The Deflection of Donut Type Hollow Slab Considering Crack Behaviors

Recently, various types of slab systems which can reduce self-weight of slabs have been studied as the height and width of building structures rapidly increase. A hollow slab system is widely known as one of the effective slab system which can reduce self-weight of slab. According to previous studies, the hollow slab with donut type hollow sphere had enough flexural strength. On the other hand, there were some differences in flexural stiffness and deflection between general RC slab and donut type hollow slab. The deflection of hollow slab was influenced by the shapes of hollow spheres due to its different second moment of inertia and amount of concrete surrounding bottom re-bar. Especially, the cracking behaviors also influence the deflection of slab. General RC slab deflection has been sufficiently investigated and some models to consider the crack behavior such as crack width, crack space, tension stiffening effect, bond-slip relationship. However, there is no study about the crack behavior on the hollow slab. Therefore, the purposes of this paper are to presents the cracking behavior of donut type hollow slab and to evaluate the deflection considering the crack behavior under flexural load.

The Influence of Different Subbase Materials on the Crack of Cement Stabilized Macadam Base during Construction

According to actual axle load data and the measured mechanical parameters of cement stabilized macadam material with different cement dosages, the bottom tensile stresses of different subbase structures are calculated and the results show that: to graded gravel subbase, the weight of construction vehicle is inadvisable to be more than 35t and the cement dosage of base course shall be more than 3.0%; and, the maximum bottom tensile stress of graded gravel subbase shall be much more than that of lime-flyash soil subbase. According to the measured dry shrinkage strain and dry shrinkage coefficient, the dry shrinkage crack space of base course is analyzed and the results show that: under the same cement dosage, the crack space of the base course with graded gravel subbase is smaller than that of lime-flyash soil subbase; with the increase of cement dosage, the crack space of base course increase first and then decrease, and when the cement dosage is 3.5%, the dry shrinkage strain and dry shrinkage coefficient is minimum and the crack space of base course is maximum.

The Regression Analysis of Corresponding Crack in Asphalt Pavement under Temperature Load

By use of the theory of fracture mechanics, the plain-strain model is established to simulate the four-layer asphalt pavement of corresponding crack.. And then, applying the segmented integral method and power function form, the stretching stress intensify factors in the conditions that four limited layer combined status and different crack space are calculated and analyzed under the action of pavement and basement shrinkage. Moreover, the regression formulas are given which can meet requirements of the engineering regression equation precision.

Study on the Stress Intensity Factor of Double Cracks Parallel to and Lying on the Interface in the Cladding Material Structure

Taking the cladding material structure with double interface cracks parallel to and lying on the interface as the study object, based on the theoretical study on the crack tip stress intensity factor(SIF), using the finite element software ANSYS, the SIFs are researched by changing the crack space, crack length, thickness ratio, load and crack location. The results show that, the crack SIFs increase firstly and then decrease with the crack space increase, increase with the increases of the crack length and the load, decrease a little with the thickness ratio increase, decrease firstly and then increase with the increase of distance between the crack and the boundary.