A self-developed elasto-plastic finite element program was used to analyze the construction sequence of high rock slope's stabilization in a coal-coking plant, and the result was compared with that employing the u...A self-developed elasto-plastic finite element program was used to analyze the construction sequence of high rock slope's stabilization in a coal-coking plant, and the result was compared with that employing the ultimate equilibrium method. Based on the results of finite element analysis, the stress contour graphs and displacement vector graphs at different construction steps were obtained, and the behavior of the slope during stabilization construction process was analyzed quantitatively. Based on the analysis of safety factors of three different schemes of stabilization and two different construction schemes, the assessment of stability and bracing design of the construction process were performed. The results show that the original reinforcement design is improper; the stability of the rock slope is controlled by a developed structural plane, the stability factor after excavation is less than 1, and the free surface should be braced in time; for stability, the construction sequence should adopt that bracing follows excavation step by step up to down; the local slide occurred during the construction process agrees with the dangerous slide determined by the numerical analysis, which proves the validity and rationality of the adopted method.展开更多
China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization an...China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.展开更多
Quality traceability plays an essential role in assembling and welding offshore platform blocks.The improvement of the welding quality traceability system is conducive to improving the durability of the offshore platf...Quality traceability plays an essential role in assembling and welding offshore platform blocks.The improvement of the welding quality traceability system is conducive to improving the durability of the offshore platform and the process level of the offshore industry.Currently,qualitymanagement remains in the era of primary information,and there is a lack of effective tracking and recording of welding quality data.When welding defects are encountered,it is difficult to rapidly and accurately determine the root cause of the problem from various complexities and scattered quality data.In this paper,a composite welding quality traceability model for offshore platform block construction process is proposed,it contains the quality early-warning method based on long short-term memory and quality data backtracking query optimization algorithm.By fulfilling the training of the early-warning model and the implementation of the query optimization algorithm,the quality traceability model has the ability to assist enterprises in realizing the rapid identification and positioning of quality problems.Furthermore,the model and the quality traceability algorithm are checked by cases in actual working conditions.Verification analyses suggest that the proposed early-warningmodel for welding quality and the algorithmfor optimizing backtracking requests are effective and can be applied to the actual construction process.展开更多
In order to improve the efficiency of EPS integral thermal insulation building design and optimize the construction process of insulation construction, this paper uses experiment parts and simulation form to design th...In order to improve the efficiency of EPS integral thermal insulation building design and optimize the construction process of insulation construction, this paper uses experiment parts and simulation form to design the thermal insulation construction process, and evaluates the effect of heat preservation. Based on the finite element theory this paper designs adding process of insulation material EPS in the thermal insulation layer, and establishes the radiation heat conduction model of EPS material, finally obtains the solid heat conduction equation. Finally this paper uses ANSYS software to do simulation on the strength and temperature of EPS construction, and evaluates the quality of construction works, which provides technical reference for the design of integrated thermal insulation buildings.展开更多
Over the years, China's economy has developed rapidly, which has also provided favorable conditions for the development of all walks of life. On this basis, the income level of our people has continuously improved...Over the years, China's economy has developed rapidly, which has also provided favorable conditions for the development of all walks of life. On this basis, the income level of our people has continuously improved, and the quality of life has also begun to continuously improve. More and more people begin to install HVAC systems in their homes. In order to better meet people's needs and actively respond to the national call for environmental protection, the relevant construction industry should pay attention to BIM technology and strive to achieve the goal of environmental protection and energy conservation through this technology. This paper makes an in-depth analysis on the energy-saving effect of BIM in the HVAC construction process, with a view to promoting the sustainable and healthy development of the construction industry.展开更多
At present, China's urbanization process is further accelerated, people also have more and more requirements for landscape architecture projects, in such a situation, it is necessary to do a more effective job in ...At present, China's urbanization process is further accelerated, people also have more and more requirements for landscape architecture projects, in such a situation, it is necessary to do a more effective job in landscape architecture construction, for the construction of various management work in the process of project construction should also be effectively strengthened, in the on-site construction link to further improve the management level, and then for the effective improvement of the quality of landscape architecture construction to provide the necessary guarantee. Combined with this situation, this paper explores the relevant contents of on-site management measures in the construction process of landscape architecture, hoping that the analysis of this paper can provide certain enlightenment for relevant practitioners, and then promote the quality of urbanization development to be more effectively improved.展开更多
In the process of carrying out construction projects, quality and safety should always be the core of development, so as to strengthen the protection of residents' lives and property safety. In this process, atten...In the process of carrying out construction projects, quality and safety should always be the core of development, so as to strengthen the protection of residents' lives and property safety. In this process, attention should be paid to the construction management and quality control. Meanwhile, scientific and perfect management measures should be adopted to improve the project quality, thus promoting the common development of economic and social benefits of construction enterprises and enhancing the overall level of market competition. In order to further realize the sustainable development of the project, it is necessary to strengthen the discussion on the quality control measures of the project construction so as to realize the stable development of the project.展开更多
At present, according to the specific situation of urban construction projects, many enterprises attach great importance to the construction quality in the operation process. In order to improve the construction quali...At present, according to the specific situation of urban construction projects, many enterprises attach great importance to the construction quality in the operation process. In order to improve the construction quality, they will formulate corresponding construction management system to optimize the project management and construction. With the continuous development of society, it is necessary to innovate the construction of projects, so as to promote the deepening reform of urban construction projects in our country and promote the all-round development of urban construction projects.展开更多
With the increasing number of construction projects in our country, the standardization and scientificalness of project management are gradually improving. In the process of project construction, project management is...With the increasing number of construction projects in our country, the standardization and scientificalness of project management are gradually improving. In the process of project construction, project management is related to project quality and project cost. The construction unit should pay attention to the project management, strengthen the control of the construction process, put forward targeted control countermeasures, optimize the project management effect, improve the overall construction quality of the project, and promote the sustainable development of the construction industry in our country. Based on this, this paper studies the construction process control in urban construction management for reference.展开更多
In the process of China's social and economic development, agriculture is the foundation of its development. At the same time, the "three rural" problem is also the key problem that needs to be solved ur...In the process of China's social and economic development, agriculture is the foundation of its development. At the same time, the "three rural" problem is also the key problem that needs to be solved urgently in China's socialist construction. Therefore, in order to further promote the development of rural agricultural economy and solve the problems of water shortage, relatively low income of farmers and low quality of agricultural water use caused by bad factors such as climate and region, we should pay more attention to the construction of farmland water conservancy projects. However, although the rural irrigation and water conservancy project has brought higher economic benefits to farmers and improved the overall yield of grain, all kinds of construction problems can not be ignored. It is necessary to continuously improve the construction of water conservancy project, so as to better improve the construction quality of rural irrigation and water conservancy project.展开更多
In recent years, under the influence of various favorable factors, China's construction engineering industry has developed in an all-round way. At the same time, it also intensifies the competition situation in th...In recent years, under the influence of various favorable factors, China's construction engineering industry has developed in an all-round way. At the same time, it also intensifies the competition situation in the whole industry. In the whole construction engineering field, it is very important to improve the overall rationalization and labeling of management work, which is also the core interest of the construction project and the important foundation to ensure the steady and healthy development of the construction unit. Industrial and civil buildings are referred to as civil buildings for short. In the process of organizing and carrying out construction work, civil engineering usually needs to use many different types of construction technology. The level of construction technology will often have a huge impact on the quality of civil engineering. Therefore, when organizing and implementing various construction work in practice, it is necessary to fully combine the actual situation to carry out the whole-process construction technology management on site to ensure the orderly and efficient development of various work.展开更多
Urbanization has led to the rapid development of the construction industry.However,this has also led to higher requirements for the construction engineering management.Other than the quality monitoring of engineering ...Urbanization has led to the rapid development of the construction industry.However,this has also led to higher requirements for the construction engineering management.Other than the quality monitoring of engineering construction,the energy-saving properties of the building should also be considered.Therefore,a scientific management approach should be adopted to improve green building management.This paper primarily examines the importance of quality management in green building construction,along with the factors influencing it.It also identifies the quality issues present in current green building construction.Finally,it proposes measures for quality management in the green building construction process to facilitate the industry’s healthy development.展开更多
In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expan...In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.展开更多
This paper proposes a universal framework for constructing bivariate stochastic processes,going beyond the limitations of copulas and offering a potentially simpler alternative.The achieved generality of the construct...This paper proposes a universal framework for constructing bivariate stochastic processes,going beyond the limitations of copulas and offering a potentially simpler alternative.The achieved generality of the construction methods extends its applicability to diverse stochastic processes also including discrete as well as continuous time cases.The initially given two arbitrary univariate stochastic processes{Y_(t)},{Z_(t)},are only assumed to share the same time t.When considered as describing(time dependent)random quantities that are physically separated(the baseline case),the processes are independent.From this trivial case we move to the case when physical interactions between the quantities make them stochastically dependent random variables at any moment t.For each time epoch t,we impose stochastic dependence on two“initially independent”random variables Y_(t),Z_(t) by multiplying the product of their survival functions by a proper“dependence factor”φ_(t)(y_(t), z_(t)),obtaining in this way a universal(“canonical”)form valid for any(!)bivariate distribution.In some known cases,however,this form may become complicated thou it always exists and is unique.The dependence factor,basically,but not always,has the form φ_(t)(y, z)=exp[-∫^(y)_(0)∫^(z)_(0)Ψ_(t)(s ,u )dsdu]whenever such a continuous function Ψ_(t)(s ,u ) exists,for each t.That representation of stochastic dependence by the functions Ψ_(t)(s ,u ) leads,in turn,to the phenomenon of change of the original(baseline)hazard rates of the marginals,similar to those analyzed by Cox and,especially Aalen for single pairs(or sets)of,time independent,random variables.That is why,until Section 4,we consider only single random vectors(Y,Z)'joint survival functions,mostly as a preparation to the theory of bivariate stochastic processes{(Y_(t),Z_(t))}constructions as initiated in Section 4.The bivariate constructions are illustrated by examples of some applications in biomedical and econometric areas.展开更多
A newnumerical method based on vector form intrinsic finite element（VFIFE） is proposed to simulate the integral lifting process of steel structures. First, in order to verify the validity of the VFIFE method, taking...A newnumerical method based on vector form intrinsic finite element（VFIFE） is proposed to simulate the integral lifting process of steel structures. First, in order to verify the validity of the VFIFE method, taking the steel gallery between the integrated building and the attached building of Nanjing M obile Communication Buildings for example, the static analysis was carried out and the corresponding results were compared with the results achieved by the traditional finite element method. Then, according to the characteristics of dynamic construction of steel structure integral lifting, the tension cable element was employed to simulate the behavior of dynamic construction. The VFIFE method avoids the iterative solution of the stiffness matrix and the singularity problems. Therefore, it is simple to simulate the complete process of steel structure lifting construction.Finally, by using the VFIFE, the displacement and internal force time history curves of the steel structures under different lifting speeds are obtained. The results show that the lifting speed has influence on the lifting force, the internal force, and the displacement of the structure. In the case of normal lifting speed, the dynamic magnification factor of 1. 5 is safe and reasonable for practical application.展开更多
A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate...A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.展开更多
In this study, we examined the thermal effects throughout the process of the placement of span-scale girder segments on a 6×110-m continuous steel box girder in the Hong Kong-Zhuhai-Macao Bridge. Firstly, when a ...In this study, we examined the thermal effects throughout the process of the placement of span-scale girder segments on a 6×110-m continuous steel box girder in the Hong Kong-Zhuhai-Macao Bridge. Firstly, when a span-scale girder segment is temporarily stored in the open air, temperature gradients will significantly increase the maximum reaction force on temporary supports and cause local buckling at the bottom of the girder segment. Secondly, due to the temperature difference of the girder segments before and after girth-welding, some residual thermal deflections will appear on the girder segments because the boundary conditions of the structure are changed by the girth-welding. Thirdly, the thermal expansion and thermal bending of girder segments will cause movement and rotation of bearings, which must be considered in setting bearings. We propose control measures for these problems based on finite element method simulation with field-measured temperatures. The local buckling during open-air storage can be avoided by reasonably determining the appropriate positions of temporary supports using analysis of overall and local stresses. The residual thermal deflections can be overcome by performing girth-welding during a period when the vertical temperature difference of the girder is within 1 °C, such as after 22:00. Some formulas are proposed to determine the pre-set distances for bearings, in which the movement and rotation of the bearings due to dead loads and thermal loads are considered. Finally, the feasibility of these control measures in the placement of span-scale girder segments on a real continuous girder was verified: no local buckling was observed during open-air storage;the residual thermal deflections after girth-welding were controlled within 5 mm and the residual pre-set distances of bearings when the whole continuous girder reached its design state were controlled within 20 mm.展开更多
Time and cost are two of the most important factors to consider in each construction project. In order to maximize performance, both the client and the contractor will work to optimize both the duration of the project...Time and cost are two of the most important factors to consider in each construction project. In order to maximize performance, both the client and the contractor will work to optimize both the duration of the project and its cost. We show a model of linear entire mixed programming to solve the considered problem. The aim is to minimize the project total time, by means of the assignment of equipments of work to the different production lines of the activities to realizing. The fundamental beginning is to support the same production （rate of production in meters/day of the activity in view of the equipment of work） for tbe different equipments to achieve the maximum efficiency in each period of time. With the limited availability of resources, the work must be continuous and the period of time between operations and final must be kept. However, this paper also presents the bibliographical study on methodologies of the optimization of construction processes in response to the two objectives： time and cost. This will consider the use of recta-heuristic techniques, such as population based algorithms.展开更多
In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the enviro...In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the environment are increasingly complex, thus it has greater demands on project managers and cost managers that deliver processes on time. However the process of construction is limited to unforeseeable and variable factors, resulting from many sources. The aim of the report is to analyze determining factors about causing budget overrun and time delays by reviewing and identifying past cases. Furthermore, the construction process is made up of three critical phases, i.e. conception, design, construction. Generally, the majority of time delays and cost overrun happen in the period of construction, where many factors are always unforeseeable, and time delays usually associate with cost overruns. （Chan and Kumaraswamy, 1997）展开更多
Ground condition and construction （excavation and support） time and costs are the key factors in decision-making during planning and design phases of a tunnel project. An innovative methodology for probabilistic est...Ground condition and construction （excavation and support） time and costs are the key factors in decision-making during planning and design phases of a tunnel project. An innovative methodology for probabilistic estimation of ground condition and construction time and costs is proposed, which is an integration of the ground prediction approach based on Markov process, and the time and cost variance analysis based on Monte-Carlo （MC） simulation. The former provides the probabilistic description of ground classification along tunnel alignment according to the geological information revealed from geological profile and boreholes. The latter provides the probabilistic description of the expected construction time and costs for each operation according to the survey feedbacks from experts. Then an engineering application to Hamro tunnel is presented to demonstrate how the ground condition and the construction time and costs are estimated in a probabilistic way. In most items, in order to estimate the data needed for this methodology, a number of questionnaires are distributed among the tunneling experts and finally the mean values of the respondents are applied. These facilitate both the owners and the contractors to be aware of the risk that they should carry before construction, and are useful for both tendering and bidding.展开更多
基金Scientific and Technological Support and Guidance Plan Projects of Zhejiang Province(Grant No.2008C23019)
文摘A self-developed elasto-plastic finite element program was used to analyze the construction sequence of high rock slope's stabilization in a coal-coking plant, and the result was compared with that employing the ultimate equilibrium method. Based on the results of finite element analysis, the stress contour graphs and displacement vector graphs at different construction steps were obtained, and the behavior of the slope during stabilization construction process was analyzed quantitatively. Based on the analysis of safety factors of three different schemes of stabilization and two different construction schemes, the assessment of stability and bracing design of the construction process were performed. The results show that the original reinforcement design is improper; the stability of the rock slope is controlled by a developed structural plane, the stability factor after excavation is less than 1, and the free surface should be braced in time; for stability, the construction sequence should adopt that bracing follows excavation step by step up to down; the local slide occurred during the construction process agrees with the dangerous slide determined by the numerical analysis, which proves the validity and rationality of the adopted method.
基金National Natural Science Foundation of China,No.41130748No.41471143
文摘China＇s reform and opening-up policy has brought the country a great development opportunity. The high-speed growth of the economy not only led China to a period of industrialization, urbanization, informatization and agricultural modernization, but also exacerbated the situation of the urban–rural dual structure. Based on the review of current studies, we first used the analytic hierarchy process（AHP） method to evaluate the urban–rural development and transformation level by population transformation index, land transformation index, industrial transformation index and social transformation index between 1996 and 2012 around the Bohai Rim Region. Then, based on the results of each index, we used the exploratory spatial data analysis（ESDA） method to investigate the spatial autocorrelation of the change in the urban–rural development transformation index during the 16-year period using Global Moran＇s I index and Local Moran＇s I index. Finally, we investigated the mechanism of change of the urban–rural development transformation index at county level, summarizing five main factors：（1） the radiation from the surrounding big cities,（2） the acceleration of the urbanization process,（3） the upgrading of the industrial structure,（4） the publishing and implementation of a macro development strategy and regional policy, and（5） natural factors such as topology.
基金funded by Ministry of Industry and Information Technology of the People’s Republic of China[Grant No.2018473].
文摘Quality traceability plays an essential role in assembling and welding offshore platform blocks.The improvement of the welding quality traceability system is conducive to improving the durability of the offshore platform and the process level of the offshore industry.Currently,qualitymanagement remains in the era of primary information,and there is a lack of effective tracking and recording of welding quality data.When welding defects are encountered,it is difficult to rapidly and accurately determine the root cause of the problem from various complexities and scattered quality data.In this paper,a composite welding quality traceability model for offshore platform block construction process is proposed,it contains the quality early-warning method based on long short-term memory and quality data backtracking query optimization algorithm.By fulfilling the training of the early-warning model and the implementation of the query optimization algorithm,the quality traceability model has the ability to assist enterprises in realizing the rapid identification and positioning of quality problems.Furthermore,the model and the quality traceability algorithm are checked by cases in actual working conditions.Verification analyses suggest that the proposed early-warningmodel for welding quality and the algorithmfor optimizing backtracking requests are effective and can be applied to the actual construction process.
文摘In order to improve the efficiency of EPS integral thermal insulation building design and optimize the construction process of insulation construction, this paper uses experiment parts and simulation form to design the thermal insulation construction process, and evaluates the effect of heat preservation. Based on the finite element theory this paper designs adding process of insulation material EPS in the thermal insulation layer, and establishes the radiation heat conduction model of EPS material, finally obtains the solid heat conduction equation. Finally this paper uses ANSYS software to do simulation on the strength and temperature of EPS construction, and evaluates the quality of construction works, which provides technical reference for the design of integrated thermal insulation buildings.
文摘Over the years, China's economy has developed rapidly, which has also provided favorable conditions for the development of all walks of life. On this basis, the income level of our people has continuously improved, and the quality of life has also begun to continuously improve. More and more people begin to install HVAC systems in their homes. In order to better meet people's needs and actively respond to the national call for environmental protection, the relevant construction industry should pay attention to BIM technology and strive to achieve the goal of environmental protection and energy conservation through this technology. This paper makes an in-depth analysis on the energy-saving effect of BIM in the HVAC construction process, with a view to promoting the sustainable and healthy development of the construction industry.
文摘At present, China's urbanization process is further accelerated, people also have more and more requirements for landscape architecture projects, in such a situation, it is necessary to do a more effective job in landscape architecture construction, for the construction of various management work in the process of project construction should also be effectively strengthened, in the on-site construction link to further improve the management level, and then for the effective improvement of the quality of landscape architecture construction to provide the necessary guarantee. Combined with this situation, this paper explores the relevant contents of on-site management measures in the construction process of landscape architecture, hoping that the analysis of this paper can provide certain enlightenment for relevant practitioners, and then promote the quality of urbanization development to be more effectively improved.
文摘In the process of carrying out construction projects, quality and safety should always be the core of development, so as to strengthen the protection of residents' lives and property safety. In this process, attention should be paid to the construction management and quality control. Meanwhile, scientific and perfect management measures should be adopted to improve the project quality, thus promoting the common development of economic and social benefits of construction enterprises and enhancing the overall level of market competition. In order to further realize the sustainable development of the project, it is necessary to strengthen the discussion on the quality control measures of the project construction so as to realize the stable development of the project.
文摘At present, according to the specific situation of urban construction projects, many enterprises attach great importance to the construction quality in the operation process. In order to improve the construction quality, they will formulate corresponding construction management system to optimize the project management and construction. With the continuous development of society, it is necessary to innovate the construction of projects, so as to promote the deepening reform of urban construction projects in our country and promote the all-round development of urban construction projects.
文摘With the increasing number of construction projects in our country, the standardization and scientificalness of project management are gradually improving. In the process of project construction, project management is related to project quality and project cost. The construction unit should pay attention to the project management, strengthen the control of the construction process, put forward targeted control countermeasures, optimize the project management effect, improve the overall construction quality of the project, and promote the sustainable development of the construction industry in our country. Based on this, this paper studies the construction process control in urban construction management for reference.
文摘In the process of China's social and economic development, agriculture is the foundation of its development. At the same time, the "three rural" problem is also the key problem that needs to be solved urgently in China's socialist construction. Therefore, in order to further promote the development of rural agricultural economy and solve the problems of water shortage, relatively low income of farmers and low quality of agricultural water use caused by bad factors such as climate and region, we should pay more attention to the construction of farmland water conservancy projects. However, although the rural irrigation and water conservancy project has brought higher economic benefits to farmers and improved the overall yield of grain, all kinds of construction problems can not be ignored. It is necessary to continuously improve the construction of water conservancy project, so as to better improve the construction quality of rural irrigation and water conservancy project.
文摘In recent years, under the influence of various favorable factors, China's construction engineering industry has developed in an all-round way. At the same time, it also intensifies the competition situation in the whole industry. In the whole construction engineering field, it is very important to improve the overall rationalization and labeling of management work, which is also the core interest of the construction project and the important foundation to ensure the steady and healthy development of the construction unit. Industrial and civil buildings are referred to as civil buildings for short. In the process of organizing and carrying out construction work, civil engineering usually needs to use many different types of construction technology. The level of construction technology will often have a huge impact on the quality of civil engineering. Therefore, when organizing and implementing various construction work in practice, it is necessary to fully combine the actual situation to carry out the whole-process construction technology management on site to ensure the orderly and efficient development of various work.
文摘Urbanization has led to the rapid development of the construction industry.However,this has also led to higher requirements for the construction engineering management.Other than the quality monitoring of engineering construction,the energy-saving properties of the building should also be considered.Therefore,a scientific management approach should be adopted to improve green building management.This paper primarily examines the importance of quality management in green building construction,along with the factors influencing it.It also identifies the quality issues present in current green building construction.Finally,it proposes measures for quality management in the green building construction process to facilitate the industry’s healthy development.
文摘In recent years,China has made significant progress in the construction of highways,resulting in an improved highway network that has provided robust support for economic and social development.However,the rapid expansion of highway construction,power supply,and distribution has led to several challenges in mechanical and electrical engineering technology.Ensuring the safe,stable,and cost-effective operation of the power supply and distribution system to meet the diverse requirements of highway operations has become a pressing issue.This article takes an example of a highway electromechanical engineering power supply and distribution construction project to provide insight into the construction process of highway electromechanical engineering power supply and distribution technology.
文摘This paper proposes a universal framework for constructing bivariate stochastic processes,going beyond the limitations of copulas and offering a potentially simpler alternative.The achieved generality of the construction methods extends its applicability to diverse stochastic processes also including discrete as well as continuous time cases.The initially given two arbitrary univariate stochastic processes{Y_(t)},{Z_(t)},are only assumed to share the same time t.When considered as describing(time dependent)random quantities that are physically separated(the baseline case),the processes are independent.From this trivial case we move to the case when physical interactions between the quantities make them stochastically dependent random variables at any moment t.For each time epoch t,we impose stochastic dependence on two“initially independent”random variables Y_(t),Z_(t) by multiplying the product of their survival functions by a proper“dependence factor”φ_(t)(y_(t), z_(t)),obtaining in this way a universal(“canonical”)form valid for any(!)bivariate distribution.In some known cases,however,this form may become complicated thou it always exists and is unique.The dependence factor,basically,but not always,has the form φ_(t)(y, z)=exp[-∫^(y)_(0)∫^(z)_(0)Ψ_(t)(s ,u )dsdu]whenever such a continuous function Ψ_(t)(s ,u ) exists,for each t.That representation of stochastic dependence by the functions Ψ_(t)(s ,u ) leads,in turn,to the phenomenon of change of the original(baseline)hazard rates of the marginals,similar to those analyzed by Cox and,especially Aalen for single pairs(or sets)of,time independent,random variables.That is why,until Section 4,we consider only single random vectors(Y,Z)'joint survival functions,mostly as a preparation to the theory of bivariate stochastic processes{(Y_(t),Z_(t))}constructions as initiated in Section 4.The bivariate constructions are illustrated by examples of some applications in biomedical and econometric areas.
基金The National Natural Science Foundation of China(No.51308105)
文摘A newnumerical method based on vector form intrinsic finite element（VFIFE） is proposed to simulate the integral lifting process of steel structures. First, in order to verify the validity of the VFIFE method, taking the steel gallery between the integrated building and the attached building of Nanjing M obile Communication Buildings for example, the static analysis was carried out and the corresponding results were compared with the results achieved by the traditional finite element method. Then, according to the characteristics of dynamic construction of steel structure integral lifting, the tension cable element was employed to simulate the behavior of dynamic construction. The VFIFE method avoids the iterative solution of the stiffness matrix and the singularity problems. Therefore, it is simple to simulate the complete process of steel structure lifting construction.Finally, by using the VFIFE, the displacement and internal force time history curves of the steel structures under different lifting speeds are obtained. The results show that the lifting speed has influence on the lifting force, the internal force, and the displacement of the structure. In the case of normal lifting speed, the dynamic magnification factor of 1. 5 is safe and reasonable for practical application.
文摘A convenient approach is proposed for analyzing the ultimate load carrying capacity of concrete filled steel tubular (CFST) arch bridge with stiffening girders. A fiber model beam element is specially used to simulate the stiffening girder and CFST arch rib. The geometric nonlinearity, material nonlinearity, influence of the construction process and the contribution of prestressing reinforcement are all taken into consideration. The accuracy of this method is validated by comparing its results with experimental results. Finally, the ultimate strength of an abnormal CFST arch bridge with stiffening girders is investigated and the effect of construction method is discussed. It is concluded that the construction process has little effect on the ultimate strength of the bridge.
基金Project supported by the National Natural Science Foundation of China(Nos.51578496 and 51878603)the Zhejiang Provincial Natural Science Foundation of China(No.LZ16E080001)。
文摘In this study, we examined the thermal effects throughout the process of the placement of span-scale girder segments on a 6×110-m continuous steel box girder in the Hong Kong-Zhuhai-Macao Bridge. Firstly, when a span-scale girder segment is temporarily stored in the open air, temperature gradients will significantly increase the maximum reaction force on temporary supports and cause local buckling at the bottom of the girder segment. Secondly, due to the temperature difference of the girder segments before and after girth-welding, some residual thermal deflections will appear on the girder segments because the boundary conditions of the structure are changed by the girth-welding. Thirdly, the thermal expansion and thermal bending of girder segments will cause movement and rotation of bearings, which must be considered in setting bearings. We propose control measures for these problems based on finite element method simulation with field-measured temperatures. The local buckling during open-air storage can be avoided by reasonably determining the appropriate positions of temporary supports using analysis of overall and local stresses. The residual thermal deflections can be overcome by performing girth-welding during a period when the vertical temperature difference of the girder is within 1 °C, such as after 22:00. Some formulas are proposed to determine the pre-set distances for bearings, in which the movement and rotation of the bearings due to dead loads and thermal loads are considered. Finally, the feasibility of these control measures in the placement of span-scale girder segments on a real continuous girder was verified: no local buckling was observed during open-air storage;the residual thermal deflections after girth-welding were controlled within 5 mm and the residual pre-set distances of bearings when the whole continuous girder reached its design state were controlled within 20 mm.
文摘Time and cost are two of the most important factors to consider in each construction project. In order to maximize performance, both the client and the contractor will work to optimize both the duration of the project and its cost. We show a model of linear entire mixed programming to solve the considered problem. The aim is to minimize the project total time, by means of the assignment of equipments of work to the different production lines of the activities to realizing. The fundamental beginning is to support the same production （rate of production in meters/day of the activity in view of the equipment of work） for tbe different equipments to achieve the maximum efficiency in each period of time. With the limited availability of resources, the work must be continuous and the period of time between operations and final must be kept. However, this paper also presents the bibliographical study on methodologies of the optimization of construction processes in response to the two objectives： time and cost. This will consider the use of recta-heuristic techniques, such as population based algorithms.
文摘In this thesis,construction industries face with the major challenges are cost overruns and time delays, which have existed in most of projects, especially in developing countries. Construction projects and the environment are increasingly complex, thus it has greater demands on project managers and cost managers that deliver processes on time. However the process of construction is limited to unforeseeable and variable factors, resulting from many sources. The aim of the report is to analyze determining factors about causing budget overrun and time delays by reviewing and identifying past cases. Furthermore, the construction process is made up of three critical phases, i.e. conception, design, construction. Generally, the majority of time delays and cost overrun happen in the period of construction, where many factors are always unforeseeable, and time delays usually associate with cost overruns. （Chan and Kumaraswamy, 1997）
文摘Ground condition and construction （excavation and support） time and costs are the key factors in decision-making during planning and design phases of a tunnel project. An innovative methodology for probabilistic estimation of ground condition and construction time and costs is proposed, which is an integration of the ground prediction approach based on Markov process, and the time and cost variance analysis based on Monte-Carlo （MC） simulation. The former provides the probabilistic description of ground classification along tunnel alignment according to the geological information revealed from geological profile and boreholes. The latter provides the probabilistic description of the expected construction time and costs for each operation according to the survey feedbacks from experts. Then an engineering application to Hamro tunnel is presented to demonstrate how the ground condition and the construction time and costs are estimated in a probabilistic way. In most items, in order to estimate the data needed for this methodology, a number of questionnaires are distributed among the tunneling experts and finally the mean values of the respondents are applied. These facilitate both the owners and the contractors to be aware of the risk that they should carry before construction, and are useful for both tendering and bidding.
