| 《Design standard for energy efficiency of rural residential buildings》(GBT 50824-2013)provides that the heat transfer coefficient of the maintenance structure in cold area should not be greater than the value of 0.5W/(m2 ·K);the commonly used clay brick wall thickness should reach 1m to meet the heat transfer coefficient requirements.Based on the orthogonal test of compressive strength on compression molding haydite concrete,new self-thermal insulation concrete block with high thermal resistance is developed through adding mineral wool and slag to adjust the mixing ratio of the original concrete hollow block.Test results showed that when the thickness of the concrete is only 280mm,the heat transfer coefficient of the new insulation block with 3.5MPa and 5MPa could reach 0.31 W/(m2 ·K)and 0.39W/(m2 ·K)respectively,which meet the building energy efficiency requirements of current specification,meanwhile greatly reduce the wall thickness and save the material and increase the usable area.Previous research has found that the theory of "block strength is generally higher than that of the mortar"in GB50003-2011 could not be applied to new self-insulation block due to the large hollow rate.In this study,axial compression test on the two kinds of self-insulated blocks through 45 compression block specimens were carried out.Test results depicted that when the strength of the mortar is higher than that of the block but lower than that of the base material,the utilization coefficient of the masonry strength is the highest.Moreover,the calculated compressive strength of self-insulated block masonry according to the formula of the specification is slightly higher than the test value.Based on basis of the formula in code of GB50003-2011,the reduction coefficient related to the block hollowness is obtained,which might be suitable to calculate the compression strength of the new block.The elastic modulus,poisson’s ratio and shear modulus of self-insulation masonry were obtained by analyzing the stress-strain curve of the masonry,and the curve was fitted to obtain the constitutive relation.Pure shear test on the two self-insulation block of 32 specimens was carried out.The test results showed that the shear strength of this kind self-insulation masonry is higher than the value in Table B.0.1-2 in the code,which is contributed to the blind holes,generated by the EPS board inserted in the gap of self-insulation block,effectively avoid leakage of the masonry.Masonry shear test strength is higher than the value calculated by the formula in the code.Therefore,the shear strength calculation formula of the existing standard could be used for the masonry shear strength calculation of the new self-insulation block.In the process of finite element modelling,the interface model is used to simulate the mortar interface,and its normal contact criterion and tangential contact criterion are defined,then the finite element method for masonry separation modeling is given.Through the finite element analysis and calculation of the masonry compression test,the damage load and failure phenomena of the specimens are in good agreement with those of the test,which verify the rationality and applicability of the masonry separation modeling method.In this paper,the overall and separation modeling method are carried out to simulate the performance of the wall under the horizontal load and to analyze the lateral bearing capacity and the failure mode of the wall.By changing the upper load and aspect ratio,the influence of upper vertical load and aspect ratio on the seismic performance of masonry wall is analyzed.The results show that with the increase of the vertical load,the initial stiffness of the wall is constant and the bearing capacity increases while decreases in the ductile section;meanwhile,with the increase of the aspect ratio,the initial stiffness and lateral bearing capacity of the wall decreases.In addition,high aspect ratio could lead to the bending damage of the wall. |
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