The Temperature Crack Analysis And Control Research Of Super-long Concrete Structure

In the recent years, with the rapidly economic development, constructiontechnology level improved continuously, and large-scale public buildings andindustrial buildings sprang up like bamboo shoots after a spring rain in our country.In order to satisfy the function of architecture and the integrity of the structure,these buildings usually have less or even no expansion joint, which leads to the reallength of whole structure oversteps the value our country Code prescribed, sosuper-long structures have appeared. For the super-long structure, temperatureeffect has to be considered in design. Because temperature effect is the main reasonof causing temperature cracks, so it is very important to research the temperatureeffect and control measures of temperature cracks.The finite element software MIDAS/Gen is used in this paper to analyze andcompare temperature effects of super-long concrete structures which are set of notemperature crack controlling measures and expansive strengthening band. Themain researching contents of this article are as follows:Firstly, the finite element model of the super-long concrete structure withoutusing any crack controlling measures is established by using the finite elementsoftware MIDAS/Gen. The temperature effects under the most harmful temperatureloads are analyzed. The results which in concluded from the deformation featureand force distribution of the structure showed that: in the height direction,thetemperature deformation gets its minimum at the bottom floor, increases as theincreasing of the layers of the structure and reaches the maximum of temperaturedeformation at the top floor; the temperature force gets its maximum at the bottomfloor, decreases as the increasing of the layers of the structure. In the horizontaldirection, the temperature deformation gets its minimum at the central axis,increases as the increasing of the distance to the central axis and reaches themaximum of temperature deformation at the end of the longitudinal direction; thetemperature force of slabs gets its maximum at the central axis, decreases as theincreasing of the distance to the central axis. But the phenomenon that stressconcentration easily occurs at irregular planes should be noticed.Secondly, the finite element model of the super-long concrete structure whichis set of expansive strengthening band is established by using the finite elementsoftware MIDAS/Gen. The temperature effects under four different percentage ofrestrained expansion are analyzed. It is compared with the temperature effects of the super-long concrete structure without using any crack controlling measures. Theresults showed that: whether the super-long concrete structure is set of expansivestrengthening band or not, the rules of temperature deformation and forcedistribution of the structure is similar. The temperature effects of the super-longconcrete structure which is set of expansive strengthening band are decreased as theincreasing of percentage of restrained expansion.In addition, temperature stress of floorslab between expansive strengtheningband and settlement is influenced greater, than that between the ends of thestructure and expansive strengthening band. Therefore, the places of the expansivestrengthening bands should be located at where temperature stress is the strongest.Expansive strengthening band could offset more temperature stress over there sothat preventing most extremely to cracks of super-long concrete structure. In thereal engineering design of projects, it can supply some helpful information andinstruction to structural designers.