According to the requirements of Document Jian Biao[2006]No.77—Noticeon Printing and Distributing the Development and Revision Plan of Engineering Construction Standards and Codes in2006(Batch 1)issued by the former Ministry of Construction(MOC),this code was revised from GB 50011-2001Code for Seismic Design of Buildingsby China Academy of Building Research(CABR)together with other design,survey,research and education institutions concerned.

During the process of revision,the editorial team summarized the experiences in building seismic damages during Wenchuan Earthquake in 2008;adjusted the seismic precautionary intensities of the relevant disaster areas;added some compulsory provisions on the sites in mountainous areas,the arrangements of the infilled wall in frame structure,the requirements for staircase of masonry structure and the construction requirements of seismic structure;and raised the requirements for the details of the precast floor slab and for the reinforced elongation.Hereafter,the editorial team carried out studies on specific topics and some tests concerned,investigated and summarized the experiences and lessons from the strong earthquakes occurred in recent years home and abroad(including Wenchuan Earthquake),adopted the new research achievements of earthquake engineering,took the economc condition and construction practices in China into account,widely collected the comments from the relevant design,survey,research and education institutions as well as seismic administration authorities nationwide.Through a multi-round discussion,revision,substantiation,and with pilot designs as well,the final version has been completed and reviewed by an expert panel.This newly-revised version comprises 14 Chapters and 12 Appendixes.Besides remaining those provisions partially revised in 2008,the main revisions at this edition are:

1.supplementing the provisions on the seismic measures for areas with the seismic precaution Intensity 7(0.15g)and Intensity 8(0.30g);

2.adjusting the Design Earthquake Groups of Main Cities in China in accordance with GB18306-2001Seismic Ground Motion Parameter Zonation Map of China;

3.improving the soil liquefaction discriminating equation;

4.adjusting the damping modification parameter of design response spectrum;

5.modifying the damping ratio and the seismic adjusting factor for load-bearing capacity of steel structure;

6.modifying the calculation methods of the horizontal seismic-reduced factor of seismically isolated structure

7.supplementing the calculation method for horizontal and vertical earthquake action of large-span buildings;

8.raising the seismic design requirements for concrete frame structure buildings and for masonry buildings with RC frames on ground floors;

9.proposing the classification method for the seismic grades of steel structure buildings,and adjusting the provisions on seismic measures,correspondingly;

10.improving the seismic measures for multi-story masonry buildings,concrete wall buildings and reinforced masonry buildings;

11.expending the application scope of seismically isolated and energy-dissipated buildings;

12.adding the principles on performance-based seismic design of for buildings as well as the seismic design provisions for large-span buildings,subterranean buildings,frame-bent structure factories,buildings with composite steel brace and concrete frame structures,and buildings with composite steel frame and concrete core tube structures;

13.canceling the contents related to multi-story masonry buildings with inner frames.

The provisions printed in bold type are compulsory ones and must be enforced strictly.

The Ministry of Housing and Urban-Rural Development of the People′s Republic of China is in charge of the administration of this code and the explanation of the compulsory provisions hereof.China Academy of Building Research(CABR)is responsible for the explanation of specific technical contents.All relevant organizations are kindly requested to sum up and accumulate your experiences in actual practices during the process of implementing this code.The relevant opinions and advice,whenever necessary,can be posted or passed on to the Management Group of the National StandardCode for Seismic Design of Buildingsof the China Academy of Building Research(Address:No.30,Beisanhuan East Road,Beijing City,100013,China;E-mail:GB50011-cabr@163.com).

Chief Development Organization:

China Academy of Building Research(CABR).

Participating Development Organizations:

Institute of Engineering Mechanics(IEM)of China Earthquake Administration,China Architecture Design&Research Group,China Institute of Building Standard Design&Research,Beijing Institute of Architectural Design,China Electronics Engineering Design Institute,China Southwest Architectural Design and Research Institute,China Northwest Architectural Design and Research Institute,China Northeast Architecture Design and Research Institute,East China Architectural Design and Research Institute,Central-South Architectural Design Institute,the Architectural Design and Research Institute of Guangdong Province,Shanghai Institute of Architecture Design and Research,Institute of Building Design and Research of Xinjiang Uygur Autonomous Region,Yunnan Province Design Institute,Sichuan Architectural Design Institute,Shenzhen General Institute of Architectural Design and Research,Beijing Geotechnical Institute,Shanghai Tunnel Engineering and Rail Transit Design and Research Institute,China Construction(Shenzhen)Design international,Architecture Design General Institute of China Metallurgical Group Corporation,China National Machinery Industry Corporation,China IPPR International Engineering Corporation,Tsinghua University,Tongji University,Harbin Institute of Technology,Zhejiang University,Chongqing University,Yunnan University,Guangzhou University,Dalian University of Technology and Beijing University of Technology

Chief Drafting Staffs:

Huang Shimin,Wang Yayong

(The following is according to the Chinese phonetic alphabetically)

Ding Jiemin Fang Taisheng,Deng Hua,Ye Liaoyuan,Feng Yuan,Lu Xilin,Liu Qiongxiang,Li Liang,Li Hui,Li Lei,Li Xiaojun,Li Yaming,Li Yingmin,Li Guoqiang,Yang Linde,Su Jingyu,Xiao Wei,Wu Mingshun,Xin Hongbo,Zhang Ruilong,Chen Jiong,Chen Fusheng,Ou Jinping,Yu Yinquan,Yi Fangmin,Luo Kaihai,Zhou Zhenghua,Zhou Bingzhang,Zhou Fulin,Zhou Xiyuan,Ke Changhua,Lou Yu,Jiang Wenwei,Yuan Jinxi,Qian Jihong,Qian Jiaru,Xu Jian,Xu Yongji,Tang Caoming,Rong Baisheng,Cao Wenhong,Fu Shengcong,Zhang Yiping,Ge Xueli,Dong Jincheng,Cheng Caiyuan,Fu Xueyi,Zeng Demin,Dou Nanhua,Cai Yiyan,Xue Yantao,Xue Huili and Dai Guoying

Chief Examiners:

Xu Peifu,Wu Xuemin,Liu Zhigang

(The following is according to the Chinese phonetic alphabetically)

Liu Shutun,Li Li,Li Xuelan,Chen Guoyi,Hou Zhongliang,Mo Yong,Gu Baohe,Gao Mengtan,Huang Xiaokun and Cheng Maokun

Announcement of Ministry of Housing and Urban-Rural Development of the People′s Republic of China

No.609

Announcement on Publishing the National Standard Code for Seismic Design of Buildings

The standard Code for Seismic Design ofBuildings has been approved as a national standard with the serial number of GB 50011-2010 and shall be implemented on December 1,2010.Therein,Articles 1.0.2,1.0.4,3.1.1,3.3.1,3.3.2,3.4.1,3.5.2,3.7.1,3.7.4,3.9.1,3.9.2,3.9.4,3.9.6,4.1.6,4.1.8,4.1.9,4.2.2,4.3.2,4.4.5,5.1.1,5.1.3,5.1.4,5.1.6,5.2.5,5.4.1,5.4.2,5.4.3,6.1.2,6.3.3,6.3.7,6.4.3,7.1.2,7.1.5,7.1.8,7.2.4,7.2.6,7.3.1,7.3.3,7.3.5,7.3.6,7.3.8,7.4.1,7.4.4,7.5.7,7.5.8,8.1.3,8.3.1,8.3.6,8.4.1,8.5.1,10.1.3,10.1.12,10.1.15,12.1.5,12.2.1and 12.2.9 are compulsory ones and must be enforced strictly.The former standard GB 5001 1-2001 Code for Seismic Design of Buildings shall be abolished simultaneously.

Authorized by the Research Institute of Standard and Norms of the Ministry,this code is published and distributed by China Architecture&Building Press.

Ministry of Housing and Urban-Rural Development of the People′s Republic of China

May 31,2010

目录

Announcement of Ministry of Housing and Urban-Rural Development of the People′s Republic of China

Foreword

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 Precaution of Buildings

3.2 Earthquake Ground Motion

3.3 Site and Soil

3.4 Regularity of Building Configuration and Structural Assembly

3.5 Structural System

3.6 Structural Analysis

3.7 Nonstructural Components

3.8 Isolation and Energy-Dissipation

3.9 Materials and Construction

3.10 Seismic Performance-Based Design of Buildings

3.11 Seismic Response Observation System of Buildings

4 Site,Soil and Foundation

4.1 Site

4.2 Natural Soil and Foundation

4.3 Liquefied Soil and Soft Soil

4.4 Pile Foundation

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 for the Sections of Structural Member

5.5 Seismic Checking for the Story Drift

6 Multi-story and Tall Reinforced Concrete Buildings

6.1 General

6.2 Essentials in Calculation

6.3 Seismic Details for Frame Structures

6.4 Seismic Details for Seismic Wall Structures

6.5 Seismic Details for Frame-seismic-Wall Structures

6.6 Requirements for Seismic Design of Slab-column-seismic-Wall Structures

6.7 Requirements for Seismic Design of Tube Structures

7 Multi-story Masonry Buildings and Multi-story Masonry Buildings with RC Frames on Ground Floors

7.1 General

7.2 Essentials in Calculation

7.3 Seismic Details for Multi-story Brick Buildings

7.4 Seismic Details forMulti-story Concrete Block Buildings

7.5 Seismic Details for Multi-story Masonry Buildings with RC frames and Seismic-walls on ground floors

8 Multi-Story and Tall Steel Buildings

8.1 General

8.2 Essentials in Calculation

8.3 Seismic Details for Steel Frame Structures

8.4 Siesmic Details for Steel Frame-concentrically-braced Structures

8.5 Seismic Details for Steel Frame-eccentrically-braced Structures

9 Single-storey Factory Buildings

9.1 Single-storey Factory Buildings with Reinforced Concrete Columns

9.2 Single-storey Steel Factory Buildings

9.3 Single-storey Factory Buildings with Brick Columns

10 Large-span Buildings

10.1 Single-storey Spacious Buildings

10.2 Large-span Roof Buildings

11 Earth,Wood and Stone Houses

11.1 General

11.2 Unfired Earth Houses

11.3 Wood Houses

11.4 Stone Houses

12 Seismically isolated and energy-dissipated buildings

12.1 General

12.2 Essentials in Design of Seismically Isolated Buildings

12.3 Essentials in Design of Seismic-energy-dissipated Buildings

13 Nonstructural Components

13.1 General

13.2 Basic Requirements for Calculation

13.3 Basic Seismic-Measures for Architectural Members

13.4 Basic Seismic-Measures for the Supports ofMechanical and Electrical Components

14 Subterranean Buildings

14.1 General

14.2 Essentials in Calculation

14.3 Seismic Details and Anti-liquefaction Measures

Appendix A The Seismic Precautionary Intensity,Design Basic Acceleration of Ground Motion and Design Earthquake Groups ofMain Cities in China

Appendix B Requirements for Seismic Design of High Strength Concrete Structures

Appendix C Requirements for Seismic Design of Prestressed Concrete Structures

Appendix D Section Seismic Check for the Beam-column Joint Core Zone of Frames

Appendix E Requirements for Seismic Design of the Transfer Story Structures

Appendix F Requirements for Seismic Design of reinforced Concrete Small-sized Hollow Block Seismic-Wall Buildings

Appendix G Requirements for Seismic Design of Buildings with Steel Brace-Concrete Frame Structures and Steel Frame-Reinforced Concrete Core Tube Structures

Appendix H Requirements for Seismic Design of Multi-storey Factory Buildings

Appendix J Seismic Effect Adjustment for Transversal Planar-Bent of Single-Story Factory

Appendix K Longitudinal Seismic Check for Single-Story Factory

Appendix L Simplified Calculation for Seismically Isolated Design and Seismically Isolated Measures of Masonry Structures

Appendix M Reference Procedures of Performance-Based Seismic Design

Explanation of Wording in This Code

List of Quoted Standards

1.0.2 All the buildings situated on zones of Seismic Precautionary Intensity 6 or above must be carried out with seismic design.

1.0.4 The Seismic Precautionary Intensity must be determined in accordance with the documents(drawings)examined,approved and issued by the authorities appointed by the State.

3.1.1 The seismic precautionary category and the seismic precautionary criterion of buildings shall be determined in accordance with the current national standard GB 50223 Standard for Classification of Seismic Protection of Building Constructions.

3.3.1 During the selection ofa building site,a comprehensive assessment to the region shall bemade according to the project demand and the relevant information on the seismicity,engineering geology and seismogeology of the region,and the assessment result such as the favorable,common,unfavorable or hazardous section shall be given simultaneously.At the unfavorable section.the building site shall be avoided to locate orbe treated with some effective measures if unable to avoid.In the hazardous sections,the buildings assigned to Category A or B must not be constructed and the buildings assigned to Category C shall not be constructed.

3.3.2 If the building site is of Class I,it shall be permitted to adopt details of seismic design according to the requirements of local seismic precautionary intensity for the buildings assigned to Category A and B,and to the requirements of the reduced Intensity that shall be taken as one grade less than the local seismic precautionary intensity,but not less than Intensity 6,for the buildings assigned to Category C.

3.4.1 The building design shall specify the regularity of building configuration according to the requirements of seismic concept design.For irregular buildings,strengtheningmeasures shall be taken as required;for especially irregular buildings,special strengthening measures shall be taken through special study and demonstration;severely irregular buildings shall not be built.

Note:The building configuration refers to the variations in the plane,elevation and vertical section of a building.

3.5.2 The structural system shall meet the following requirements:

1 The structural system shall have clear analysis model and reasonable paths for the transmission of seismic forces.

2 The structural system shall have adequate robustness to avoid the losses of seismic capacity or gravity ioad-bearingcapacity due to the failure ofportion of structure or components.

3 The structural system shall have necessary seismic capacity,favorable deformation ability and seismic energy dissipation ability.

4 For the weak portions that may appear,necessary measures shall be taken to improve the seismic capacity.

3.7.1 Nonstructural components,including the nonstructural components and the auxiliary mechanical and electrical equipments of buildings,and the connections to the main structures shall be designed and constructed to withstand seismic action.

3.7.4 For frame structures,the unfavorable effects of infilled walls including enclosure walls and partition walls on seismic performance of structure shall be estimated and taken into account,and the irrational arrangement of infilled walls that would cause damage to main structure shall be avoided.

3.9.1 The special requirements of seismic structures on materials and construction quality shall be clearly stated in the design documents.

3.9.2 The property indexes of structural materials shall meet the followingminimumrequirements:

l Thematerials of masonry structure shall meet the following requirements:

1)The strength grade of common brick and hollow-brick shall not be less thanMUl0 and the strength grade of mortar for the bricks shall not be less thanM5;

2)The strength grade of small-sized concrete hollow block shall not be less than MU7.5and the strength grade of its masonry mortar shall not be less thanMb7.5.

2 Thematerials of concrete structures shall meet the following requirements:

1)The strength grades of concrete for frame-supported beams and columns as well as frame beams and columns and connection cores assigned to seismic grade 1 shall not be less than C30;and the strength grades of concrete for tie-columns,core columns,ring-beams and other members shall not be less than C20;

2)For the ordinary reinforcements used as the longitudinal reinforcements of frames and diagonal bracing members(including the stair)assigned to seismic grade 1,2and 3,the ratio of the measured tensile strength to the measured yield strength shall not be less than 1.25,the ratio of the measured yield strength to the standard value of yield strength shall not be larger than 1.3,and the measured overall elongation under the maximum tensile stress shall not be less than 9%.

3 The materials of steel structures shall meet the following requirements:

1)The ratio of the measured yield strength to the measured tensile strength shall not be larger than 0.85;

2)The steels shall have obvious yield steps and their elongation rate shall not be less than 20%;and

3)The steels shall have good weldability and qualified impact ductility.

3.9.4 During the construction,if the longitudinal reinforcements in original design have to be replaced by those with higher strength grade,the conversion shall bemade according to the principle of equal tensile capacity design values of reinforcements,and shall also comply with requirement of minimum reinforcement ratio.

3.9.6 During the construction of themasonry seismic walls in buildings adopting reinforced concrete tie-columns or masonry buildings with RC frames on ground floors,the masonry walls shall be laid out prior to casting the tie-colmnns and concrete frames.

4.1.6 Based on the equivalent shear wave velocity of soil profile and the thickness of overlaying layer,the site shall be classified as Site Class Ⅰ,Ⅱ,Ⅲ or Ⅳ in accordance with Table 4.1.6,wherein the Site Class Ⅰ consists of two subclasses:IandI.If reliable shear wave velocity and thickness of overlaying layer are available and their values are near to the divisional line of site class listed in Table 4.1.6,the design characteristic period used in earthquake action calculation shall be permitted to determine by interpolation method.

4.1.8 When buildings assigned to Category C or A or B are needed to be built in unfavorable sections such as stripe-protruding spur,lonely tall hill,non-rocky or highly weathered rocky steep slope,river banks or boundary of slopes and so on,the stability of foundations under the earthquake ground motion shall be guaranteed,and meanwhile,the possible amplification effects of unfavorable sections to the design parameters of ground motion shall be estimated,and the maximum value of horizontal seismic influence coefficient shall be multiplied by the enhancement coefficient which shall be determined from 1.1 to 1.6 depending on the specific conditions of the unfavorable section.

4.1.9 The geotechnical engineering investigations of the site shall include the following works:

1 According to the actual demand,to classify the region as favorable,common,unfavorable or hazardous sections;

2 To provide the Class of the site;

3 To evaluate the geotechnical stability under earthquake ground motion(including landslide,collapse,liquification and seismic subsidence characteristics);

4 For buildings that the time history analysis method need to be used as the supplement of the modal response spectrum analysis,the soil profile,the thickness of overlaying layer and the relevant dynamic parameters shall also be provided according tothe design requirements.

4.2.2 During seismic checking for the natural soil and foundation,thecharacteristic combination of earthquake action effects shall be used,and the seismic soil bearing capacity shall be taken as the product of the soil bearing capacity characteristic value and the seismic adjustment coefficient of soil bearing capacity.

4.3.2 For the subsoil including saturated sand and saturated silt,liquefaication discrimination shall bemade except for Intensity 6.And for the subsoil including liqhefied soil,corresponding messures shall be taken according to the precautionary category of building,the liquification grade and other actual conditions.

Note:The requirements for the liquifieationdiserimination(identification)of saturated soil specified in this article do not include loess and powdery clay.

4.4.5 The reinforcement range of pile in liquefied soil or seismic subsidence soft soil shall cover from the pile top down to the level that is below the liquification depth and meets the requirements of eliminating completely the liquefaction differential settlement.The longitudinal reinforcements shall be same as the pile top and the hoops shall be thickened(by increasing diameter)and densified(by reducing spacing).

5.1.1 The earthquake actions of various building structures shall comply with the following requirements:

1 Generally,the horizontal earthquake actions shall be at leastcalculated separately along the two orthogonal major axial directions of the building structure;and the horizontal earthquake action in each direction shall be undertaken by the lateral-force-resisting components in this direction.

2 For the structures having the oblique lateral-force-resisting components with intersectionangle greater than 15°,the horizontal earthquake action along the direction of each lateral-force-resisting component shall be calculated respectively.

3 For the structures having obvious asymmetric mass and stiffness distribution,the torsional effects caused by bi-directional horizontal earthquake actions shall be considered;for other cases,it shall be permitted to consider the torsional effects by adjusting the earthquake action effect.

4 For the large-span structures and long-cantilevered structures with seismic precautionary intensity 8 or 9 and the tall buildings with seismic precautionary Intensity 9,the vertical earthquake action shall be calculated.

Note:Forseismically isolated building structures with seismic precautionary Intensity 8 and 9.the vertical earthquakeaction shall be calculated according to relevant regulations of this code.

5.1.3 In the calculation of earthquake action,the representative value ofthe gravity load of building shall be taken as the sumof the standard value ofthe weight of structure and its components and the combination values of variable loads on the structure.The combination coefficient for variable loads shall be taken from Table 5.1.3.

5.1.4 The seismic influence coefficient of a building structure shall be determined according to the Intensity,site class,design earthquake group,and natural vibration period and damping ratio of structure.Themaximum value of horizontal seismic influence coefficient shall betaken fromTable 5.1.4-1.The characteristic period shall be taken from Table 5.1.4-2 based on the site class and design earthquake group,and the characteristic period shall be increased by 0.05s for rare earthquake ground motion.

Note:For the building structures with period larger than 6.0s,the seismic influence coefficientused for analysis shall be studied especially.

5.1.6 The section seismic check of structure shall comply with the following requirements:

1 For the buildings with Intensity 6(excluding the irregular buildings as well as the higher buildings built on Class Ⅳ site)and the unfired earth houses and wood houses,the section seismic check of structural members shall be permitted to not be performed.However,the relevant seismic detail requirements for those buildings shall be satisfied.

2 For the irregular buildings and the higher buildings built on Class Ⅳ site with Intensity 6,and the buildingswith seismic precautionaryintensity higher than or equal to Intensity 7(excluding the unfired earth houses and wood houses,etc.),the section seismic check of structural members under frequent earthquake ground motion shall be carried out.

Note:For seismically isolated building structures,the seismic check shall comply with the relevant regulations.

5.2.5 The horizontal seismic shear force at any story of the structure shall comply with the requirements of the following equation:

Where V——The ithstory shear corresponding to the standard value of total horizontal earthquake action;

λ——Shear coefficient,which shall not be less than the minimum seismic shear force coefficient of story as specified in Table 5.2.5.For the weak-soft stories of vertical irregular structures,the values listed in Table 5.2.5 shall be also multiplied by an enhancement coefficient of 1.15;

G——The representative value of gravity load of the j story.

5.4.1 The fundamental combination of the earthquake action effects and other load effects of the structural members shall be calculated from the following equation:

Where S——Design values of combination of the internal forces in a structural member,including the design values of the combinedbendingmoment.combined axial force and combined shear force,etc.;

γ——Partial coefficient of gravity load,which generally shall be taken as 1.2 and shall be not greater than 1.0 if the gravity load effect is favorable to the bearing capacity of member;

γ,γ——The partial coefficients of the horizontal and vertical earthquake actions respectively,which shall be taken from Table 5.4.1;

γ——Partial coefficient of wind load,which shall be taken as 1.4;

S——Effects of the representative value of gravity load,which may be determined according to Article 5.1.3 of this code.however,it still shall include the effect of the standard value of hanging weight if crane is used;

S——Effects of the standard value of horizontal earthquake action,which shall be also multiplied by the corresponding enhancement coefficient or adjustment coefficient;

S——Effect of the standard value of vertical earthquake action,which shall be also multiplied by the corresponding enhancement coefficient or adjustment coefficient;

S——Effect of standard value of wind load;

ψ——Combination value coefficient ofwind load,which shall be 0.0 for ordinary structures and shall be 0.2 for tall buildings on which the wind load plays the control action.

Note:Generally,the subscript representing the horizontal direction is omitted in this code.

5.4.2 Seismic checking for section of structural member shall be performed using the following design expression:

Where γ——seismic adjustment coefficient of load-bearing capacity,which,unless otherwise specified,shall be taken from Table 5.4.2;

R——Design value of the load-bearing capacity of structural member.

5.4.3 If only the vertical earthquake action is considered,the seismic adjustment coefficient of load-bearing capacity of various structural members shall be taken as 1.0.

6.1.2 The reinforced concrete building shall be assigned a seismic grade based on the seismic precautionary category,seismic precautionary intensity,structural type and building height,and shall be designed in accordance with the corresponding requirements of calculation and details.The seismic grade of buildings assigned to CategoryC shall be determined from Table 6.1.2.

6.3.3 Arrangement of reinforcements for beams shall meet the following requirements:

1 The ratioof the height to the effective height of the concrete compression zone(its end cross-section)with the compression reinforcement considered(counted)in shall not be greater than 0.25 for frames assigned to Grade 1 and 0.35 for frames assigned to Grade 2 or 3.

2 In addition to being determined through calculation,the ratioof the bottom-reinforcements to the top-reinforcements of the end cross-section of beams shall also not be less than 0.5 for frames assigned to Grade 1 and 0.3 for frames assigned to Grade 2 or 3.

3 The length ofcritical region of beam,the maxiinum spacing of hoops and the minimum diameter of hoops shall be taken from Table 6.3.3.If the reinforcement ratio of tension zone of the end cross-section exceeds 2%,the minimum diameters of hoops in the Table shall be increased by 2mm.

6.3.7 Arrangement of reinforcements for columns shallcomply with the following requirements:

1 The minimum total reinforcement ratio of columns shall betaken from Table 6.3.7-1,meanwhile,the reinforcement ratio of each side of the cross-section shall not be less than 0.2%;for the taller buildings built at Site-class Ⅳ site,theminimum total reinforcement ratio shall be increased by 0.1%.

2 Thehoops ofcolumns shall be densified within the critical regions,the spacing and diameter of hoops in the critical hoops shall comply with the following requirements:

1)Generally,the maximum spacing and the minimum diameter ofhoops shall be taken from Table 6.3.7-2

2)For the frame columns assigned to Grade 1 with hoop diameter greater than 12mm and spacing of hoop limbs greater than 150mm as well as the columns assigned to Grade 2 with hoop diameter not less than 10mm and spacing of hoop limbs not greater than 200mm,except for the lower ends of columns at the bottom story,the maximum spacing of hoops shall be permitted tobetakenas 150mm.For the columns assigned to Grade 3 with sectional dimension not greater than 400mm,the minimumdiameter of hoop shall bepermitted tobe taken as 6mm.For columns with shear-spanration not greater than 2,assigned to Grade 4,the diameter of hoop shall not be less than 8mm.

3)As for the frame-supporting columns and the frame columns with shear-span ratio not greater than 2,the hoop spacing shall not be greater than 100mm.

6.4.3 The vertically andhorizontally distributed reinforcements of seismic-wall shall comply with the following requirements:

1 Theminimum reinforcement ratio of the vertically andhorizontally distributed reinforcements shall not be less than 0.25%for seismic-walls assigned to Grade 1,2or 3,and 0.20%for seismic-walls assigned to Grade 4.

Note:For the Grade 4seismic walls with height less than 24m and very small shear compression ratio,the minimum reinforcement ratio of the vertically distributed reinforcements may be taken as 0.15%.

2 For the bottom strengthening portion of seismic walls of partial frame-supported seismic-wall structures,the reinforcement ratio of vertically and transversely distributed reinforcements shall not be less than 0.3%.

7.1.2 The total height and number of stories of multi-story buildings shall meet the following requirements:

1 In general conditions,the total height and number of stories of the masonry buildings shall not exceed those specified in Table 7.1.2.

2 For multi-story masonry buildings with fewer transverse walls,the total height shalibe reduced 3m than those specified in Table 7.1.2.and the numbers of stories shall be reduced by one correspondingly;for multi-storymasonry buildings with very few transverse walls at each story,the number of stories number still shall be reduced onemore.

Note:Themulti-story masonary buildings with fewer transverse walls refer to the buildings inwhich the roomswith span greater than 4.2m occupy more than 40%of the total areaofthe same story;hereinto,the multi-story masonary buildings with very few transverse walls refer to the buildings inwhichthe roomswith span not greater than4.2moccupy less than 20%of the total area of the story and rooms with span greater than 4,8m occupy more than s0%of the total area of the story.

3 For the multi-story masonry buildings with fewer transverse walls assigned to Category C,located at the zone of Intensity 6 and 7,if the strengtheningmeasures are taken in accordance with the provisions and the requirements of seismic capacity are satisfied,the total heights and numbers of stories shall be permitted to be taken from Table 7.1.2.

4 For the masonry buildings with autoclaved lime-sand bricks and autoclaved fly ash bricks,if the shear strength of masonry only reaches 70%that of the masonry with common clay bricks,the number of stories shall be reduced by one from that of common brick buildings,and the total height shall be reduced by 3m;if the shear strength of masonry reaches that of the masonry with common clay bricks.the requirements of the number of storiesand total height of buildings shall be as the same of the common brick buildings.

7.1.5 The spacing of seismic transverse walls of buildings shall not exceed those specified in Table 7.1.5:

7.1.8 The structural arranement of masonry buildings with RC frames and seismic-walls on ground floors shall meet the following requirements:

1 Besides the exceptional wallfragment nearby the staircase,the upper masonry walls shall be aligned with the bottom frame beams or seismic walls.

2 At the bottom of the buildings.the certain quantity of seismic walls shall be arranged evenly and symmetrically along longitudinal and transverse directions.For the masonry buildings with RC frames and seismic-walls on ground floors which have no more than 4 stories and are loacted at the regions of Intensity 6,the masonry seismic walls with confined common brick masonry or confined small block masonry infilled in the frames shall be permitted tobeused;but the additional axial force and shear force applied on frames by the masonry walls shall be counted in and the seismic check for ground floors shall be carried out,and the reinforced concrete seismic wall and confined masonry seismic wall shall not be used simultaneously in the same direction.For other cases,the reinforced concrete seismic wall shall be used for Intensity 8,the reinforced concrete seismic wall or the seismic wall of small block masonry with reinforcement shall be used for Intensity 6 and 7.

3 In the longitudinal and traBsverse directions of masonry buildings with RC frames and seismic-walls on ground floors,the ratio of the lateral stiffness of the second story,with the effect of the constructional column counted in,to the lateral stiffness ofthe ground floor,shall not be greater than 2.5 for Intensity 6 and 7.and 2.0 for Intensity 8,wherever,the ratio shall not be less than 1.0.

4 In the longitudinal and transverse directions of masonry buildings with RC frames and seismic-walls on two stories from ground floors,the lateral stifnesses of the ground floor and the second story of the bottom shall be close to each other;the ratio of lateral stiffness of the third story,counted in the effect of the constructional column,to the lateral stiffness of the second story of the bottom shall not be greater than 2.0 for Intensity 6and 7,and 1.5 for Intensity 8,wherever,the ratio shall notbelessthan 1.0.

5 For the seismic walls of masonry buildings with RC frames and seismic-walls on ground floors,the foundations of good integrity such as strip foundationsand raft foundations shall be used.

7.2.4 Theseismic effect ofmasonry buildings with RC frames and seismic-walls on ground floors and shall be adjusted according to the following requirements:

1 Formasonry buildings with RC framesand seismic-walls on ground floors,the design value of the longitudinal and transverse seismic shear force on the ground floor all shall be multiplied the enhancement coefficient;the value of the enhancement coefficient shall be permitted to be taken within therangeof 1.2~1.5;according to the principle that if the lateral stiffness ratio of the second story to ground floor is greater.then greater value shall be taken.

2 For masonry buildings with two stories of RC frames and seismic-walls at bottom portion,the design value of the longitudinal and transverse seismic shear force on the ground floor and the second story shall all bemultiplied the enhancement coefficient;the value of the enhancement coefficient shall bepermitted tobe taken within the range of 1.2~1.5 according to the principle that if the lateral stiffness ratio of the third story to the second story is greater,then greater value shall be taken.

3 The design value of the longitudinal and transverse seismic shear force on the ground floor orthe two stories from the ground floor shall be undertaken by the seismic wallsalong the directionand distributed according to the proportion of lateral stiffness.

7.2.6 The design value of seismic shear strength along the ladder shaped damage of various masonry structures shall be determined according to the following equation:

Where f——The design value of seismic shear strength along the ladder shaped damage of masonry;

f——Design value of the shear strength of masoniy with the non-seismic design;

ξ——Normal stress influence coefficient of the seismic shear strength of masoniy,which shall be taken from Table 7.2.6.

7.3.1 Eor various multi-story brick masonry buildings,the cast-in-situ reinforced concrete constructional columns(hereinafter refefred to as"constructional colunm")shall be arranged according to the following requirements:

1 The arranged position of the constructional column generally shall meet the requirements specified in Table 7.3.1.

2 For multi-story buildings with gallery type corridor or one-side type corridor,the constructional columns shall be arranged according tothose specified in Table 7.3.1,but the building shall be assumed with one more story,and the longitudinal walls on the both sides of the one-sided corridor shall be regarded as exterior walls.

3 For buildings with fewer transverse walls,the constructional column shall be arranged according to those specifiedin Table 7.3.1.but the buildings shall beassumed with one more stories.If such buildings are designed as the multi-story masonry buildings with gallery type corridor or one-side type corridor,the constructional column shall be arranged according to the requirements of Item 2 of this article;but if the building does not exceed four stories for Intensity 6,three stories for Intensity 7 and two stories for Intensity 8,the constructional column shall be arranged according to the assumption of the building with two more stories.

4 For buildings with very few transverse walls at eachstory,the constructional columns shall be arranged according to the story number increased by two.

5 As for the masonry buildings adopted with autoclaved lime-sand bricks and autoclaved fly ash bricks,if the shear strength ofmasonry only reaches 70%of that of the masonry with common clay bricks,the constructional columns shall be arranged in accordancewith the requirements of Item 1~4 of this article based on the story number increased by one;but it shall be treated according to the story number increased bytwo if the building does not exceed four stories for Intensity 6,three stories for Intensity 7 or two stories for Intensity 8.

7.3.3 The arrangement of the cast-in-situ reinforced concrete ring-beam of multi-story brick masonry buildings shall meet the following requirements:

1 As for fabricated reinforced concrete floors and roofs or the wooden roofs,the ring-beams shall be arranged according to those specified in Table 7.3.3;for the buildings designed using longitudinal wall as the bearing wall,the spacing of ring-beams on the seismic transverse wall shall be reduced properly.

2 For the building with in-situ cast or assembly-monolithic reinforcement concrete floors and roof that have reliable connection with the walls,the ring-beams shall be permitted to notbe installed,but the strengthened reinforcements of in-situ slabs shall be arranged along the wall perimeters and shall be reliably connected with corresponding constructional columns.

7.3.5 Thefloors and roofs of multi-story brick masonry buildings shall meet the following requirements:

1 The length that the cast-in-situ reinforced concrete floor-slab or roof slab extends into the longitudinal or transverse wall all shall not be less than 120mm.

2 For fabricated reinforced concrete floor slab or roof slab,if the ring-beams are not arranged at the same elevation of the slab,the slab shallextend into the external wall with lenth not less than 120mm;the slab shall extend into the internal wall with length not less than 100mm,or be connected with the wall by adopting the hard-strut framework;the slab shall be supported on the beam with length not less than 80mm or shall be connected by adopting the hard-strut framework.

3 For the precast slabwith span greater than 4.8m and parallel to the exterior wall.the side of the precast slab next to the exterior wall shall be tied with the exterior wall or ring-beam.

4 The precast slabs ofthe large roomat the end of the building.which are used as the roof for Intensity 6 oras the floors and roof for Intensity 7-9,shall be tied with each other,and connected with the beam,wall or the ring-beam installed at the bottom of the slab.

7.3.6 Reinforced concrete girders or roof trusses of the floor and roof shall be reliably connected with walls and columns(including constructional columns)or ring-beams;independent brick columns shall not be used as supporting members.For the grider withe span not less than 6m,the supporting members shall be designed using strengthening measures such as combination masonry and satisfy the bearing capacity requirements.

7.3.8 The staircasealso shall meet the following requirements:

1 For the staircasewall ofthe top story,thetiebarsof 2φ6 extending through the full length of the wall and tie meshes composed by spot welding inφ4 distributed short reinforcement plane orφ4 mesh reinforcement steel fabric composed by spot welding,shall be arranged every 500mm along the wall height;for the staircase wall ofother story for Intensity 7~9,the reinforced concrete stripswith thickness of 60mmand longitudinal reinforcement not less than 2φ10,or the reinforced brick strips with layers not less than 3 layers.reinforcements not less than 2φ6 in each layer,the mortar strength grade not less than M7.5 or themortar strength grade ofthe wall on the same story,shall be arranged on the stair landing or half height of the story.

2 At the staircase or the salient corner of the interior wall for the vestibule,the girder shall be supported on the wall with a supporting length not less than 500mm,and shall also beconnected with the ring-beam.

3 The precast waist slabs shall bereliably connectedwith the beamof the landing platform,the precast waist slabs shall not be used for Intensity 8 or 9;the stairs with the cantilevered steps tread from wall or the steps riser interposed the walls shall not be used,and the plain brick railing shall not be adopted.

4 For staircase or elevator shaft exceedipg the roof level,the constructional column shall be extended tothe topandbeconnectedwith the top ring-beam,thetiebarsof 2φ6 extending through the full length of the wall and tie meshes composed by spot welding inφ4 distributed short reinforcement plane orφ4mesh reinforcement steel fabric composed by spot welding,shall bearrangedevery 500mm along the wall height.

7.4.1 For multi-story small block buildings,the reinforced concrete core columns shall be arranged according to those specified in Table 7.4.1.For multi-story buildings with gallery corridor andone-side corridor,buildings with fewer transverse walls and buildings with very a few transverse walls on each story,the core columns shall be arranged in accordance with Table 7.4.1 and the corresponding requirements on adding the story number specified in Item 2,3and 4in Article 7.3.1 of this code,respectively.

7.4.4 The arranged position of cast-in-situ reinforced concrete ring-beams ofmulti-story small block buildings shall be implemented according to the ring-beamrequirements ofmulti-story brick masonry buildings specified in Article 7.3.3 ofthis code,the ring-beam width shall not be less than 190mm,the reinforcement shall not be less than 4φ12,and the stirrup spacing shall not be greater than 200mm.

7.5.7 The floor(and roof) of masonry building with RC frames and seismic walls on ground floors shall be in accordance with the following requirements:

1 For the transitional story,the floor shall adopt in-situ reinforced concrete slab.This slab thickness shall not be less than 120mm;the openings in slab shall be cut down or small;when the dimension of the opening exceeds 800mm,boundary beams shall be installed along the perimeters of the opening.

2 For other stories.when precast reinforced concrete slabs are adopted,in-situ cast ring-beams shall be installed;only in-situ reinforced concrete slabs are adopted,ring-beams shall bepermittednot installed,but the strengthened reinforcements of in-situ slabs shall be arranged along the wall perimeters and shall be reliably connected with corresponding constructional columns.

7.5.8 The reinforced concrete spandrel girder of buildings with bottom-frame shall comply with the following requirements:

1 The cross sectional width of the girder shall not be less than 300mm,and the cross sectional height shall not be less than 1/10 of the span.

2 Thediameter of the hoops shall not be less than 8mm,and the spacing of hoops shall not be greater than 200nun.At the girder end within 1.5 times of girder height and not less than 1/5of the clear span,and the both sides for the opening of the upper wall within 500mm and not less than the girder height,the spacing of hoops shall not be greater than 100mm.

3 The spacer bars shall be arranged along the girder height,the amount shall not be less than 2φ14,and the spacing shall not be less than 200mm.

4 The main reinforcements and spacer bars of the girder shall be developed to the column according to the requirements for tensile bars;besides,the developed length of the upper longitudinal bars of girder in the support shall comply with relevant requirements for reinforced concrete frame-supporting girders.

8.1.3 Steel structure buildings shall be assigned to different seismic grades according to the precautionary category,Intensity and building height,and also shall satisfy the corresponding calculation and details requirements.The seismic grade of Category C buildings shall be determined from Table 8.1.3.

8.3.1 The slenderness ratio of frame columns shall benot greater than 60for Grade 1,80for Grade 2,100forGrade 3 or 120for Grade 4.

8.3.6 As for the rigid connection of beams and columns,within the range of 500mm up and down the beamflange,the full penetration groove weld shall be adopted for the attachment weld between the column flange and the colmnn web plate or the box column wallboards.

8.4.1 The limits for slenderness ratio ofmember bars and for width-to-thickness ratio of plates of the concentrically braces shall meet the following requirements:

1 When the braced member bars is designed according to compression bars,the slendernessratioof it shall not be greater than 120;the design of tie rods shall not be adopted for concentrically supports for Grade 1.2and 3;the slenderness ratio shall not be greater than 180 when the design of tie rods is adopted for Grade 4.

2 The plate width-to-thickness ratio ofbrace member bars shall not be greater than the specified limit in Table 8.4.1.The strength and stability of gusset plates shall be noticed when connecting by adopting gusset plates.

8.5.1 The steel yield strength of energy-dissipating beam-segment on eccentrically-braced frames shall not be greater than 345MPa.For the energy-dissipating beam-segment and other beam segment at the same span,the width-to-thickness ratio of plates shall not be greater than the limits specified in Table 8.5.1.

10.1.3 The load-bearing structures for the hall of single-storey spacious building shall not adopt plain brick columns in the following situations:

1 The halls of the buildings for Intensity 7(0.15g),Intensity 8 and Intensity 9.

2 The halls with cantilever platform inside.

3 For Intensity 7(0.10g),the halls that the span is greater than 12mor the top elevation of column is greater than 6m.

4 For Intensity 6,the halls that the span is greater than 15m or the top elevation of column is greater than 8m.

10.1.12 The seismic checking of out-of-plane for the buttress of the tall gable wall shall be carried out for Intensity 8 and 9.

10.1.15 The transversal walls connecting the ante-hall with hall or the hall with stage shall comply with the following requirements:

1 The tie-columns or reinforced concrete columns shall be installed on the two ends of the transverse wall,the supports of longitudinal girders and both edges of large opening of the walls.

2 The some transversal wall that built-in plane of the reinforced concrete frame columns shall be designed according to Grade 2 reinforcement concrete wall.

3 The reinforcement concrete structure shail be adopted for girder and columns of the front of stage.For the bearing masonry wall above the girder in front of the stage.the pillars spacing not exceeding 4m and tie-beams spacing not exceeding 3m shall be installed.And their cross-sectional dimension,reinforcement ratio,and connection with the masonry wall shall conform to the requirements for multi-story masonry buildings.

4 Brick wall onthe girder in front of the stage shall not be used for bearing loads for Intensity 9.

12.1.5 For the design for the seismically isolated and energy-dissipated buildings.the seismic isolator units and the energy-dissipating devices shall comply with the following requirements:

1 The design parameters of the seismic isolator units and the energy-dissipating devices shall be determined by testing.

2 At the location where the seismic isolator units or the energy-dissipating diveces are installed,the measuresfor the convenience of check and renewal shall be taken.

3 The property requirements for seismic-isolator units and energy-dissipating devices shall be stated clearly in the design document.The sampling check of prototype shall be carried out before installation to ensure that the properties are in accordance with the requirements.

12.2.1 For the design of seismically isaolated buildings,the approptiate seismic isolation layer consisting of seismic isolator units and wind resistance devices shall be selected,according to the excepted vertical bearing capacity,horizontal seismic-reduced factor and the requirements for seismic displacement contr0l.

For the seismic isolator units,the check of the vertical bearing capacity and the horizontal displacement under rarely earthquake groun motions shall be carried out.

For the upper portion ofthe structure,the horizontal seismic action shall be determined according to the horizontal seismic-reduced factor,and the standardvalues of vertical seismic action shall be not less than 20%.30%and 40%of the total gravity representative values of the upper portion of the structure for Intensity 8(0.20g),Intensity 8(0.30g)and Intensity 9,respectively.

12.2.9 The lower portion of the structure and the foundation shall be in accordance with the following requirements:

1 The seismic check of loading capacity for the buttresses,the pillars and the con nected elements shall be carried out according to the vertical force,horizontal force and moment at the bottom of the isolator units under rarely earthquakes.

2 The relevant components of the lower portion(including basement and the base-plate of tower)of structure that directly support the upper portion,shall comply with the requirements of rigidity ratio for fixed ends,the requirements of earthquake resistant capacity that ensure the componets still in elastic phase under precautionary earthquakes including the seismically isolation effects.and the requirements of shear bearing capacity that ensure the sections of the componets remain interity under rarely earthquakes.The storey drift of the lower portion ofthe structure above ground under rarely earthquakes shall be in accordance with the requirments specified in Table 12.2.9.

3 The seismic check for the foundation and the foundation treatment of the seismic-isolated buildings shall be carried out according to the local Intensity.The anti-liquefaction measures for buildings assigned to Category A and B shall be determined accorming to one grade higher than the liquefaction grade.until all liquefaction settlements are eliminated.