Research On Progressive Collapse Of Reinforced Concrete Frame Structure Under Fire

Structure collapses under fire happens frequently in recent years.Owing to the progressive collapse of a structure that often disproportions between large collapse and initial damages,these accidents caused significant casualties and serious economic losses.For some continuous collapse accident which caused by the initial damage is very serious,it is difficult to avoid accidents,such as the events of 9.11,the world trade center collapsed.For some small initial damage caused by continuous collapse,if carried out comprehensive related design specifications,and adopt reasonable measures in the design and construction.Some continuous collapse accidents can be avoided or ease.the heating problem of internal environment generally adopt international standard heating up curve directly instead of the actual temperature curve.It will make the results of the calculation error.In this paper,through the use of fire simulation software FDS to draw more real and accurate temperature curve,and then on the basis of the finite element software ANSYS is used to analyze components of the temperature field and deformation.Mainly does the following work:1.Use FDS to simulate the hotel of a reinforced concrete frame structure for release rate curves and fire curves.The first hotel of a reinforced concrete frame structure of combustible case investigation,and then uses the fire simulation software FDS input of relevant parameters,modeling,set the observation points and so on were simulated.It is concluded that the heat release rate curve of the hotel and fire heating curves,provides data basis for the following ANSYS analysis.2.The fire in the process of material thermal properties and mechanical properties with the increase of temperature drop,by raising the temperature of FDS simulation curve to calculate the different times and different observation point temperature,then respectively calculate the parameters such as coefficient of thermal conductivity,specific heat of concrete and steel.Transient thermal analysis by ANSYS structural components,different moment of the beam and column section and internal temperature field distribution of nodes,as the study of the structure of the refractory performance lay the foundation.3.Using ANSYS thermal coupling analysis of reinforced concrete frame structure model,structure of the displacement distribution cloud,through it is concluded that horizontal displacement nephogram and vertical displacement nephogram,provide a reference for the hotel's fire,the fire temperature contrast midspan deflection analysis of the changes.And by dismantling a dangerous Angle simulation under the condition of demolition of Angle deformation under fire,and on the sixth floor add a bigger modulus of standby power transmission,standby power transmission support on the one hand can provide tension to the downstairs,on the one hand can provide support to upstairs,and then compare the two models displacement nephogram,provide certain reference for later design of hotel.This article analysis is the displacement nephogram of numerical for fire resistant design and analysis of structural fire performance of provides the certain reference.Including the removal of corner post only consider the demolition of a corner case,add backup force support only consider to add on the sixth floor,this is just one of the forms,hope to provide a certain reference to the research and design for later.