GB 55003-2021Code for design of building foundation (English PDF)

2.1 Basic requirements

2.1.4 The design service life of the foundation shall meet the following requirements.

2.1.6 The construction of foundation works shall adopt materials, components, equipment, that have passed quality inspections. The construction plan shall be formulated, according to the design requirements and engineering needs. The construction quality control and engineering monitoring shall be carried out.

Engineering monitoring shall ensure the integrity, authenticity, reliability of the data.

2.2 Design

2.2.1 Foundation engineering shall be designed, according to the design

service life, the environmental category of the proposed site, the overall geology of the site and the survey results, the action and action combination of the foundation. It shall propose the construction and acceptance requirements, engineering monitoring requirements, maintenance requirements during normal use.

3.1 General requirements

3.1.1 The geotechnical survey results of the proposed site shall include the following contents.

3.2 Specific requirements

3.2.1 When there are special rocks and soils on the site and foundation, the geotechnical engineering survey results shall not only meet the requirements of clause 3.1 of this Code, but also include the following contents.

3.2.2 When there are unfavorable geological effects and geological disasters in the proposed site and its vicinity, the geotechnical engineering survey results shall not only meet the requirements of clause 3.1 of this Code, but also include the following contents.

4.1 General provisions

4.1.1 The foundation design shall meet the following requirements.

4.1.2 After excavation of the foundation trench (pit) to the design elevation, it

shall carry out the inspection of foundation trench (pit).

4.2 Foundation design

4.2.1 When the axial load actions, the pressure on the bottom surface of the foundation shall meet the requirements of the following formula.

4.2.2 When the eccentric load actions, the pressure on the bottom surface of the foundation shall not only meet the requirements of formula (4.2.1), but also meet the requirements of the following formula.

4.2.3 The characteristic value of the bearing capacity of the natural foundation shall be comprehensively determined, through load tests or other in-situ tests, formula calculations, combined with engineering practical experience.

4.3 Special rock foundation design

4.3.1 The buried depth of the foundation of the building (structure), in the expansive soil area, shall not be less than 1 m. The action of horizontal expansion force shall be considered, when checking the stability of expansive soil foundation. Buildings (structures), in expansive soil areas, shall adopt foundation measures, construction measures, structural measures, to prevent expansion and contraction deformation.

4.4 Construction and acceptance

4.4.1 Before foundation construction, it shall prepare the foundation

engineering construction program or foundation engineering construction plan, which shall include. foundation construction technical parameters, foundation construction process, foundation construction methods, technical measures of foundation construction safety, emergency plans, engineering monitoring requirements, etc.

5.1 General provisions

5.1.1 The design calculation or check calculation of the pile foundation shall include the following contents.

5.1.2 The materials used for the pile foundation, the connection between the pile segments, the pile foundation structure shall meet the durability requirements, in the environment category of the site, where it is located.

5.1.3 Engineering piles shall be inspected for bearing capacity and pile quality.

5.2 Design of pile foundation

5.3 Pile foundation design for special rock and soil

5.3.1 For the pile foundation in the site of self-weight collapsible loess, the pile end shall penetrate the collapsible loess layer, OR it shall take measures to eliminate the influence of the collapsibility of the soil layer on the pile foundation.

5.3.2 When soil squeezing piles or partial soil squeezing piles are used, in saturated soft soil foundation, it shall take treatment measures to reduce the soil squeezing effect.

5.4 Construction and acceptance

5.4.1 The construction of pile foundation engineering shall meet the following requirements.

5.4.2 The settlement of the following pile foundation projects shall be monitored, during construction and use, until the settlement reaches a stability criterion.

5.4.3 The construction acceptance inspection of pile foundation engineering shall meet the following requirements.

6.1 General provisions

6.1.1 The burial depth of the foundation shall meet the requirements of foundation's bearing capacity, deformation, stability. For the engineering structure located on the rock foundation, the burial depth of the foundation shall meet the requirements of anti-sliding stability.

6.1.2 The concrete foundation shall be subjected to the calculations of punching shear bearing capacity, shear bearing capacity, bending bearing capacity, local compressive bearing capacity.

6.2 Design of extended foundation

6.2.1 The calculation of the extended foundation shall meet the following requirements.

6.2.2 The thickness of the under-column (wall) pile foundation cap shall meet the requirements for the punching shear of the column (wall) to the cap AND the punching shear bearing capacity of the pile to the cap.

6.2.3 For the under-column (wall) pile foundation cap, it shall check the shear bearing capacity of the oblique section of the through cap, which is formed by the column (wall) side, the variable step position, the line of the pile side, respectively.

6.2.4 The concrete strength grade of the extended foundation shall not be lower than C25; the minimum reinforcement ratio of the stressed steel bars shall not be less than 0.15%. When the reinforced concrete foundation is equipped with a concrete cushion, the thickness of the concrete protective layer of the longitudinally stressed steel bars shall be calculated, from the bottom of the foundation, AND shall not be less than 40 mm.

6.3 Design of raft foundation

6.3.1 The slab thickness of the flat raft foundation shall meet the requirements of punching shear capacity.

6.4 Construction and acceptance

6.4.1 The construction of foundation work shall meet the following requirements.

6.4.2 The acceptance inspection of foundation engineering shall meet the following requirements.

7.1 General provisions

7.1.1 The supporting structure of the foundation pit shall be designed, according to the limit state of the bearing capacity AND the limit state of the normal service.

7.1.2 The calculation of the limit state design of the bearing capacity of the foundation pit's supporting structure shall include the following.

7.1.3 For foundation pit engineering, which has a safety level of supporting structure in level I and level II, it shall calculate the deformation of the supporting structure AND the deformation of the surrounding soil of the foundation pit;

meanwhile, it shall analyze and evaluate the surrounding environmental impact.

7.2 Design of supporting structure

7.2.1 When the supporting structural members are designed according to the limit state of bearing capacity, they shall conform to the following formula.

7.2.3 The stability check calculation of the foundation pit's supporting structure shall meet the following requirements.

7.2.4 The pile body concrete's strength grade of the row pile supporting structure shall not be lower than C25.The thickness of the concrete protective layer of the longitudinally stressed steel bars of the pile shall not be less than 35 mm; OR it shall not be less than 50 mm, when the underwater pouring process is used.

7.3 Groundwater control design

7.3.1 The design of groundwater control shall meet the requirements of pit bottom anti-surge, the requirements for anti-seepage stability check calculations of pit bottom and side wall, as well as the settlement control requirements for the municipal facilities such as surrounding buildings (structures) of the foundation pit, underground pipelines, roads, urban rail transits.

7.4 Construction and acceptance

7.4.1 Prior to the construction of the foundation pit project, it shall prepare a

special construction plan for the foundation pit project. The content shall include the construction technical parameters, such as supporting structure, groundwater control, earth excavation and backfilling; the construction process of the foundation pit project; the construction methods of foundation pit project;

safety technical measures for foundation pit construction, emergency plans, engineering monitoring requirements, etc.

8.1 General provisions

8.1.1 The engineering design of the slope shall meet the following requirements.

8.1.2 The overall stability analysis and calculation of the slope engineering design shall be carried out, according to different working conditions. The permanent slope retaining structure and components, slope surface drainage facilities, underground drainage facilities, etc. shall meet the durability requirements, in the environmental category of the site, where they are located.

8.1.4 During the construction and use of the building (structure), which is located in the slope collapse area, it shall monitor the slope top displacement, the surface cracks, the settlement deformation of the building (structure). The monitoring time, after the completion of the permanent slope project, shall not be less than 2 years.

8.2 Design of retaining structure

8.2.1 The design calculation or check calculation of the slope retaining structure shall include the following contents.

8.4 Construction and acceptance

8.4.1 Prior to the construction of the slope project, it shall prepare a special

construction plan for the slope project. Its content shall include the technical parameters of retaining structure, slope engineering drainage and slope protection, rock and soil excavation, construction technology process of slope engineering, construction method of slope engineering, construction safety technical measures of slope engineering, emergency plan, engineering monitoring requirements, etc.

8.4.2 The rock and soil excavation of the slope shall meet the following requirements.

8.4.3 Drainage system shall be set, during the construction of retaining wall's

support. The replace-filled foundation of retaining wall shall be paved and compacted in layers.

8.4.4 During the construction of the anchor rod (cable), it shall not damage the retaining structure and components and the foundation of adjacent buildings (structures).

8.4.5 It shall take anti-seepage measures, for the installation of the slope

drainage hole, interception and drainage ditch, in the construction of spray-anchor support. After the anchor rod is stretched and locked up to the standard, the anchor head of the permanent anchor rod shall be sealed AND subject to anti-corrosive treatment.