Journal of Civil Engineering and Materials Application
Volume:6 Issue: 1, Winter 2022

This study investigates faults propagation in granular soils using the developed elemental-like direct shear-faulting box by detecting shear bands formation within soil samples. For this sake, first, some modifications are applied to the direct shear box in the Earthquake Research Institute. In this regard, two blocks are built at an angle of 45 degrees that can be moved relative to each other. Transparent walls are employed to increase the static resistance. Moreover, four screws are installed on the floor of the device. The friction in the test is reduced by using several ball bearings. The required thickness for the box walls is determined using a numerical simulation in ABAQUS software. To investigate faulting in granular soils, Firoozkooh sand is utilized and placed in the developed shear box. The overhead load is modeled by applying air pressure to a rubber membrane containing water. By continuous imaging of soil profiles, alterations in the soil surface are recorded, and an image correlation method is employed to predict the amount of fault-induced displacements, strains, and dilations. Results verify that the dilation effect elevates with increasing moisture content and wanes with the addition of fine-grained percentage and by boosting vertical loads. Moreover, various behavior has been observed without softening for cementitious sands.

In a situation where terrorist attacks on civilian places and facilities are on the rise, the safe design of buildings against the impact loads caused by explosions is very important. Steel structures are very sensitive to heat and the pair of explosions and fire can cause progressive failure in such structures. Since explosion is usually associated with fire structures, in this study, the effect of the explosion on steel flexural frames under fire conditions was investigated. This study investigates two five-span frames of the same steel bending frame with differences in their height, one three and the other five-story, which explode under the TNT material at a distance of 10 meters from the frame. The results of numerical calculations for the maximum impact pressure caused by the explosion, the duration of the positive phase of the explosion, and the duration of the negative phase of the explosion equal to 0.1 kgf/〖cm〗^2 , 3.89 s, and 0.0139 s, respectively, were entered into the modeling of Abaqus software. Three- and five-story frames were modeled on Abaqus software and subjected to the force of the explosive explosion outside the frame. To compare the explosion behavior of the two frames, stress analysis, displacement, roof floor acceleration, rotation, and work performed on the frame were performed. The minimum stress in a three-story frame (9.07 kgf/cm2) is approximately 2 times less than in a five-story frame (17.25 kgf/cm2) and equivalent compressive loading has created less force in the three-story frame.

Bangladesh is a land of rivers and there are more than 230 rivers. Bank protection of rivers is an important thing all over the country because river banks are damaged by water flow and natural disasters every year. This paper’s purpose is the make Mortar blocks with used plastic to protect the Riverbank erosion. Plastic is one of the most significant innovations of the 20th century, and there is a lot of waste after use. Only 1 to 2% of waste plastic is used for various purposes in America and there are10.5 million tons of plastic waste released every year. Plastic waste is now a serious environmental threat to modern civilization so, the reuse of plastic waste in the mortar blocks to minimizes the environmental threat. The plastic bottles are filled with Course sand with cement and water-cement ratio in 35%. In the project, the cement-sand ratio is 1:3. In this study, five types percentage of replacement waste plastic bottles are used to determine the exact percentage of replacement waste plastic bottles. For 6"×6"×6" mortar block the required strength of 12 MPa occurred at 11% of bottle content. But the compressive strength of the mortar block decrease with the increase of the size of the mortar block.

C3A contents of Portland cement have significant role in chloride ion binding in chloride-contaminated environments. Cations release due to NaCl and CaCl2 in chloride environments, are the most common and aggressive agents. In this research, various simulated pure C3A made using calcium hydroxide and aluminum hydroxide including 5%, 8%, 10%, and 12%. Moreover, the different concentrations of sodium and calcium cations in NaCl and CaCl2 in the simulated Portland cement paste were added the bonding performances were investigated. X-ray diffraction (XRD) of prepared C3A samples identified for major phases of specimens. Thermo-gravimetry analysis (TGA) was used to quantify the simulated C3A. Standard test methods including ASTM C1152 and ASTM C1218 were utilized to measure the acid-soluble and water-soluble chloride in prepared specimens respectively. The results showed that the amount of acid-soluble and water-soluble chloride for NaCl and CaCl2 cations decreased with an increase of the C3A, which indicates that the better chloride ion binding potential. Moreover, it was concluded that CaCl2 cations have more chloride binding capacity than NaCl. For calcium cations in CaCl2, the increase of C3A is distinguished in water-soluble chloride in comparison with NaCl cations. Then, in areas contaminated with NaCl ions, it is recommendable to use more C3A content in the Portland cement.

The T-stub connection, which is considered a screw connection and is usually considered in the semi-rigid connection range, was first simulated in Abaqus finite element software by selecting a laboratory sample of the T-stub screw connection. To determine the validity of the software, and modeling method used in this research. Next, to introduce the structural elements, loading, materials, and type of analysis used in the experiment and also to determine 52 samples of controlled T-Stub connection with executive and design constraints to determine a series of targeted data by changing the geometric configuration and strength The materials of the components of the t-stub connection are discussed, finally, by performing nonlinear analysis in Abaqus finite element software and determining the maximum limit state function of the screw tensile force in terms of random variables such as screw diameter, cross-sectional width, and thickness at two levels of yield and rupture performance. The web plate was analyzed by Monte Carlo statistical method. Results The failure probability (PF) for all samples under both performance levels was zero. This result is due to the fact that when selecting the samples, the condition of no rupture mode was observed in the T-Stub connection. Thus, the specimens of the specified T-Stub connection are of the strong screw type, hence the value of the probability of failure (PF) or the same probability of the screw surrendering in the non-threaded part after submitting the web plate and the screw breaking in the threaded part after rupture, the web plate is equal to zero.