Structural design: Take a look at how Vanke does it!

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Structural design: Take a look at how Vanke does it! Section 1: Residential Buildings http://img.civilcn.com/d/file/zhishi/jggc/2019-08-30/fd152062cd38835053e0f1cfeaaaedfe.png Notes: A. The ceiling height of residential buildings is 2.9 meters, and there is no underfloor heating. B. Adjustment of reinforcement content: For a seismic resistance grade of 6°, the reinforcement content is reduced by 3–5 kg ； At a seismic resistance level of 8°, the amount of reinforcement increases by 5–7 kg. C. Structural limit design change index: for villas and multi-story buildings, it is 1.1% of the completed work volume ； Low-rise buildings account for 1.0% ； The high-rise rate is 0.8%. D. Ground-based indicators are included in the terms of the design contract; if the values are below the set limits, designers are rewarded proportionally ； If it exceeds 5–7% of the limit, a fine of a certain amount will be imposed on the design firm and the project company, depending on the actual circumstances. The penalty clause is determined at the time of signing the contract. E. The underground indicators listed in the table are reference indicators; the specific engineering measures shall be adjusted based on the geotechnical investigation report and the foundation type approved by the Design Management Center. The adjusted figures shall be included in the supplementary provisions of the design contract. Section 2. Clubs and social venues: http://img.civilcn.com/d/file/zhishi/jggc/2019-08-30/cdc3929b8c6c39dbc5beafe1cba920fd.png Section 3. Commercial pedestrian streets: http://img.civilcn.com/d/file/zhishi/jggc/2019-08-30/db63a63c99e0054f11909a4ef53f817c.png Section 4. Hotel-style apartments: http://img.civilcn.com/d/file/zhishi/jggc/2019-08-30/1ce33330865fb19018f7ac86c16ea6fe.png Section 5. Separate underground parking garages: http://img.civilcn.com/d/file/zhishi/jggc/2019-08-30/a8acf1675c2ba1ec78b026e007f79ab6.png Part II. General principles for structural design Section 1. General principles of structural design: 1. It is necessary to strictly comply with the mandatory provisions in the relevant codes; no violations are allowed. 2. The structural form generally adopts reinforced concrete structure. 3. The structural scheme should be reasonable, taking both safety and cost into account; that is, under the premise of ensuring structural safety, the principle of minimizing costs should be adhered to. 4. Unless required for calculations and conceptual design, the lower values specified in the codes shall be adopted for member dimensions and reinforcement. Section 2. Requirements for live load values in various types of premises: In addition to strictly adhering to the “Code for Loads on Building Structures”: 1. The permissible floor load for individual shops in commercial pedestrian streets is set at 4.0 kN per square meter. 2. The load for use in the gym and dance hall of the club is set at 4.0 KN/square meter, while the load for other areas is 2.0 KN/square meter. 3. The load on the roof of an independent underground garage shall be calculated in sections based on the landscape layout plan or written specifications, and must meet the value criteria specified in the Technical Specifications for Green Roof Engineering. Value of live load on the top slab: 1.5 kN/m² for green spaces ； For small squares, use 4.0 KN per square meter ； Motor vehicle lanes generally also serve as fire lanes; their specifications can be determined in accordance with the relevant provisions of the “Code for Loads on Building Structures”. 4. For planted roofs on public buildings, the thickness of the fill soil is 500 mm. The live load values are: 1.5 kN/m² for green areas and 3.0 kN/m² for observation areas ； When soil filling is required for the entrance garden and terrace of a residence, the fill thickness should be 200 mm, with a live load of 2.0 KN per square meter. Section 3. Range of values for beam and column cross-sections and reinforcement ratios: 1. The height of the main beam cross-section is generally taken as 1/10 to 1/14 of the span, while a reasonable calculated reinforcement ratio lies between 0.8% and 1.6%. 2. The cross-sectional height of the secondary beam is generally taken as 1/14 to 1/18 of the span, with a reasonable calculated reinforcement ratio ranging from 0.4% to 1.4%. 3. Apart from brick-concrete structures, the height of the perimeter beams must also meet architectural requirements. Generally, when the distance from the bottom of the beam to the top of the opening is less than 150, the beam height should be set to reach the top of the window. 4. Beams with large spans (greater than 10 meters) and large overhangs (greater than 2.5 meters) shall be specifically checked for deflection and cracking. 5. The consolidation coefficient for beam reinforcement shall be set at 0.15, and the reinforcement shall be arranged strictly in accordance with the calculation results; it should not be increased arbitrarily. 6. When the web height of the beam is less than 450, no structural web reinforcement is provided. (An exception applies if the calculation results require the installation of torsion-resistant waist rebar.) 7. The stirrups of the cantilever beam should be densely arranged throughout their entire length. 8. At the intersections of primary and secondary beams, it is preferable to use additional stirrups; the inclusion of suspension bars should be determined based on the shear envelope diagram in the calculation results. If they are not necessary, they should not be installed arbitrarily in order to avoid complications during construction. 9. Sleeves should be used for pipes passing through beams, and reinforcement bars should be installed at openings in circular holes with a diameter greater than 30 (or square holes of 30X30 dimensions). 10. Generally, no counterbeams are provided at the mid-span of roofs and terrace slabs. If counterbeams are used, water passages should be reserved on them according to the drainage requirements; the location and size of these passages must be indicated, and measures should be taken to ensure proper drainage from those openings. 11. The cross-section of the column can be determined based on requirements such as the number of floors, floor height, and axial compression ratio, with efforts being made to keep the column’s axial compression ratio as close as possible to the limits specified in the codes. 12. When the variation in reinforcement calculation along the vertical column exceeds 15%, reinforcement should be arranged in layers ； The merging coefficient for reinforcement in columns on the same floor is set at 0.15, and the reinforcement should be arranged strictly in accordance with the calculation results; it should not be increased arbitrarily. 13. The tension bars in the column cross-section shall hook onto the main stirrups and be included in the calculation of the volume stirrup ratio. Section 4. Plate thickness and reinforcement requirements: 1. The floor load must meet the decorative requirements. 2. The thickness of floor slabs is generally taken as 1/30 to 1/35 of the span, and a reasonable calculated reinforcement ratio is usually between 0.20% and 0.6%. 3. The negative reinforcement in floor slabs should not be continuous over large areas, except in small sections such as bathrooms, areas with many concealed pipelines, weak parts of the building’s structure, and areas subject to high temperature stresses. 4. The reinforcement of floor slabs shall meet the relevant requirements of local standards. 5. For plates with the same span, the same support conditions, and the same load, the thickness and reinforcement of each unit must be exactly identical. 6. Finite element analysis should be conducted for the design of irregular plates; for those with large spans, elastic-plastic deflection and crack formation should be checked. 7. The equipment engineering team and the structural engineering team should work closely together; there should be no large concentrations of wiring ducts in the floor slabs, nor should these ducts intersect with each other across more than two floors. Otherwise, measures must be taken to prevent cracks in the concrete. 8. Radiating ribs should be provided at the corners of the window sill slab. The side panels of the window sill should be made of cast-in-place reinforced concrete. 9. All roof slabs are made of fine aggregate concrete ； Plate thickness ≥120mm, crack width ≤0.2mm ； Reinforcement of C8@150 in a double-layer, two-way arrangement; where the reinforcement in larger sections is insufficient, additional reinforcement shall be added to make up for it. Section 5: Requirements regarding the exterior walls and roof slabs of basements: 1. All basements shall be constructed using reinforced concrete structures, and no temperature deformation joints shall be provided in structures with excessive length. Reinforcement strips are used in the design to prevent the formation of cracks. 2. The roof slab and exterior walls of the basement shall undergo strength calculations and deformation checks. 3. The type of cement to be used in the basement should have good water resistance, low bleeding, low hydration heat, and a certain degree of erosion resistance; the cement grade required is not less than 425. The concrete grade should be less than or equal to C35. 4. The minimum thickness of the concrete exterior wall panels shall meet the waterproofing requirements, and the construction joints in the exterior walls shall be equipped with water-stop measures (steel plate water stops). 5. If basement pipes need to pass through beams, their location should be chosen at the point where the beam bears the least stress, and reinforcement bars should be installed at the openings. 6. All openings in the exterior walls shall be equipped with waterproof sleeves, and the periphery of these sleeves shall be fully welded with water-stop steel plates. 7. All underground retaining walls within the building area should be integrated with the main structure; gravity-type retaining walls should be avoided. 8. All underground retaining walls that require waterproofing are constructed as concrete walls. 9. When designing retaining walls, it is necessary to communicate with the architecture and landscape design teams to ensure that the form of the retaining wall matches the appearance and texture requirements specified by those fields. 10. The water resistance grade of concrete should meet the waterproofing requirements; generally, S6 is used. (Specific areas to be determined separately) Section 6. Comparison principles for basic design schemes: 1. The foundation design should be safe, economical, and feasible; based on geological conditions and the characteristics of the superstructure, general engineering design firms submit two options for approval by the design management office, while for important projects, the choice is made at a foundation design review meeting. 2. Independent foundation: A. To ensure construction quality, the independent foundation is designed in a stepped format. B. Tie beams are installed only in the primary frame and in the case of independent foundations under special circumstances; no tie beams are used elsewhere. (With the exception of those used as foundations for bottom fill walls,) the height of tie beams is taken as 1/10 of the average span, and the reinforcement ratio is generally 0.4% to 0.6%; tie beams used as foundations for bottom fill walls are designed based on the actual loading conditions. 3. Pile foundation: A. Two piles of different diameters can be used in the same unit. When prestressed pipe piles are used, such as those with a diameter of 400 or 500, it is advisable to use a smaller number of larger-diameter piles instead of a larger number of smaller-diameter piles. When using driven piles, such as those with a diameter of 800 or 1000, small-diameter piles should be used instead of large-diameter piles whenever possible. B. When the number of individual engineering piles exceeds 300, or when there are subsequent projects in the same plot, it is recommended to drive three static load test piles in advance; the foundation design should be carried out after the characteristic value of the bearing capacity per pile has been determined. 4. Foundation selection in the soft soil areas of the Jiangnan region: (Refer to table) 5. Foundation selection in northern areas with clay (silt) soil or where the bedrock is shallow: (Refer to table) 6. In high-rise shear wall residences, piles should be installed as close as possible to the axis line; the foundation slab should consist of a cap beam along with a waterproof bottom slab. Section 7. Issues related to post-cast strips (reinforcement strips) in extra-long structures: 1. Extra-long structures should have post-cast strips (reinforcement strips) installed at appropriate locations, with a spacing of 35–40 meters between such strips ； 2. The post-cast strips (reinforcement strips) for the basement slab, exterior walls, and top slab should be arranged in a closed configuration whenever possible ； 3. Within 800 mm on either side of the post-cast strip (reinforcement strip), the rebar shall not overlap, and additional rebar must be provided ； Steel plates are used to prevent water leakage at the construction joints on both sides ； An additional waterproofing layer is applied to the water-facing side of the post-cast strip (reinforcement strip); the post-cast strip (reinforcement strip) is poured using concrete of a higher grade along with a certain proportion of expansion agent. 4. Details of the post-cast strip (reinforcement strip) are provided in Appendices 1–2, Section 8. Calculation data: 1. The design institute shall provide the PK.PM electronic model for review by the design management center before drawings can be prepared. 2. The calculation sheet should be complete; for any parts that were not calculated using computers, manual calculations must be provided, such as the calculation of loads on building roofs, the determination of reinforcement requirements for stair beams and slabs, the adjustment of the bearing capacity of natural foundations, the calculation of the bearing capacity of individual piles, the analysis of shear and bending forces on cap slabs, the calculation of the thickness and reinforcement required for raft slabs at the top of piles, as well as the calculation of the strength and deformation of underground wall structures. 3. Macroscopic parameters such as axial compression ratio, period, displacement, shear-to-weight ratio, and stiffness-to-weight ratio should be kept within appropriate ranges, satisfying the requirements of the codes without excessive excess. Section 9: Requirements for drawing production: 1. The structural zones should be the same as those of the building. 2. The structure must follow any adjustments made to the building, maintaining consistency with it. 3. Facades and joints should preferably be constructed using concrete structures; if steel structures are necessary, joint construction drawings must be prepared. 4. If there is auxiliary steel structure on the main reinforced concrete structure, the loads transferred from the steel structure must be fully considered during calculations, and a layout drawing of the embedded steel structure components shall be prepared. Where there are curtain walls, their own weight must be taken into account, and a layout plan for the embedded components should be prepared prior to construction. 5. All sections using prestressed or steel structures shall have their construction drawings prepared together with the complete set of construction drawings, without any need for secondary design work. 6. The floor elevation mark should indicate the structural elevation. 7. The holes for equipment and the embedded sleeves in walls, beams, and columns should be indicated on the positioning drawings. 8. The exact locations of the structural columns in the peripheral filling walls must be indicated in the structural plan template. 9. For projects with basements, a separate drawing of the basement exterior wall formwork should be prepared, indicating the location and size of the sleeves passing through the walls. 10. For projects with basements, a separate drawing of the floor formwork should be prepared, indicating the location and dimensions of drainage ditches, sump pits, grit chambers, etc., along with detailed drawings of the specific structural elements. 11. The natural foundation plan should indicate which soil layer constitutes the bearing stratum, what the characteristic value of foundation bearing capacity fak is, what the corrected value fa is, and what requirements there are for construction ； The pile layout plan should specify the pile type, pile diameter, pile length, the reference number of the atlas used, the soil layer number of the pile tip bearing stratum, the characteristic value of the single pile bearing capacity, the requirements for pile testing, and the construction precautions. 12. The specific location of the post-cast strips should be indicated on the formwork drawings for the cast-in-place slabs, specifying whether they are temperature-induced post-cast strips or settlement-induced post-cast strips. Detailed drawings of these strips should also be provided, along with instructions regarding the construction requirements. 13. Settlement observation points should be marked at appropriate locations. 14. The technical standards and drawing standards for each project sub-item must be unified. 15. The drawings should be prepared in accordance with the **standard flat drawing sets 《03G101-1》《04G101-3》. Part Three: Scope of Material Selection Section 1. Walls 1. Load-bearing walls shall use MU7.5~MU10 clay bricks or load-bearing porous clay bricks, along with M5~M10 cement mortar or cement-based mixed mortar. 2. The exterior walls of the infill wall are constructed using MU5 non-load-bearing porous clay bricks and M5 cement mortar. The interior walls are constructed using aerated concrete blocks and M5 cement mortar. 3. For the bottom 200 mm of the fill walls in kitchens and bathrooms, C20 plain concrete or MU5 non-load-bearing porous clay bricks are used, with M5 cement mortar. 4. For the fill walls in basements, MU5 cement-lime sand bricks or MU5 non-load-bearing porous clay bricks are used, along with M5 cement mixed mortar. 5. In frame, frame-shear wall, shear wall, and tube-in-frame structures, the area below the parapet height is constructed with reinforced concrete beams or C20 plain concrete, while the area above it is made of MU5 non-load-bearing porous clay bricks along with M5 cement mortar. 6. Requirements for aerated concrete masonry and materials: (1) Dry bulk density ≤ 7 KN/M3; (2) Masonry density (unit weight) of 8–9 KN/M3 (usually 9 KN/M3); (3) Strength of interior wall blocks: MU5 (A5.0), strength of exterior wall blocks: MU5 (A5.0) ； (4) Interior walls: 100 mm thick with M5 mortar (H≤2.4 m), 200 mm thick with M5 mortar (H≤4.4 m) ； (5) Connection of block walls: Block walls should be connected to reinforced concrete columns or shear walls. For the tying method, hot-rolled steel bars with a diameter of Φ6 can be installed every 600 mm along the height of the column or shear wall. The length of the rebar extending into the masonry should not be less than 1/5 of the wall length, nor less than 700 mm. The anchorage of the post-installed rebar is 100 mm. Section 2. Concrete 1. Foundation: C25~C35 2. Main structure: Brick-concrete with C20 ； The rest should be no lower than C25 ； Wall columns in multi-story and low-rise buildings are generally made of C25~C30 grade concrete ； The wall columns at the upper levels are generally made of C30~C35 concrete. Section 3. Reinforcing Bars 1. For the longitudinal reinforcing bars in beams and slabs, HRB400 (III) grade steel is the preferred choice. 2. For primary stress-bearing bars and longitudinal reinforcement in walls and columns, HRB400 (III) grade steel is the preferred choice ； Grade II steel bars can be used when the calculation results meet the structural requirements. 3. For the stirrups of beams and columns, grade I steel or HRB400 (III) grade steel is selected based on the calculation results. 4. The decorative strips and structural rebar used in the structure shall be made of Grade I rebar; when the diameter of the rebar exceeds 12 mm, Grade II or Grade III rebar may be used. 5. Cold-rolled ribbed steel bars shall not be used. Part IV: Specific requirements for various types of buildings Section 1: Residential buildings 1. Calculation models and data for computerized and manual calculations – PK.PM electronic models are provided ； Calculation of roof load values for buildings ； Calculation of reinforcement for stair beams and slabs ； Calculation of the strength and deformation check for the exterior wall of the basement ； Basic calculation. 2. Technical requirements A. Beams: There should be no beams in the ceilings of all rooms ； There should be no beams in the area where the living room and dining room meet without a wall in between ； When the floor span is not large and the reinforcement is used for structural purposes, it is not necessary to provide beams under partition walls ； The clear height where there is no wall beneath the beam shall be not less than 2.4 meters ； It should be avoided for the beam to tilt toward the room with the lower floor level, causing the floor surface to rise ； When structurally lowering the floor levels of terraces, balconies, bathrooms, etc., the beam surfaces in the middle of such areas should also be lowered to prevent them from protruding above the lowered floor level ； The height of the exterior beams of the structure is detailed in the table below: B. Slabs: The structural surfaces such as halls, rooms, and indoor corridors are 50 lower than the building’s outer surface ； The structural surfaces of the public stairwells and elevator lobbies are level with those of the rooms in those areas ； The structural grade of the kitchen is 30 points lower than that of the living room ； The slight reduction in the height of the bathroom is: the structural level is 30 units lower than that of the living areas ； The reduction in the floor level of the bathroom is as follows: the structural level is reduced by 300 compared to that of the living areas; if the bedroom in the same household is located on the bathroom floor, this reduction should be decreased to 250 ； The structural grade of the balcony connected to the room is 50 degrees lower than that of the room’s structure ； The structural grade of the balcony connected to the kitchen is 100 lower than that of the living room area ； The structural grade of the entrance garden is 150 lower than that of the living room ； The structural grade of the terrace area is 250 lower than that of the indoor areas ； Roof deck reduction in the commercial section: The structural elevation is reduced by 200~250 compared to that of the residential areas, to prevent insufficient roof deck reduction from causing difficulties in creating the necessary slope outside. C. Shear walls: Refer to the atlas of edge members for shear walls. D. Hidden design: Take into account the loads resulting from additions in the areas designated for such additions; 100*8 (width*thickness) steel plates should be embedded on the sides of the structural members surrounding these addition areas, with their upper edges at the same elevation as the top surface of the added floor ； The pseudo-duplex second-floor mezzanine is calculated as a steel structure mezzanine. E. Leak prevention measures: A concrete counter-beam or counter-step 300 in height (relative to the structural surface) should be installed on the side of the outdoor staircase that is connected to the building ； The air-conditioning slab is cast in place with a thickness of 100, and a concrete counterfort 150 high (relative to the structural surface) is constructed at its base ； Generally, a concrete counter-beam or counter-step 150 high (relative to the balcony’s structural surface) is constructed at the edge of the balcony ； At the edges of terraces where soil covering is required, a concrete counter-beam or counter-step 500 high (relative to the structural surface) shall be constructed ； At the edges of the patio areas where soil covering is required, a concrete counterbeam or counterstep 500 units in height (relative to the structural surface) should be installed ； The counter-beams and counter-thresholds should be poured together with the main structure ； In the floor-mounted bathroom, a side-mounted floor drain with a diameter of Ф50 is provided right at the bottom of the floor panel. Section 2. Independent Underground Garage 1. Calculation model and computerized/manual calculation data: A. PK.PM electronic model provided ； B. Calculation of roof load values ； C. Calculation of the strength and deformation check for the exterior walls of the basement ； D. Foundation and anti-floating calculations ； (The anti-floating design water level determined by Party A is to be used for anti-floating calculations.) E. Data for civil air defense calculations: roof slab, floor slab, retaining walls, openings, etc. 2. Technical requirements A. Column grid: generally 5.1~5.4 meters X 8.0~8.2 meters, with a column cross-section of 500X500 ；