The pipe gallery bridge is a unique project of a comprehensive pipe gallery at the overhead crossing. It is essential to ensure its quality and security due to its complex structure and stress state. Based on a pipe gallery bridge with a large cross-section and high loading, the beam and solid element models are established separately to research the stress of the bridge when it is under construction, completed and service stage. The results show that the stresses of the pipe gallery bridge are in good agreement with the current codes, and the results have been used for the design of the bridge.
In order to accurately assess the load carrying capacity and actual working condition of a newly constructed continuous girder bridge, the load test of a newly constructed three-span prestressed variable cross-section continuous girder bridge is taken as the engineering background, and the check coefficient of the static load test, relative residuals and other parameters are used to judge whether the indexes such as the strength and stiffness of the structure satisfy the requirements or not. The results show that the deflection and strain calibration coefficients are less than 1 and the relative residual value is not more than 20
The design management of large-scale construction project is very important.In the whole life cycle of construction project,it can realize the cost control and quota design.Taking a large-scale public building project as an example,this paper analyzes the rationality of architectural design management and its social and economic value.
钢结构厂房屋面围护结构通常采用压型钢板复合保温屋面系统,其有2种构造方式:一是檩条外露式结构,即底层压型钢板固定于钢檩条的上表皮,结构檩条外露;二是檩条暗藏式结构,底板压型钢板固定在钢檩条的下表面,使室内看不到檩条.檩条暗藏式双层屋面板设计做法为屋面檩条上面铺一层彩钢板,中间是保温棉,屋面檩条下固定一层彩钢板,好似给厂房做了吊顶,增加了厂房内部空间的美观性.因此受到设计师和业主的青睐,近年来在大型工业厂房中应用也越来越广泛.
This paper introduces the construction and application of the 300 m long basement drainage layer system in the Taiziwan New World Parent-Child Shopping Mall in Shenzhen.Through controlling the drainage pipe layout,gravel pavement,concrete protective plate construction and other processes,a novel process is proposed,including the slope of the drainage layer in sections,PVC tube type support formworks for support piers of cast-in-situ protective plates,and direct drainage system in the drainage layer.At present,the phased operation test has been conducted.The garage floor is dry without any water stains.After the whole system is put into use in the subsequent stage,appropriate dry conditions can be provided for the basement in case of failure of the active waterproofing system at the bottom.This provides a reference for waterproofing construction of similar high-level,ultra-deep and ultra-long basement engineering.
More and more large-diameter steel pipes are applied in hydraulic engineering.Welding is critical for the quality control and service life during the installation of these steel pipes.Through comparison of a number of technological experiments in Lot 6 of the Hexi Branch supporting the South-to-North Water Diversion Project,a set of construction technology for welding of large-diameter steel pipes was summarized,thus accelerating the construction,meeting the technical indicator and quality requirements for welds and making the appearance superior and elegant.Welding parameters of steel pipes can be finally determined through steel pipe welding tests on site in order to guide the construction.
Intelligent construction is a critical way for construction transformation in the new era,in which advanced technologies and digital means are applied to integrate the conventional construction process with modern technologies,in order to achieve the purpose of efficient,accurate and sustainable construction.Taking the library of the College Park of Xiong'an Startup Zone as an example,a digital twin-driven intelligent construction framework was built for the application of a variety of key technologies in construction.This paper describes the application of information technologies such as BIM in the library construction of the College Park of Xiong'an Startup Zone.The application of these technologies such as BIM ensures the safety and efficiency of construction and improves the construction quality.This provides a reference for the research and application of intelligent construction technologies in construction.
Taking rural residential buildings in Hangzhou for example,the indoor temperature and illuminance were analyzed with different sunshade component parameters through field investigation and measurement.Experimental results show that external sunshade components have obvious influence on the energy consumption of buildings.In order to further study the parameters of optimal sunshade components,the lighting performance and energy consumption of building models with horizontal,vertical,comprehensive and baffle sunshades were analyzed through the Grasshopper parametric design platform.Results showed:when the exterior sunshade with a protrusion length of 0.6m is adopted,the total energy consumption of buildings is the lowest(4 856 kW·h),and the energy saving efficiency is 3.67%.Research results provide a reference for optimization of sunshade component parameters in green building design.
In order to overcome difficulties in lifting machinery selection,hoisting sequence and temporary fixing in steel hollow beam construction,construction simulation was carried out for a project based on the BIM technology.In addition,a complete set of technical measures were summarized with test data and other data to successfully solve relevant problems.This provides a reference for construction of similar projects.
In order to overcome the influence of existing cracks on the thermal conductivity and moisture content of concrete,a crack model was made by 3D printing.With the crack volume and concrete test block volume as variables,the study was conducted on the thermal conductivity,water absorption coefficient,water diffusion coefficient and vapor permeability coefficient of concrete with different crack volume ratios.Results showed:The thermal conductivity of concrete increased when the moisture content rose,but decreased when the crack volume ratio increased.In addition,the sensitivity of thermal conductivity to crack volume decreased gradually.Compared with uncracked concrete,the thermal conductivity of dry concrete with a crack volume ratio of 0.1%-0.3%increased by 7.96%to 30.9%.The curves of relationships between the water absorption coefficient and water expansion coefficient of concrete and the crack volume ratio were obtained by fitting.Both the water absorption coefficient and water expansion coefficient increased when the crack volume ratio rose.The curves of changes in the vapor permeability coefficient and moisture content of concrete with different crack volume ratios were obtained by fitting.The curve slope increased gradually.Both the moisture content and vapor permeability coefficient of concrete increased as the crack volume ratio rose.
The development of seismic performance design methods has a great influence on the seismic analysis of structures.In response to a series of problems in performance analysis,the application of seismic performance design in practical engineering was analyzed,taking a frame-core composite structure with reinforced layer as an example.This paper describes how to choose structural performance objectives and evaluate the compliance with member performance objectives in minor,medium and major earthquakes,providing a reference for seismic performance analysis of similar buildings.
The structural envelope system is the most vulnerable to typhoon damage.When the typhoon appears,a great number of constructions are in the construction process,but the structural design has less consideration for the wind resistance design of each working condition during the construction of the enclosure structure.However,there might be obvious differences between the wind effect characteristics of the unfinished envelope structure and the wind effect characteristics of the finished envelope structure during the construction process.Based on the characteristics of the Zhuhai Airport project and the results of the wind tunnel test,this paper optimizes the construction sequence of the enclosure structure before the construction of the enclosure structure,reduces the damage of the typhoon to the enclosure structure during the construction process,and achieves the effect of risk reduction.
In the current urban rail transit,it is difficult to fit the sections of underground channels under normal and special conditions based on standard channel sections.Through consulting and analysis of available data,a solution is proposed systematically for underground sections under normal and special conditions of urban rail transit,with specific geometric relationships and dimensional calculations of underground sections.In addition,design cases of active and passive avoidance type underground channel sections(typical special underground sections)are analyzed.Results show that a precise fitting process is indicated for underground channel sections in the aforesaid solution.After fitting,sections are connected smoothly,with less stress mutation,so structures are stressed reasonably.This is also a flexible solution to section design problems under special conditions and design basis for similar projects.
Sumps are set up in most of underground projects with drainage needs,as a well for collection and storage of groundwater or leaking water.Due to insufficient considerations or lack of awareness of design and construction technicians,there are sump problems such as inadequate and unreasonable structural optimization,poor appearance and impact on the comfort in use.These problems can be avoided by design deepening at the early stage.The key points for design deepening and construction of sumps are explored based on the key laboratory cluster project of Harbin Institute of Technology(Shenzhen).The practical experience in this project can be used for reference in similar projects.
In recent years,with the rapid development of prestressed concrete technology and cantilever construction technology,large-span wide PC continuous rigid frame bridges have been developed fast.However,research and analysis show that prestress loss occurs over time,and the deflection of bridges is closely associated with prestress loss.Taking Longxi Jialingjiang Super-large Bridge as the research object,which is the continuous rigid frame bridge over highways and municipal roads in Chongqing,a finite element model is built with finite element software.Through research on the impact of the frictional resistance of reinforced pipes and the prestress loss of prestressed steel cables of concrete sections on the deflection of the bridge,it is found that the frictional resistance of reinforced pipes is associated little with the deflection of the bridge,while the prestress loss of prestressed steel cables has significant impact on the deflection of the bridge.Importance should be attached to this aspect in terms of bridge deflection.Research results are of positive significance to control the deflection of large-span continuous rigid frame bridges.
With the urban renovation more and more stadiums have been completed,and long-span steel structures have undergone significant changes.The Citizen Fitness Stadium in Tai'an has a steel-concrete structure.Its steel roof consists of the beam string structure and orthogonal single-beam structure.The internal beam string structure is a long-span steel structure with a span of 42 m.In the conventional construction method,one tower crane should be set up nearby,which increases the costs.If a mobile crane is used,one large mechanical crane is required,which will also increase the costs.Accordingly,a series of construction measures should be taken based on the actual situation and engineering characteristics of the project during the construction of large-span steel structures in the blind area of lifting,in order to ensure the construction quality,reduce costs and improve the construction efficiency.
Aiming at the design and construction of section steel cantilever scaffolds that are widely used in high-rise building construction,the design calculation model for section steel cantilever beams is analyzed,and the valuing standard of model parameters are proposed based on calculation results.A triangular prism model was developed to study the anchor damage of the U-type pull ring on a concrete floor,and a design calculation method for anchor bearing capacity is provided.Defects in engineering applications of cable-stayed wire ropes are summarized.It is recommended to cancel cable-stayed wire ropes.
As a retaining structure for deep foundation pits,rigid secant pile walls are constructed by rotary drilling and rigid cutting of slurry retaining walls.Taking the pile foundation project(Project 188 for short)in Phase I of the urban innovation unit in the industrial zone at No.188,Yuanshan Road,Longgang District as an example,the drilling,pile quality and secant pile wall quality cannot meet design requirements in high-permeability soft soil layers.To solve these problems,the effects of rigid secant pile walls in high-permeability soft soil layers are deeply explored in terms of adaptability,safety and economy by studying the working principle,construction process and reinforcement effect of rigid secant pile walls in high-permeability soft soil layers.Results show that rigid secant pile walls in high-permeability soft soil layers cannot only effectively strengthen foundations and enhance the stability of high foundation pits,but also can greatly improve the construction efficiency and quality,reduce construction difficulties and costs,shorten the construction time and bring more economic benefits,as a solution to construction problems in high-permeability soft soil layers.Research results can also be applied for reference in the construction technology for rigid secant pile walls in high-permeability soft soil layers.
A combination of permanent and temporary water and electricity works in engineering construction is to install permanent fire risers and bury permanent lighting pipelines through penetration of permanent fire risers and permanent lighting pipes,wires and fixtures in advance in the stage of construction of main works,in order to achieve the purposes of using permanent fire risers for temporary fire water and construction water supply and permanent lighting systems for lighting in construction.This not only greatly improves the site image of safe and civilized construction,but also meets the requirements for green construction,energy saving and environmental protection.Therefore,a combination of permanent and temporary water and electricity works has promising prospects of development,promotion and application.
Taking the deep foundation pit of a seaside building above the subway tunnel in Shenzhen as the research object,the design and construction of foundation pits above completed subway tunnels under poor geological conditions such as silty soil are analyzed.A combination of grille reinforcement + uplift pile + ballast plate is applied as a subway protection measure to control the structural deformation of subway tunnels under foundation pits within the allowable range.The whole construction process is simulated with midas GTS 3D spatial finite element calculation software,and the impact of construction under subway structures under different working conditions is analyzed.Numerical simulation results show that the existing subway protection measures meet the requirements for safety control indicators of tunnel structures.The feasibility of the subway tunnel deformation control and protection are verified by means of automatic monitoring.
