2025-03-31    151

Excessive Deviation in Foundation Positioning Axes and Bearing Surface Elevation of Steel Columns

Causes:

• Errors in foundation survey control network, measurement layout, and elevation setting

• Insecure foundation formwork installation

• Template displacement caused by high concrete pouring height or vibration impact

• Use of uncalibrated measuring tools (steel tape, theodolite, level)

• Misinterpretation of drawings or axis identification errors

• Unconsolidated bearing surface without secondary finishing

• Lack of fixation measures for embedded steel plates (or supports)

• Concrete settlement and shrinkage

Consequences:
These deviations may lead to installation axis misalignment and support elevation errors, affecting overall structural installation quality.

Preventive Measures:

1. Measurement Control

• Verify all instruments (levels, theodolites, measuring tapes) through calibration or metrological verification

• Implement strict checking procedures for survey networks and layout

2. Formwork Installation

• Ensure formwork possesses adequate strength and rigidity

• Conduct periodic inspections during concrete pouring using measuring tools or plumb bobs

• Immediately rectify any detected deviations before continuing work

3. Concrete Operations

• Primary alignment: Before concrete placement

• Secondary alignment: During concrete hardening

• Perform secondary surface finishing and leveling before initial concrete setting

• Implement two-stage alignment for embedded components:

4. Component Fixation

• Install proper anchoring devices for base support plates or pedestals

• Maintain position stability during concrete placement

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Rectification Methods:
For minor deviations:

• Column base adjustment

• Bolt hole enlargement

• Shim insertion

For significant deviations:

• Conduct technical consultation with relevant parties

• Develop and implement approved corrective

Quality Assurance:

• Establish multi-stage inspection protocol (layout, formwork, embedding, final acceptance)

• Maintain comprehensive construction records for traceability

• Implement error prevention measures throughout the construction process