Countermeasure Study And Test Analysis Of Crack Of Steel Plate-concrete Shear Wall In Super High-rise Building

Early age crack is common in mass concrete of high performance. Research athome and abroad is mainly focused on temperature crack in plain concrete or massconcrete of low steel percentage, where temperature and shrinkage is mainlyresponsible for the early age cracks. But for massive steel plate-concrete shear wallwall structure, internal steel plate constrains the deformation of temperature andshrinkage, which changes the forming conditions of temperature cracks and shrinkagecracks. Meanwhile additional stress is increased according to different linearexpansion coefficient of steel plate and concrete. These complex factors together leadto crack of steel plate-concrete shear wall at early age.A test on crack was performed based onteel steel plate-concrete shear wall of ahigh-rise building. In the aspect of theory, calculation method about separatingtemperature and shrinkage and gap was built using the theory of early age cracking,bonding and slipping and constraints contraction; factors that cause the crack wasstudied and corresponding countermeasures was put forward.As to the design of experiment, a test was designed and performed to monitor thetemperature, shrinkage, coefficient of linear expansion, autogenous shrinkage, dryingshrinkage and strain in rebar. Multi-gradient temperature points were arranged on theplate to achieve the highest temperature during concrete pouring, cooling rate, therange of temperature, the surface temperature; According to the law of developmentof early expansion along with age and temperature stability, a reasonable coefficientof linear expansion was obtained by the contrast of a briquette of14days under theequal condition and standard condition; Based on the steel plate-concrete shear wallrespectively at different positions of the inside and surface of the autogenousshrinkage and drying shrinkage of concrete test,the degree of cracking was estimatedby comparing the autogenous shrinkage and drying shrinkage in different parts ofconcrete; Strain of the plate, studs, steel was monitored, which trends and straindistribution of concrete was studied based on deformation compatibility to provide thebasis for the separation of the concrete temperature stress.Finally, the reason of crack was analyzed and conclusions as follows wereobtained: For internal concrete of steel shear wall, temperature is the main factors thatcause the concrete crack, which causes60%of cracks; For the concrete in the surface, shrinkage is the main factors that cause the concrete crack, which causes80%of thecracks; And countermeasures must be taken in respect of concrete curing materials,design and construction to prevent the early age cracking.