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According to the requirements of Document JIANBIAO [2013] No. 169 issued by the Ministry of Housing and Urban-Rural Development (MOHURD) - “Notice on Printing and Distributing ‘the Development and Revision Plan of professional engineering construction standards in 2014'”, this code is revised by the drafting group based on extensive investigation, careful summarization of practical experience, reference to relevant international and foreign advanced standards and widely solicitation for opinions.
Main technical contents of this code cover general provisions (Chapter 1), terms and symbols (Chapter 2), basic requirements (Chapter 3), deformation observation methods (Chapter 4), layout and surveying of benchmarks (Chapter 5), deformation observation for field, ground and surroundings (Chapter 6), deformation observation for foundation and upper structure (Chapter 7), results compilation and analysis (Chapter 8) and quality inspection and acceptance (Chapter 9).
The following main technical contents have been revised with respect to this code: requirements on technical design and implementation are strengthened; new technical methods for deformation measurement are added and such methods used less at present are added, and benchmark stability analysis in the former Chapter 8 is incorporated into Chapter 5; the former Chapters 5, 6 and 7 are comprehensively modified and are adjusted into the present Chapters 6 and 7 according to deformation measurement objects and types, convergence deformation observation and structural health monitoring are added, layout requirements, determination methods and result requirements of monitoring points in various deformation measurements; the former Chapters 8 and 9 are expanded and the requirements on quality inspection and acceptance of results are emphasized; contents in annexes are greatly adjusted.
In this code, the provisions printed in bold type are compulsory and must be implemented strictly.
The Ministry of Housing and Urban-Rural Development is in charge of the administration of this standard and the explanation of the compulsory provisions, and CIGIS (China) Limited is responsible for the explanation of specific technical contents. Any comment or suggestion arising from the implementation of this standard is kindly requested to be sent to CIGIS (China) Limited (address: No. 177 Dongzhimen Neidajie, Dongcheng District, 100007, Beijing).
Code for Deformation Measurement of Building and Structure
1 General Provisions
1.0.1 This code is formulated with view to implementing China's relevant technical and economic policies in the deformation measurement of building and structure and achieving safety applicability, advanced technology, economic rationality and guaranteed quality.
1.0.2 This specification is applicable to technical design implementation, results compilation and quality inspection and acceptance for deformation measurement of various buildings and structures during construction period and service period.
1.0.3 Deformation measurement of building and structure shall not only meet those specified in this code, but also comply with the requirements of relevant national current standards.
2 Terms and Symbols
2.1 Terms
2.1.1 deformation
a phenomenon of changes in shape or position of the building and structure generated under the action of load. It may be classified into two categories of settlement and displacement. The former indicates vertical deformation, including sinking and elevating, while the latter is a general term for deformations (except settlement), including horizontal displacement, inclination, deflection, crack, convergence deformation, wind loading deformation and sunshining deformation etc.
2.1.2 deformation measurement of building and structure
observation on the changes in the shape or position of the field, ground, foundation, upper structure and surroundings of the building or structure generated under the action of load, as well as processing, expression and analysis on observation results
2.1.3 differential settlement
the non-uniform settlement generated at different positions during the same period
2.1.4 inclination
inclination includes foundation inclination and upper structure inclination. The former refers to the differential settlement caused by non-uniform settlement on both ends of the foundation, while the latter refers to the deviation of center line of the building and structure or certain point on its wall and column from the corresponding point at the bottom
2.1.5 deflection
the deformation of foundation, member or upper structure of the building and structure caused by deflection under the action of the bending moment
2.1.6 convergence deformation
the deformation of the buildings and structures like tunnel and culvert due to changes in surrounding rock stress during construction or operation
2.1.7 wind loading deformation
the deformation of the building and structure generated under the action of strong wind.
2.1.8 sunshining deformation
the deformation of the building and structure generated due to non-uniform heating by sunshining
2.1.9 deformation value
the value of deformation, also referred to as deformation amount
2.1.10 allowable deformation value
deformation control value determined in order to guarantee normal use of the building and structure
2.1.11 prewarning deformation value
warning value calculated in certain proportion of allowable deformation value or given directly according to deformation sensitivity of the building and structure within the range of allowable deformation value
2.1.12 benchmark, reference point
stable and long-time measuring point arranged for the purpose of deformation measurement, which may be classified into settlement benchmark and displacement benchmark according to types of the deformation measurement
2.1.13 working reference point
relatively stable measuring point arranged for the convenience of field deformation observation, which may be classified into settlement working reference point and displacement working reference point according to types of the deformation measurement
2.1.14 monitoring point
the measuring point, arranged at sensitive places of the field, ground, foundation, upper structure or surroundings of the building and structure, that can reflect their deformation characteristics, which may be classified into settlement monitoring point and displacement monitoring point
2.1.15 rate of deformation
the deformation amount per unit time.
2.1.16 observation frequency
observation times in certain time
2.1.17 observation cycle
the time interval between two adjacent observations
2.1.18 deformation factor
such factors causing deformation in the building and structure as load and time etc.
2.1.19 time series
a series of numbers arranged by a series of observation data with equal time interval in order of observation time
2.1.20 structural health monitoring
such work to acquire the characteristic information about the structure such as geometry, stress and strain in real time by means of automatic monitoring system, and further analyze and identify health conditions of the structure
2.2 Symbols
2.2.1 Deformation
A——the amplitude of wind force;
d——the displacement component; the deviation value;
fc——the relative curvature of foundation;
f1——the deflection value in horizontal direction;
f1——the deflection value in vertical direction;
s——the settlement;
α——the inclination; the included angle;
Δ——the deformation amount during two periods;
Δd——the displacement component difference;
Δs——the settlement difference.
2.2.2 Observation
D——the distance; side length;
h——the height difference;
L——the length of annexed line, loop or collimation line;
n——the observation set number; the station number; the height difference number;
S——the sight length;
αv——the vertical angle;
v——the height of prism.
2.2.3 Root mean square error (RMSE)
md——the root mean square error in determination of displacement component or deviation value;
mΔd——the root mean square error in determination of displacement component difference;
mh——the root mean square error of station height difference;
m0——the root mean square error in single-range observation of each station height difference in leveling;
ms——the root mean square error in determination of settlement;
mΔs——the root mean square error in determination of settlement difference;
mα——the root mean square error in determination of direction;
mβ——the root mean square error of angle observation;
μ——the root mean square error of unit weight.
2.2.4 Instrument parameters
i——the included angle between collimation axis of level gauge and level tube axis;
k——the linear expansion coefficient for temperature of convergence meter;
2C——two times the collimation error of theodolite.
2.2.5 Other symbols
K——the vertical refraction coefficient of atmosphere;
R——the average curvature radius of earth.
3 Basic Requirements
3.1 General Requirements
3.1.1 Deformation measurement shall be carried out for the following buildings and structures during construction period and service period:
1 Building and structure with Class A ground and foundation design.
2 Building and structure with Class B ground and foundation design on the soft ground.
3 Storey-adding and extended building and structure, or ones on treated ground.
4 Building and structure influenced by the adjacent construction or change in environmental factors such as field groundwater.
5 Building and structure with new foundation or structure adopted.
6 Large urban infrastructure.
7 Building and structure with long and narrow shape and obvious change in ground soil.
3.1.2 Deformation measurement of building and structure during construction period shall meet the following requirements:
1 For various buildings and structures, settlement observation shall be carried out, and settlement observation for ground, settlement observation for foundation soil layers and slope displacement observation should be carried out.
2 For foundation pit engineering, deformation observation for foundation pit and supported structure and deformation observation for surroundings shall be carried out; for Class I foundation pit, rebound observation for foundation pit shall be carried out.
3 For high-rise and super high-rise building and structure, inclination observation shall be carried out.
4 In case of any crack in building and structure, crack observation shall be carried out.
5 If required by construction of building and structure, other types of deformation observations shall be carried out.
3.1.3 Deformation measurement of building and structure during service period shall meet the following requirements:
1 For various buildings and structures, settlement observation shall be carried out.
2 For high-rise/super high-rise building and structure and towering structure, horizontal displacement observation and inclination observation shall be carried out.
3 For super high-rise building and structure, deflection observation, sunshining deformation observation and wind loading deformation observation shall be carried out.
4 For large-span building and structure such as municipal bridge, exhibition hall and stadium, deflection observation and wind loading deformation observation shall be carried out.
5 For tunnel and culvert etc., convergence deformation observation shall be carried out.
6 In case of any crack in building and structure, crack observation shall be carried out.
7 Where there operation of building and structure affects the surroundings, deformation observation for surroundings shall be carried out.
8 For super high-rise / large-span / irregular building and structure as well as large municipal infrastructures such as underground public facilities, culvert, bridge and tunnel, structural health monitoring should be carried out.
9 If required by operation and management of building and structure, other types of deformation observations shall be carried out.
3.1.4 Independent plane-coordinate system and height datum may be adopted for the deformation measurement of building and structure. For large project or ones with special requirements, China Geodetic Coordinate System 2000 and National Height Datum 1985 or plane-coordinate system and height datum used at the city of the project should be adopted.
3.1.5 Common era and Beijing time should be adopted as the unified time reference for the deformation measurement of building and structure.
3.1.6 Under one of the following conditions during the deformation measurement of building and structure, safety plan shall be immediately implemented and observation frequency shall be increased or observation contents shall be added simultaneously:
1 In case of abnormal change in deformation amount or rate.
2 Where the deformation amount or rate of deformation gets up to or exceeds the prewarning deformation value.
3 In case of collapse and landslide on excavation surface.
4 In case of abnormality in building and structure themselves or their surroundings.
5 In case of other abnormal deformation conditions caused by natural disasters such as earthquake, rainstorm and freezing/thawing.
3.1.7 Safety precautions shall be taken during deformation measurement of building and structure on the field.
3.2 Accuracy Class
3.2.1 Deformation measurement of building and structure shall take the root mean square error as the accuracy index and two times of the root mean square error as the limit error.
3.2.2 For the general deformation measurement items of building and structure, proper observation accuracy class may be selected from Table 3.2.2 according to the building and structure type, deformation measurement type, project survey, design, construction and use requirements or the requirements of the client.
1 General Provisions
2 Terms and Symbols
2.1 Terms
2.2 Symbols
3 Basic Requirements
3.1 General Requirements
3.2 Accuracy Class
3.3 Technical Design and Implementation
4 Deformation Observation Methods
4.1 General Requirements
4.2 Leveling Survey
4.3 Hydrostatic Leveling
4.4 Trigonometric leveling
4.5 Surveying with Total Station
4.6 Surveying with GNSS
4.7 Laser-based Surveying
4.8 Close Range Photogrammetry
5 Layout and Surveying of Benchmarks
5.1 General Requirements
5.2 Layout and Surveying of Settlement Benchmarks
5.3 Layout and Surveying of Displacement Benchmarks
5.4 Stability Analysis of Benchmarks
6 Deformation Observation for Field, Ground and Surroundings
6.1 Settlement Observation for Ground
6.2 Settlement Observation for Foundation Soil Layers
6.3 Slope Displacement Monitoring
6.4 Deformation Observation for Foundation Pit and Supported Structure
6.5 Deformation Observation for Surroundings
7 Deformation Observation of Foundation and Upper Structure
7.1 Settlement Observation
7.2 Horizontal Displacement Observation
7.3 Inclination Observation
7.4 Crack Observation
7.5 Deflection Observation
7.6 Convergence Deformation Observation
7.7 Sunshining Deformation Observation
7.8 Wind Loading Deformation Observation
7.9 Structural Health Monitoring
8 Results Compilation and Analysis
8.1 General Requirements
8.2 Data Compilation
8.3 Monitoring Points Analysis
8.4 Modeling and Prediction
9 Quality Inspection and Acceptance
9.1 General Requirements
9.2 Quality Inspection
9.3 Quality Acceptance
Annex A Deformation Observation Results
Annex B Quality Inspection Log
Explanation of Wording in This Code
List of Quoted Standards
