标准编号:	DGJ 08-9-2013
中文名称:	建筑抗震设计规程
英文名称:	Codeforseismicdesignofbuildings
行业分类:	DG
发布机构:	上海市城乡建设和交通委员会
发布日期:	2013-09-04
实施日期:	2013-11-1
标准状态:	被替代
被新标准替代:	DG/TJ08-9-2023
替代旧标准:	DG J08-9-2003 建筑抗震设计规程 DG J08-9-2003 建筑抗震设计规程
翻译语言:	英文
文件格式:	PDF
中文字符数:	392000 字
翻译价格(元):	15000.00 元
交付时间:	付款后 1 个工作日

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.



According to the Shanghai Engineering Construction Standard Design and Development Plan in 2010 (the second batch) issued based on HUJIANJIAO [2010] No.731, the revision group composed of Tongji University and other units has comprehensively revised DGJ08-9-2003 Code for seismic design of buildings as the Shanghai Engineering Construction Standard. During the revision, this code was developed based on the objectives of advanced technology, economic rationality, convenience for implementation and coordination with other standards, by making reference to the national standard GB 50011-2010 Code for seismic design of buildings.



This code consists of 14 clauses and 11 annexes. With respect to GB 50011-2010 Code for seismic design of buildings, this code has the following main differences: (1) Different seismic design response spectrum and seismic ground motion parameters, and different characteristic period (frequent earthquakes and rare earthquakes), period range applicable to the descent section of the design response spectrum, and maximum of acceleration time history used in the time history analysis of rare earthquakes; (2) 14 seismic wave acceleration time histories applicable to time history analysis are added in the annex; (3) The performance-based seismic design method is supplemented and modified; the division basis of seismic performance levels and performance objectives is defined; the maximum limits of inter-story displacement angle of various structures are provided corresponding to seismic performance levels; (4) The requirement of strength grade of steel bar is improved for the popularization and application of high-strength steel bar; (5) The judgment method of irregular structure plane is different; for convex structure, double control indicators (protruding length and width) are used as the judgment basis, and the explanation of provisions is more detailed according to the actual engineering situation in Shanghai; (6) The provisions of site, subgrade and foundation are different, which are basically consistent with the current Shanghai Engineering Construction Standard DGJ08-11-2010 Foundation design code, and the liquefaction judgment equation based on standard penetration test is consistent with Shanghai Engineering Construction Standard DGJ08-37-2012 Code for investigation of geotechnical engineering; (7) The checking indicators of structural seismic deformation is further detailed, and the limits of elastic inter-story displacement angles are added for structures such as RC wall, frame-shear wall and frame-supported story (the upper story of embedded end); (8) The limits of axial compression ratio is further detailed, and the calculation method of axial compression ratio of steel tube and concrete composite columns is added; (9) In combination with JGJ 3-2010 Technical specification for concrete structures of tall building, the relevant regulations of Classes A and B reinforced concrete structures are supplemented; (10) The conditions and design measures for liberalizing the seismic shear force limit of the frame part in the frame-core tube structure are supplemented; (11) The seismic design requirements of slab-column structure are supplemented; (12) The condition of basement roof as the embedded part of superstructure is more clear, and the ratio of lateral stiffness of the first story underground to the first story aboveground is different, and the estimation method of stiffness ratio is supplemented; (13) The seismic design requirements of buildings with reinforced small block masonry walls are added in the text (in the annex as for the national standard), and further supplemented and improved; (14) The relevant regulations on seismic design for multi-story split-level brick masonry buildings are added; (15) The relevant regulations on seismic design of precast concrete structures are added; (16) The tall buildings are excluded from seismic design of steel structure buildings, since Shanghai has issued DG/TJ08-32-2008 Specification for steel structure design of tall buildings, and the concept of seismic grade is not adopted; (17) The provisions of isolation and energy-dissipation design are revised, which is more in line with the actual situation of Shanghai; (18) The clauses concerning single-story brick column factory buildings, and earth, wood and stone buildings are deleted.



The provisions printed in bold type in this code are compulsory and must be enforced strictly. With respect to GB 50011-2010 Code for seismic design of buildings, this code has added the following mandatory provisions: 7.1.4 related to precast RC structures; 8.6.1, 8.6.6, 8.6.8 and 8.6.15 related to buildings with reinforced small block masonry wall; and 8.7.3 related to multi-story split-level brick masonry buildings.



General Market Management Station of Shanghai Building Material Industry



April, 2013





Code for seismic design of buildings



1 General



1.0.1 This code is prepared with a view to implementing the national laws and regulations on earthquake prevention, disaster mitigation and architectural engineering, executing the prevention first policy and reducing the earthquake damage, casualty and economic loss after taking seismic protection measures.



1.0.2 This code is applicable to the seismic design, isolation and energy-dissipation design of general buildings on Categories III and IV sites in Shanghai. Performance-based seismic design of buildings may be carried out according to the basic methods specified in this code. The seismic design for special buildings and buildings with special industry requirements shall comply with relevant standards and specifications.



1.0.3 The buildings designed according to this code shall meet such seismic protection objectives that the major structures may be used continuously without damage or repair when affected by frequent earthquakes with the seismic protection intensity lower than that in this area; they may be damaged while can still be used after general repair when affected by an earthquake with the seismic protection intensity equivalent to that in this area; and they shall not encounter collapse or serious damage endangering life when affected by a rare earthquake with the seismic protection intensity higher than that in this area. For buildings with special functional or other requirements, the protection objectives higher than the basic ones can be adopted in the performance-based seismic design (if adopted).



1.0.4 The seismic design of buildings complying with this code shall also meet the requirements of the current relevant standards of the nation and Shanghai in addition to those of this code.



1.0.5 The seismic design of buildings shall follow the principle of equal importance on conceptual design and calculation as well as the design idea of unified aesthetic appearance and seismic safety of structures.



2 Terms and symbols



2.1 Terms



2.1.1

seismic protection intensity

seismic intensity which is approved as the criterion of seismic precaution of an area according to the authority specified by the nation



Note: "Intensities 6, 7 and 8" in this code is short for "seismic protection intensities 6, 7 and 8".



2.1.2

seismic protection criterion

scale for measuring the seismic protection requirements, which is determined by seismic protection intensity or design parameters of earthquake ground motions and seismic protection categories of buildings



2.1.3

seismic ground motion parameter zonation map

map in which the whole country is divided into areas with different seismic protection requirements, based on the seismic ground motion parameters (the intensity of earthquake action is expressed by acceleration)



2.1.4

earthquake action

dynamic action of structure caused by ground motion, including horizontal earthquake action and vertical earthquake action



2.1.5

design parameters of earthquake ground motions

seismic acceleration (speed and displacement) time history curve, acceleration response spectrum and peak acceleration for seismic design



2.1.6

design basic acceleration of ground motions

design value of acceleration of earthquake with exceeding probability of 10 % during the 50-year design reference period



2.1.7

design characteristic period of ground motions

periodic value corresponding to the start point of descending segment reflecting such factors as earthquake magnitude, epicentral distance and site category in the seismic influence coefficient curve used for seismic design



2.1.8

site

location of the engineering groups, with similar response spectrum characteristics, within the scope equivalent to the plant area, residential quarter and natural village or the plane area not less than 1.0 km2



2.1.9

seismic concept design of buildings

process of making the general arrangement for the buildings and structures and of determining details, based on the fundamental design principles and design concept obtained from the experiences in the earthquake disasters and projects



2.1.10

details of seismic design

various detail requirements which must be taken for structural and nonstructural parts generally without calculation according to seismic concept design principle



2.1.11

seismic measures

seismic design content excluding earthquake action calculation and resistance calculation; it includes details of seismic design



2.1.12

seismic performance levels

damage status of buildings after earthquakes and affection degree of their functions to continued use



2.1.13

seismic performance objectives

desired seismic performance levels of buildings based on the ground motion level



2.1.14

performance-based seismic design

design with reasonable seismic performance objectives and based on the seismic performance analysis of buildings, so that the designed buildings have the expected seismic performance when subjected to possible earthquakes in future



2.1.15

precast RC structure

reinforced concrete structure produced by precasting and assembly technology



2.1.16

precast composite RC wall

seismic composite reinforced concrete wall with precast concrete (PCF board) on one side and cast-in-place concrete on the other side



2.1.17

shear wall structure with precast composite RC wall

shear wall structure with precast composite RC wall as the exterior wall, and ordinary seismic reinforced concrete wall as the interior wall



 

2.1.18

reinforced small block masonry wall

wall reinforced with vertical and horizontal steel bars in the holes and grooves of small hollow concrete blocks that are filled with grout concrete so as to bear vertical and horizontal earthquake action



2.2 Symbols



2.2.1 Actions and effects



FEk, FEvk——the standard value for total structural horizontal and vertical earthquake action;



GE, Geq——the representative value of structure (member) gravity load and total equivalent gravity load in earthquake;



wk——the standard value of wind load;



SE——the earthquake action effect (bending moment, torque, axial force, shear force, stress and deformation);



S——the fundamental combination of earthquake action effect and other load effects;



Sk——the effect of action and standard value of load;



M——the bending moment;



N——the axial pressure;



V——the shear force;



p——the pressure on bottom of foundation;



u——the lateral displacement;



θ——the displacement angle of story.



2.2.2 Material properties and resistance



K——the stiffness of structure or member;



R——the bearing capacity of structural member;



f, fk, fE——the design value, standard value and seismic design value of various material strength (including the bearing capacity of subgrade) respectively;



[θ]——the limit for displacement angle of story.



2.2.3 Geometric parameters



A——the sectional area of member;



As——the sectional area of steel bar;



B——the total width of structure;



H——the total height of structure and column height;



L——the total length of structure (unit);



α——the distance;



as, ——the minimal distance from the force concurrence point of all longitudinal tensile and compressive steel bars to the margin of section;



b——the section width of member;



d——the depth or thickness of soil layer, or diameter of steel bar;



h——the height of calculated story or sectional height of member;



l——the length or span of member;



t——the thickness of shear wall or thickness of floor slab.



2.2.4 Calculation coefficients



α——the horizontal seismic influence coefficient;



αmax——the maximum value of horizontal seismic influence coefficient;



αvmax——the maximum value of vertical seismic influence coefficient;



γG, γE, γw——the partial coefficient of action;



γRE——the seismic adjustment factor of bearing capacity;



ζ——the calculation coefficient;



η——the enhancement or adjustment factor of earthquake action effect (internal force and deformation);



λ——the slenderness ratio or scale coefficient of member;



λv——the characteristic value of minimum stirrups;



ξy——the yield strength coefficient of structure (member);



ρ——the reinforcement ratio or ratio;



φ ——the stability coefficient of compressive member;



Ψ——the combination value coefficient or influence coefficient.



2.2.5 Others



T——the natural vibration period of structure;



N——the standard penetration blow count;



Ile——the liquefaction index of subgrade in earthquake;



Xji——the vibration mode coordinate of displacement (relative displacement of the ith mass point of the jth vibration mode in Direction x);



Yji——the vibration mode coordinate of displacement (relative displacement of the ith mass point of the jth vibration mode in Direction y);



Фji——the vibration mode coordinate of rotation (relative rotation of the ith mass point of the jth vibration mode in rotating direction);



n——the total number, such as number of stories, mass points, steel bars and spans, etc.;



vse——the equivalent shear wave velocity of soil layer.



3 Basic requirements of seismic design



3.1 Category and criterion for seismic protection of buildings



3.1.1 For all buildings under seismic protection, seismic protection category and seismic protection criterion shall be determined according to the requirements of the current national standard GB 50223 Standard for classification of seismic protection of building constructions.



3.1.2 The seismic protection intensity 7 can apply to all districts and counties in Shanghai.



3.2 Seismic influences



3.2.1 The seismic influences suffered by the locations of the buildings shall be characterized by the design basic acceleration of ground motion and the design characteristic period of ground motion corresponding to the seismic protection intensity.



3.2.2 If Shanghai is in frequent earthquakes and earthquakes of seismic protection intensities, the design characteristic period of ground motion in Category III site shall be 0.65 s and that in Category IV site shall be 0.9 s; if Shanghai is in rare earthquakes, the design characteristic period of ground motion in Category III and Category IV sites shall be 1.1 s. The design basic acceleration of ground motion corresponding to the seismic protection intensity shall be selected according to those specified in Table 3.2.2.



Table 3.2.2 Corresponding relationship between seismic protection intensity and design basic acceleration of ground motion

Seismic protection intensity 6 7 8

Design basic acceleration of ground motion 0.05 g 0.10 g 0.20 g



Note: g just above is the gravity acceleration.



3.3 Site and subgrade



3.3.1 To select a building site, comprehensive evaluation shall be made on favorable, general, unfavorable and dangerous sections for seismic resistance according to relevant data such as engineering requirement, seismic activity, engineering geology and seismic geology: For unfavorable section, requirements for avoiding it shall be put forward; when it is impossible to avoid it, effective measures shall be taken; For dangerous section, it is strictly prohibited to build Categories A and B buildings, and Category C buildings shall not be built.



3.3.2 The design of subgrade and foundation shall meet the following requirements:



1 The foundation of the same structural unit should not be set on the subgrades with completely different properties;



2 Natural subgrade and pile foundation should not be adopted in the same structural unit. If different types of foundations are adopted or the buried depth of the foundation is significantly different, corresponding measures shall be taken at the relevant parts of the foundation and superstructure according to the settlement difference between the two parts of the subgrade and foundation as well as to ensure reliable transmission of horizontal forces in the two parts during the earthquake;



3 For the subgrade composed of soft clay, liquefied soil, new fill or extremely non-uniform soil, corresponding measures shall be taken according to the differential settlement of subgrade in earthquake and other adverse influence.



3.3.3 The site, subgrade and foundation of buildings on slopes shall meet the following requirements:



1 Slope stability evaluation and prevention scheme and suggestions shall be provided during investigation of site of buildings on slopes.



2 The slope engineering shall adapt to the seismic protection requirements based on local conditions, according to the geological and topographic conditions and use requirements. The slope design shall meet the requirements of the current national standard GB 50330 Technical code for building slope engineering; during stability check, the relevant friction angle shall be corrected accordingly according to the seismic intensity.



3 The building foundation near the slope shall be designed for seismic stability. Enough distance shall be reserved between the foundation of the buildings and the edge of soil slope, which shall be determined according to the seismic intensity, and measures shall be taken to prevent the subgrade and foundation from being damaged during earthquake.



3.4 Regularity of building configuration and structural assembly



3.4.1 Architectural design shall define the regularity of building configuration according to the requirements of seismic concept design. Irregular buildings shall be reinforced as specified; normal irregular buildings shall be specially researched and demonstrated, for which special reinforcement measures shall be taken; seriously irregular buildings shall not apply.



Note: Building configuration refers to the change of plane shape, elevation and vertical profile of a building.



3.4.2 Architectural design shall emphasize the influence of the regularity of plane, elevation and vertical profile on seismic performance and economic rationality, In order to avoid the abrupt change of lateral stiffness and bearing capacity, it is suggested to select regular shape, regular and symmetrical layout of lateral-force-resisting members, uniform change of lateral stiffness along vertical direction, and gradual decrease of cross-section size and material strength of vertical lateral-force-resisting members from bottom to top.



The seismic design of the irregular buildings shall comply with the relevant provisions of 3.4.4 of this code.



3.4.3 The plane and vertical irregularities of building configuration and structural assembly shall be divided according to the following requirements:



1 Concrete buildings, steel buildings and steel-concrete hybrid buildings, in which a type of plane irregularity listed in Table 3.4.3-1 or a type of vertical irregularity listed in Table 3.4.3-2 or a similar irregularity exists, shall belong to irregular buildings;



Table 3.4.3-1 Main type of plane irregularity

Irregularity type Definition and indicator limit

Torsional irregularity The maximum elastic horizontal displacement (or inter-story displacement) of story under specified horizontal force is greater than 1.2 times of the mean of elastic horizontal displacement (or inter-story displacement) at both ends of this story

Concave-convex irregularity The concave length of structural plane is greater than 30 % of the overall dimension in corresponding projection direction; or the convex length is greater than 30 % of the overall dimension in corresponding projection direction and the convex width is less than 50 % of the convex length

Local discontinuity of floor slab The dimension of floor slab and the stiffness of plane change rapidly, for instance, the effective width of floor slab is less than 50 % of the typical width of floor slab at this story, or the opening area is greater than 30 % of the floorage of this story or split-level exists in larger story (split-level height is greater than the sectional height of floor beam or greater than 0.6 m)



Table 3.4.3-2 Main type of vertical irregularity

Irregularity type Definition and indicator limit

Lateral stiffness irregularity The lateral stiffness of this story is less than 70 % of the adjacent upper story or less than 80 % of the mean lateral stiffness of the adjacent three stories; except for the top story or out-of-roof small buildings, the horizontal dimension of partial take-in is greater than 25 % of the adjacent lower story

Discontinuity of vertical lateral-force-resisting member The internal forces of vertical lateral-force-resisting members (columns, shear walls and seismic support) are transmitted downward by horizontal conversion members (beams, trusses, etc.)

Abrupt change in story bearing capacity Lateral-force-resisting structures have an inter-story shear capacity of less than 80 % of the adjacent upper story



2 The division of plane and vertical irregularities of masonry buildings, single-story industrial factory buildings, single-story spacious buildings, long-span roof buildings and underground buildings shall meet the provisions of relevant clauses of this code.



3 In case of a building with many irregularities or with an irregularity largely exceeding the specified reference index shall be a seriously irregular building.

Foreword i
1 General
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements of seismic design
3.1 Category and criterion for seismic protection of buildings
3.2 Seismic influences
3.3 Site and subgrade
3.4 Regularity of building configuration and structural assembly
3.5 Structural system
3.6 Structural analysis
3.7 Nonstructural members
3.8 Isolation and energy-dissipation design
3.9 Structural materials and construction
3.10 Performance-based seismic design of buildings
3.11 Strong seismic response observation system of buildings
4 Site, subgrade and foundation
4.1 Site
4.2 Judgment and treatment for subgrade liquefaction
4.3 Seismic strength check for subgrade and foundation
4.4 Seismic measures
5 Earthquake action and seismic checking for structures
5.1 General
5.2 Calculation of horizontal earthquake action
5.3 Calculation of vertical earthquake action
5.4 Seismic checking of section
5.5 Seismic checking for deformation
6 Multi-story and tall reinforced concrete buildings
6.1 General
6.2 Essentials in calculation
6.3 Basic details of seismic design for frame structures
6.4 Basic details of seismic design for shear wall structures
6.5 Basic details of seismic design for frame-shear wall structures
6.6 Seismic design requirements for slab-column-shear wall structures
6.7 Seismic design requirements for tube structures
7 Precast RC structures
7.1 General
7.2 Seismic design requirements for precast RC frame
7.3 Seismic design requirements for precast composite RC wall
8 Masonry buildings and masonry buildings with RC frames on ground stories
8.1 General
8.2 Essentials in calculation
8.3 Details of seismic design for multi-story brick masonry buildings
8.4 Details for multi-story small block buildings
8.5 Details of seismic design for masonry buildings with frame-shear wall on ground story
8.6 Seismic design for buildings with reinforced small block masonry walls
8.7 Seismic design for multi-story split-level brick masonry buildings
9 Steel buildings
9.1 Multi-story steel buildings
9.2 Single-story steel factory building
10 Single-story factory buildings with RC columns
10.1 General
10.2 Essentials in calculation
10.3 Details of seismic design
11 Large-span buildings
11.1 Single-story spacious buildings
11.2 Long-span roof buildings
12 Seismically isolated and energy dissipation buildings
12.1 General
12.2 Essentials in design of seismically isolated buildings
12.3 Essentials in design of energy-dissipation buildings
13 Nonstructural members
13.1 General
13.2 Essentials in calculation
13.3 Essential seismic measures for architectural nonstructural members
13.4 Essential seismic measures for supports of mechanical and electrical components
14 Subterranean buildings
14.1 General
14.2 Essentials in calculation
14.3 Details of seismic design and anti-liquefaction measures
Annex A Time history curves of earthquake ground motion acceleration
Annex B Requirements for seismic design of high strength concrete structures
Annex C Seismic design requirements of prestressed concrete structures
Annex D Seismic checking of section for the core area of beam-column joint of frame structure
Annex E Seismic design requirements for transition story structures
Annex F Seismic design for composite steel bracing – concrete frame structures and composite steel frame - concrete core tube structures
Annex G Seismic design for multi-story industrial factory buildings
Annex H Adjustment of transverse earthquake action effect of plane bent frame of single-story factory buildings
Annex J Seismic checking for single-story reinforced concrete column factory building in longitudinal direction
Annex K Simplified calculation of seismic isolation design and seismic isolation measures for masonry structures
Annex L Reference methods for performance-based seismic design
Explanation of wording in this code
List of quoted standards

1 总则
1.0.1 为贯彻执行国家有关防震减灾、建筑工程的法律法规并实行以预防为主的方针，使建筑经抗震设防后，减轻建筑的地震破坏，避免人员伤亡，减少经济损失，制定本规程。
1.0.2 本规程适用于上海市场地类别为Ⅲ类和Ⅳ类的一般建筑的抗震设计及隔震、消能减震设计。建筑基于性能的抗震设计，可采用本规程规定的基本方法。特殊建筑及行业有特殊要求的建筑抗震设计，尚应按有关标准、规定执行。
1.0.3 按本规程设计的建筑，其基本的抗震设防目标是：当遭受低于本地区抗震设防烈度的多遇地震影响时，主体结构不受损坏或不需修理可继续使用；当遭受相当于本地区抗震设防烈度的设防地震影响时，可能发生损坏，但经一般性修理仍可继续使用；当遭受高于本地区抗震设防烈度的罕遇地震影响时，不致倒塌或发生危及生命的严重破坏。使用功能或其他方面有特殊要求的建筑，当采用基于性能的抗震设计时，可采用比基本抗震设防目标更高的设防目标。
1.0.4 应用本规程进行建筑工程的抗震设计，除应符合本规程要求外，尚应符合国家和上海市其他现行有关标准的规定。
1.0.5 建筑工程的抗震设计应贯彻概念设计与计算并重的原则；应遵循建筑形体美观与结构抗震安全相统一的设计思想。
2 术语和符号
2.1 术语
2.1.1 抗震设防烈度 seismic protection intensity
按国家规定的权限批准作为一个地区抗震设防依据的地震烈度。
注：本规程“6度、7度、8度”即“抗震设防烈度为6度、7度、8度”的简称。
2.1.2 抗震设防标准 seismic protection criterion
衡量抗震设防要求高低的尺度，由抗震设防烈度或设计地震动参数及建筑抗震设防类别确定。
2.1.3 地震动参数区划图 seismic ground motion parameter zo-nation map
以地震动参数(以加速度表示地震作用强弱程度)为指标，将全国划分为不同抗震设防要求区域的图件。
2.1.4 地震作用 earthquake action
由地震动引起的结构动态作用，包括水平地震作用和竖向地震作用。
2.1.5 设计地震动参数 design parameters of earthquake ground motions
抗震设计用的地震加速度(速度、位移)时程曲线、加速度反应谱和峰值加速度。
2.1.6 设计基本地震加速度 design basic acceleration of ground motions
50年设计基准期内超越概率为10％的地震加速度的设计取值。
2.1.7 设计特征周期 design characteristic period of ground motions
抗震设计用的地震影响系数曲线中，反映地震震级、震中距和场地类别等因素的下降段起始点对应的周期值，简称特征周期。
2.1.8 场地 site
工程群体所在地，具有相似的反应谱特征，其范围相当于厂区、居住小区和自然村或不小于1.0km2的平面面积。
2.1.9 建筑抗震概念设计 seismic concept design of buildings
根据地震灾害和工程经验等所形成的基本设计原则和设计思想，进行建筑和结构总体布置并确定细部构造的过程。
2.1.10 抗震构造措施 details of seismic design
根据抗震概念设计原则，一般不需计算而对结构和非结构各部分必须采取的各种细部要求。
2.1.11 抗震措施 seismic measures
除地震作用计算和抗力计算以外的抗震设计内容，包括抗震构造措施。
2.1.12 抗震性能水准 seismic performance levels
建筑物在震后的损坏状况及其可继续使用功能的受影响程度。
2.1.13 抗震性能目标 seismic performance objectives
针对各级地震动水准期望建筑物达到的抗震性能水准。
2.1.14 基于性能的抗震设计 performance-based seismic design
选择合理的抗震性能目标，以建筑的抗震性能分析为基础进行设计，使设计的建筑在遭受未来可能发生的地震时具有预期的抗震性能。
2.1.15 预制混凝土结构 precast RC structure
采用预制、装配工艺生产的钢筋混凝土结构。
2.1.16 预制钢筋混凝土叠合抗震墙 precast composite RC wall
一侧预制(PCF板)、一侧现浇的钢筋混凝土叠合抗震墙，简称叠合抗震墙。
2.1.17 预制钢筋混凝土叠合抗震墙结构 shear wall structure with precast composite RC wall
结构外墙采用预制钢筋混凝土叠合抗震墙、结构内墙采用普通钢筋混凝土抗震墙的抗震墙结构。
2.1.18 配筋小砌块砌体抗震墙 reinforced small block masonry wall
在混凝土小型空心砌块的孔洞和凹槽中按规定要求配置竖向钢筋和水平钢筋、并采用灌孔混凝土填实孔洞、能够承受竖向和水平向地震作用的墙体。
2.2 主要符号
2.2.1 作用和作用效应
FEk、FEvk——结构总水平、竖向地震作用标准值；
GE、Geq——地震时结构(构件)的重力荷载代表值、等效总重力荷载代表值；
wk——风荷载标准值；
SE——地震作用效应(弯矩、扭矩、轴向力、剪力、应力和变形)；
S——地震作用效应与其它荷载效应的基本组合；
Sk——作用、荷载标准值的效应；
M——弯矩；
N——轴向压力；
V——剪力；
p——基础底面压力；
u——侧移；
θ——楼层位移角。
2.2.2 材料性能和抗力
K——结构或构件的刚度；
R——结构构件承载力；
f、fk、fE——各种材料强度(含地基承载力)设计值、标准值和抗震设计值；
[θ]——楼层位移角限值。
2.2.3 几何参数
A——构件截面面积；
As——钢筋截面面积；
B——结构总宽度；
H——结构总高度、柱高度；
L——结构(单元)总长度；
a——距离；
as、 ——纵向受拉、受压钢筋合力点至截面边缘的最小距离；
b——构件截面宽度；
d——土层深度或厚度、钢筋直径；
h——计算楼层层高、构件截面高度；
l——构件长度或跨度；
t——抗震墙厚度、楼板厚度。
2.2.4 计算系数
α——水平地震影响系数；
αmax——水平地震影响系数最大值；
αvmax——竖向地震影响系数最大值；
γG、γE、γw——作用分项系数；
γRE——承载力抗震调整系数；
ζ——计算系数；
η——地震作用效应(内力和变形)的增大或调整系数；
λ——构件长细比、比例系数；
λv——最小配箍特征值；
ξy——结构(构件)屈服强度系数；
ρ——配筋率、比率；
φ——构件受压稳定系数；
ψ——组合值系数、影响系数。
2.2.5 其它
T——结构白振周期；
N——标准贯入锤击数；
Ile——地震时地基的液化指数；
Xji——位移振型坐标(j振型i质点的x方向相对位移)；
Yji——位移振型坐标(j振型i质点的y方向相对位移)；
Фji——转角振型坐标(j振型i质点的转角方向相对位移)；
n——总数，如楼层数、质点数、钢筋根数、跨数等；
vse——土层等效剪切波速。
3 抗震设计的基本要求
3.1 建筑抗震设防分类和设防标准
3.1.1 抗震设防的所有建筑应按现行国家标准《建筑工程抗震设防分类标准》GB 50223确定其抗震设防类别及其抗震设防标准。
3.1.2 上海市各区县的抗震设防烈度均可按7度采用。
3.2 地震影响
3.2.1 建筑所在地区遭受的地震影响，应采用相应于抗震设防烈度的设计基本地震加速度和设计特征周期来表征。
3.2.2 上海地区多遇地震和设防烈度地震时，Ⅲ类场地的设计特征周期取为0.65s，Ⅳ类场地的设计特征周期取为0.9s，罕遇地震时Ⅲ、Ⅳ类场地的设计特征周期都取为1.1 s。相应于各抗震设防烈度的设计基本地震加速度取值，应按表3.2.2采用。
表3.2.2 抗震设防烈度和设计基本地震加速度值的对应关系
抗震设防烈度 6 7 8
设计基本地震加速度值 0.05g 0.10g 0.20g
注：表中g为重力加速度。
3.3 场地和地基
3.3.1 选择建筑场地时，应根据工程需要和地震活动情况、工程地质和地震地质的有关资料，对抗震有利、一般、不利和危险地段做出综合评价。对不利地段，应提出避开要求，当无法避开时应采取有效的措施。对危险地段，严禁建造甲、乙类的建筑，不应建造丙类的建筑。
3.3.2 地基和基础设计应符合下列要求：
1 同一结构单元的基础不宜设置在性质截然不同的地基上。
2 同一结构单元不宜部分采用天然地基部分采用桩基；当采用不同基础类型或基础埋深显著不同时，应根据地震时两部分地基基础的沉降差异及保证两部分水平力的可靠传递，在基础、上部结构的相关部位采取相应措施。
3 地基为软弱黏性土、液化土、新近填土或严重不均匀土时，应估计地震时地基不均匀沉降和其它不利影响，并采取相应的措施。
3.3.3 坡地建筑的场地和地基基础应符合下列要求：
1 坡地建筑场地勘察应有边坡稳定性评价和防治方案建议。
2 应根据地质、地形条件和使用要求，因地制宜设置符合抗震设防要求的边坡工程。边坡设计应符合现行国家标准《建筑边坡工程技术规范》GB 50330的要求；其稳定性验算时，有关的摩擦角应按设防烈度的高低相应修正。
3 边坡附近的建筑基础应进行抗震稳定性设计。建筑基础与土质边坡的边缘应留有足够的距离，其值应根据设防烈度的高低确定，并采取措施避免地震时地基基础破坏。
3.4 建筑形体及其构件布置的规则性
3.4.1 建筑设计应根据抗震概念设计的要求明确建筑形体的规则性。不规则的建筑应按规定采取加强措施；特别不规则的建筑应进行专门研究和论证，采取特别的加强措施；严重不规则的建筑不应采用。
注：形体指建筑平面形状和立面、竖向剖面的变化。
3.4.2 建筑设计应重视其平面、立面和竖向剖面的规则性对抗震性能及经济合理性的影响，宜择优选用规则的形体，其抗侧力构件的平面布置宜规则对称、侧向刚度沿竖向宜均匀变化，竖向抗侧力构件的截面尺寸和材料强度宜自下而上逐渐减小，避免侧向刚度和承载力突变。
不规则建筑的抗震设计应符合本规程第3.4.4条的有关规定。
3.4.3 建筑形体及其构件布置的平面、竖向不规则性，应按下列要求划分：
1 混凝土房屋、钢结构房屋和钢-混凝土混合结构房屋存在表3.4.3—1所列举的某项平面不规则类型或表3.4.3—2所列举的某项竖向不规则类型以及类似的不规则类型，应属于不规则的建筑。
表3.4.3—1 平面不规则的主要类型
不规则类型 定义和指标限值
扭转不规则 在规定的水平力作用下，楼层的最大弹性水平位移(或层间位移)，大于该楼层两端弹性水平位移(或层间位移)平均值的1.2倍
凹凸不规则 结构平面凹进的长度大于相应投影方向总尺寸的30％；或凸出的长度大于相应投影方向总尺寸的30％，且凸出的宽度小于凸出长度的50％
楼板局部不连续 楼板的尺寸和平面刚度急剧变化，例如：有效楼板宽度小于该层楼板典型宽度的50％，或开洞面积大于该层楼面面积的30％，或较大的楼层错层(错层高度大于楼面梁的截面高度或大于0.6m)
表3.4.3—2 竖向不规则的主要类型
不规则类型 定义和指标限值
侧向刚度不规则 该层的侧向刚度小于相邻上一层的70％，或小于其上相邻三个楼层侧向刚度平均值的80％；除顶层或出屋面小建筑外，局部收进的水平向尺寸大于相邻下一层的25％
竖向抗侧力构件不连续 竖向抗侧力构件(柱、抗震墙、抗震支撑)的内力南水平转换构件(梁、桁架等)向下传递
楼层承载力突变 抗侧力结构的层间受剪承载力小于相邻上一楼层的80％
2 砌体房屋、单层工业厂房、单层空旷房屋、大跨屋盖建筑和地下建筑的平面和竖向不规则性的划分，应符合本规程有关章节的规定。
3 当存在多项不规则或某项不规则超过规定的参考指标较多时，应属于特别不规则的建筑。
3.4.4 建筑形体及其构件布置不规则时，应按下列要求进行地震作用计算和内力调整，并应对薄弱部位采取有效的抗震构造措施：
1 平面不规则而竖向规则的建筑，应采用空间结构计算模型，并应符合下列要求：
1)扭转不规则时，应计入扭转影响，且楼层竖向构件最大的弹性水平位移和层间位移分别不宜大于楼层两端弹性水平位移和层间位移平均值的1.5倍，当最大层间位移远小于规程限值时，可适当放宽；
2)凹凸不规则或楼板局部不连续时，应采用符合楼板平面内实际刚度变化的计算模型；高烈度或不规则程度较大时，宜计入楼板局部变形的影响；
3)平面不对称且凹凸不规则或楼板局部不连续时，可根据实际情况分块计算扭转位移比，对扭转较大的部位应采用局部的内力增大系数。
2 平面规则而竖向不规则的建筑，应采用空间结构计算模型，刚度小的楼层的地震剪力应乘以不小于1.15的增大系数，其薄弱层应按本规程有关规定进行弹塑性变形分析，并应符合下列要求：
1)竖向抗侧力构件不连续时，该构件传递给水平转换构件的地震内力应根据烈度高低和水平转换构件的类型、受力情况、几何尺寸等，乘以1.25～2.0的增大系数；
2)侧向刚度不规则时，相邻层的侧向刚度比应依据其结构类型符合本规程相关章节的规定；
3)楼层承载力突变时，薄弱层抗侧力结构的受剪承载力不应小于相邻上一楼层的65％。
3 平面不规则且竖向不规则的建筑，应根据不规则类型的数量和程度，有针对性地采取不低于本条1、2款要求的各项抗震措施。特别不规则的建筑，应经专门研究，采取更有效的加强措施或对薄弱部位采用相应的基于性能的抗震设计方法。
3.4.5 体型复杂、平立面不规则的建筑，应根据不规则程度、地基基础条件和技术经济等因素的比较分析，确定是否设置防震缝，并分别符合下列要求：
1 当不设置防震缝时，应采用符合实际的计算模型，分析判明其应力集中、变形集中或地震扭转效应等导致的易损部位，采取相应的加强措施。
2 当在适当部位设置防震缝时，宜形成多个较规则的抗侧力结构单元。防震缝应根据抗震设防烈度、结构材料种类、结构类型、结构单元的高度和高差以及可能的地震扭转效应的情况，留有足够的宽度，其两侧的上部结构应完全分开。
3 当设置伸缩缝和沉降缝时，其宽度应符合防震缝的要求。
3.5 结构体系
3.5.1 结构体系应根据建筑的抗震设防类别、抗震设防烈度、建筑高度、场地条件、地基、结构材料和施T等因素，经技术、经济和使用条件综合比较确定。
3.5.2 结构体系应符合下列各项要求：
1 应具有明确的计算简图和合理的地震作用传递途径。
2 应避免因部分结构或构件破坏而导致整个结构丧失抗震能力或对重力荷载的承载能力。
3 应具备必要的抗震承载力，良好的变形能力和消耗地震能量的能力。
4 对可能出现的薄弱部位，应采取措施提高其抗震能力。
3.5.3 结构体系尚宜符合下列各项要求：
1 宜有多道抗震防线。
2 宜具有合理的刚度和承载力分布，避免因局部削弱或突变形成薄弱部位，产生过大的应力集中或塑性变形集中。
3 结构在两个主轴方向的动力特性宜相近。
3.5.4 结构构件应符合下列要求：
1 混凝土结构构件应控制截面尺寸和受力钢筋、箍筋的设置，防止剪切破坏先于弯曲破坏、混凝土的压溃先于钢筋的屈服、钢筋的锚固粘结破坏先于钢筋破坏。
2 预应力混凝土构件，应配有足够的非预应力钢筋。
3 钢结构构件的尺寸应合理控制，避免局部失稳或整个构件失稳。
4 多、高层的混凝土楼、屋盖宜优先采用现浇混凝土板。当采用预制装配式混凝土楼、屋盖时，应从楼盖体系和构造上采取措施确保各预制板之间及预制板与周边构件之间连接的整体性。
3.5.5 结构各构件之间的连接，应符合下列要求：
1 构件节点的破坏，不应先于其连接的构件。
2 预埋件的锚固破坏，不应先于连接件。
3 装配式结构构件的连接，应能保证结构的整体性。
4 预应力混凝土构件的预应力钢筋，宜在节点核心区以外锚固。
3.5.6 装配式单层厂房的各种抗震支撑系统，应保证地震时厂房的整体性和稳定性。
3.5.7 砌体结构应按规定设置钢筋混凝土圈梁和构造柱、芯柱，或采用约束砌体、配筋砌体等。
3.6 结构分析
3.6.1 除本规程特别规定者外，建筑结构应进行多遇地震作用下的内力和变形分析，此时，可假定结构与构件处于弹性工作状态，内力和变形分析可采用线性静力方法或线性动力方法。
3.6.2 不规则且具有明显薄弱部位可能导致重大地震破坏的建筑结构，应按本规程有关规定进行罕遇地震作用下的弹塑性变形分析。此时，可根据结构特点采用静力弹塑性分析或弹塑性时程分析方法。
当本规程有具体规定时，尚可采用简化方法计算结构的弹塑性变形。
3.6.3 当结构在地震作用下的重力附加弯矩大于初始弯矩的10％时，应计入重力二阶效应的影响。
注：重力附加弯矩指任一楼层以上全部重力荷载与该楼层地震平均层间位移的乘积；初始弯矩指该楼层地震剪力与楼层层高的乘积。
3.6.4 结构抗震分析时，应按照楼、屋盖的平面形状和平面内变形情况确定为刚性、分块刚性、半刚性、局部弹性和柔性等的横隔板，再按抗侧力系统的布置确定抗侧力构件间的共同工作并进行各构件间的地震内力分析。
3.6.5 质量和侧向刚度分布接近对称且楼、屋盖可视为刚性横隔板的结构，以及本规程有关章节有具体规定的结构，可采用平面结构模型进行抗震分析。其它情况，应采用空间结构模型进行抗震分析。
3.6.6 利用计算机进行结构抗震分析，应符合下列要求：
1 计算模型的建立、必要的简化计算与处理，应符合结构的实际T作状况，计算中应考虑楼梯构件的影响。
2 计算软件的技术条件应符合本规程及有关标准的规定，并应阐明其特殊处理的内容和依据。
3 在对复杂结构进行多遇地震作用下的内力和变形分析时，应采用不少于两个合适的不同力学模型，并对其计算结果进行分析比较。
4 所有计算机计算结果，应经分析判断确认其合理性后方可用于工程设计。
3.7 非结构构件
3.7.1 非结构构件，包括建筑非结构构件和建筑附属机电设备，自身及其与结构主体的连接，应进行抗震设计。
3.7.2 非结构构件的抗震设计，应由相关专业人员分别负责进行。
3.7.3 附着于楼、屋面结构上的非结构构件，以及楼梯间的非承重墙体，应与主体结构有可靠的连接或锚固，避免地震时倒塌伤人或砸坏重要设备。
3.7.4 框架结构的围护墙和隔墙，应估计其设置对结构抗震的不利影响，避免不合理设置而导致主体结构的破坏。
3.7.5 幕墙、装饰贴面与主体结构应有可靠连接，避免地震时脱落伤人。
3.7.6 安装在建筑上的附属机械、电气设备系统的支座和连接，应符合地震时使用功能的要求，且不应导致相关部件的损坏。
3.8 隔震与消能减震设计
3.8.1 隔震与消能减震设计，可用于对抗震安全性和使用功能有较高要求或专门要求的建筑。
3.8.2 采用隔震或消能减震设计的建筑，当遭遇到本地区的多遇地震影响、设防地震影响和罕遇地震影响时，可按高于本规程第1.0.3条的基本设防目标进行设计。
3.9 结构材料与施工
3.9.1 抗震结构对材料和施工质量的特别要求，应在设计文件上注明。
3.9.2 结构材料性能指标，应符合下列要求：
1 砌体结构材料应符合下列规定：
1)普通砖和多孔砖的强度等级不应低于MU10，其砌筑砂浆强度等级不应低于M5；
2)混凝土小型空心砌块的强度等级不应低于MU7.5，其砌筑砂浆强度等级不应低于Mb7.5。
2 混凝土结构的材料应符合下列规定：
1)混凝土的强度等级，框支梁、框支柱及抗震等级为一级的框架梁、柱、节点核芯区，不应低于C30；构造柱、芯柱、圈梁及其它各类构件不应低于C20；
2)抗震等级为一级、二级、三级的框架和斜撑构件(含梯段)，其纵向受力钢筋采用普通钢筋时，钢筋的抗拉强度实测值与屈服强度实测值的比值不应小于1.25；钢筋的屈服强度实测值与屈服强度标准值的比值不应大于1.3，且钢筋在最大拉力下的总伸长率实测值不应小于9％。
3 钢结构的钢材应符合下列规定：
1)钢材的屈服强度实测值与抗拉强度实测值的比值不应大于0.85；
2)钢材应有明显的屈服台阶，且伸长率不应小于20％；
3)钢材应有良好的焊接性和合格的冲击韧性。
3.9.3 结构材料性能指标，尚宜符合下列要求：
1 普通钢筋宜优先采用延性、韧性和焊接性较好的钢筋；普通钢筋的强度等级，纵向受力钢筋应选用符合抗震性能指标的不低于HRB400级的热轧钢筋；箍筋宜选用符合抗震性能指标的不低于HRB400级的热轧钢筋，也可选用HPB300级热轧钢筋。
注：钢筋的检验方法应符合现行国家标准《混凝土结构工程施工质量及验收规范》GB 50204的规定。
2 混凝土结构的混凝土强度等级，抗震墙不宜超过C70，其他构件，8度时不宜超过C70。
3 钢结构的钢材宜采用Q235等级B、C、D的碳素结构钢及Q345等级B、C、D、E的低合金高强度结构钢；当有可靠依据时，尚可采用其它钢种和钢号。
3.9.4 在施工中，当需要以强度等级较高的钢筋替代原设计中的纵向受力钢筋时，应按照钢筋受拉承载力设计值相等的原则换算，并应满足最小配筋率要求。
3.9.5 采用焊接连接的钢结构，当接头的焊接拘束度较大、钢板厚度不小于40mm且承受沿板厚方向的拉力时，钢板厚度方向截面收缩率不应小于国家标准《厚度方向性能钢板》GB/T 5313关于Z15级规定的容许值。
3.9.6 钢筋混凝土构造柱和底部框架-抗震墙房屋中的砌体抗震墙。其施工应先砌墙后浇构造柱和框架梁柱。
3.9.7 混凝土墙体、框架柱的水平施工缝，应采取措施加强混凝土的结合性能。对于抗震等级为一级的墙体和转换层楼板与落地混凝土墙体的交接处，宜验算水平施工缝截面的受剪承载力。
3.10 建筑基于性能的抗震设计
3.10.1 当建筑结构采用基于性能的抗震设计时，应根据其抗震设防类别、设防烈度、场地条件、结构类型和不规则性，建筑使用功能和附属设施功能的要求、投资大小、震后损失和修复难易程度等因素选择抗震性能目标，并进行技术和经济可行性的综合分析和论证。
3.10.2 应根据实际需要和可能选择建筑结构的抗震性能目标，可分别针对整个结构、结构的局部部位或关键部位、结构的关键部件、重要构件、次要构件以及建筑非结构构件和附属机电设备支座选择性能目标，且选择的性能目标不应低于本规程1.0.3条中有关基本的抗震设防目标的要求。
3.10.3 关于地震动水准，对设计使用年限为50年的建筑，可选用本规程的多遇地震、设防地震和罕遇地震的地震作用，其中，设防地震的加速度应按本规程表3.2.2的设计基本地震加速度采用，设防地震的地震影响系数最大值，6度、7度和8度可分别采用0.12、0.23和0.45。对设计使用年限超过50年的建筑，宜考虑实际需要和可能，经专门研究后对地震作用做适当调整。对处于发震断裂两侧10km以内的建筑，地震动参数应计入近场影响，5km以内宜乘以增大系数1.5，5km以外宜乘以不小于1.25的增大系数。
3.10.4 关于性能设计指标，应选定分别提高结构或其关键部位的抗震承载力、变形能力或同时提高抗震承载力和变形能力的具体指标，尚应计及不同水准地震作用取值的不确定性而留有余地。设计宜确定在不同地震动水准下结构不同部位的水平和竖向构件承载力的要求(含保持弹性、不超过屈服承载力、不超过极限承载力、不发生脆性剪切破坏等)；宜选择在不同地震动水准下结构不同部位的预期弹性或弹塑性变形状态，以及相应的构件延性构造的高、中或低要求。当构件的承载力要求提高时，相应的延性构造可适当降低。
3.10.5 建筑结构基于性能的抗震设计的计算应符合下列要求：
1 分析模型应正确、合理地反映地震作用的传递途径和结构的实际受力状况。
2 弹性分析可采用线性方法，弹塑性分析可根据性能目标所预期的结构弹塑性状态，分别采用增加阻尼的等效线性化方法以及静力或动力非线性分析方法。
3 结构的非线性分析模型相对于弹性分析模型可有所简化，但二者在多遇地震作用下的线性分析结果应基本一致；应合理确定弹塑性参数，采用构件的实际尺寸和配筋(混凝土构件的实配钢筋和钢骨、钢构件的实际截面规格等)，可通过与理想弹性假定计算结果的对比分析，着重发现构件可能破坏的部位及其弹塑性变形程度。
4 对于复杂结构，宜进行施工模拟分析，应以施工全过程完成后的内力状态为初始状态。
3.10.6 结构的抗震性能目标及结构构件的设计要求可按本规程附录L.1的规定采用。
3.11 建筑物地震反应观测系统
3.11.1 抗震设防烈度为7度、8度时，高度分别超过160m、120m的大型公共建筑，应按建设主管部门的要求设置建筑结构的地震反应观测系统，建筑设计应留有观测仪器和线路的位置。
4 场地、地基和基础
4.1 场地
4.1.1 上海市的建筑场地，远郊低丘陵地区少数基岩露头或浅埋处以及湖沼平原区浅部有硬土层分布区，宜按土层等效剪切波速和场地覆盖层厚度判定场地类别，其余建筑场地多属于现行国家标准《建筑抗震设计规范》GB 50011所划分的Ⅳ类场地。
4.1.2 抗震设防类别为甲、乙类的建筑物应避免在不稳定场地(如岸坡边缘，古河道，暗埋的塘、浜、沟等)采用浅埋基础建造。必须建造时，应由专门的勘察、试验及计算证明其能满足抗震要求或者采取适当的稳定地基的措施。
4.1.3 对于抗震设防的工程，岩土工程勘察报告应提出关于场地稳定性及地基液化的评价；对需要采用时程分析法补充计算的建筑，岩土工程勘察报告尚应根据设计要求提供土层剖面、场地覆盖层厚度和有关的动力参数。必要时可由场地地震安全性评价报告提供场地反应谱或场地地震输入时程曲线。
4.2 地基液化的判别和处理
4.2.1 当设防烈度为6度以上，且地面下20m深度范围内存在饱和砂土和饱和粉土时，应进行液化判别；对判别有液化土层的地基，应根据建筑的抗震设防类别、地基的液化等级，结合具体情况采取相应的措施。
当设防烈度为6度时，除对液化沉降敏感的甲、乙类建筑物外，可不考虑液化影响。
4.2.2 当需要进行液化判别时，可根据标准贯入试验或静力触探试验结果进行土层液化可能性的判别，并确定液化强度比，两种试验判别方法同等有效。情况复杂时，可补充现场波速试验或取土室内模拟试验进行综合分析。
1 用标准贯入试验结果判别
当实测标准贯入锤击数N(未经杆长修正)小于临界标准贯入锤击数Ncr时，应判为可液化土。在地面下20m深度范围内，液化判别标准贯入锤击数临界值可按下式计算：

(4.2.2—1)
式中：Ncr——液化判别标准贯入锤击数临界值；
N0——液化判别标准贯入锤击数基准值，可取7；
β——调整系数，取0.8；
ds——标准贯入试验点深度(m)；
dw——地下水位埋深(m)；
ρc——粘粒含量百分率，小于3时取3。
注：用于液化判别的粘粒含量采用六偏磷酸钠作分散剂测定，采用其他方法时应按有关规定换算。
2 用静力触探试验结果判别
当单桥探头实测比贯入阻力ps小于临界比贯入阻力pscr或双桥探头实测锥尖阻力qc小于临界锥尖阻力qccr时，应判为可液化土。临界比贯入阻力pscr或临界锥尖阻力qccr可分别按公式(4.2.2—2)或公式(4.2.2—3)确定。实测比贯入阻力ps或实测锥尖阻力qc可按每个触探孔中每米厚度的平均值取用。粘粒含量的取值应真实可靠。对不同地质单元要分区评价。对砂质粉土或砂土层中比贯入阻力ps或锥尖阻力qc明显减少的夹层或砂土与粘性土互层情况，宜在旁侧采取土样进行验证：

(4.2.2—2)

(4.2.2—3)
式中：ps0、qc0——分别为液化临界比贯入阻力基准值和临界锥尖阻力基准值(MPa)，可分别取2.60MPa和2.35MPa；
ds——静力触探试验点深度(m)；
a、b——系数，分别取1.0和0.75。
其余符号意义同上。
4.2.3 对于存在可液化土层的地基，应探明各液化土层的深度和厚度，按下列公式计算每个钻孔的液化强度比Flei和液化指数Ile，并按表4.2.3划分地基的液化等级，作为判别土层及地基液化危险性和危害程度的依据。
(4.2.3—1)
(4.2.3—2)
(4.2.3—3)
(4.2.3—4)
式中：Flei——第i分层的液化强度比，当Flei＞1.0时，取Flei＝1.0；
Ile——液化指数；
di——第i分层的厚度(m)；
wi——可液化土层的埋深权数(m—1)，当该层中点深度不大于5m时应采用10，等于20m时应采用零值，5m～20m时按线性内插法取值；
n——可液化土层范围内的分层总数。
表4.2.3 液化等级
液化等级 轻微 中等 严重
液化指数 0＜Ile≤6 6＜Ile≤18 Ile＞18
4.2.4 地基抗液化措施应根据建筑物的抗震设防类别和地基的液化等级参照表4.2.4结合具体情况予以确定。不宜将未经处理的可液化土层作为建筑物基础的持力层。
表4.2.4 抗地基液化措施选择原则
抗震设防类别 地基的液化等级
轻微 中等 严重
甲类 (1) (1) (1)
乙类 (2)或(3) (1)或(2)＋(3) (1)
丙类 (3)或(4) (3)或(2) (1)或(2)＋(3)
丁类 (4) (4) (3)或更经济的措施
注：1.表中：
(1)——全部消除地基液化沉陷的措施，如采用桩基、加大基础埋置深度、深层加同至液化层下界，挖除全部液化土层等；
(2)——部分消除地基液化沉陷的措施，如加固或挖除一部分液化土层等，处理后地基的液化指数应不大于6；
(3)——基础和上部结构处理，一般指减小不均匀沉降或使建筑物较好适应不均匀沉降的措施等；
(4)——可不采取措施；
2.表中措施未考虑倾斜地层和液化土层严重不均匀的情况。
4.2.5 全部消除地基液化沉陷的措施，应符合下列要求：
1 采用桩基时，桩端进入可液化土层以下的稳定土层不应小于1.5m和2倍桩径的较大值。
2 加大基础埋置深度时，基础底面进入可液化土层以下的稳定土层深度不应小于0.5m。
3 采用加密法加固液化地基的适用方法主要为：强夯、沉管碎石桩、沉管砂桩、注浆等。加固时，应处理至可液化土层深度下界。
4 用非液化土替换全部液化土层。
5 采用加密法或换土法处理时，在基础边缘以外的处理宽度，应超过基础底面下处理深度的1/2，并且不应小于2.5m。
4.2.6 部分消除地基液化沉陷的措施，应符合下列要求：
1 处理深度应使处理后的地基液化指数减小，其值不宜大于6。
2 采用沉管碎石桩、沉管砂桩等加固后，桩间土的标准贯入试验值或静力触探试验值不宜小于本节第4.2.2条规定的液化判别的临界值。
3 基础边缘以外的处理宽度，应符合本节4.2.5条第5款的要求。