For the use of external energy sources, this paper studies the changes in physical parameters and mutual response principle of the metallic thermal protection system of aerospace crafts under rapid aerodynamic heating...
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Based on the one-dimensional wave theory for an anchoring system,according to the energy intensity change and phase shift for stress wave’s reflection signals in different wave impedances,research on the non-destruct...
Based on the one-dimensional wave theory for an anchoring system,according to the energy intensity change and phase shift for stress wave’s reflection signals in different wave impedances,research on the non-destructive detection test has been carried out for an anchor system with different locations of defect,defect length,and grouting compactness by using the bolt *** results show that due to the influence of the stress wave’s reflection signal at the anchor rod’s defect section,the deformity is generated on the waveform *** characteristic of the tested stress wave curve changes with the defection length and position and the tested defect position is relatively close to the real *** research work illustrates the practicability of the use of stress wave to perform the anchor quality’s non-destructive test.
The application of rock bolting in the reinforcement of underground engineering and tunnel engineering is becoming more extensive, and the stress distribution pattern of rock bolt is a necessary means for quality moni...
The application of rock bolting in the reinforcement of underground engineering and tunnel engineering is becoming more extensive, and the stress distribution pattern of rock bolt is a necessary means for quality monitoring. To investigate the stress characteristics of the rock bolt during usage, this paper tests the stress and strain changes of the full-length anchoring rock bolt and the end anchoring rock bolt under the action of pulling force based on the wireless sensor network (WSN) technology, it analyzes the strain characteristics of the exterior of the rock bolt. The research shows that the axial force of the full-length anchoring rock bolt increased with the increase of the load, when the load reached 28MPa, the bolt at the end of rock bolt rod slid; the longitudinal strain of the base of the end anchoring rock bolt was only affected by the top pressure, the shear stress of the middle hollow anchoring section was 0, and the axial strain was the largest; for the full-length anchoring rock bolt, the shear stress was distributed along the whole length of the rod body, and the strain value at the front end was the largest; for the two anchoring methods, both the wavelength drift of the fiber Bragg grating (FBG) measuring points on the rod body of rock bolt and the strain of the base increased with the increase of the load. This study lays a theoretical foundation for long-term quality monitoring and evaluation of rock bolting based on WSN.
The complex environment around the foundation pit affects the selection of foundation pit support, and the excavation works become more complicated. Taking the foundation pit engineering of Central Hospital of Shengli...
The complex environment around the foundation pit affects the selection of foundation pit support, and the excavation works become more complicated. Taking the foundation pit engineering of Central Hospital of Shengli Oil Field in Dongying as an example, the finite element analysis of pile anchor, double row pile, double row pile and inclined bracing combined support form is carried out by using MADIS GTS/NX three-dimensional finite element analysis software. The variation trend and stiffness variation of foundation pit displacement under different supporting forms are analyzed. The combined support form is a complicated support form. The result of finite element calculation shows that because of the different stiffness of the supporting structure, the stress concentration phenomenon and the structural displacement abrupt exist near the boundary of different support forms, but under the same support form, the displacement of soil mass increases with the distance of the distance to the corner of the foundation pit. As the length of foundation pit increases, the displacement of foundation pit has obvious spatial effect.
With the rapid development of modern society, energy consumption is a major concern all over the world. Building energy consumption takes a large proportion in the total energy consumption, and thus attracts much atte...
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With the rapid development of modern society, energy consumption is a major concern all over the world. Building energy consumption takes a large proportion in the total energy consumption, and thus attracts much attention. Thermal performance of building envelopes is the determinant factor of building energy consumption. Building envelope retrofitting is an effective way of reducing energy consumption in existing building. For different climates, there may exist different optimal retrofitting schemes. In this paper, two most popular retrofitting methods, namely thermal insulation and high-reflectivity coating on building walls in cooling dominate cities are investigated. Four cities with different climates are selected, and the impacts of internal versus external thermal insulation are investigated. Result indicates that in cooling dominate cities employing both thermal insulation and high reflectivity coating could significantly reduce cooling load through building external wall. Also, performance of retrofitting on different wall surface varies with different orientations. In climates with little diurnal temperature change in the summer season, internal insulation performs better than external insulation in reducing air-conditioning load, which typically operates during part of a day, whereas in climates in which there is a free cooling period during the night, external insulation will perform better.
With the trend of large span in the development of footbridge, its nonlinear characteristic is more and more obvious. Bifurcation has a great influence on the nonstationary trivial solution and its boundary stability ...
With the trend of large span in the development of footbridge, its nonlinear characteristic is more and more obvious. Bifurcation has a great influence on the nonstationary trivial solution and its boundary stability of nonlinear vibration. Based on the Millennium Bridge in London, this paper deduces its nonlinear transverse vibration equation. Also, the method of Galerkin and multi-scale method is used to obtain the judgment condition of nonstationary trivial stability. Based on the bifurcation theory, the influence of nonlinear behavior on nontrivial solution as well as its stability is studied in the paper under two situations, a 1 − σ bifurcation and a 1 − ζ2 bifurcation of parameter plane respectively.
作者：
Bei LiuXianbin SunMaster graduate student
School of Civil Engineering and Environment Hubei University of Tech. Wuhan 430068 China Research direction for the construction and civil engineering telephone number:*** China professor
Hubei University of Technology Research direction forengineering measurement China
With the rapid development of urban roads, especially the construction of subway rail transit, it is an effective way to alleviate urban traffic congestion. There are limited site space, complex resource allocation, t...
With the rapid development of urban roads, especially the construction of subway rail transit, it is an effective way to alleviate urban traffic congestion. There are limited site space, complex resource allocation, tight schedule, underground pipeline complex engineering problems. BIM technology, three-dimensional visualization, parameterization, virtual simulation and many other advantages can effectively solve these technical problems. Based on the project of Shenzhen Metro Line 9, BIM technology is innovatively researched throughout the lifecycle of BIM technology in the context of the metro rail transit project rarely used at this stage. The model information file is imported into Navisworks for four-dimensional animation simulation to determine the optimum construction scheme of the shield machine. Subway construction management application platform based on BIM and private cloud technology, the use of cameras and sensors to achieve electronic integration, dynamic monitoring of the operation and maintenance of underground facilities. Make full use of the many advantages of BIM technology to improve the engineering quality and construction efficiency of the subway rail transit project and to complete the operation and maintenance.
作者：
Jun HanXiao BenlinMaster graduate student
School of Civil Engineering and Environment Hubei University of Tech. Wuhan 430068 China Research direction for the construction and civil engineeringtelephone number:*** China professor
Hubei University of Technology Research direction forengineering measurement China
In recent years, with the rapid development of highways and railways in our country, there have been many new bridges that need to cross the existing routes. If the conventional construction methods are used, the exis...
In recent years, with the rapid development of highways and railways in our country, there have been many new bridges that need to cross the existing routes. If the conventional construction methods are used, the existing traffic will be affected and the traffic will be built above the busy traffic lines, so there is a big security risk, the construction methods must be improved and innovated. In this paper, it intends to research and develop some key technologies of swivel construction. According to the construction features to use finite element method of swivel cable-stayed bridge to analyse the cable-stayed bridge . The swivel construction process is carried out to solve the technical problems and difficulties in the construction.
This investigation evaluates the characteristics of alkali-activated controlled low-strength materials (CLSM) that were produced using a mixture of red mud (RM) and ground granulated blast-furnace slag (GGBFS) with di...
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In recent years, demand-based control in HVAC systems have achieved a great amount energy saving by providing precise services in according to actual demand. As the premise of determining actual demand, occupancy info...
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In recent years, demand-based control in HVAC systems have achieved a great amount energy saving by providing precise services in according to actual demand. As the premise of determining actual demand, occupancy information has a significant impact on building heating, cooling and ventilation in building control and energy auditing. In this paper, a Wi-Fi probe based occupancy detection method is applied to detect the occupancy in typical office buildings. Given the Wi-Fi coverage and smart devices are widely used in modern buildings, Wi-Fi probe requires no initial investment and could scan the Internet connection request and response of occupants. Previous studies suggest time-series and stochastic characteristics of occupancy information, this research proposed a Time-Window based Markov Chain (TWMC) model to detect occupancy. An on-site experiment was conducted in this study to validate the proposed method. The results report an accuracy of over 80% (x-accuracy when x equals 4). Compared to actual occupancy profile, the proposed model shows over 88% of supply air amount reduction in energy simulation with an absolute deviation less than 20%. By integrating the proposed TWMC model based on Wi-Fi probe and demand-based control system, the energy consumption of HVAC system could be significantly reduced.
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