How to place the length and length of the raft steel bars
In construction projects, the layout of steel bars on the raft foundation is a key link, especially the length and length of the steel bars are arranged directly affecting the bearing capacity and durability of the structure. This article will combine popular topics and hot topics across the network for the past 10 days to structure the layout principles of the length and short direction of the raft steel bars, and provide practical data references.
1. Basic principles for the length and length layout of raft steel bars
The layout of raft steel bars must follow the following core principles:
1.The direction of stress is preferred: Long-direction steel bars are usually arranged in the direction with greater stress (such as the long-span direction of the column net), while short-direction steel bars are arranged in the direction of secondary stress.
2.Economic considerations: Short-direction steel bars are generally located below long-direction steel bars to reduce the amount of steel bars.
3.Specification requirements: According to the "Concrete Structure Design Code" (GB 50010), the spacing, diameter and number of layers of steel bars must meet the minimum reinforcement rate requirements.
2. Key data on the layout of length and length to steel bars
| parameter | Long-direction steel bars | Short-direction reinforcement |
|---|---|---|
| Arrangement location | Lower layer (default) | Upper layer (default) |
| Spacing range | 150-250mm | 150-250mm |
| Common diameters | 16-25mm | 12-20mm |
| Protective layer thickness | ≥40mm (Environmental Category 2a) |
3. Frequently Asked Questions and Solutions in Construction
1.Rebar layer sequence error: Some construction sites mistakenly place short-direction steel bars on the lower floor, resulting in insufficient bearing capacity. Solution: Before construction, the design drawings must be marked and technical briefing must be conducted.
2.Improper node processing: The steel bars in the lower column need to be encrypted, but are often ignored. It is recommended to refer to the following table:
| area | Long-term reinforcement requirements | Short-direction reinforcement encryption requirements |
|---|---|---|
| 1.5 times the thickness range of plate under column | Spacing ≤100mm | Spacing ≤100mm |
4. Hot topic discussions and case references across the network
In the past 10 days, a popular topic from a well-known architectural forum has shown:
1.Controversy point: Do the two-way stressed rafts must strictly distinguish between length and short direction? Expert reply: When the two-way spans are similar, they can be arranged according to the principle of equal strength.
2.Innovative practice: A project is constructed by the warehouse jump method, and temperature cracks are reduced by adjusting the length and short distance of the steel bars (long direction 200mm/short direction 150mm).
5. Summary
The length and length layout of the raft steel bars requires comprehensive stress analysis, economy and specification requirements, and the layer sequence and node processing should be strictly inspected during construction. It is recommended to refer to the data table of this article to optimize the design to ensure the safety and reliability of the structure.
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