碳纤维加固混凝土结构的应用技术探讨

粘贴碳纤维结构加固技术是指采用高性能粘结剂将碳纤维布粘贴在建筑结构构件表面，使两者共同工作，提高结构构件的（抗弯、抗剪）承栽能力，由此而达到对建筑物进行加固、补强的目的，某市会展中心改造工程2．3万平米改造工程采用该方法进行改造加固。     

某房屋工程加固改造施工研究

随着经济建设和建筑业的飞速发展，现有建筑有相当一部分由于设计荷载标准低，房屋面积较小，难以满足使用上的要求而需要进行加固和增层改造。本文通过某工程的加固设计与施工．探讨由于使用功能改变导致结构体系改变的问题及其解决办法。该工程采用的加固方法和思路．对同类工程具有一定的参考价值。     

高性能复合砂浆钢筋网加固RC框架梁方案及施工技术

高性能复合砂浆钢筋网加固混凝土结构是一种新型加固工艺。本文介绍了使用这种加固方法加固某RC框架梁的施工方案及施工技术．该工程检验加固效果良好，可广泛推广应用到加固领域。     

浅谈预应力锚固工程施工质量控制

现代工程中．预应力技术不仅在杆件体系的钢筋混凝土结构中被采用．在大体积混凝土结构以及岩体加固工程中也得到了推广应用。如大尺寸弧形闸门的闸墩就采用预应力锚索加固．解决了闸墩锚块中的应力集中问题。预应力岩锚的应用也日渐普及．广泛应用于地下洞室的围岩加固、高边坡的治理，大坝基层深层抗滑等工程中。预应力工程项目施工质量的控制．是保证整个工程质量的关键。     

混凝土结构加固实例综述

混凝土结构加固实例综述张孝培，何林（四川省建筑科学研究院，成都，６１００８１）１某制盐化工厂蒸发厂房砼结构的加固处理１．１工程概况本工程系三跨四层现浇框架结构的生产性工业厂房，砼强度等级设计采用Ｃ２８。该工程上部结构于１９８８年６月开始施工，在施工二...     

钢筋混凝土结构加固法的讨论

针对工程实际，提出了钢筋混凝土结构加固的方法，并对不同方法的加固原理、技术特点、适用范围等进行了阐述，以利于工程实践中结构加固方法的选择，从而延长混凝土结构的使用寿命。     

某高层建筑鉴定及加固改造

分析钢筋混凝土高层建筑在局部改动后结构抗震性能的变化，为加固方案的确定提供提供依据，并针对工程中受力复杂的部位，根据分析精度的要求，采用大型商用有限元程序进行分析，依据内力分析的结果采取相应的加固措施．使加固方案更具经济性。     

浅谈建筑物加固常用方法

在现代建筑结构设计和施工中．建筑结构的安全、可靠是建筑工程的头等人事。文章中分析和介绍了目前建筑结构常用的加固方法，重点介绍了各种加固方法的主要特点、用途和适用范围。同时结合实际工程体会。指出了在建筑结构检测与加固工作中一些需要注意的问题。     

加固技术在凯旋门工程中的应用

根据具体工程概况，介绍了其加固设计思路，分别论述了结构粘钢加固、加大截面法、碳纤维布加固等方法在工程中的应用方法，通过多种加固方案的实施，该工程取得了良好的效益。     

工程加固处理中的耐久性问题

在工程加固处理中，只关心结构的强度和刚度是不够的，必须注意选择合适的材料、结构类型及施工方法，使加固的工程恢复或提高其耐久性，以免结构过早破坏。     

Numerical evaluation of secondary reinforcement effect on geosynthetic-reinforced retaining walls

A finite difference method was employed to evaluate the effect of secondary reinforcement on the performance of Geosynthetic-Reinforced Retaining (GRR) walls. The two-dimensional numerical models used a Cap-Yield soil constitutive model to represent the behavior of backfill. The numerical model was first calibrated and verified by the measured results from a full-scale field test. A parametric study was then performed to investigate the effects of secondary reinforcement length, secondary reinforcement stiffness, secondary reinforcement connection, and secondary reinforcement layout. The numerical results show that an increase in secondary reinforcement length and stiffness can reduce the deflection of the GRR wall and the maximum tensile stress of primary reinforcement. The mechanical connection of secondary reinforcement can also reduce the wall facing deflection and result in relatively small maximum tensile stress and connection stress in the primary reinforcement as compared with no connection to the secondary reinforcement. In addition, a wall with fewer but longer secondary reinforcement layers at certain elevations had relatively smaller wall facing deflections than the baseline case. This comparison demonstrates that more optimal layout of secondary reinforcement exists that could further reduce the maximum wall facing deflections and create a better performing wall while the same or less amount of geosynthetic reinforcement material is used.     

加筋土挡墙拉筋轴向应力分布规律研究

基于剪力滞模型基本原理对加筋土挡墙筋土作用机理进行了研究。根据拉筋轴向应力是由拉筋周围土体发生剪切位移而产生,紧邻拉筋周围土体仅受剪应力作用的假定,将加筋体单元中土体分为内、外两层,建立了拉筋轴向受力平衡方程,推导出了加筋土挡墙拉筋轴向应力特解。理论分析表明,加筋土挡墙中拉筋轴向应力沿拉筋长度L呈非线性分布,且在x≤L/2时出现一个峰值;当水平拉筋沿筋长方向出现凹陷或凸起时,在该位置将产生拉力峰值。该研究成果合理解释了加筋土挡墙中拉筋轴向应力出现多个峰值以及越靠近墙底部潜在破裂面位置越接近墙面板的原因。     

加固用钢量对框架结构抗震性能的影响

基于原有研究开发并经试验验证的纤维模型程序,对某抗弯承载力不足的钢筋混凝土框架结构基于粘钢加固方法分别采用五种不同加固用钢量下的抗震性能进行了分析,初步探讨了加固用钢量对加固后框架结构整体性能的影响,以期为加固改造领域中粘钢加固设计奠定基础。     

钢筋算量问题分析及解决思路

基于钢筋工程量计算的重要性,从钢筋长度、搭接、钢筋锚固取值及计算精度等方面分析了钢筋工程量计算中存在的问题,并提出了解决问题的思路,即钢筋人才专业化和钢筋计算电算化,以处理好钢筋的算量问题.     

软土深基坑被动区超前加固变形控制效果研究

依托某实际工程,利用FLAC 3D软件建立了3种不同地层参数的基坑有限差分数值模型,验证了土体本构模型的硬化模型比摩尔-库仑模型更适用于基坑工程中,对比分析了裙边加固和满堂加固的加固效果,同时借鉴基坑底部被动区加固思路,提出了在软土深基坑中对开挖段进行超前加固,以控制基坑开挖过程中支护结构位移的方法。结果表明:裙边加固的合理加固宽度为0.5h(h为基坑开挖深度),合理加固深度则与坑底的地层条件密切相关; 满堂加固的合理加固深度可取0.3h,在某些基坑位移控制特别严格的情况下,满堂加固深度超过0.5h后,可考虑优先加固最后一道撑到坑底的土体; 开挖段的满堂超前加固可以使首道撑位置下移,为减少支撑道数提供了可行方案; 研究为同类工程设计提供了参考依据,进一步丰富了软土地区的深基坑变形控制措施。     

基于点云的钢筋数量和间距自动检查算法

为改进钢筋骨架质量自动检查方法,提出了基于点云的钢筋骨架中钢筋数量和钢筋间距的自动检查算法。该算法在获取钢筋骨架实际点云和设计点云的基础上,首先对这两片点云分别进行降采样,以得到空间密集程度相同的钢筋骨架实际点云和设计点云; 其次,对降采样后的钢筋骨架实际点云和设计点云使用基于主成分分析(PCA)的方法进行粗配准。由于粗配准后的钢筋骨架实际点云和设计点云的配准精度较低,无法直接用于钢筋数量和钢筋间距的检查,对粗配准后的钢筋骨架实际点云和设计点云进行精配准。最后,基于精配准得到的钢筋骨架实际点云和设计点云,依次对钢筋骨架中的钢筋数量和钢筋间距进行检查。结果表明:精配准后的钢筋骨架实际点云和设计点云的配准精度较高,可以用于钢筋数量和钢筋间距的检查; 该算法对钢筋数量检查的准确率为100%,对钢筋间距检查的准确率为80%; 应用该算法可以有效提高复杂钢筋骨架中钢筋数量和钢筋间距检查的效率,降低人工成本。     

Long-term behavior of GRS retaining walls with marginal backfill soils

The creep of geosynthetics leads to the increase of Geosynthetic-Reinforced Soil (GRS) wall's deformation. More importantly, the influences of creep of geosynthetics are also affected by the creep properties of soils. In this paper, a Finite Element procedure was validated against a model test on the creep response of a clay–geotextile composite. An extensive parametric study was then carried out to investigate the long-term response of 8-meter-high model GRS walls with marginal backfill soils. The influences of backfill creep, reinforcement creep, reinforcement stiffness, reinforcement length and reinforcement spacing were analyzed. A long-term analysis was conducted for 5 years and the results at the end of construction (EOC) and 5 years afterwards were compared. It is found from the analysis that the relative creep rate between geosynthetic reinforcement and backfill soil influenced not only wall deformation but also reinforcement loads and stress states in the soils. The load distribution in backfill soil and reinforcement is the result of battling between their time-dependent properties. Large reinforcement creep can lead to large post-construction deformation and increase in soil stress; on the other hand, large soil creep can induce a significant increase in reinforcement load. It is hence necessary to take into account the relative creep rate of reinforcement and backfill soil in the design of GRS walls. It may not be adequate to consider only the long-term strength of reinforcement, which is the state-of-the-practice at present.     

碳纤维布的结构加固应用

简要介绍了碳纤维的材料性能,加固原理及优点,分别阐述了碳纤维在混凝土梁加固、框架柱加固、大型预制空心楼板加固等工程中的应用情况,并对碳纤维加固工艺及应注意事项作了具体说明,以促进该加固技术的推广应用。     

A new generation of soil-geosynthetic interaction experimentation

A new device was developed to comprehensively assess the interaction between soil and reinforcement as well as the interaction between neighboring reinforcement layers in a reinforced soil mass, under both working and ultimate interface shear stress conditions. An understanding of these two interactions is required to assess the mechanical behavior of a geosynthetic-reinforced soil mass considering varying vertical reinforcement spacings. Specifically, the new device allows direct visualization of the kinematic response of soil particles adjacent to the geosynthetic reinforcement layers, which facilitates evaluation of the soil displacement field via digital image analysis. Evaluation of the soil displacement field allows quantification of the extent of the shear influence zone around a tensioned reinforcement layer. Ultimately, the device facilitates investigating the load transfer mechanisms that occur not only at the soil-reinforcement interface, but also at distances farther from the interface, thereby providing additional insight into the effect of vertical reinforcement spacing on a reinforced soil mass. Finally, the device allows monitoring of dilatancy within the reinforced soil mass upon shear stress generation at the interface between soil and reinforcement. Overall, the device was found to provide the measurements needed to adequately predict the strains developing both in reinforcement layers tensioned by direct application of external loads as well as in reinforcement layers tensioned by the shear transfer induced by adjacent geosynthetic reinforcements. Ultimately, the proposed experimentation technique allows generation of data required to evaluate the load transfer mechanisms amongst soil and reinforcement layers in reinforced soil structures. The strain magnitude in the neighboring reinforcements was found to exceed a magnitude of 10% of the strain magnitude obtained in the active reinforcement. The zone of shear stress transfer from the soil-reinforcement interface was found to exceed 0.2 m on each side of the active reinforcement.     

Torsional response of fibrous reinforced concrete members: Effect of single type of reinforcement

Studies on the torsional behaviour of reinforced concrete members in general and fiber reinforced members in particular are of interest to several researchers as torsional rigidity, torsional stiffness and torsional toughness of the members play a vital role in the analysis of structures subjected to Seismic loads and Wind loads. In the present paper an investigation of the behaviour of steel fiber reinforced concrete members having single type of reinforcement, viz., longitudinal reinforcement or transverse reinforcement, has been presented. Torsion tests on 10 reinforced SFRC members revealed that single type of reinforcement, either longitudinal or hoop reinforcement, can not improve the torsional strength of the member beyond the torsional strength of the plain member without any reinforcement. However, single type reinforcement improved the ductility of the member. Steel fibers improved the cracking torque of the members noticeably.