Study On Stability And Status Monitoring Technology Of Cuplok Scaffold System In Bridge Construction

Cuplok scaffold systems are widely used in construction for their convenient installation and demolition, large carrying capacity and so on, especially being the most important template support system of bridge construction cast in place. The theory and method of its calculation, the reliability of its erection, and the defects of its components are the key factors to influence the overall stability of the scaffold system. However, as temporary structures in construction, the safety of cuplok scaffolds is rarely considered.In this paper, based on the mechanical properties analysis of cuplok joints, the relationships between tightening degree and rotation stiffness of cuplok joints are obtained. On the basis of the above research results, the load carrying capacity and the instability state for the different loading modes of cuplok scaffolds are analyzed. This paper studies the feasibility of monitoring the tightness degree of cuplok joints using piezoelectric transducer by the experiment, and discuses a method for monitoring the stability of cuplok scaffold systems based on the dynamic characteristics. This paper gets some load-frequency curves of the whole process of the structural instability and the curves can be used to monitor the stability of cuplok scaffold systems.1. Based on contact nonlinearity, geometric nonlinearity and material nonlinearity, a finite element model of the whole structure of the cuplok joint is established. The stress situation of the cuplok joint in the elastic and elastic plastic stage is analyzed. This paper studies the effect of different structural model and the tightening torque on the stiffness of vertical and horizontal rotation, and gets the relationship curve of the cuplok joint between moment and rotation.2. This paper studies the influence of the support beams on the U-jack and initial imperfections on the capacity of the scaffold system based on the results of the semi-rigid rotational stiffness of this paper, and propose the rules of the stability capacity of the scaffold system considered as the variation of joint’s modes and loading modes, such as steps, step distance, uneven load, settlement, and gives some suggestions on the simulation calculation and construction of cuplok scaffolds.3. The local and overall nonlinear interactive buckling of the cuplok scaffold systems is studied, and gets the effect of local buckling on the overall stability capacity for different joint connections, and analyzes the instability order of the others after one of standing tubes is instable. In the case of partial cuplok joints untighted in the cuplok scaffold system, this paper studies on the variation of the overall stability capacity, considering different spatial distribution of the cuplok joints untighted.4. A method of monitoring the tightness degree of cuplok joints using piezoelectric transducer by the experiment is proposed, and wavelet packet and time reversal are used to deal with the monitoring signals, and compares advantages of the two methods, and verifies the feasibility of the methods. The results show the method on time reversal is more practical application in engineering for its stability, noise immunity.5. This paper studies on the relationship between the load and frequency based on the dynamic characteristics of the cuplok scaffold systems, and gets the load-frequency curves of the systems in the instable process such as the overall instability, uneven settlement, uneven load, steps, and step distance. The results can provide a basis for the early warning in monitoring stability of the cuplok scaffold system.