Ansys Fire Behavior Based Multi-span Concrete Composite Beam Floor Cages Analysis

In the course of human evolution and development, the fire has been playing an important role. The use of fire as a double edged sword, on the one hand, it can help people warm, refined metal; hand, with the continuous development of society, but also moments of high frequency fire threatens the safety of property and people’s lives. Which is the highest number of building fires, the most serious form of the loss of the occurrence of various types of fire fire. Concrete composite beam floor cage floor as a new form, with a saving of steel and concrete, lighter weight, the advantages of high capacity, and has been more widely used in engineering. Therefore, to carry out the new concrete composite beam floor cages fire behavior for large spaces, large span areas is necessary.This article is the use of finite element software ANSYS multi-span composite floor beams cages simulated fire tests, the main contents are two:First, through SOLID70functional unit of life and death, the analog composite bottom plate before and after bursting floor temperature field and gives the overall composite tank floor temperature distribution cloud, cloud and temperature distribution along the rib section of the beam cross-section of different heights temperature-time curve; the second is based on the simulation of the temperature field, the heat unit into the structure unit, analyzing composite beam floor cage deformation in the temperature field and the combined effect of uniformly distributed load and gives the displacement contours superimposed cages beam floor, side frame beam across the vertical displacement-time curve and floor vertical displacement-time curve. Finally, the simulation results were compared with the experimental analysis of the main draw the following conclusions:(1) the use of the thermal unit SOLID70ANSYS element birth and death feature, you can simulate the distribution of temperature field cages under fire concrete composite beam floor after floor burst through the rib section of the beam at different heights temperature-time curve can be seen the experimental results agree well with the simulation results.(2) during the test, as the temperature rises, floor surface inlet. Laminated container floor temperature contours directly reflects the law during the test floor surface appears inlets.(3) After the composite bottom plate burn, because magnesium plate glass laminated container sidewall protection, but its temperature contours with ordinary T-beams on three sides by the fire cloud temperature is different.(4) the results of the finite element analysis results agree with the experimental measurement of the good, but a little out, the cause may be:the analysis ignores the evaporation loss of water in the concrete heat; thermal parameters of materials, mechanical parameters of the specimen there is a difference true value; impact is not fully burn the bottom plate superimposed on the temperature field.(5) composite beam floor cages at a temperature field effect generated temperature stress, and there is a large temperature gradient along the thickness direction of the plate, resulting in thermal expansion deformation, deformation and subjected to column constraints, frame beam and girder web floor area grating role in the fire were to anti-arch, thus making the upper cross beam and the top surface area grid plate tensile stress, then at the top of the frame beam net beam floor grid and district boards, and a large number of vertical beam cracks. Laminated container floor displacement by cloud directly reflects the phenomenon of vertical cracks in the testing process.(6) During the test, a large number of slit-shaped " class arc" superimposed on the four corners of the box floor, cracks and the general effect of the floor that is not identical to the fire, and the intermediate portion of such cracks axis angle of45°, and both ends of the vertical frame beams.(7) As the temperature increases, the bottom plate overlap burst strength of materials continue to reduce the external loads, the net floor upper beam, on both sides of the frame including a large number of beams to the main axis parallel to the fracture through overlapping box floor displacement contours visually see the presence of cracks.