretes carrier's and so on serious defect Liang, column in the compression zone concretes intensity reinforcement.

    3) The caking outsourcing section reinforcement law

    Outside the Baotou Steel Factory reinforcement is wraps in the section or the steel plate is reinforced component's outside, outside the Baotou Steel Factory reinforces reinforced concrete Liang to use the wet outsourcing law generally, namely uses the epoxy resinification to be in the milk and so on methods with to reinforce the section the construction commission to cake a whole, after the reinforcement component, because is pulled with the compressed steel cross sectional area large scale enhancement, therefore right section supporting capacity and section rigidity large scale enhancement.

    This law also said that the wet outside Baotou Steel Factory reinforcement law, the stress is reliable, the construction is simple, the scene work load is small, but is big with the steel quantity, and uses in above not suitably 600C in the non-protection's situation the high temperature place; Is suitable does not allow in the use obviously to increase the original component section size, but requests to sharpen its bearing capacity large scale the concrete structure reinforcement.

    4) Sticks the steel reinforcement law

    Outside the reinforced concrete member in bending sticks the steel reinforcement is (right section is pulled in the component supporting capacity insufficient sector area, right section compression zone or oblique section) the superficial glue steel plate, like this may enhance is reinforced component's supporting capacity, and constructs conveniently.

    This law construction is fast, the scene not wet work or only has the plastering and so on few wet works, to produces is small with the life influence, and after reinforcing, is not remarkable to the original structure outward appearance and the original clearance affects, but the reinforcement effect is decided to a great extent by the gummy craft and the operational level; Is suitable in the withstanding static function, and is in the normal humidity environment to bend or the tension member reinforcement.

    5) Glue fibre reinforcement plastic reinforcement law

    Outside pastes the textile fiber reinforcement is pastes with the cementing

    material the fibre reinforcement compound materials in is reinforced the component to pull the region, causes it with to reinforce the section joint work, achieves sharpens the component bearing capacity the goal. Besides has glues the steel plate similar merit, but also has anticorrosive muddy, bears moistly, does not increase the self-weight of structure nearly, durably, the maintenance cost low status merit, but needs special fire protection processing, is suitable in each kind of stress nature

     concrete structure component and the general construction.

    This law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.

    6) Reeling law

    This law's good and bad points with enlarge the method of sections to be close; Is suitable reinforcement which is insufficient in the concrete structure component oblique section supporting capacity, or must exert the crosswise binding force to the compressional member the situation.

    7) Fang bolt anchor law

    This law is suitable in the concretes intensity rank is the C20~C60 concretes load-bearing member transformation, the reinforcement; It is not suitable for already the above structure which and the light quality structure makes decent seriously.

    1.2 The indirect reinforcement's general method

    1) Pre-stressed reinforcement law

    (1)Thepre-stressed horizontal tension bar reinforces concretes member in bending,because the pre-stressed and increases the exterior load the combined action, in the tension bar has the axial tension, this strength eccentric transmits on the component through the pole end anchor (, when tension bar and Liang board bottom surface close fitting, tension bar can look for tune together with component, this fashion has partial pressures to transmit directly for component bottom surface), has the eccentric compression function in the component, this function has overcome the bending moment which outside the part the load produces, reduced outside the load effect, thus sharpened component's anti-curved ability. At the same time, because the tension bar passes to component's pressure function, the component crack development can alleviate, the control, the oblique section anti-to cut the supporting capacity also along with it enhancement.

    As a result of the horizontal lifting stem's function, the original component's section stress characteristic by received bends turned the eccentric compression, therefore, after the reinforcement, component's supporting capacity was mainly decided in bends under the condition the original component's supporting capacity

    (2) After the reinforced concrete component uses under the pre-stressed to

    support the type tension bar reinforcement decides, forms one by to reinforce the component and under supports the compound ultra statically determinate structure system which the type tension bar is composed, under the outside load and the pre-stressed combined action, in the tension bar has the axial force and through (next supports and pole end anchor spot) with component's combining site transmits for is reinforced the component, has counter-balanced outside the part the load, changed the original component section endogenic force characteristic, thus sharpened

     component's bearing capacity.

    This law can reduce is reinforced component's stress level, not only causes the reinforcement effect to be good, moreover can also the great scope enhance the structure overall supporting capacity, but after reinforcing, has certain influence to the original structure outward appearance; Is suitable as well as is under the high stress, the high strained condition concretes component's reinforcement in the great span or the heavy structure reinforcement, but in the non-protection's situation, cannot use in the temperature above 600C in the environment, is also not suitable uses in the concrete shrinkage continuous variation big structure.

     2)Increases the supporting reinforcement law

    The addition pivot reinforcement law is through the reduced member in bending effective span, achieves the reduced function, in is reinforced on the component to carry the effect, raises the structure load bearing level the goal. This law simple reliable, but easy to harm building's original condition and the use function, possibly and reduces uses the space; Is suitable in the concrete term permission concrete structure reinforcement.

    1.3 The concrete structure reinforcement transformation necessary use's technology

    1) The request trades the technology

    It is the joist (either truss) opens the column (or wall), the joist terminal and the joist trades technologies and so on column to call generally; Belongs to one kind of comprehensive technology, by the related structure reinforcement, the superstructure goes against rises with to reposition as well as abandons technologies and so on component demolition to be composed; Is suitable in had building's reinforcement transformation; Compares with the traditional practices, has the construction time to be short, the expense low, affects and so on merits slightly to the life and the production, but is high to the specification, must complete by the skilled worker, can ensure the security.

    2(Plants the muscle technology

    It is one item is simple and direct to the concrete structure, the effective connection and the anchor technology; May implant the ordinary steel bar, may also implant the bolt type anchor muscle; Has widely applied in had building's

    reinforcement improvement project, for example: In the construction leaks buries the steel bar or the steel bar deviation designs the position the recovery, the component increases the section reinforcement to make up the muscle, the superstructure expands cross, goes against rises to Liang, column's lengthening by joining, the house superimposed layer terminal and the high-rise construction addition shearing force

     wall plants the muscle and so on.

    3(Crack patching technology

    According to the concretes crack's cause, the character and the size, use seal differently protect the method to carry on patching, one kind of skill which causes the structure because to crack reduces the use function which and the durability can restore; Is suitable in had in the building each kind of crack processing, but to the stress crack, besides patching, still should use the corresponding reinforcement measure. The internal patching law is with the forcing pump the cementing material pressure concretes crack, renders the young or up and coming generation to sew up the function, and makes the original structure through its cementation to restore the integrity, this method is suitable for the crack opening is big, and durable and so on is influential to the structure integrity and the security, or has request and so on waterproof anti-seepage crack patching.

    4(Carbonized concretes repair technology

    It is refers to through restores the concretes the alkalinity (inactivation) or increases its impedance to enable the steel bar corrosion which the carbonization creates to obtain the containment technology.

    5(Concretes surface treatment technology

    It is refers to uses cleaning up concretes surface stains, the oil mark, the residual as well as the other attachment and so on chemistry method, mechanical method, sand blasting method, vacuum cleaning method, injection method skill.

    6(Coagulation mantle of soil seal technology

    It is refers to uses flexible methods and so on aquaseal backfill, polymer grouting, paint film to carry on the waterproofing to the concretes, moisture-proof and against crack processing technology. Like the structure, the component shift the technology, the adjustment structure base frequency technology and so on.

    7(Other technologies

    Like the structure, the component shift the technology, the adjustment structure base frequency technology and so on.

    2 Bricking-up structure

    Bricking-up structure reinforcement method: The bricking-up structure's reinforcement divides into when the direct reinforcement and reinforces two kinds indirectly, the design, may act according to the actual condition and the operation

requirements choice being suitable method.

    2.1 suitable for the bricking-up structure direct reinforcement method

     1) Outside reinforced concrete superimposed layer reinforcement law

    This law belongs to the compound section reinforcement method one kind. Its merit is the construction craft simple, compatible, after the bricking-up reinforcement, the supporting capacity has enhances greatly, and has the mature design and the construction experience; Is suitable in the column, the belt wall wall reinforcement; Its shortcoming is the scene construction wet operating time is long, to produces has certain influence with the life, and after reinforcing the building clearance has certain reduction.

    2) Outside reinforced concrete mortar superimposed layer reinforcement

    law

    This law belongs to the compound section reinforcement method one kind. Its merit and outside the reinforced concrete the superimposed layer reinforcement law is close, but enhances the supporting capacity to be inferior to the former; Is suitable in the bricking-up wall reinforcement, sometimes also uses in outside the reinforced concrete when the superimposed layer reinforcement belt engaged column wall the both sides put on the wall stirrup the seal.

    3) The addition holds the engaged column reinforcement law

    This law belongs enlarges the section reinforcement method one kind. Its merit the superimposed layer reinforcement law is also close with the reinforced concrete outside, but the supporting capacity enhances limitedly, and difficult to satisfy the earthquake resistance request, generally only in peneseismic country application.

    2.2 Suitable for the bricking-up structure indirect reinforcement method

1(Non-caking outsourcing section reinforcement law

    This law belongs to the traditional reinforcement method, its merit is the construction is simple, the scene work load and the wet work are few, the stress is more reliable; Is suitable in does not allow to increase the original component section size, actually requests to enhance the section supporting capacity large scale the bricking-up column's reinforcement; Its shortcoming is high for the reinforcement expense, and must use the similar steel structure the protective measure.

    2) Pre-stressed stay rod reinforcement law

    This law can the great scope sharpen the bricking-up column's bearing capacity, and the reinforcement effect is reliable; Is suitable processes the high stress, the high strained condition bricking-up structure reinforcement in the reinforcement; Its

shortcoming cannot use in the temperature in the 600C above environment.

    2.3 Bricking-up structure constructivity reinforcement and patching

     1) Addition grid reinforcement

    When the grid establishment does not meet the present design code requirement, either the vertical cross wall interface point nips rubs has the obvious flaw, when either the house integrity is bad, should additionally build the grid to carry on the reinforcement

    2)Additionally builds the Liang pad reinforcement

    When under the summer beam the brick setting the wall presents by under the partial squash or the summer beam the partial vertical split, should additionally build Liang the pad to carry on the reinforcement.

    3)The bricking-up opens partially builds

    When house partial breakage but after investigating thoroughly its breakage reason when not yet affects load-bearing and the security, may burst the wall partial demolition, and according to enhances the mortar strength first-level to fill in with the full sized brick builds.

    4)Bricking-up crack patching

    Before carrying on crack patching, should act according to bricking-up component's stressful condition and crack factors and so on characteristic, determined that creates the bricking-up crack the reason, with the aim of carrying on crack patching target-oriented or using the corresponding reinforcement measure.

    3 Steel structures

    Steel structure reinforcement method: The steel structure reinforcement's main method includes: Reduces the load, the change structure computation graph, to enlarge the original structural unit section and the joint strength, the impediment fracture growth and so on. When has the mature experience, may also use other reinforcement method.

    1) Changes the structure computation graph

    The change structure computation graph's reinforcement method is refers to uses the change load spread condition, the power transmission way, the node nature and the boundary condition, the addition attachment member and the support, exerts the pre-stressed that measures and so on consideration space joint operation to carry on the reinforcement to the structure the method

    2)Enlarges the component section the reinforcement

    Uses enlarges when the section reinforces the steel lumber, chooses the section form to be advantageous in the reinforcement specification and considered already

has the flaw and the damage condition.

    3)Connection reinforcement and reinforcing member connection

    The steel structure connection method, namely the welded joint, the rivet, the ordinary bolt and the high strength bold fastening method's choice, should the reason which, the goal, the stress condition, the structure and the execution conditions needs to reinforce according to the structure, and considers the structure original connection method determination.

    The steel structure reinforcement general uses the welded joint connection, the friction high strength bold fastening suitably, has when the basis may also use the welded joint and the friction high strength bolt's mixed connection. When uses the welded joint connects, should use after the evaluation approval welding process and the connection material.

    4) Crack repair and reinforcement

    Because the structure the load affects and the choice of material, the structure, the manufacture, the work repeatedly improper and so on produces has the extension or breaks time crisply the tendentious crack damage, should try to repair. Before the repair, must analyze has the crack reason and the influence gravity, adopts the improvement structure practical work target-oriented or carries on the reinforcement the measure, to is not suitable uses the repair reinforcement the component, should give the demolition replacement

    Reference

    [1] "Built-in reliability Appraisal And Reinforcement Technology" Caoshuangyin Qiuhongxing arranges

    [2] "Concrete structure Durability" Jin weiliang arranges

    [3] "Aged Concretes Cross section Characteristic And Damage Descriptive study" Zhaozhenyang

[4] "Reinforced concrete Principle And Analysis" Guozhenhai Shixudong writes

译文,

    混凝土结构配筋设计

    sheyanbo?wangchenjia?

    ?基础工程有限公司;黑龙江东宇

    ?黑龙江省;东建筑基础工程有限公司;煤

    摘要,在长期自然环境和使用环境下的功能;其功能是不可避免地逐渐减弱;我们结构工程的职责不仅仅是要完成建设项目前期工作;但必须能够科学评价结构损伤的客观规律和程度;并采取有效的方法保证结构的安全性使用结构加固;这将成为一个重要的工作。可以预见的是第二十一世纪;人类建筑的混凝土结构;钢结构;砌体结构等为主;现阶段我认为我们在结构加固这方面的研究也应该以此为主要突破方向。

     关键词,混凝土结构加固砌体结构加固钢结构加固

    1混凝土结构的加固

    混凝土结构的加固分为直接和间接两种加固加固;设计时可根据实际条件和使用要求选择适宜的方法和必要的技术。

    1.1直接加固的一般方法

    1(加大截面加固法

    加混凝土现浇在钢筋混凝土受弯构件受压区;可增加截面有效高度;扩大横截面积;从而提高构件正截面抗弯;斜截面anti-cuts能力和截面刚度;起加固作用。

    在适当的肌肉范围变化曲线;混凝土构件正截面承载力增加随着钢筋面积和强度的提高。在原构件正截面配筋率不太高的情况下;增加了主筋面积可以提出高原构件正截面抗弯承载力有效。拉是在部分地区增加现浇混凝土夹克加大构件截面;通过新加拿大部分原来的组成部分共同工作;但增强构件承载力的有效改善性能;正常运行。

    加大截面加固法的施工工艺简单;兼容;并有成熟的设计和施工经验:适用于梁;板;柱;墙和普通结构混凝土加固:但现场施工的湿作业时间长;对生产有一定影响的生活;和加固后的建筑间隙有一定的减少。

    2(置换混凝土加固法

    本法的优点放大方法部分被关闭;并加固后;不影响建筑物的间隙;但同样存在建设工作时间长的缺点是湿的:适宜偏低或混凝土承运人等严重缺损;列在受压区混凝土强度加固。

    3(粘结外包截面加固法

    在包头钢铁厂加固是包在该部分或钢板加固构件的外;在包头钢铁厂加强钢筋混凝土梁使用湿式外包法律一般;即采用环氧树脂是在牛奶等方法;加强节蛋糕整体建设委员会后;钢筋组成部分;因为拉与压缩钢截面面积大幅度提高;因此右段承载力和截面刚度大幅度提高。

    该法还说;湿的包头钢铁厂加固法;应力可靠;结构简单;现场工作量小;但大的用钢量;并利用上述不适当的作用在非保护的情况下高温的地方:是不允许在使用明显增加原构件截面尺寸;但要求提高其承载能力的大型混凝土结构加固。

4(粘钢加固法

    在钢筋混凝土受弯构件粘钢加固,右部分拉构件承载力不足的扇形区域;正截面受压区或斜截面(表面粘贴钢板;这样可以提高构件的承载能力增强;且施工方便。

    该法施工快速;现场不湿工作;或仅有抹灰等潮湿的作品;是小生产和生活的影响;以及加固后;不显著的外观和原来的影响;但加固效果很大程度上取决于粘性工艺和操作水平:适用于承受静态函数;并在正常环境湿度弯曲或紧张成员加固。

    5(胶纤维增强塑料加固法

    外贴纤维加固贴用的胶凝材料的纤维增强复合材料在加固构件拉地区;使之与加强部分共同工作;达到提高构件承载力的目标。除了具有粘贴钢板类似的优点;但也有防腐泥泞;耐潮湿;不增加结构自重近;耐用;维修费用低等优点;但是需要特殊的防火处理;适用于各种混凝土结构构件应力的性质和一般建筑。 本法的优缺点与扩大的方法;部分被关闭:适用于加固是不够的混凝土结构构件斜截面承载力;或施加一定的横向约束力的挤压成员情况。

    6(缫丝法

    本法的优缺点与扩大的方法;部分被关闭:适用于加固是不够的混凝土结构构件斜截面承载力;或施加一定的横向约束力的挤压成员情况。

    7(锚栓锚固法

    本法适用于混凝土强度等级是C型混凝土承重成员~改造;加固:它不适合已上述结构和轻质结构进行比较严重。

    1.2间接加固的一般方法

    1(预应力加固法

    1(thepre-stressed横拉杆加固混凝土受弯构件;由于预应力和增加外部负载的联合行动;在拉伸杆的轴向拉力;这种力量传输组件通过偏心杆端锚,;当张力杆和梁板底面紧密贴合;张力杆可以找曲调一起组成部分;这种方式已部分压力直接发送部分底部表面(;有偏心压缩功能的组件;该函数克服了弯矩外部分负荷生产;减少外荷载效应;从而提高了构件的抗弯能力。同时;由于张力杆组件压力的功能;构件裂缝发展可以缓解;控制;斜截面抗剪承载力也随之提高。

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