Mineral admixtures including silica fume,fly ash and slag,have been commonly used to partially replace Portland cement in normal and high-strength *** ecological and economic benefits provide incentives to study the i...
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Mineral admixtures including silica fume,fly ash and slag,have been commonly used to partially replace Portland cement in normal and high-strength *** ecological and economic benefits provide incentives to study the influence of mineral admixtures on the mechanical performance and durability of cementitious *** a lot of works were conducted to study the physical properties of cementitious composites microstructures modified by mineral ***,the influence of mineral admixtures on the mechanical properties of cementitious composites microstructures has not been fully understood.C-S-H(Calcium-silicate-hydrate) gel is the most important hydration product of cement and contributes the most to the engineering performances of cement-based ***,to reveal the influence of mineral admixtures on the mechanical properties of cementitious composites,this paper is to investigate the micro-mechanical properties of C-S-H gel influenced by mineral admixtures.
Constructed wetlands are increasingly being designed and used to treat wastewaters. The majority of constructed wetlands are designed based on steady-state releases of pollutant loading. However, in some cases (i.e., ...
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Current heritage analysis applications and documentation techniques for timber roof structures rely on manual measurements to provide the spatial data. Major simplifications are made to document these structures effic...
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Recently, rehabilitation of concrete structures with fiber reinforced polymer (FRP) has grown to be an extensively used system in most parts of the world. The main aim for this is that it is possible to obtain a suita...
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A building retrofitted with wing walls in the bottom story, which was damaged during the 2008 M8.0 Wenchuan earthquake in China, is introduced and a corresponding 1/4 scale wing wall-frame model was subjected to shake...
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A building retrofitted with wing walls in the bottom story, which was damaged during the 2008 M8.0 Wenchuan earthquake in China, is introduced and a corresponding 1/4 scale wing wall-frame model was subjected to shake table motions to study the seismic behavior of this retrofitted structural system. The results show that wing walls can effectively protect columns from damage by moving areas that bear reciprocating tension and compression to the sections of the wing walls, thus achieving an extra measure of seismic fortification. A ‘strong column-weak beam＇ mechanism was realized, the flexural rigidity of the vertical member was strengthened, and a more uniform distribution of deformation among all the stories was measured. In addition, the joint between the wing walls and the beams suffered severe damage during the tests, due to an area of local stress concentration. A longer area of intensive stirrup is suggested in the end of the beams.
Bucking of longitudinal bars in concrete columns under earthquake may lead to seismic behaviour deterioration and bearing capacity degradation, or even component invalidation and structural collapse. In the existing m...
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Bucking of longitudinal bars in concrete columns under earthquake may lead to seismic behaviour deterioration and bearing capacity degradation, or even component invalidation and structural collapse. In the existing material tests of steel bar and experimental studies of reinforcing concrete component, it's common to define the beginning of bending under compression as the onset of buckling through visual observation, which is inaccurate. Three determining methods are proposed to predict the onset of buckling based on experimental results of cyclic tension-compression tests of steel bars and analysis of the strain difference of opposite faces,lateral deflection and their variation respectively. The analytical results of 23 cyclic loading tests of steel bars using these methods indicate that the combination of "critical lateral deflection " method and "critical variation of lateral deflection" method can predict the onset of buckling more reasonably and accurately.
A reliability-based analysis method considering spatial variability of soil properties was proposed for stability analysis of pile-reinforced slope system in this paper. A total of 71 three dimensional (3D) finite ele...
A reliability-based analysis method considering spatial variability of soil properties was proposed for stability analysis of pile-reinforced slope system in this paper. A total of 71 three dimensional (3D) finite element simulation results were used to develop a Polynomial Regression (PR) model relating the safety factor (FOS) of the slope system to the key input parameters. The PR model was proved to be reasonably accurate with a high coefficient of determination. It was subsequently implemented into a modified spreadsheet involving First-order reliability method (FORM) and spatial variability factors to perform spatial variability and reliability analyses. Based on the results, some useful conclusions are arrived with regard to the effects of spatial variability factors. In addition, a useful guideline for geotechnical engineers to choose suitable pile locations in engineering practices is provided.
This study aims to automate earthworks by digitizing earthwork sites through a three-dimensional (3D) geotechnical analysis platform. Institutionalization is required to promote the development of related component te...
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This study aims to automate earthworks by digitizing earthwork sites through a three-dimensional (3D) geotechnical analysis platform. Institutionalization is required to promote the development of related component technologies and applications of the technologies suitable to the characteristics of construction projects in South Korea. The 3D geotechnical analysis platform has already been developed and completed demonstration tests. Through the tests, it is verified that the database derived from the platform contains coordinates of topography, soil quality, drilling, earthwork quantity, cutting or filling information, which is the basic information of earthwork planning used in fleet management. Furthermore, the study aims to understand the current systems, standards and manuals on earthwork automation in the US and Japan to establish measures to institutionalize and promote the earthwork automation for South Korea. Additional research will be performed to define the cell types in consideration of various ground shapes to plan movement directions and stop locations of the equipment.
Foamed Cement Banking filling technology is one of the most effective methods in soft foundation treatments, such as the bumping at joints of a bridge-road, the different settlement of subgrade broadening and the stab...
Foamed Cement Banking filling technology is one of the most effective methods in soft foundation treatments, such as the bumping at joints of a bridge-road, the different settlement of subgrade broadening and the stability problem of a high-filling embankment. To study on the characteristics of stress and strain for air-foam-treated lightweight soil, specimens were prepared at an optimized mixing ratio, and triaxial tests were conducted for strain and stress fitting. An ideal elastic-plastic model was used to simplify the relationship of strain and stress in an engineering sense, plus numerical simulation. The research results have great significance for addressing the issues of the stress-strain relationship, selecting design parameters and guiding engineering application with respect to air-foam-treated lightweight soil.
The energy use for materials and on-site construction assumes significance after we reach a threshold regarding building operational energy efficiency. Integration of energy use and emissions into construction plannin...
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