The Experiment Of Fire Extinguishing With Water Mist And Analysis On The Frame Structure Resistance Of Underground Parking Garage

In recent years,with the rapid development of economy,the number of private cars is increasing.The underground parking garage of reinforced concrete frame structure is increasing rapidly,and the risk of fire is more and more serious.It is of great significance to carry out the research on the fire-resistant performance of the reinforced concrete frame structure underground garage and to take protective measures in the fire.According to our current norms and initial conditions,we choose reasonable parameters of reinforced concrete and concrete,design a single span reinforced concrete frame structure with PKPM software,and get the reinforcement layout.Reinforced concrete frame structure design analysis and simulation using ABAQUS finite element software changes in the two-dimensional temperature field of different ventilation modes,the coupled thermal mechanical analysis of reinforced concrete frame structure,the vertical displacement of each moment of the obtained images,and the time displacement curve.The results show that,under the conditions of this experiment,0.5m/s mechanical smoke exhaust poses a greater threat to the safety of personnel and structure in the fire.Under the condition of natural ventilation,the beam and column end of the fire did not reach the fire resistance limit.Beam cross maximum displacement is 29.14mm.Only 23.28%of the maximum deflection under the prescribed fire resistance limit.The vertical displacement and horizontal displacement are produced at the end of the column,the vertical displacement is 16.9mm,and the horizontal displacement is 19.3mm.Only 42.25%of the maximum vertical displacement under the prescribed fire resistance limit.Further,the same model is used to carry out the water mist fire suppression experiment,and to adjust the start-up time of the water mist,and to test and analyze the evolution process of the fire temperature under the action of water mist.The influence of water mist on the structure temperature field is compared and analyzed by ABAQUS.Then the thermo mechanical coupling simulation is carried out,and compared with the fire extinguishing measures,the most favorable influence of water mist fire extinguishing mechanism on the reinforced concrete frame structure is analyzed.The results show that 0.5m/s mechanical exhaust will inhibit the fire extinguishing effect of water mist.The application of water mist fire extinguishing measures at the initial stage of fire and natural ventilation can effectively protect the reinforced concrete structure,maintain the original bearing capacity and reduce the structural deformation caused by the high temperature of fire.The deformation of beam cross is slowed down rapidly.The vertical displacement of the beam span in the whole process is only about 2.5mm,and the end deformation of the column is basically stopped,and it is maintained at about 1.5mm.