Research On Connection Quality Control Technology Of Prefabricated Concrete Structure In Site

The prefabricated building has the advantages of quick construction,reduced labor costs,energy saving and environmental protection,etc.It is in line with the basic concept of sustainable development,and meets the requirements of the transformation and upgrading of the construction industry.One of the basic design concepts of fabricated concrete structures is “Equivalent Cast-in-place”.The key to its realization lies in the connection between prefabricated components.The research on the connection form and seismic performance of prefabricated concrete structures at home and abroad shows that,a reasonable connection form can ensure the reliability of the connection quality in design.It can effectively connect the individual structural components as a whole,and in harmony with entire building structure.However,at present,there are few researches on the construction process of prefabricated concrete structures connection,and there are no strict rules and regulations for controlling the construction quality,which leads to the uneven construction quality.The quality of the connection in site is usually difficult to meet the accuracy of design requirements.Basing on the construction process of prefabricated concrete structures connection,this article investigates the connection in site quality and carries out the visual simulation craft test for the purpose of quality control measures and detection methods.At the same time,the seismic performance of prefabricated concrete shear wall based on different construction processes was evaluated through low-cycle repeated loading tests and finite element simulations.The main work and conclusions of the paper are as follows:(1)For the vertical prefabricated member connected by sleeve grouting,it is recommended to set the exhaust and observation tube at a height of about 150 mm above,or to set up a microgravity flow supplementation and observation tube at the sleeve discharge hole for guaranteeing the quality of sleeve grouting.If the level of grouting material falls,the gravitational supplement is required before the grouting material maintains a certain fluidity-within half an hour.The microgravity flow supplementation and observation tube is also a non-destructive testing method for grouting quality.As long as the height of the filling tube is detected during the grouting process,the quality of the internal grouting can be indirectly detected.It is a kind of no-damage,convenient and efficient,reliable grouting quality detection method suitable for the construction site.(2)Furthermore,low-cycle tests were performed on full-scale models of three shear wall joints,including two prefabricated shear wall joints using a different grouting construction process and a cast-in-place contrast component.By comparing and analyzing the failure modes,hysteresis curves,bearing capacity,and energy dissipation capacity,it was found that the seismic performance of shear wall specimens using the connected cavity grouting method was better than that of cast-in-place specimens.The seismic performance of the shear wall specimens with the grouting layer and single-point grouting method is slightly lower than that of cast-in-place specimens,basically achieving the design principle of equivalent cast-in-place.(3)Finally,finite element software ABAQUS was used to analyze the specimens reasonably.The simulation results were compared with the test results to verify the rationality and accuracy of the finite element model.In addition,the parametric analysis of the finite element model was conducted to compare the influence of different parameters on the seismic performance of prefabricated concrete shear walls.