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基于振动法和频率法测量斜拉桥锚索预应力的理论方法,将其用于预应力梁板和边坡锚索的钢绞线有效预应力测量。本文通过实验方法应用静载锚固试验机对钢绞线分级加载拉力荷载,根据对声波反射信号的研究,以反射波谱能比强度曲线获得预应力钢绞线的声波波速,以反射波频谱图获得预应力锚索自由端的振动基频,进而计算出钢绞线在不同荷载稳定状态下波速和基频对应的张力,其计算值与实际加载值相近,具有较好的拟合度和线性相关性。在波速和基频确定的情况下,基于频率法和弦振波动法推算钢绞线有效张力的方法可行有效,可分别用于已知钢绞线长度的预应力梁板检测以及无法直接获取锚索长度的埋入式边坡预应力锚索检测。
Based on the vibration method and frequency method to measure the prestressing force of cable-stayed bridge, this method is applied to the effective prestressing measurement of prestressed steel bar of prestressed beam and slope cable. In this paper, static load anchoring testing machine was used to classify the tensile load of strands according to the experimental method. Based on the study of acoustic reflection signals, the acoustic wave velocity of prestressed steel strand was obtained by the reflected spectrum energy-intensity curve, The fundamental frequency of the strand at the free end of the prestressed anchor cable is calculated, and then the tension corresponding to the wave speed and the fundamental frequency of the strand under different load steady states is calculated. The calculated value is similar to the actual loaded value, and has good fitting degree and linear correlation . In the case of determining the wave speed and the fundamental frequency, the method of estimating the effective tension of the strand based on the frequency method and the chord vibration method is feasible and effective, which can be used for the prestressed beam plate detection of the known strand length and the inability to directly obtain the anchor cable Length of Embedded Slope Prestressed Anchor Cable Inspection.