Research On The Applicability Of Intelligent Steel Strands In A New Prestressed Rapid Assembly Frame System

The new prefabricated prestressed assembly frame system(PPEFF system)is a new generation of “dry” assembly frame system,which has the characteristics of fast and efficient construction,low cost,good disaster resistance and can be applied in areas with high seismic fortification intensity.Promotion potential.Partially bonded prestressed steel strands play a key role in the PPEFF system,providing friction and shear bearing capacity and flexural bearing capacity under normal use,self-reset ability under earthquake action and resistance to unexpected action Continuous collapse ability.In the system research and engineering practice of the PPEFF system,intelligent steel strands are required to measure or monitor the state of the prestressed bars in different states and different parts of the structure during construction,normal use,earthquakes,and local component failures.This article combined with the experiment,systematically studied the applicability of intelligent steel strands in the PPEFF system,including the following:(1)The characteristics of various types of intelligent steel strands were systematically studied.Two types of grating optical fiber intelligent steel strands with carbon fiber replacing middle wire and middle wire with micro-grooves were selected as the research objects,and the structure and measurement mechanism were analyzed;(2)Using the single-frame full-scale test of the PPEFF system as a carrier,the static measurement accuracy of the intelligent steel strand in the full-scale experiment of the PPEFF system was studied and analyzed;the largest five-layer full-scale PPEFF in the world was monitored using the intelligent steel strand The anti-continuous collapse test of the system structure successfully captured the dynamic stress change of the steel strand in the state of drawing column,and verified each other with the measured value of the pressure sensor to verify the accuracy of the intelligent steel strand dynamic measurement.(3)The survival rate of the intelligent steel strand measuring points in the four research or engineering projects of the PPEFF system is analyzed,the survival rate of the intelligent steel strand measuring points of different construction methods is analyzed,and the influence intelligence is given in combination with the construction site conditions.Factors and relevant suggestions for the survival rate of steel strand measurement points;(4)The change of the initial prestress of the prestressed tendons of different parts of the structure by the prestressed tendons of the same layer and the upper and lower layers of the PPEFF system during the construction of the structure was monitored by intelligent steel strands.The initial prestress effect of the system is limited.(5)Comparatively analyze the difference between the actual prestress loss of the PPEFF system and the normative theoretical prestress loss,which provides a reference for the later PPEFF system prestress loss.