Combined with the engineering practice of Shanghai Fengxian District Youth Activity Center Project,in view of the characteristics of continuous circular arch on the top of most single buildings and the large number and types of special-shaped steel components,a set of key hoisting construction technologies,such as high-precision measurement and control,optimization of connection nodes,secondary pre-assembly and controllable small deformation hoisting,are adopted.It solves many problems such as complex special-shaped steel structure component processing,on-site assembly,high-altitude hoisting in place,welding quality and so on,which can provide reference for similar special-shaped steel structure project construction.
Combined with the engineering practice,the corresponding technical research is carried out to solve the construction problems of long cantilever length,short construction period and narrow site of variable cross-section H-shaped steel reinforced concrete beam.On the premise of ensuring the construction safety and not affecting the construction of the lower concrete structure,the formwork erection and pouring of the SRC beam were completed by using the self-bearing hanging formwork,the high-altitude hanging operation platform and the high-altitude formwork erection platform through innovative methods.The practice shows that the construction technology of high-altitude platform composed of self-supporting hanging formwork,hanging operation platform and high-altitude formwork support platform has the advantages of safety,reliability,simple construction,saving construction period and reducing cost,which is worth popularizing and applying in engineering.
Combined with the engineering practice,the sinking precision control problem of open caisson construction in deep and thick silt layer is tackled.By designing the sinking construction process,a waterproof curtain and a sinking-aid stabilizing pile are used for auxiliary sinking.By adopting the pre-pasting ash cakes and adjusting the left and right inclination for removing or increasing the ash cakes in the sinking process,by adopting a mode of combining drainage sinking and non-drainage sinking for carrying out twice sinking and carrying out twice underwater bottom sealing,the safety and stability of the sinking of the open caisson in a deep and thick silt layer are ensured,the speed and accuracy of caisson sinking are guaranteed and can provide a reference for the construction of large caissons in deep silt layers in other cities.
Taking the construction of a supporting pedestrian tunnel for traffic relief in Guangzhou Baiyun International Airport as an example,the current environment and construction difficulties of the project are emphatically analyzed,and combined innovative technologies such as horizontal freezing reinforcement technology of pipe jacking receiving portal,rectangular pipe jacking shell abandonment construction technology without receiving conditions,curtain grouting reinforcement technology of rectangular pipe jacking tunnel,and key technology of ecological underground excavation construction are adopted.It solves the problem of rectangular pipe jacking construction safely reaching the designed receiving position and smoothly connecting with the original subway station under the sensitive environmental conditions of complex geology,complex pipelines and no receiving site.The construction technology has high safety,can effectively isolate groundwater,reduce the settlement and collapse of the tunnel entrance,and has little impact on the surrounding environment and pollution,which can provide a reference for similar projects.
Taking the Urbancore reconstruction project in Plot J as the background,as the surrounding buildings have been completed,the construction site is limited,and the upper steel staircase structure is complex,the construction period is urgent,and the construction is difficult.The installation and construction of complex steel stairs in existing buildings are implemented from the aspects of construction equipment selection,installation area division,temporary construction measures and safety measures.Through the application of the construction software,the construction measures are simplified,the construction period is shortened,and satisfactory results are achieved,which has reference significance for similar construction projects.
In response to the quality problems of component surface pitting,peeling,sanding,staining,component missing edges and corners,angular deviation,large dimensional deviation,formwork expansion,and inconsistent drop height at the floor lifting board during construction,a"mortise-type square steel composite formwork"with simple structure,safety,fast turnover and use is developed for use in formwork construction at the floor lifting board on the construction site.During on-site construction,it can be directly assembled by mortising,which improves construction efficiency and reduces construction costs.After formwork removal,the concrete appearance quality is good,which accumulates experience for similar projects.
Taking the linear accelerator room of Zhejiang Provincial Hospital of Traditional Chinese Medicine(Phase I)as an example,according to the characteristics of the project,the civil construction technology of linear accelerator room is summarized from the aspects of steel bar binding,formwork support,mass concrete pouring,crack resistance and seepage control,so as to accumulate experience for similar projects.
Taking a large deep foundation pit construction project adjacent to subway in Shanghai as an example,the complete process and main tasks of deep foundation pit engineering are described from construction planning and scheme preparation to onsite implementation,in order to elaborate on the main content and implementation steps of refined construction management for deep foundation pits.By elaborating on specific implementation examples of fine construction management for deep and large foundation pits adjacent to the subway,the operation and application of fine construction management for deep and large foundation pits are further refined.The summarized experience can be used as a reference for similar projects in the future.
As an important underground engineering structure,the waterproof performance of the pipe gallery is crucial to ensure the normal operation of underground equipment.To calculate and design the lining structure,it is necessary to evaluate the influence of composite interfaces on the mechanical behavior of the lining structure.To study the influence of a new acrylate waterproof membrane on the mechanical properties of the pipe gallery lining structure,a beam bending loading test is conducted to test the mechanical properties of a new polymer waterproof membrane reinforced concrete beam,and the effect of composite materials is quantitatively calculated.The research conclusion:Under the bonding effect of the waterproof membrane,the reinforced concrete beam with a polymer waterproof membrane has a strong composite effect,and its strength and stiffness are also significantly improved than those of beams with sheet-like waterproof rolls.
In order to achieve better architectural effect,many large commercial complexes will design the lighting roof as the focus and highlight of green construction.These lighting roofs are often designed to be large and complex because of the lighting needs of the inner courtyard.In order to ensure the smooth hoisting construction of the large-span lighting roof in narrow space,the pulley block of the winch is used for hoisting and traction,and the lifting installation of the large-span,ultra-long and ultra-heavy steel structure unit is realized,which not only ensures the quality and safety,but also realizes the cost saving.
In order to solve the problem that the conventional integral lifting scaffold is difficult to meet the requirements of safe construction when the structure changes due to the complex external facade and the existence of internal and external concave-convex building structure,an internal and external double-layer combined integral lifting scaffold is developed based on the traditional attached lifting scaffold.The new scaffold can meet the construction requirements of different facades of super high-rise structures,increase the construction working surface,improve the construction safety,avoid the hidden danger of repeated installation and disassembly of scaffolding at the contraction of the structure,and has good application and promotion value.
Longitudinal joint is the weak position of shield tunnel lining structure strengthened by bonding steel plate.In order to study the influence of interface anchor bolt on the mechanical performance of longitudinal joint strengthened by steel plates,based on the test results of joint strengthened by steel plates under positive and negative moment conditions,numerical parameter analysis is carried out for the number of rows of interface anchor bolt.The conclusions are as follows:the corner stiffness and bearing capacity of the joint strengthened by positive moment steel plate increase with the increase of the number of interface anchor rows,and when the parameters reach a certain level,the interface anchor does not yield before the joint is destroyed;the performance of the joint strengthened by negative moment steel plate is less affected by the number of anchor rows.
Relying on the construction project of a five-star hotel in Daxing District,Beijing,this paper makes a comprehensive study on the sound insulation and vibration reduction methods of various equipment rooms and pipelines in five-star hotels,and discusses and analyzes some key technologies with high standards and good noise control effect,which can provide reference for similar engineering construction.
To better control the quality of steel cage in the construction process of ultra-deep diaphragm wall,the manufacturing process of steel cage is studied.According to the higher brittle performance of special HRB600-type reinforcement,the measures such as preheating multiple times are taken first;for the reinforcement cage of the ultra-deep diaphragm wall,two main bars are connected to the lifting point steel plate to ensure that the lifting point of the reinforcement cage is evenly stressed during lifting;by modeling and analyzing the stress situation at the bottom of the reinforcement cage,the connection between the rigid joint and the reinforcement at the bottom of the cage is strengthened.Through the above measures,the construction quality of the steel reinforcement cage is ensured,and the accumulated experience can be used as reference for similar projects.
To study the impact of different connection methods between the outlet branch pipes and the main pipes of chilled water on the management of internal fluid flow,and based on reference to similar literature,numerical simulations are conducted on different radian and right-angle connections,and corresponding data were obtained.The results are analyzed to provide technical support for engineering construction.
As to the traditional nature of existing ultra-high concrete pumping technology and the lack of detailed theoretical guidance,the stress state of the concrete delivery pipe during pumping is studied through a combination of numerical simulation and experimental research.By establishing a detailed numerical model of concrete pumping fluid and a solid numerical model of concrete delivery pipe,fluid-solid coupling calculations are conducted,focusing on exploring the changes and losses of pressure in the flow field during concrete pumping,as well as its impact on the structure of the delivery pipe itself,and it is compared with field experiments.The result shows that the numerical simulation was in good agreement with the experimental data,providing theoretical guidance for the formulation of ultra-high concrete pumping technology solutions.
Based on the construction of the west tower of the Shenzhen Xinghe Yabao Twin Towers,the key technologies of the application of the new-type loa d-bearing internal climbing tower crane in the west tower of the Galaxy Yabao Twin Towers are introduced.Research are conducted on the difficulties of long construction period,high risk of object strike to the lower operators,adverse effects of advanced construction of thin-walled core tube on the attachment of tower crane,and complex environment for dismantling tower crane.Through the comprehensive application of a series of technologies,the construction period is effectively reduced and the construction safety risks are lowered.The experience summarized can be used as reference for similar projects.
In view of the complexity of the surrounding environment of downtown projects and the high requirements for ensuring the safety of the surrounding environment,the key technologies are studied in combination with the actual construction.This paper introduces the construction planning of deep foundation pit under complex environmental conditions,and the key construction technologies such as supporting structure,base reinforcement,earth excavation and dewatering,and support and support replacement.The practice proves that the construction effect is good,and the relevant construction experience provides a reference for similar projects.
Relying on the new project of Minhang District Geriatric Nursing Home,the integrated mode of deepening design and construction is adopted to comprehensively plan and implement the problems that may exist in the construction in advance,such as the optimization of complex nodes,the optimization of multi-layer steel bar avoidance between beams and columns in the beam-column joint area,the optimal arrangement of connecting steel bars in important structural joints,and the structural form optimization of each structural module,processing,construction,installation and embedding,etc.,so as to ensure the smooth progress of the project.The summarized research results can provide reference for similar integrally fabricated public construction projects in the future.
