1. Inspection Criteria

（Code for Design of Building Structures Load - GB50009-2012

（2) "Code for Design of Concrete Structures (GB50010-2010, 2015 Edition)"

（3) "Concrete Structure Field Testing Technical Standard" (GB/T 50784-2013)

（4) "Code for Foundation Design Standards" (DGJ08-11-2018)

（6) "Civil Building Reliability Assessment Standard" (GB50292-2015)

（7) Unified Standard for Design Reliability of Building Structures (GB 50068-2018)

（8) "Seismic Evaluation Criteria for Buildings" (GB50023-2009)

（9) "Seismic Fortification Classification Standard for Construction Engineering" (GB50223-2008)

（10) "Seismic Design Code for Buildings (GB50011-2010) (2016 Edition)"

（11) "Residential Property Condition Assessment Standard (Trial) (Document No. 678, City Residence [84])"

（12) Structural design drawings provided by the client.

2. Inspection Work Content and Methods

（1) Residential Usage Survey and Architectural & Structural Drawing Mapping

Through on-site surveying, establish technical data such as building plans, elevations, sections, typical construction details, foundation plans, structural plans, typical structural member cross-sections, and joint constructions, especially the connection and reliability of the addition to the original structure.

（2) Structural System Inspection

The main load-bearing structure consists of concrete beams, columns, brick walls, etc. The key focus of the structural system inspection is the arrangement and connection details of components such as the foundation, concrete beams, columns, and brick walls.

（3) Structural Dimensions and Reinforcement Inspection

Component cross-sectional dimensions are surveyed; reinforcing bars are tested using a combination of ultrasonic testing and local excavation, with random sampling as the main method, focusing primarily on the reinforcement verification of typical components and on areas where the load may be increased as key inspection zones.

（4) Structural Material Testing

The content and methods of structural material testing mainly include:

Concrete Strength - Non-destructive testing by rebound method is used, with core drilling method for verification under site conditions, when available.

（5) Detection of appearance quality defects and structural damage

Defect detection for component appearance, including columns, beams, board supports, roof systems, cladding systems, etc.

 Inspect the appearance defects of components, such as deformation, damage, rust, and warping. Record the findings in both photographic and written form. The detection results can be categorized as severe and general defects, with additional notes on the location and extent of severe defects for consideration in resistance calculations.

（6) Component Deformation Detection

Due to the verticality of vertical components being a crucial indicator of their performance and also affecting the load-bearing capacity (influence of secondary bending moments), it is very necessary to measure the column inclination. On-site, Leica can be used.The TCR1202 total station is used in conjunction with the steel tape method for measuring the inclination of columns, with the sampling ratio following the small sample size of the structural sampling inspection.

（7) Building Settlement and Overall Slope Measurement

Utilize LeicaThe NA2 level instrument measures the elevation of the column base, detecting any uneven settlement in the structure and any insufficient bearing capacity. Depending on the presence of original level control points on-site, the benchmark reference point can be established using each floor window sill, floor, or parapet. Observation points should be set at the corners of the building, large turning points, and every 5 to 10 meters along the outer wall or at each column, to measure the relative uneven settlement of the structure.

Measure the horizontal height at the ends and mid-span of concrete or steel beams using a total station, and calculate the mid-span deflection of the beams by utilizing the horizontal height difference at the measurement points; use a theodolite or total station to measure the inclination of the corner edges of steel columns, and calculate the column's inclination rate by determining the horizontal displacement difference.8) Calculation Analysis

Calculation software utilizes the China Academy of Building ResearchPKPMCAD Engineering Department's PKPM series design software. The structural model utilizes the actual structure, inspected on-site, for overall analysis and calculation. The main contents of the calculation and analysis include the selection of the calculation model, the calculation of loads, and the analysis of structural responses.

（8) Seismic Evaluation and Assessment of Building Structures

Based on the results of on-site inspections and calculations, along with the intended future use of the property, a safety and seismic performance assessment of the building structure is conducted to provide technical support for subsequent renovation and design.

（9) Draft inspection reports, provide inspection conclusions and processing recommendations

Based on the comprehensive on-site inspection and calculation analysis results, determine if the existing building structure aligns with the original design; analyze the primary causes of building damage; assess the structural safety, seismic construction, and seismic bearing capacity, and propose treatment suggestions based on the actual situation. The structural safety assessment includes the calculation of structural resistance, quantitative analysis of safety within the target service period based on the load effect and interface resistance calculation results or on-site test results, as well as qualitative analysis of structural safety according to the actual construction of the building structure and relevant standards. Seismic analysis includes investigation and analysis of seismic construction settings and seismic bearing capacity calculations.