Civil Engineering

This research presents an experimental finding on the mechanical properties of concrete with waste steel scrap. The recycling of scrap metal as a concrete base reinforcement eliminates the issue of disposal. The laboratory tests for compressive strength and splitting tensile strength were conducted for different percentages of waste steel scrap (0%, 0.5 %, 0.75 %, and 1.5 %) determined by the volume of concrete. The compression behavior was obtained using uniaxial compression tests while the tensile behavior was obtained using splitting tensile tests. Laboratory testing of 12 cubic specimens and 12-cylinder specimens was conducted on the 28th day of curing. With the addition of waste steel scrap, it was found in the test results that the compressive strength increased by 26.8 % for 0.5 %, 30.7 % for 0.75 %, and reduced by 5.3 % for 1.5 % by volume of concrete. The splitting tensile strength increased by 11.2 % for 0.5 %, 5.8 % for 0.75 % and 2.5 % for 1.5 % by volume of concrete. The test outcomes showed that the modulus of elasticity and peak strain contains a remarkable increment with the increase in waste steel scrap volume. Compared with plain concrete, the strength properties of concrete with steel scrap were improved, however, with an increased amount of waste scrap, the workability of concrete was reduced.

Steel fiber reinforced concrete exhibits ductility. This ductility behavior enables redistribution of moment between the negative and positive moment zones in continuous SFRC beams. The sectional capacity of an SFRC continuous beam was determined using the moment-curvature response, the ductility of the member using the moment-rotation response, and the moment redistribution behavior using the moment-rotation response. The theoretical moment-curvature response was calculated from the stress-strain response for 0 % (control), 0.5 %, 0.75 %, and 1.5 % SFRC member which served the basis for the defined moment-rotation behavior and FEA. A five-point bending test was conducted on a two-span beam using a constitutive material model in the FEA software package, Abaqus/CAE. The concrete damage plasticity (CDP) model was used to conduct a displacementcontrolled analysis on the fully integrated 3D hexahedral element (C3D8). The numerical study revealed that the flexural behavior, bending capacity, rotation capacity, and ductility of the 0.5 %, 0.75 %, and 1.5 % SFRC beams were significantly enhanced than the 0 % SFRC beam. However, as steel fiber volume increased, the quantity of moment redistribution in the SFRC beam decreased. The amount of moment redistribution obtained was 21.8 % for 0 %, 19 % for 0.5 %, 18.1 % for 0.75 %, and 13.9 % for 1.5 % SFRC.

advancement in steel fabrication technology extends the structural and constructional advantages of cellular steel beams into arched cellular steel structure members. However, less attention is given to understanding the in-plane and out-of-plane structural behavior and performance of arched cellular steel beams. is article presents a numerical study using the nite element package ABAQUS to investigate the e ect of arch axis geometry (circular and parabolic) and the impact of end support types on the inplane inelastic buckling strength and buckling mode of I-section arched cellular steel beams. In the nonlinear nite element analysis of the model material nonlinearity, a second-order e ect due to large deformation and initial geometric imperfection was incorporated in predicting inelastic buckling load and buckling mode. Furthermore, nite element analysis results were veri ed by comparing them to the existing experimental work. Test models covering shallow to deep arches of subtended angle in a range of 45-180 were investigated under uniformly distributed vertical loads and mid-span point loads. It was found that nonlinear nite element results fairly replicate the experimental work in predicting inelastic buckling load and post-buckling behavior. From the parametric investigation, it was found that deep parabolic arched cellular steel beams are structurally more e cient than their equivalent circular arched cellular steel beams. Pinned in-plane and free out-of-plane end support conditions result in a reduced inelastic ultimate buckling load capacity of arched cellular steel members when compared to other possible end support types. e geometry of an arch axis has no noticeable impact on the buckling mode of arched cellular steel beams.

The advancement in steel fabrication technology extends the structural and constructional advantages of cellular steel beams into arched cellular steel structure members. However, less attention is given to understanding the in-plane and out-of-plane structural behavior and performance of arched cellular steel beams. This article presents a numerical study using the finite element package ABAQUS to investigate the effect of arch axis geometry (circular and parabolic) and the impact of end support types on the in-plane inelastic buckling strength and buckling mode of I-section arched cellular steel beams. In the nonlinear finite element analysis of the model material nonlinearity, a second-order effect due to large deformation and initial geometric imperfection was incorporated in predicting inelastic buckling load and buckling mode. Furthermore, finite element analysis results were verified by comparing them to the existing experimental work. Test models covering shallow to deep arc...

Compressed stabilized soil block is a sustainable building material primarily made up of stabilized damp soil compressed under pressure. Soil properties and the type of the stabilizer used in producing compressed soil blocks have a signifcant impact on the quality and behavior of the soil blocks. This study presents the physical and mechanical behavior of lime-cement-stabilized compressed interlock soil blocks produced from two types of natural soil. Te two types of soil have diferent index properties and mineral oxide compositions. Lime-cement combination and cement standalone was used as a binder in the production of test sample blocks depending on the index properties of the soil. 2%lime + 6%cement, 3%lime + 8%cement, and 4%lime + 10%cement were used for the soil block produced from silty clay soil of medium plasticity index. On the other hand, 6%, 8%, and 10% cement by dry mass of soil were used to stabilize silty sand soil. Te behaviors of the blocks, such as dry density, the initial rate of water absorption, saturated absorption of water, compressive strength, and stress-strain relation, were examined. Te result shows that the compressed soil blocks produced from lime-cement-stabilized silty clay soil has a low rate of initial water absorption and a low dry unit weight when compared to cement-stabilized sandy soil blocks. Soil blocks produced from cement-stabilized silty sand soil attain greater compressive strength by more than 50% of the compressive strength of silty clay soil blocks stabilized by a combination of lime and cement at 60 days after production. Te initial tangent modulus of the soil blocks produced using a manual compressing machine from a clay soil stabilized by the lime-cement proportions of 2%L + 6%C, 3%L + 8%C, and 4% L + 10%C is about 1,700 MPa-2,300 MPa with a dry density greater than 1,660 kg/m 3 .

Compressed stabilized soil block is a sustainable building material primarily made up of stabilized damp soil compressed under pressure. Soil properties and the type of the stabilizer used in producing compressed soil blocks have a significant impact on the quality and behavior of the soil blocks. This study presents the physical and mechanical behavior of lime-cement-stabilized compressed interlock soil blocks produced from two types of natural soil. The two types of soil have different index properties and mineral oxide compositions. Lime-cement combination and cement standalone was used as a binder in the production of test sample blocks depending on the index properties of the soil. 2%lime + 6%cement, 3%lime + 8%cement, and 4%lime + 10%cement were used for the soil block produced from silty clay soil of medium plasticity index. On the other hand, 6%, 8%, and 10% cement by dry mass of soil were used to stabilize silty sand soil. The behaviors of the blocks, such as dry density, t...

В статье описывается математические модель проектирования для обоснования концепции патрульного катера, предназначенного для Союза Мьянма. Основные кораблестроительные элементы определяются как результаты решения задачи математического программирования (оптимизации). В состав математической модели входят расчеты нагрузки, вместимости, остойчивости, ходкости, запаса плавучести. Критерием эффективности взято отношение вероятности перехвата нарушителя к приведенным годовым затратам. Для решения оптимизационной задачи используется алгоритм случайного поиска. Для реализации разработанной математической модели проектирования создан программный комплекс модульной архитектуры в оболочке DELPHI. В рамках исследования математической модели оценивалась её адекватность, чувствительность и устойчивость. Результаты исследования оказались удовлетворительными, что доказывает возможность применения разработанной математической модели для решения проектных задач на начальных стадиях разработки проект...