Applied Mechanics and Materials Vols. 193-194

Abstract: The paper puts forward to the differential relationship of heating, and has solved the simulative relation-formula for design conditions of direct heating pipe network. This paper indicated the discipline concerning the user temperature (or load) changes with the flow, and proposed the terms such as limit load ratio and allowable relative flow ratio, and Etc. This paper lay the groundwork for heating pipe network simulation design of thermal conditions.

Abstract: In order to ensure the safety of the runway expansion project in Qingyang airport, the paper conduct an in-depth analysis of construction safety features from the aspects of construction machinery and equipment, intercrossed construction, the construction team, the surrounding environment, and the construction time limit. First of all, measures are taken in terms of the safety regulatory agencies, the responsibility realization, related management systems, safety publicity, and three-level education. Then further measures are taken from the aspects of safety investment, safety facilities, hazardous source identification, and on-site safety management. These measures work together to make the whole project construction process without any security accidents and realize the intended goal.

Abstract: The bond behavior on the FRP-concrete interface is a key factor to affect the behavior of members strengthened with FRP. In this paper, an analytical model to simulate the bond behavior on FRP-concrete interface between two adjacent cracks is derived; furthermore, the calculation method of the steel strain at the crack which is the key parameter in this model is given. Comparison between experimental result and theoretical calculation on FRP stain distribution in beam indicates that the analytical model can well predict the test results.

Abstract: In order to solve subgrade problems during the road construction in the shallow ground water area, light well point drainage technology is used, combined with the zhengbian logistics road. This paper expounds application principle of the light well point drainage, calculation and construction methods. When using light well point drainage, the appropriate permeability coefficient is 4 m/d relatively. If using water rushed law construction, water pressure should be controlled in 0.3-0.7 MPa. After well point equipment operates for 3-5 days, the foundation will form the precipitation funnel; then, soil can be excavated after drainaging 7-8d. It is shown that the light well point drainaging can reduce underground water lefficiently.

Abstract: As a passive cooling strategy aimed at controlling increased surface temperatures and creating cooler urban environments, a passive evaporative cooling wall constructed of moist void bricks was developed. The wall is capable of absorbing water and allows wind penetration, thus reducing their surface temperatures by means of water evaporation. This paper presents a numerical simulation method to predict and evaluate microclimatic modifying effects (air temperature reduction, ventilation cooling and vapor generation) of the wall in urban locations where installation of the wall is under consideration. This simulation is performed by coupling computational fluid dynamics (CFD) with a 3D-CAD-based thermal simulation tool. Methodology of the coupled simulation was described in this paper. In order to demonstrate the applicability of the proposed simulation method, a case study was performed to predict and evaluate the thermal improvement effect of the wall on thermal comfort at a rest station where the wall was installed. Simulation results show that, in terms of air temperature, airflow, humidity and surface temperature distributions, this simulation method can provide quantitative predictions and evaluations of microclimatic modifying effects resulting from the application of the wall.

Abstract: As an important index reflecting residential quality, the lighting environment level of residential buildings exerts tremendous influence on both physical and psychological health of residents. Taking a typical rural house in Weihe Plain as example, with indoor lighting environment test, lighting habits of the resident and Ecotect software, the paper studies indoor lighting environment quality of rural residential buildings in Weihe Plain and analyzes the influence of residential buildings' design on lighting environment. The result shows that rural residents in Weihe Plain usually don’t attach due importance to the lighting environment quality of living space, and the design of indoor space goes against effective utilization of natural light. Thus, the paper eventually brings forward a method to consummate the lighting environment of rural residential buildings and explores the buildings’ potential of saving energy by making use of natural light.

Abstract: Engineering bridge construction is a very complicated system work. The potential risk would occur frequently in the process from construction preparation to completion. The bridgework has fundamental features in huge investment, complex technology, broad engineering, long project life cycle and big impact if an accident happened. Compared to other highway construction process,there are more risks in the process of the bridgework. According to the method of steel tube concrete composite column bridge pier construction on bridge engineering, this thesis identifies the bigger risk factors in the procedure with the analytic hierarchy process. Combined with the technology of the MIDAS/CIVIL and imitating upper structure construction of actual construction process, it quantificationally analyses the construction risk. This could be for the reference to risk analysis on bridge project construction.

Abstract: In this paper, a great deal of research undertaken to study the dynamic responses of a high-speed railway bridge subjected to moving trains. Based on coupling vibration analysis of a rigid frame-continuous bridge, the effect on the kinetic characteristics induced by track irregularities, temperature and creep is discussed. The results show that great changes occur in parameters of trains such as rate of wheel load reduction, the vertical acceleration and the vertical Sperling index when considering the effect of temperature and creep compared with regarding track irregularities only. It is recommended that the combination of track irregularities, temperature and creep is essential to evaluate dynamic feature of train-bridge coupled system for high-speed railways.

Abstract: In the construction of deep, large, and irregular foundation pit, Shanghai Museum of Natural History, with another foundation pit of Metro Line 13 in it, lowering confined water has an large effect on the safety of the foundation pit construction and the protection of the surrounding environment. Many confined water pumping tests were carried out in this construction, and with the help of numerical simulation, the results indicate that the dewatering effect of pumping wells with filter tube of 8 m is better, although two different pumping wells with filter tube of 4 m and 8 m have the same flow rate and influential radius; the barrier effect is not obvious if the depth of underground continuous wall inserted into confined water layer is less than one third of the thickness of confined water layer; it takes less than 360 minutes to reach 80% of the total drawdown, the drawdown decreases to 90% of the total drawdown 10 minutes after the wells are stopped. Then the schemes of dewatering and pumping wells cooperated with the excavation are developed based on the seepage laws.

Abstract: By the experiment of 13 RC beam strengthened with CFRP, the paper mainly study the effect on the load carrying capacity of normal section of CFRP-strengthened beams for CFRP debonding. The results show that for the strengthened beams without any anchorage at plate-end, they lost load carrying capacity soon after CFRP debonded and quitted working, or went on carrying load like an ordinary RC beam. Besides, the formula for the effective CFRP strain when CFRP end debonded was proposed. For the strengthened beams with sufficient anchorage at plate-end, the strengthened beams should be simplified as simply supported unbonded concrete member after CFRP debonded. A reduction factor was adopted to modify the ultimate tension strain derived from the planar section assumption. The calculated results of ultimate carrying capacity were in reasonable agreement between the suggested formula and the test results.