Research on the Construction Method of External Prestressed Reinforcement Project of Building Connecting Corridor
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摘要: 传统的建筑连廊加固技术容易受到混凝土张拉控制力影响,造成钢管应力和位移与实际数据相差较大,导致加固效果不理想,严重影响施工质量和施工安全。鉴于此,提出了一种新的建筑连廊体外预应力加固工程施工方法。以四川观堂建筑工程设计有限公司的钢结构工程为研究对象,根据结构加固设计图纸对连廊(一)中GL6和连廊(二)中GL3、GL4a进行加固设计。在完成顶升卸载后进行相应小组的次梁体外预应力张拉施工,通过进行局部切割计算预应力筋张拉伸长值、截面面积、弯曲率半径、相对向上位移数值,由此确定合理的张拉力和预应力。采用ANSYS对体外预加力转向块进行接触分析,构建转向器有限元组合模型,施加体外预应力束的竖向和横向分力。将建筑连廊体外预应力加固工程施工分为钢结构加固、钢梁切割加固、牛腿加固三个施工部分,首先在连廊卸载支撑点增设压力传感器并进行同步分级反顶,使用反顶支撑钢板,采用预加力产生的内力来抵消局部受力,根据压力传感器的同步数值对反顶力进行控制,以此加固钢结构。采用等离子切割机切割钢梁部位,使用Q345B钢板作为新增翼缘,新增翼缘与原结构需进行打坡口满焊作业,并保证焊接作业的施工质量。用20~30 mm的不连续的焊缝进行点焊,对切割后钢梁余留截面进行焊接补强施工,以此完成钢梁切割加固。按照材料进场验收—牛腿钢板材料号料加工—钻孔锚固钢筋—原加固梁表面凿毛—清洗梁表面—安装加工好的钢牛腿—钢板与原牛腿灌胶粘贴—养护—验收等步骤,使用植筋加固材料完成牛腿部分的加固施工。为了验证研究的可靠性,进行了试验,设计了正常加载和极限加载两个工况场景,同时在加固过程中对连廊变形状态进行监测。由试验结果可知,采用提出的建筑连廊体外预应力加固工程方案,在X方向应力分析结果与实际应力分析结果存在最大为0.5 MPa的误差,位移分析结果与实际位移分析结果存在最大为2.0 mm的误差,表明采用所研究方法与实际数据相差较小,能够在分析体外预应力和张拉力的基础上设计有效的加固施工方案,为建筑连廊稳定施工提供技术支持。Abstract: The traditional strengthening technology of building connecting corridor is easy to be affected by the tensile control force of concrete, resulting in the phenomenon that the stress and displacement of steel pipe are quite different from the actual data, which leads to the unsatisfactory reinforcement effect and seriously affects the construction quality and construction safety. In view of this, a new construction analysis and research of external prestressed reinforcement engineering of building connecting corridor was proposed. Taking the steel structure project of Sichuan Guantang Architectural Engineering Design Co., Ltd. as the research object, the reinforcement construction scheme of GL6, GL3 and GL4a in connecting corridor (一) and connecting corridor (二) was designed according to the structural reinforcement design drawings. After the completion of lifting and unloading, the external prestressed tension construction of the secondary beam of the corresponding team was carried out. The tensile length value, section area, bending radius and relative upward displacement value of the prestressed tendons were calculated by local cutting, so as to determine the reasonable tensile tension and prestress. The contact analysis of the steering block with external prestress was carried out by finite element ANSYS, and the finite element combination model of the steering gear was constructed. The vertical and transverse components of the external prestress bundle were applied. The external prestressed reinforcement engineering of the building corridor was divided into three construction parts:steel structure reinforcement, steel beam cutting reinforcement and bull leg reinforcement. Firstly, the pressure sensor was added to the unloading support point of the corridor, and synchronous grading counterjacking was used to support the steel plate, and the internal force generated by the prestress was used to offset the local force. The counterjacking force was controlled according to the synchronous value of the pressure sensor, to strengthen the steel structure. Plasma cutting machine was used to cut the steel beam and Q345B steel plate was used as the new flange. The new flange and the original structure need to be fully welded to ensure the construction quality of welding. The remaining section of the steel beam after cutting was reinforced by spot welding with the discontinuous weld of 20-30 mm, so as to complete the cutting and strengthening of the steel beam. According to the steps of material approach acceptance- processing of steel plate material number-drilling and anchoring of steel bars-gouging of the surface of the original reinforced beam-cleaning of the surface of the beam-installation of the processed steel leg-gluing of steel plate and the original leg-maintenance-acceptance, the reinforcement construction of the leg part was completed with planting reinforcement materials. In order to verify the reliability setting experiment studied in this paper, two working conditions, normal loading and ultimate loading, were designed, and the deformation state of the corridor was monitored during the reinforcement process. It can be seen from the experimental results that, using the external prestressed reinforcement engineering scheme of the building connecting corridor proposed in this paper, there was a maximum error of 0. 5 MPa between the stress analysis results and the actual stress analysis results in the X direction, and a maximum error of 2. 0 mm between the displacement analysis results and the actual displacement analysis results. The experimental results showed that there was a small difference between the studied method and the actual data. It could design effective reinforcement construction scheme on the basis of analyzing external prestress and tension, and provide technical support for stable construction of building corridor.
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Key words:
- building corridor /
- external prestressing /
- reinforcement works /
- construction analysis /
- finite element
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