A brief introduction of prestressed steel combination support technology
Prestressed fish bellytype Foundation pit steel support Technology is made up of fish belly beam, counter brace, Angle brace,stateThe column,cross Beam, connecting rod, high strength connectionpoint, prestressed loading device and other standard components of deep foundation pit support structure system.
Two, prefabricated steel combination support construction process
Equipment and materials approach→Column pile construction→Steel enclosing purlin installation and concrete ring beam construction→ tooltypeSteel support installation→Application of prestress→Earthwork to the bottom of the foundation pit → Pour concrete cushion, bottom plate and side wall→The structural strength of the basement andIn holdReach design strength→Remove and recover tool-type supports →The project is complete.
Three, the characteristics of prefabricated steel combination support process
1,prestressedSteel combinationThe support adopts standardized components, connected by bolts, easy to install and remove support.
2,steelsupportEasy installation and demolition, fast construction speed, no maintenance, shorten the whole foundation pit construction cycle.
3,The prestressed steel support system isHigh degree of muscleStatically indeterminate steel structure system;
4,The failure form is ductile failure, which greatly improves the safety of the support system.
5,The lateral displacement of the envelope can be controlled by applying prestress.
6,Recyclable, in line with the national energy conservation and emission reduction and environmental protection policy requirements.
7,Construction site clean, low noise, good environmental protection effect.
8,It can coordinate construction with earthwork and main structure construction to realize pipelining operation.
9,Large construction space can be formed, which makes the excavation and transportation of earth and the construction of underground structure convenient and fast.
Four, case introduction
Huzhou Inner Ring (North Line) rapid transformation Project second section
1, Project overview
The second section of Huzhou Inner Ring (North Line) rapid transformation Project is from Qiliting Road to Qingtang Road, which is about long3710Meters, mainly including viaduct, wind bridge, tunnel three parts. The Second Ring Road North tunnel is located in the inner ring (North line) rapid transformation project main line, wide31.5 meter Total length 1244Meters, west Kaia section287 Meters, east open section277M, buried section 680 meter
2,Key points of project
(1)The project is located in the downtown area, high environmental requirements;
(2)The surrounding environment is complex, including customs warehouse, sewage treatment plant, high voltage cable, subway planning section, etc.
(3)Field investigation shows that the silt silt and clay layer in the stratum of the proposed project is thick, and the excavation of the foundation pit is easy to lead to the instability of the pit wall, basement uplift, soil flow, and inrush.
(4)The construction period was strict to reduce the impact on local traffic.
3, Solutions
(1)steelsupportThe standardized steel members are connected by bolts, and the construction is noiseless. Components can be recycled, no construction waste, green environmental protection;
(2) can apply very high prestress,Improve the strength and stiffness of the fish belly beam, effectively control the displacement of the foundation pit, protect the surrounding buildings and roads;
(3)The long-span fish belly beam support makes the support and purlin form a whole through the tension of steel strand, and the force is even, so as to control the deformation of foundation pit evenly.
(4)Steel component site splicing and disassembly, flexible construction; Large construction space, digsoilHigh efficiency, short construction period.
In addition, the project has been carefully designed from the aspects of construction scheme, quality management and personnel arrangement to ensure the quality and safety of construction.
Comparison of steel bracing force between traditional bracing and prestressed fish-belly bracing
4, project progress
The foundation pit of the project has been completed45%, the construction period is shorter than expected30%The left and right sides. ShanghaiStrong foundationThe engineering team will continue to maintain an efficient and high-quality construction pace and deliver satisfactory results to Party A.
View of prestressed fish-belly foundation pit steel support construction site
Shanghai Qiangqiang Foundation Engineering Co., Ltd. has completed more than 1,000 projects in the fields of housing construction, underground space, subway, railway, highway, bridge, tunnel, airport, sea reclamation, and so on. Hundreds of projects it has participated in have won the "Luban Award of China Construction Engineering" or the "Magnolia Award of Shanghai Construction Engineering". Contact Number: 400-100-2850
