预应力侧向叠合加固混凝土梁技术及其工程应用

Prestress strengthening technology of lateral superimposed reinforced concrete beams and its engineering application

为了解决大跨梁改造加固工程中的梁高受限问题,开展预应力侧向叠合加固混凝土梁技术及其工程应用研究。依托杭州某混凝土框架结构建筑工程案例,提出了预应力侧向叠合加固混凝土梁的方法。通过数值模拟、现场监测,分析了预应力侧向叠合加固后的受力特征和变形规律。研究结果表明:采用预应力侧向叠合加固混凝土梁技术加固的大跨度混凝土梁,叠合面两侧的变形协调一致;加固完成变形稳定后,竖向位移小,加固效果良好;加固后应力水平显著下降,混凝土受拉区域减少,有效改善了大跨梁应力分布;加固后竖向位移减小,且沿梁跨方向变化更加平缓,有效控制了大跨度梁的竖向位移;加固后裂缝分布区域和最大裂纹宽度减小,有效提高了梁的抗裂能力。基于工程案例结合数值与现场试验研究结果可见,当既有建筑对梁的竖向位移和裂缝控制、抗震性能、耐久性及延性要求较高时,预应力侧向叠合加固混凝土梁技术具有较好的优势及应用潜力。

In order to solve the problem of beam height limitation in the reconstruction and reinforcement project of long-span beams,the technology of prestressed lateral superimposed reinforced concrete beams and its engineering application were carried out.Relying on a concrete frame structure construction project case in Hangzhou,a method of prestressed lateral superposition reinforcement of concrete beams was proposed.Through numerical simulation and on-site monitoring,the force characteristics and deformation law after prestressed lateral superposition reinforcement were analyzed.The research results show that when the long-span concrete beams are reinforced by prestressed lateral superimposed concrete beam technology,and the deformation on both sides of the superimposed surface is coordinated.The deformation is stable,the vertical displacement is small,and the reinforcement effect is good.The stress level decreases significantly,and the tensile area of concrete is reduced,which effectively improves the stress distribution of long-span beams.The vertical displacement decreases,and the change along the beam span direction is more gentle,which effectively controls the vertical displacement of the long-span beam.The crack distribution area and maximum crack width are reduced,which effectively improves the crack resistance of the long-span beam.Based on the results of engineering cases combined with numerical and field test results,it can be seen that when the requirements for vertical displacement and crack control,seismic performance,durability and ductility of existing buildings on beams are high,the prestressed lateral superimposed reinforcement concrete beam technology has good advantages and application potential.