In general, the process of building construction makes the inevitable wastes such as nails, formwork, steel and concrete. In order to reduce these wastes, parts of building have therefore been produced by using the ma...
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To establish a working system in field to evaluate the degree of fire-damage readily for both brittle and ductile tunnel supporting materials, this research focused on the failure characteristics and evolution on both...
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ISBN:
(纸本)9791156103158
To establish a working system in field to evaluate the degree of fire-damage readily for both brittle and ductile tunnel supporting materials, this research focused on the failure characteristics and evolution on both macro-scale (stiffness, strength and toughness) as well as micro-scale (localization, crack initiation and propagation). After applying various heat-driven-damage treatments, both brittle material such as concrete (rock-like material) and ductile steel were conducted uniaxial compressive and tensile tests respectively. Furthermore, this study propose a velocity ratio, defined as VS/VP, to be an index to identify the degree of thermos-induced damage in field. By applying maximum temperature varied from 25 to 1200 with constant rate of heating (5 /min), exposure time (300 mins), and cooling condition (cooling in furnace), the uniaxial compressive and tensile tests with post-peak behavior were obtained by controlling the lateral COD (crack opening displacement) as a feedback signal to conduct the closed-loop experiences. Associated with ultrasonic pulse (UP) and synchronized acousto-optic nonintrusive technique (AE & ESPI), macro- and micro-scale failure of materials were examined corresponding to entire loading histories of uniaxial compressive tests. The results show that VS/VP has a positive correlation with degree of thermos-induced damage on concrete, the correlation coefficient of VS/VP between stiffness, strength and toughness are -0.90, -0.87 and -0.77 respectively. It proves that the VS/VP can be used to identify the degree of thermos-induced damage such as fire disaster. In macro-scale, concrete suffer heat-driven damage cause the post-peak stability from snap back (Class II) convert to snap through (Class I), and the transition temperature is between 200 to 400. In micro-scale, as the maximum temperature increase, the more severe the degree of thermos-induced damage, in addition, it leads to more insignificant "localization" phenomenon graduall
Insulated concrete sandwich panels are composed of two concrete wythes separated by an insulation layer and connected by shear connectors. This paper develops a multifunctional photovoltaic (PV) integrated insulated c...
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In present work thermal and moisture concentration effects on laminated composite hypars is explored. Third degree thickness coordinate is considered in plane displacement variables. The twist curvatures of hypars is ...
In present work thermal and moisture concentration effects on laminated composite hypars is explored. Third degree thickness coordinate is considered in plane displacement variables. The twist curvatures of hypars is considered in present analysis. The shear correction factor is eliminated due to actual representation of transverse shear in present work. Imposition of nil transverse shear stress conditions at top and bottom of the surface of hypars is done mathematically. Finite element (FE) formulation of present mathematical model is done using a nine noded curved isoparametric element with seven unknowns at each node. FE formulation is coded in FORTRAN. The comparison study of present work is found to be consistent with previous published works by different methods. The parametric study is done by varying different parameters like moisture concentration, temperature variations, and boundary conditions.
Tibetan stone masonry is different from common masonry structure. However, currently, few studies on its structural characteristics and mechanical properties are conducted. This paper summarizes the materials, composi...
Tibetan stone masonry is different from common masonry structure. However, currently, few studies on its structural characteristics and mechanical properties are conducted. This paper summarizes the materials, composition and masonry methods of Tibetan stone masonry, and analyzes its structural characteristics. A uniaxial compression test on the small specimens built in the laboratory and the full-scale wall specimens on the site is conducted to explore the damage mechanism of the Tibetan stone masonry. Based on the compression performance of Tibetan stone masonry, this paper proposes the factor set, weight coefficient, and rating criteria of the safety assessment of the Tibetan stone masonry components by using the fuzzy comprehensive evaluation and analytic hierarchy method. The evaluation method of the safety status of components is also put forward, which is validated by the test results.
Erythromycin（ERY）,a widely used antibiotic,has recently been detected in municipal secondary effluents and poses serious threats to human health during wastewater *** this study,the removal,fate,and degradation path...
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Erythromycin（ERY）,a widely used antibiotic,has recently been detected in municipal secondary effluents and poses serious threats to human health during wastewater *** this study,the removal,fate,and degradation pathway of ERY in secondary effluent during soil aquifer treatment was evaluated via laboratory-scale SAT *** to a 92.9%reduction of ERY in synthetic secondary effluent was observed in 1.0 m depth column system,which decreased to 64.7%when recharged with wastewater treatment plant secondary ***-fractionation results demonstrated that the transphilic acid and hydrophobic acid fractions in secondary effluent compete for the adsorption sites of the packed soil and lead to a declined ERY ***,aerobic biodegradation was the predominant role for ERY removal,contributing more than 60%reduction of ERY when recharged with synthetic secondary *** of 14-member macrocyclic lactone ring and breakdown of two cyclic sugars（L-cladinose and D-desosamine） were main removal pathways for ERY degradation,and produced six new intermediates.
The internal wall and road surface of tunnel form the background of roadblock or vehicle together, and have a significant influence on the safety and comfort of tunnel lighting. In this paper, the optical simulation p...
The internal wall and road surface of tunnel form the background of roadblock or vehicle together, and have a significant influence on the safety and comfort of tunnel lighting. In this paper, the optical simulation program is adopted to analyze the correlation between the reflectivity of tunnel wall and such illumination indexes as luminance and illuminance of road surface inside a tunnel, as well as the visibility of small target etc. It shows from the study that: (1) The reflectivity of wall on the luminance gain level of road surface is closely related to the luminous intensity distribution of lamps. (2) Under the circumstance that the luminous intensity distribution of lamps is consistent, the linear relations basically exist among the reflectivity of wall, the illuminance and luminance of road surface and the luminance of wall, while the maximum growth slopes are 11.29, 0.45 and 11.50 respectively. (3) The field of vision of driver can be significantly improved by a higher reflectivity of wall. (4) Compared with the three illumination modes, the visibility of small target under the pro-beam lighting is highest (the minimum visibility is 10, and the highest visibility can reach 11.6), while the visibility of small target under the counter-beam lighting is the second-highest and the visibility of small target under the symmetric lighting is most non-obvious.
The use of S355 high strength steel in civilengineering design of structural elements of cranes, bridges or simple engineering parts allows material and economical savings to be achieved meeting the strict constructi...
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The use of S355 high strength steel in civilengineering design of structural elements of cranes, bridges or simple engineering parts allows material and economical savings to be achieved meeting the strict construction requirements. Knowledge of fatigue resistance of the material plays the key role during design and maintenance of the civilengineering structures. With this aim, the fatigue properties (Wöhler field and crack propagation rate curve) of the S355 J0 steel are analyzed according to both traditional and probabilistic models. In the latter case, the ProFatigue and ProPagation software programs are applied in the assessment of experimental fatigue data of S355 J0 for derivation of the probabilistic S–N field and fatigue crack growth rate curve, respectively, where data consist of results for different number of various investigated specimens subject to low cycle and high cycle fatigue with focus on the rolling direction. The results obtained are compared with the customary Basquin formula for the Wöhler-curve and Paris law for the crack growth rate curve, both represented as straight lines in a double-logarithmic scale.
The paper discusses the relevance of ensuring environmentally safe pipeline operation by identifying natural and industrial hazards and the potential impact. An operating trunk pipeline running west to east across a s...
The paper discusses the relevance of ensuring environmentally safe pipeline operation by identifying natural and industrial hazards and the potential impact. An operating trunk pipeline running west to east across a specific territory (constituent entity) was given as an example to show areas likely exposed to the most dangerous destructions. These are natural and man-made pipeline crossovers and intersections designated by the authors as ecologically fragile areas (EFAs). For a natural/industrial impact identification methodology, relevant hazards were identified and classified by the exposure degree for each gas pipeline EFA. Given geodynamic changes, the data collected were to be updated after each change. The article outlines the new methodology also suitable for territorial cartographic zoning subject to hazard factors. An area to be affected by degradation processes of an accident is determined by using the radii of thermal impact and scatter of pipe fragments. Such data help compute flora and fauna damage and, for the best scenario, damage prevented. The key points of this survey may be used to developing computer programs to compute an aggregate hazardous impact on an operating pipeline and simulate emergency scenarios. The practical utility consists in assuring proper EFAs monitoring for timely prevention of accidents.
The article deals with the issues of conducting renovation policy of multi-family buildings made of a large-panel technology. The authors showed a method of estimating the degree of wear of building elements using fuz...
The article deals with the issues of conducting renovation policy of multi-family buildings made of a large-panel technology. The authors showed a method of estimating the degree of wear of building elements using fuzzy logic. Then, the elements requiring repair were selected and the costs of replacing or reinforcing elements were estimated. On the basis of the elements’ wear and costs of repair, elements intended for renovation were selected.
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