Recently, the Third Company of the Eighth Bureau of China Construction has successfully applied the technology of "prestressed fish-belly beam assembly steel support" to solve the problems of high cost, long construction period, dense internal support, uncontrollable deformation, a large number of const ruction waste and noise pollution caused by dismantling support in the traditional concrete internal support, which is developed by the Engineering Research Institute of the Eighth Bureau of China Construction. Another favorable attempt of the new technology of foundation pit support.
 to press the two ends of the fish-belly beam.)
The system is composed of upper chord beam (circuit purlin), straight web member, diagonal web member, lower chord steel strand, brace, angle brace and other steel components. It is a recyclable and reusable fabricated support system in foundation pit.
Site Application
of Prestressed Fish-belly Beam Layout Plan "Prestressed Fish-belly Beam Assembled Steel Support"
Project Introduction
Senlan International Phase VI (D3-10) Project is located in Pudong New Area, Shanghai, with a construction area of 44,000 ㎡ and a floor area of 9,687 ㎡. The excavation area of the foundation pit is about 8136 ㎡, the perimeter is about 380m, and the maximum excavation depth is 10. The east side of the foundation pit of this project is Harrow International School, and the north side is Shanghai Zhuyuan Middle School and Haoqianqi Kindergarten, of which Harrow International School is less than 15m from the edge of the foundation pit. The rainwater and sewage pipelines in Harrow School are 9 m and 11 m away from the side of the foundation pit on the east side, and the rainwater and sewage pipelines in Harrow School are 4 m away from the side of the foundation pit on the north side. The environmental protection grade of the north and east sides of the foundation pit is Grade II, and the environmental protection requirements are high.
Social benefits: the pre-stressed fish-bellied beam assembly type steel support is a standardized steel member and is connected by bolts, so that the installation and disassembly are convenient, and the maintenance of concrete is avoided, so that the project construction period is shortened; the fish-bellied beam has a large span, so that a larger space is provided for earth excavation and underground structure construction, and the construction convenience is good; and the support can be repeatedly used after being disassembled, so that the construction cost is saved; Noise, dust and construction waste will not be produced when the support is removed, which is energy-saving and environmentally friendly; the fish-belly beam steel support effectively controls the deformation of the foundation pit by applying larger prestress, and the prestress can be adjusted in the construction process, which effectively protects the safety of underground pipelines and surrounding buildings, and has remarkable social benefits.
Field Application of "Prestressed Fish-bellied Beam Assembled Steel Support"
Attached: Introduction
of Similar Projects in the Past In the traditional foundation pit engineering, our common way of supporting the enclosure structure is like this: the crisscross concrete or steel structure supports, resulting in small excavation construction space. Installation and disassembly are laborious and time-consuming.
Traditional concrete internal support
, traditional steel structure internal support
and traditional internal support are inconvenient to
install, dismantle and construct. In the project of Jiangyin Chengjian Nanmen Commercial District, we have seen a new support mode of foundation pit enclosure structure: prestressed fish-bellied steel support system. Its construction site is like this:
Prestressed fish-bellied steel support site panorama
Prestressed fish-bellied steel support site local
intuitive contrast, this new support method gives us the first impression is: the support rod is very sparse, excavation construction space is very large; Support materials are less and standard parts, which are easy to install and dismantle and can be recycled.
H-shaped Steel Waist Beam: It is continuously set along the top beam around the foundation pit through bolts." Bracket for bearing pressure
on both sides: It is set below the waist beam to connect the enclosure pile body and the waist beam and play a supporting role
. 2 Fish-belly beam
Upper chord beam: straight web member and diagonal web member of waist beam
: form a truss structure. The force
bridge used for transferring the force between the steel strand and the waist beam is positioned at the end of the straight web member, The steel strand passes through
the lower chord steel strand: it can provide pretension
after tensioning. The connector is used to connect the fish-belly beam and the brace/angle brace
. The anchorage is used to tension, Lock and hold the pretension
of the steel strand 3 brace/angle brace
H-shaped steel brace/angle brace: load transfer axial support Prestressed
compression beam: perpendicular to the support direction, Between that crossbeam, a Jack is used for support and pressurizing
a force retaining box; after the Jack is use for pressurizing, the force retaining box is plugged into the pressurized crossbeam to keep an axial
prestress cover plate; the prestress retaining box is arranged at a splicing node to strengthen a braced weak part so as to form an integral
tie | the prestress retaining box is arranged between adjacent cover plates, Provides lateral restraint for overall stability
4 Column
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