Experimental Research On Material Characteristic And Life Pre-Estamate And Repairing Of Reinforceing Concrete Structure After Fire

In recent years, fire accidents have frequently occurred both at home and abroad, such as 9.11 attack and the fire disaster in Hengyang city, Hunan province in China. Both ended in the collapse of buildings and caused severe casualties. This need carry throuth research on the material characteristic of concrete structure in fire and bring forward solve means on the evaluation and repairing of concrete structure after fire.So we carry throuth below works:1 The research on microcosmic analysis and heat luminescence of concrete after fire.We particular introduce the measure technic and means of building structure after fire,value their excellent and shortcoming and apply range which help to unify the measure means,analyse the microcosmic structure and composing elements,discuss the physics change and chemistry change occurred in the composing elements of concrete in fire,and thereout bring disbennifit actions or bennifit actions on the mechanics capability of concrete,moreover,carry through the research judging the burn degree of concrete after fire with heat luminescence in projects.2 The research on material characteristic of the steel and concrete under high temperature.We carry through the experiment research about 180 steel bars and 102 groups concrete tests,mostly study the mechanics capability change of 4 kinds of ordinary steel bars and differ bone material and conctere strength degree bring the influence on the mechanics capability of concrete under high temperature,and the change of the resist pull strength,yield strength and stretch ratio on deformed steel bars after cooling in nature from high temperature,and the change of the resist compress strength and elasticity models on the concrete after cooling in nature from high temperature,and the change on the resist compress strength on the concrete after cooling by water from high temperature,these will offer base for evaluate the buildings' structure capability after fire.3 The fuzzy assess of the fire field temperature after fire. This paper focuses on the inspection of building member facade and fire remains, on the judgment of temperature of building member facade by means of macro-inspection and micro-analytical method. On the basis of these, introducing fuzzy mathematics, determining model and inspection method of judging the temperature of the building member facade are established in this paper and put into use in projects.4 we carry through 14 groups tests to progress the anchor capability experiment between reinforcing steel bar and concrete at the differ temperature,there are 6 groups tests adopting round steel bar and 8 groups tests adopting screw thread steel bar.The experiment indicates that the anchor capability between round steel bar and concrete close to linearity fall with the temperature hoisting, the anchor capability between screw thread steel bar and concrete almost does not fall under 200 ℃ and close to linearity fall over 200℃. By regressing and analyzing the experiment data, we can educe a calculate formula of the anchor capability between reinforcing steel bar and concrete with the temperature changing,bring forward the resist calculate model of concrete member after fire,these will offer evidence for checking computations the bear capability of the structure members after fire.5 We set up the connection between the remain working life of members and effect of actions with structure reliability theory and carry through estimate about the remain working life of concrete structure members after fire.6 We carry through estimate about the remain working life of concrete structure system after fire.7 We carry through a set of experiments of the long years concrete members repaired by adhibiting carbon fiber sheet on the base of simulating fire field condition and load investigate results after fire,study the positive section resist bend ability repaired by adhibiting carbon fiber sheet on the side face of hang beams and the effect repaired after pre-adding part load on the middle of beams, analyse the resistance influence factors of the concrete beams repaired on the side face and the stress lag phenomenon of the concrete beams repaired after pre-adding part load.