Issue 36

H. Zhu, Frattura ed Integrità Strutturale, 36 (2016) 191-200; DOI: 10.3221/IGF-ESIS.36.19 194 Shrinkage of concrete Shrinkage of concrete which refers to volume reduction of concrete induced by factors such as changes of water content, chemical reaction and temperature decrease includes drying shrinkage, cold shrinkage, condensation shrinkage, autogenous shrinkage, carbonization shrinkage, etc. Figure 3 : Creep of concrete under continuous loading and drying effect. Bounding force between section steel and concrete Bounding force between section steel and concrete is mainly composed of chemical bounding force, frictional resistance and mechanical interaction. On account of the bounding force between section steel and reinforced concrete, section steel can work along with concrete to shoulder load [14]. Construction leveling of high-rise building In construction, core tube and external framework will both deform under the effects of their own weights and construction loading; due to the compression of structure, the height of buildings will decrease [15]. To solve the problem, construction leveling is adopted in actual construction to make up the loss caused by vertical compressive deformation [16, 17]. The following two methods are usually adopted to perform construction leveling. (1) Improve rigidness of vertical component. In this way, vertical component can achieve the same deformation under vertical loading effect. (2) Constrain degree of freedom of vertical component. When construction is over, deformation of different floor can be obtained using the following formula. 1 1 n N k n i k i k k L P E A       (3) where ᇞ n stands for deformation of structural layer of any floor; L k stands for the height of floor k; E k A k stands for rigidness of floor k; P i stands for the load loaded by floor i. A CTUAL MEASUREMENT Protocol of actual measurement teel reinforced concrete filled double-tube structure with shear wall and truss at the bottom was measured. In Fig. 3, Shenzhen Peace Finance Building (Fig. 4) adopts a novel structure system - steel reinforced concrete filled double- tube structure with shear wall and truss at the bottom, which is different from the conventional tube structure. Floors 1 ~ 6 are equipped with shear wall and the internal and external tubes of floors above the standard floor are all steel reinforced concrete columns. S