Elevator foundation pit structure based on existing raft foundation
By adding inverted trapezoidal reinforcement parts, concrete cushion layers, expansion water stop strips and shearing tendons to the original raft slab in the building reconstruction project, a new elevator foundation pit structure was formed, and the elevator foundation pit structure support in the existing technology was solved The problems of low bearing capacity and poor connection stability improve the overall safety and waterproofing capacity of the building structure and reduce construction costs.
Patent Information
- Application Number
- CN202420810938.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-18
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-04-18
AI Technical Summary
In building reconstruction projects, the support bearing capacity of the elevator foundation pit structure of the existing raft foundation is low, and the connection stability of the backfill pouring area and the original raft foundation is poor, which affects the safety of the building structure.
On the basis of the original raft slab, an inverted trapezoidal reinforcement part, a current concrete cushion, an expansion water stop bar, a shearing tendon and a U-shaped steel bar are added to form a new elevator foundation pit structure to ensure structural stability and waterproofing ability, and to stop through expansion Water strips and waterproof layers avoid water seepage.
It improves the support stability and waterproofing capacity of the elevator foundation structure, enhances the overall safety of the building foundation, reduces construction costs, and avoids water seepage problems caused by construction.
Smart Images
Figure CN222140101U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of building reconstruction construction, in particular to an elevator foundation pit structure based on an existing raft foundation. Background Art
[0002] Building reconstruction projects are common in construction. During construction, due to customer needs or other factors, after the raft foundation construction is completed, an elevator foundation pit needs to be added due to structural changes. The steel structure of the original raft foundation will be destroyed during the construction of the newly added elevator foundation pit. In the existing reconstruction construction process, it is necessary to first cut the top steel structure of the original raft foundation, fold it to both ends after cutting, and dig out the concrete structure of the original raft foundation. The excavation process minimizes the damage to the underlying steel structure. After the excavation is completed, the bottom is appropriately expanded, and a waterproof layer is added to the expanded part to ensure the waterproof requirements of the structure. Then the disassembled underlying steel structure is spliced and connected according to the expanded structural shape, and backfilled and poured again to form a new elevator foundation pit structure. This conventional practice has the problem that the bearing capacity of the newly added elevator foundation pit structure support is relatively low, and there is a poor connection stability between the backfill pouring area and the original raft foundation, which affects the safety of the building structure. Utility Model Content
[0003] The utility model aims to provide an elevator foundation pit structure based on an existing raft foundation, which can be constructed on the original raft foundation, has strong supporting stability and waterproofing ability, ensures the integrity and safety of the building structure, and has strong scalability.
[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:
[0005] An elevator foundation pit structure based on an existing raft foundation comprises an original raft foundation structure, wherein the original raft foundation structure comprises original top-layer steel bars, original bottom-layer steel bars and an original concrete layer cast on the original top-layer steel bars and the original bottom-layer steel bars, an original concrete cushion layer is arranged at the bottom of the original bottom-layer steel bars, an original waterproof layer is arranged on the original concrete cushion layer, an inverted trapezoidal reinforcement portion is arranged at the bottom of the original raft foundation structure, an existing concrete cushion layer is arranged at the bottom of the inverted trapezoidal reinforcement portion, and both ends of the existing concrete cushion layer are connected to the original concrete cushion layer; an existing waterproof layer is arranged on the top of the existing concrete cushion layer; a new elevator foundation pit structure is arranged on the chiseled-out area and the inverted trapezoidal reinforcement portion of the original raft foundation structure, the new elevator foundation pit structure comprises U-shaped steel bars and a backfill concrete layer cast in the U-shaped steel bars; an existing raft foundation structure is arranged in the chiseled-out area and the inverted trapezoidal reinforcement portion of the original raft foundation structure, an expansion waterstop strip is arranged between the existing raft foundation structure and the original raft foundation structure; and shear-resistant embedded reinforcement is arranged between the backfill concrete layer and the existing raft foundation structure.
[0006] Preferably, the thickness of the existing concrete cushion layer and the original concrete cushion layer are both 100 mm.
[0007] Preferably, the existing waterproof layer is made of 4 mm thick waterproof membrane.
[0008] Preferably, the distance between the bottom of the new elevator foundation pit structure and the top of the existing concrete cushion layer is not less than the thickness of the original raft foundation structure.
[0009] Preferably, the shear-resistant embedded reinforcement includes a first section of embedded reinforcement and a second section of embedded reinforcement, and the first section of embedded reinforcement and the second section of embedded reinforcement are connected by welding.
[0010] Preferably, the distance between the shear-resistant embedded reinforcement and the top of the original raft foundation structure is not less than 250 mm.
[0011] Preferably, a groove is provided on the chiseled section of the original raft foundation structure, and the expansion water stop strip is installed in the groove.
[0012] Preferably, the distance between the top of the groove and the top of the original raft foundation structure is not less than 300 mm.
[0013] In the utility model, a new raft foundation structure is added at the bottom of the elevator shaft to be constructed, which ensures the structural strength of the elevator shaft to be added and avoids settlement due to the lack of bottom raft support. The existing raft foundation structure of the new construction is fixedly connected to the original raft foundation structure, which effectively ensures the stability and safety of the building foundation structure. The expansion water stop strip and waterproof layer ensure the waterproof ability of the overall structure and avoid subsequent water seepage caused by construction. The shear-resistant embedded reinforcement improves the shear resistance between the new elevator foundation pit structure and the existing slab foundation structure, enhances the connection strength between the two, and improves the safety of the overall structure. This structure is rebuilt on the basis of the existing raft, which reduces the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic cross-sectional view of the overall structure of the utility model;
[0015] In the figure: 1. Original raft foundation structure; 2. Existing concrete cushion layer; 3. Existing waterproof layer; 4. New elevator pit structure; 5. Existing raft foundation structure; 6. Existing steel bar structure; 7. Expansion water stop strip; 8. Shear-resistant embedded reinforcement; 10. Original top layer of reinforcement bars; 11. Original bottom layer of reinforcement bars; 12. Original concrete layer; 13. Original concrete cushion layer; 14. Original waterproof layer; 40. U-shaped reinforcement bars; 41. Backfill concrete layer; 42. Strengthening reinforcement bars. DETAILED DESCRIPTION
[0016] The utility model is further described below in conjunction with the accompanying drawings:
[0017] like Figure 1 The elevator foundation pit structure based on the existing raft foundation shown in the figure includes an original raft foundation structure 1, the original raft foundation structure 1 includes an original bottom steel bar 10, an original bottom steel bar 11 and an original concrete layer 12 cast on the original bottom steel bar 10 and the original bottom steel bar 11, an original concrete cushion layer 13 is arranged at the bottom of the original bottom steel bar 11, and an original waterproof layer 14 is arranged above the original concrete cushion layer 13. The original waterproof layer 14 is a 4mm thick waterproofing membrane laid on the original concrete cushion layer 13. In this embodiment, the thickness of the original concrete cushion layer 13 is 100mm. During construction, the frame of the new elevator foundation pit structure 4 is marked on the original raft foundation structure 1, the original bottom steel bar 10 is cut at the middle position of the new elevator foundation pit structure 4, the cut original bottom steel bar 10 is folded to both sides, and then folded to the inside of the new elevator foundation pit structure 4 and fixedly connected to both sides of the U-shaped steel bar 40. The cut length of the original bottom steel bar 11 is greater than the width of the new elevator foundation pit structure 4, and the remaining length of the original bottom steel bar 11 should be 500mm greater than the outer end face of the existing concrete cushion layer 2. The cantilevered 500mm length of the original bottom steel bar 11 is subsequently cast in the existing raft foundation structure 5.
[0018] An inverted trapezoidal reinforcement is provided at the bottom of the original raft foundation structure 1 (located below the chiseled area), and an existing concrete cushion layer 2 is provided at the bottom of the inverted trapezoidal reinforcement, and the two ends of the existing concrete cushion layer 2 are connected to the original concrete cushion layer 13 by pouring. An existing waterproof layer 3 is provided on the top of the existing concrete cushion layer 2, and the existing waterproof layer 3 is a 4mm thick waterproof roll material laid on the existing concrete cushion layer 2. The two ends of the existing waterproof layer 3 are overlapped on the original waterproof layer 14. In this embodiment, the thickness of the existing concrete cushion layer 2 is 100mm. An existing steel bar structure 6 is provided on the top of the existing waterproof layer 3, and the existing steel bar structure 6 is arranged along the shape of the existing concrete cushion layer 2. The two ends of the existing steel bar structure 6 are respectively fixedly connected to the two disconnected sections of the original bottom steel bars 11.
[0019] A new elevator foundation pit structure 4 is arranged on the chiseled area and the inverted trapezoidal reinforcement of the original raft foundation structure 1. The new elevator foundation pit structure 4 includes a U-shaped steel bar 40 and a backfill concrete layer 41 cast in the U-shaped steel bar 40. Four reinforcing steel bars 42 are vertically arranged at the two corners at the bottom of the U-shaped steel bar 40. The four reinforcing steel bars 42 are subsequently cast in the existing raft foundation structure 5, which improves the structural strength. The top two sides of the U-shaped steel bar 40 are folded vertically outwards to increase the fixed connection length with the original bottom steel bar 10.
[0020] The existing raft foundation structure 5 is arranged in the chiseled-out area and the inverted trapezoidal reinforcement of the original raft foundation structure 1. The existing raft foundation structure 5 is C35 slightly expansive fine stone concrete cast in an integrated manner in the chiseled-out area and the inverted trapezoidal reinforcement of the original raft foundation structure 1. The existing steel bar structure 6, the exposed original bottom steel bars 11, the exposed original bottom steel bars 10, the reinforcing steel bars 42 and the U-shaped steel bars 40 are all cast in the existing raft foundation structure 5.
[0021] An expansion waterstop strip 7 is arranged between the existing raft foundation structure 5 and the original raft foundation structure 1. In the present embodiment, a groove is arranged on the chiseled section of the original raft foundation structure 1, and the expansion waterstop strip 7 is installed in the groove. Specifically, the distance between the top of the groove and the top of the original raft foundation structure 1 is not less than 300mm, the cross-sectional dimension of the groove is 15mm×20mm, and the cross-sectional dimension of the expansion waterstop strip 7 is 30mm×20mm.
[0022] Shear-resistant embedded reinforcement 8 is arranged between the backfill concrete layer 41 and the existing raft foundation structure 5. The distance between the bottom of the new elevator foundation pit structure 4 and the top of the existing concrete cushion layer 2 is not less than the thickness of the original raft foundation structure 1. In this embodiment, the distance between the bottom of the new elevator foundation pit structure 4 and the top of the existing concrete cushion layer 2 is the same as the thickness of the original raft foundation structure 1. The shear-resistant embedded reinforcement 8 includes a first section of embedded reinforcement and a second section of embedded reinforcement, and the first section of embedded reinforcement and the second section of embedded reinforcement are connected by welding. One end of the first section of embedded reinforcement is inserted into the existing raft foundation structure 5 on the left side of the new elevator foundation pit structure 4, and one end of the second section of embedded reinforcement is inserted into the existing raft foundation structure 5 on the right side of the new elevator foundation pit structure 4. The welding connection area of the other end of the first section of embedded reinforcement and the second section of embedded reinforcement is located in the new elevator foundation pit structure 4. The distance between the shear-resistant embedded reinforcement 8 and the top of the original raft foundation structure 1 is not less than 250 mm.
[0023] The above embodiments are only some descriptions of the concept and implementation of the utility model, and are not intended to limit the concept and implementation of the utility model. Under the concept of the utility model, technical solutions that have not been substantially changed are still within the scope of protection.
Claims
1. An elevator foundation pit structure based on an existing raft foundation, comprising an original raft foundation structure, wherein the original raft foundation structure comprises an original top steel bar, an original bottom steel bar and an original concrete layer cast on the original top steel bar and the original bottom steel bar, an original concrete cushion layer is arranged at the bottom of the original bottom steel bar, and an original waterproof layer is arranged on the original concrete cushion layer, characterized in that: An inverted trapezoidal reinforcement portion is arranged at the bottom of the original raft foundation structure, and an existing concrete cushion layer is arranged at the bottom of the inverted trapezoidal reinforcement portion, and both ends of the existing concrete cushion layer are connected to the original concrete cushion layer; an existing waterproof layer is arranged on the top of the existing concrete cushion layer; a new elevator foundation pit structure is arranged on the chiseled-out area and the inverted trapezoidal reinforcement portion of the original raft foundation structure, and the new elevator foundation pit structure includes U-shaped steel bars and a backfill concrete layer cast in the U-shaped steel bars; the existing raft foundation structure is arranged in the chiseled-out area and the inverted trapezoidal reinforcement portion of the original raft foundation structure, and an expansion waterstop strip is arranged between the existing raft foundation structure and the original raft foundation structure; and shear-resistant embedded reinforcement is arranged between the backfill concrete layer and the existing raft foundation structure.
2. The elevator foundation pit structure based on the existing raft foundation according to claim 1 is characterized in that: The thickness of the existing concrete cushion layer and the original concrete cushion layer are both 100 mm.
3. The elevator foundation pit structure based on the existing raft foundation according to claim 1 or 2, characterized in that: The existing waterproof layer is made of 4mm thick waterproof membrane.
4. The elevator foundation pit structure based on the existing raft foundation according to claim 1 is characterized in that: The distance between the bottom of the new elevator foundation pit structure and the top of the existing concrete cushion layer is not less than the thickness of the original raft foundation structure.
5. The elevator foundation pit structure based on the existing raft foundation according to claim 1 is characterized in that: The shear-resistant embedded reinforcement comprises a first section of embedded reinforcement and a second section of embedded reinforcement, and the first section of embedded reinforcement and the second section of embedded reinforcement are connected by welding.
6. The elevator foundation pit structure based on the existing raft foundation according to claim 1 or 5, characterized in that: The distance between the shear-resistant embedded reinforcement and the top of the original raft foundation structure is not less than 250 mm.
7. The elevator foundation pit structure based on the existing raft foundation according to claim 1 is characterized in that: A groove is arranged on the chiseled section of the original raft foundation structure, and the expansion water stop strip is installed in the groove.
8. The elevator foundation pit structure based on the existing raft foundation according to claim 7 is characterized in that: The distance between the top of the groove and the top of the original raft foundation structure is not less than 300 mm.