Investigation And Statistical Analysis Of Variable Loads Of Concrete Building During Construction

The statistical analysis of the load during construction is an important part of the reliability study of reinforced concrete structure during the construction period and is also an important basis for the design of formwork support system.The job that make an extensive investigation and analysis on the current construction load of concrete structures and give the values in line with the actual construction situation has important theoretical significance to the safety control in the construction period of the structure,and can also provide the data support for the correction of the construction code.In past three years,variable loads of eight structures during construction were investigated in Xi’an and its surrounding areas.Different statistical methods were conducted to analyse the survey results.The main research contents and conclusions are as follows:(1)The change regularities of variable loads with the construction process were studied.The results show that the same structure type construction’s variable loads during construction has the same change regularities,the maximum load of shear wall structures often appears in wall’s steel bar binding or support demolition phase,the maximum load of frame structure appears in support demolition phase,the minimum value of two structural types appears in pouring vertical component concrete phase.(2)The influences of different statistical analysis methods on variable load during construction period is analyzed.The smaller the statistical samples are divided,the greater the value of variable loads is.The more concentrated the materials stacked,the greater the difference among the standard values obtained by different methods is.The variable loads in the construction period of each project obtained by different statistical analysis methods are basically the same in the whole construction period.(3)The differences of variable loads of different layout of buildings during construction period is analyzed and compared.The construction company are the same while the layout of the buildings is different,with the indoor area increase,the variable loads of building vertical component phase are greater,and the variable loads of building horizontal component phase increase first and then decrease.(4)The differences of variable loads during construction period of different construction companies are compared and analyzed.The layout of the buildings are the same while the construction company is different,The construction company has little effect on the variable loads in concrete pouring stage,but the effect on other stages is obvious.(5)Considering the statistical results of two structure types,A construction cycle are divided into four stages as vertical component construction,support building,horizontal component construction and support demolition,the recommended values of the variable loads during construction at each stage are given.