Research On Key Technology Of T-beam Factory Manufacturing Method

Prestressed concrete prefabricated T beams are one of the main bridges for highway construction in China,and precast T beams are currently mainly produced on construction sites with special beam yards,and have not formed a complete and efficient factory production line.At present,the traditional beam field in China mainly has the following problems: the sealing of the steam curing room is poor,causing serious heat loss,excessive local temperature difference,uneven heating of the precast concrete beam,etc.;the steam curing equipment is poor,the accuracy is low,and the temperature control is mainly Relying on manual intermittent measurement and adjustment,it is difficult to ensure the effectiveness and accuracy of temperature control at all stages of concrete maintenance;due to the strict regulations on the prestressed loading age in highway related codes and design documents,the prestressed loading age cannot be shortened,Resulting in the inability to speed up the construction progress.The factory-made manufacturing method of T-beams studied in this paper is mainly the secondary prestressed tensioning process of T-beams based on steam curing.This construction method can effectively ensure that the mechanical properties of concrete after T-curing can meet the requirements of prestressed tensioning after steam curing Pull the pre-stress,and lift the prefabricated T beam out of the beam-making mobile pedestal,shorten the service life of the pedestal,and increase the production speed of the T-beam.And it has a good effect in reducing the early prestress creep loss.In this paper,the mechanical properties of early-stage steam curing T-beams were first tested on the basis of a prefabricated beam field in Fujian.It mainly monitors the changes of beam stress,concrete strength and beam arching under key working conditions such as steam curing,prestressed tension and beam storage stage,and conducts comprehensive comparison analysis of test results to determine the application of this method of production The T-beam meets the design code requirements.Three different creep standard specifications were used to analyze the early creep loss of the steam-preserved secondary prestressed tensile T beam,and it was concluded that the pre-tensioned 60% was used to control the tensile stress,and the secondary tensile T was performed after 4 days of dry cooling.The early creep loss of Liang is the smallest.And compare the measured T-beam prestress creep loss value to verify the reliability of the creep calculation results.Based on the engineering application examples,the tensile pre-stressed tension T beams were subjected to check calculation and actual measurement analysis.Using 60% pre-tensioning to control the stress and 4 days of dry cooling time,the overall mechanical properties of the steam curing secondary pre-stressed T-beams meet the design requirements.The field T-beam measured data shows that the mechanical properties of the secondary tensioned T-beam are better than the ordinary primary tensioned T-beam,which verifies the reliability and advantages of the steam curing secondary prestressed tension T-beam in structural performance.