by On January 10, the precast structure of lot 1.3 of phase IV of Zhuyuan sewage treatment plant was completed.
Zhuyuan phase IV project is the first large-scale application of prefabrication and assembly technology in the field of water affairs.
There are 2488 precast components in this bid section, with a maximum height of about 10.12m and a maximum weight of 31.13t.
The application of prefabrication and assembly technology in the field of water affairs can effectively improve the project quality, construction efficiency and control risks, comply with the concept of sustainable development, and effectively reduce pollution and protect the environment.
In order to solve the problems of large weight, high height and limited working space of precast components in the prefabrication and assembly construction in the field of water affairs, the project team independently developed the material formula of ultra-high performance concrete (UHPC), and developed customized me full frequency conversion gantry crane, intelligent concrete mixing and pumping machine and high-precision intelligent adaptive support system.
01 customized full frequency conversion gantry crane it is reported that 40 + 16t non-standard me full frequency conversion gantry crane is used for the hoisting of precast components of the project.
According to the characteristics of large weight, high height and limited working space of precast components, the project team finally determined to adopt the customized gantry crane developed by the project team through the comparison and selection of mainstream hoisting equipment, the invitation of experts for consultation and demonstration, and the trial assembly process simulation of gantry crane in the component factory.
This customized gantry crane has many different functions.
The traditional gantry crane has a single structure, pipeline output, and most of the circuit control is resistance control, with large error, strong impact and complex operability.
The gantry crane used in the project has the functions of anti swing, inching fine adjustment, lifting, lifting and accurate positioning, which can reduce the operation difficulty and solve the problem of increasing construction time and collision due to large-scale and long-time shaking when lifting components.
As the gantry crane is located on the reaction tank and the precast slab monomer is large, it is required to be stable and properly transported during hoisting.
Therefore, the hoisting equipment is required to meet the on-site construction conditions, flexible layout and convenient operation.
02 the self-developed wet joint material is affected by the use environment of the sewage treatment project.
The self-developed new material of ultra-high performance concrete (UHPC) is used for the prefabrication and assembly of wet joints in the project.
Combined with the use experience of ultra-high performance concrete materials in bridge engineering, the project technical team finally determined the ultra-high performance concrete materials suitable for the project by selecting and adjusting the mix proportion of such concrete materials.
Based on the self-developed mix proportion of new materials, combined with the characteristics of wet joints and construction technology of the project, the tests of basic mechanical property indexes such as compressive strength and tensile strength of UHPC materials at different ages are carried out to study the development and variation characteristics of basic mechanical property indexes of UHPC materials with age, Finally, the basis and guiding principles of on-site construction process arrangement and measure implementation indicators are formed.
When the concrete curing at the joint is completed, it can reach the ultra-high strength of 120MPa.
03 intelligent concrete mixing and pumping all-in-one machine aiming at the difficulties of UHPC material sensitivity and high construction requirements, the project team carried out the accurate and customized design of intelligent UHPC mixing and pumping, realized “mixing and pouring immediately” by integrating the mixing and pumping functions, solved the problem of sensitive material properties of high-performance concrete, and ensured the construction efficiency and quality.
At the same time, through the study of multi degree of freedom in-situ steering and multi-functional integrated control system, we can realize the convenient movement in limited space, further reduce labor and improve the level of construction automation.
04 high precision intelligent adaptive support system in order to reduce the error caused by manual sagging of precast partition wall, ensure construction accuracy and improve the industrialization of cast structure construction in water industry, the project has carried out the R & D and design of high-precision intelligent adaptive support system.
At the initial stage of R & D, the project department determined the strength requirements of the support rod according to the influence of the self weight load component and wind load on the vertical positioning effect and assembly accuracy of the precast partition wall in the vertical critical state of installation and positioning, and made it clear to adjust the length of the support rod with a high-precision micro distance automatic telescopic mechanism, Then, with the help of a fixed angle laser rangefinder group, a ranging judgment system is constructed to determine the positioning state of the precast partition wall and drive the macro automatic telescopic adjustment mechanism carried on the support rod, so as to develop a high-precision intelligent adaptive support system.
Compared with manual vertical adjustment, it has higher accuracy and faster vertical adjustment speed, and the vertical measuring instrument can be used alone.
Source: past highlights of Shanghai construction site 1.
Control tips for rapid loss of concrete slump 2.
Relationship between cement quality and concrete quality 3.
Experience of application of raw materials and quality control of ready mixed concrete 4.
Examples of quality lessons of ready mixed concrete 5.
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