既有预应力检测及某预应力钢筋混凝土框架加固修复方案研究

Research on existing prestress detection and reinforcement and repair scheme of a prestressed reinforced concrete frame

既有结构中现存预应力的大小是预应力钢筋混凝土框架结构加固修复的关键指标。对钻孔法和超声波法检测混凝土现存应力的适用性和精度进行了探讨;针对某预应力框架密肋梁板结构的现场情况,采用特制工装拉离锚头的方法检测原有钢绞线的现存预应力,采用特制的开口钢垫板或钢垫圈对原有预应力大小不确定的钢绞线补张拉至确定的应力值,通过PKPM鉴定加固模块进行整体建模分析,对体外预应力加固方案中有效荷载对主梁的协调扭矩的影响进行了分析,提出了合理的加固修复方案。

The value of existing prestress in existing structures is a key index for strengthening and repairing of prestressed reinforced concrete frame structures. The applicability and accuracy of drilling method and ultrasonic method to detect existing stress of concrete were discussed. According to the site condition of a prestressed frame rib beam slab structure, existing prestress of the original steel strand, was detected by pulling the anchor head with special tools. The special opening steel plates or steel washers were used to re-tension the original steel strands with uncertain prestress to a certain stress value. The PKPM identification reinforcement module was used to carry out overall modeling analysis, the influence of the effective load on the coordinated torque of the main beam in the external prestressed reinforcement scheme was analyzed, and reasonable reinforcement and repair scheme was proposed.