同济大学：《高层建筑结构》课程教学资源（教案讲稿）Chapter 03-1 Load Action and Load Combination of Tall Buildings

2015/10/3 Chapter 3 Content Load Action and Load Combination 3.1 Combination of load effects of Tall Buildings 3.2 Vertical loads 3.3 Wind load 3.4 Earthquake action 3.5 Issues 3.1 Combination of load effects 3.1.1 Fundamental combination 3.1.1 Fundamental combination-ULS 3.1.2 Accidental combination- ULS YoS<R 3.1.3 Nominal combination-SLS 3.1.4 Quasi-permanent combination-SLS ad resistance 3.1.1 Fundamental combination 3.1.2 Combination with earthquake 5-s*ox+宫oaw S=YGSGE +YDS M+YESp +W.7.S. ToSSR S<RIYE S.Load combination effect under earthquake To be introduced next week 本课件版权归作者所有，仅供个人学习使用，请勿转载。 1

2015/10/3 1 Chapter 3 Xiong Haibei, Tongji University, 2015 Load Action and Load Combination of Tall Buildings Content 3.1 Combination of load effects 3.2 Vertical loads 3.3 Wind load 3.4 Earthquake action 3.5 Issues 3.1 Combination of load effects 3.1.1 Fundamental combination——ULS 3.1.2 Accidental combination——ULS 3.1.3 Nominal combination——SLS 3.1.4 Quasi-permanent combination-SLS  Tips: ULS=ultimate limit state  SLS=serviceability limit state 3.1.1 Fundamental combination  S－ load effect，R－ resistance , 0 －importance factor of structure;   － partial safety factor， G ＝1.2, 1.35, 1.0, 0.9;   － combination value coefficient of variable loads. 《Load Code for the Design of Building Structures》 （GB 50009-2001） Clause 3.2.3——compulsory provisions RS SSS QiSQiK n i G GK KQQ Ci    0 2 11    3.1.1 Fundamental combination Li － coefficient factor for building’s working life Li = 0.9,1.0, and 1.1 for 5 years, 50years and 100 years respectively. 《Load Code for the Design of Building Structures》 （GB 50009-2012） j j 1 1 1 i 1 i m n d G G K Q L Q K Ci Q L Q K j 1 i 2 0 d d S S S S S R                3.1.2 Combination with earthquake S－ Load combination effect under earthquake  － partial safety factor; Eh＝ 1.3, Ev＝ 0.5  － combination value coefficient of variable loads Question：live load？ E －coefficient factor for seismic design of elements / G GE Eh EhK Ev EvK w w wK E S S S S S S R            To be introduced next week 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 3.1.3 Load combinations 3.1.4 Nominal combination in tall building design Without earthquake action S=Sax+Suw+WcSox S=YoSak+Wol@S@+W.Y.S.x S<C S<R With earthquake action S=YaSae +YaSm +7pSm +W7.Su d limiting value under SLS S<RIYE eleration. stress and etc. 3.1.5 Quasi-permanent combination 3.2 Vertical loads S=Sax+Sou+∑y,S 3.2.1 Permanent loads (Dead loads) S<C 32 2 Variable loads (Live loads) 3.2.1 Dead loads Dead loads-weight of materials 3.2.1 Dead loads S.-SyaSu++.Su 1)Weight of bearing structure YS,SR (Units:kN or kN/m) Partial safety factor of gravity load oBeams .=12y=35 oColumns When dead loads are favor able Shear walls a=10a=0g Bracings Note:Every load item shall be considered,and dont over-l 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 2 3.1.3 Load combinations in tall building design  Without earthquake action  With earthquake action / G GE Eh EhK Ev EvK w w wK E S S S S S S R            RS SSSS G GK QQ QK ww wK    3.1.4 Nominal combination Applicable to SLS; C — stipulated limiting value under SLS， such as deflection、crack、amplitude of vibration、acceleration、stress and etc. CS SSS SQiK n i GK KQ Ci   2 1  3.1.5 Quasi-permanent combination CS SSS SQiK n i GK KQ qi   2 1  3.2 Vertical loads 3.2.1 Permanent loads （Dead loads） 3.2.2 Variable loads （Live loads） 3.2.1 Dead loads Dead loads —— weight of materials  Partial safety factor of gravity load  When dead loads are favorable: Note：Every load item shall be considered, and don’t over-loading . , . G G     1 2 1 35 . , . G G     1 0 0 9 j j 1 1 1 i 1 i m n d G G K Q L Q K Ci Q L Q K j 1 i 2 0 d d S S S S S R                3.2.1 Dead loads 1）Weight of bearing structure （Units：kN or kN/m )  Beams  Columns  Shear walls  Bracings 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 3.2.1 Dead loads 3.2.1 Dead loads 2)Area load kN/m2) 3)Load of partition wall Complying with actual condition RC slab a Ceiling、Pipes,etc. linearoad on beam or wall (kN/m): Estimated as uniformly distributed load Attention:Roof loads area load on floor (kN/m2). 3.2.1 Dead load 3.2.1 Dead load 4)Welght of facilities 6mengyonenf a Can simplified as equivalent uniform load.or Estimated as uniform load ▣ methods from other materials and codes 3.2.2 Live loads 3.2.1 Dead load gmeoeds (G850009-2012） compulsory provision 本课件版权归作者所有，仅供个人学习使用，请勿转载。 3

2015/10/3 3 3.2.1 Dead loads 2）Area load（ kN/m2 )  Topings  RC slab  Ceiling、Pipes, etc. Attention：Roof loads 3）Load of partition wall  Complying with actual condition linear load on beam or wall （ kN/m );  Estimated as uniformly distributed load area load on floor （kN/m2 ). 3.2.1 Dead loads 3.2.1 Dead load 4）Weight of facilities  Equipments’ weight, may concern of dynamic running action  Can simplified as equivalent uniform load, or  Estimated as uniform load （methods from other materials and codes） 3.2.1 Dead load effective distribution width of local load on simply supported slab 3.2.1 Dead load effective distribution width of adjacent local load effective distribution width of local load on cantilever slab 3.2.2 Live loads  Uniform live loads on floors 《Load Code for the Design of Building Structures》 （GB 50009-2012） Clause 5.1.1 —— compulsory provisions Item No. Type Character istic Value(kN/ m2) Coefficien t for combinati on value ψc Coefficient for frequent value ψf Coefficient for quasi￾permanent value ψq 1 ⑴ Dwelling, hostel, hotel, office, hospital ward, nursery, kindergarten 2.0 0.7 0.5 0.4 ⑵ Laboratory, reading room, meeting room, hospital outpatient room 2.0 0.7 0.6 0.5 2 Classroom, canteen, dining hall, ordinary archives 2.5 0.7 0.6 0.5 3 ⑴ Assembly hall, theater, cinema, grandstands with fixed seats 3.0 0.7 0.5 0.3 ⑵ Laundry 3.0 0.7 0.6 0.5 4 ⑴ Stores and shops, exhibition hall, station, port, airport hall and waiting room for passengers 3.5 0.7 0.6 0.5 ⑵ Stands without fixed seat 3.5 0.7 0.5 0.3 5 ⑴ Gymnasium, arena 4.0 0.7 0.6 0.5 ⑵Playground, dance hall 4.0 0.7 0.6 0.3 6 ⑴ storehouse for collecting books、 archives, storeroom 5.0 0.9 0.9 0.8 ⑵ Densely bookcase storehouse 12.0 0.9 0.9 0.8 7 Ventilator motor room, elevator motor room 7.0 0.9 0.9 0.8 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 3.2.2 Live loads etng books,whe ar is suitable to the 3.2.2 Live loads 2.live load reduction coefficients here the pre tradeo s The 2g030 n 100 0.85 0.70 0.65 0.80 0.55 3.3 Wind loads 3.3.1 Influences on tall buildings 3.3.1 Influences on tall buildings 3.3.2 Wind pressure and Wind load Horizontal movement of air:wind: 3.3.3 Influences of cross direction wind Vertical movement of air:flow,stream aWind strength: Velocity Grading sistical value in year 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 4 Item No. Type Characte ristic Value(kN /m2) Coefficie nt for combina tion value ψc Coefficie nt for frequent value ψf Coefficie nt for quasi￾permane nt value ψq 8 Vehicle tunnel and passen ger car garage ⑴ with one-way slab floor(span of slab is not less than 2m) and two-way slab floor(span of slab is not less than 3mX3m) Passen ger car 4.0 0.7 0.7 0.6 Fire truck 35.0 0.7 0.5 0.0 ⑵ with two-way slab floor(span of slab is not less than 6mX6m) and flat slab floor(column net work size is not less than 6mX6m) Passen ger car 2.5 0.7 0.7 0.6 Fire truck 20.0 0.7 0.5 0.0 9 Kitchen ⑴ dining hall 4.0 0.7 0.7 0.7 ⑵ else 2.0 0.7 0.6 0.5 10 Bathroom, toilet and washrooom 2.5 0.7 0.6 0.5 11 Corrido r, entranc e hall ⑴ hostel, hotel, hospital ward, nursery, kindergarten, dwelling 2.0 0.7 0.5 0.4 ⑵ office, dining hall, hospital outpatient room 2.5 0.7 0.6 0.5 ⑶ teaching building and other populated cases 3.5 0.7 0.5 0.3 12 Staircas e ⑴ multi-storey residence 2.0 0.7 0.5 0.4 ⑵ other 3.5 0.7 0.5 0.3 13 Balcony ⑴ when population may be concentrated 3.5 0.7 0.6 0.5 ⑵ other 2.5 0.7 0.6 0.5 3.2.2 Live loads Note: 1 Live loads listed in this table are suitable for the ordinary usable conditions. When the service load is greater or the condition may be in an exceptional case, the values of actual loads shall be adopted. 2 in the item No.6, the live load of storehouse for collecting books, when the height of bookshelf is greater than 2m, the live load of storehouse for collecting books shall be determined according to the weight of per meter height of bookshelf not less than 2.5kN/m2 . 3 In the item No.8, the live load of passenger car is suitable to the passenger car, which is parked to carry less than 9 passengers only; the live load of fire truck is suitable to the total weight of full loaded with 300kN large-scale vehlcle; when the demands of this table are not conformed, hence, the local load of truck wheel shall be converted into the equivalent uniform load according to the equivalent principles of structural effects. 3.2.2 Live loads 4 In the item No.12, the live load of staircase, where the precast trade of staircase shall still be checking calculated by the 1.5kN concentrated load. 5 The self-weight of partition wall and second decorating load are included in the loads listed in this table. For the self-weight of fined partition wall shall be considered as dead load, when the position of partition wall have a fine and flexible arrangements, the self-weight of non-fixed partition wall shall take the weight for 1/3 per meter length of wall, which is counted as the additional value (kN/ m2 ) of the live load on floors, the additional value is not less than 1.0kN m2. 6 Reduction coefficients for design of walls, columns, foundations The number of stories above the checked section 1 2~3 4~5 6~8 9~10 >20 Reduction coefficients 1.00 0.85 0.70 0.65 0.60 0.55 2. live load reduction coefficients 1）Reduction coefficients for design of floor beams ：  When the tributary area of floor beams is larger than 25m2 ,the 0.9 shall be taken； 2) Reduction coefficients for design of walls, columns, foundations  The number of stories above the calculated section 1 2~3 4~5 6~8 9~10 >20 Reduction coefficients 1.00 (0.9) 0.85 0.70 0.65 0.60 0.55 3.3 Wind loads 3.3.1 Influences on tall buildings 3.3.2 Wind pressure and Wind load 3.3.3 Influences of cross direction wind 3.3.1 Influences on tall buildings  Horizontal movement of air: wind;  Vertical movement of air: flow, stream  Wind strength：  Velocity Grading  Engineering wind speed：Maximum wind speed probably encountered in certain years, statistical value 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 Taremeedpeg wind WingEngineeringreeare Transient wind Mean wind and transient wind on tall buildings H 度风速 度风高度么 （）面 3.3.1 Influences on tall buildings 3.3.1 Wind load influences on tall Characteristics of mean wind speed buildings 。ary with height Wind speed (mean speed,transient speed) ld roughness 10min an Building shape; Height from ground to wind load's location Characteristics of transient wind oConcentration degree of buildings: v 10s an Influences by dlosely located tall buildings value s near zr ary little as height change. 本课件版权归作者所有，仅供个人学习使用，请勿转载。 6

2015/10/3 5 Transient wind speed and Mean wind speed Wing Engineering researches Field Monitory Tunnel Test Numerical Simulation Mean wind and transient wind on tall buildings Transient wind Mean wind  Characteristics of mean wind speed  vary with height;  relevant to field roughness ;  no significant change between 10min and 1h;  return years : 10years, 50years, and 100years. 3.3.1 Influences on tall buildings  Characteristics of transient wind  fluctuating wind，with period approximately 10s and larger than building’s fundamental period,  average value is near zero,  vary little as height changes. 3.3.1 Wind load influences on tall buildings  Wind speed (mean speed, transient speed);  Building shape;  Height from ground to wind load’s location；  Concentration degree of buildings；  Influences by closely located tall buildings. 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 Case study Case study Case study Case study 3.3.2 Nominal value of wind load For load-bearing structures nominal value: Pk=B从4,10 of z: -shape factor of wind load; -exposure factor for wind pressure 本课件版权归作者所有，仅供个人学习使用，请勿转载。 6

2015/10/3 6 Case study Case study Case study rectangular section high-rise building which is more than 45 m Case study Case study 3.3.2 Nominal value of wind load For load-bearing structures: nominal value: w0 — reference wind pressure(kN/m2 ) z— dynamic effect factor of wind at a height of z; s — shape factor of wind load; Z — exposure factor for wind pressure. w   szzk w0 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 Reference wind pressure For envelop elements Nominal value 1 %-2m w4=B44, wo-reference wind pressure(kN/m2); 50years retum period; Bgust factor at a height of z: P-air density.nominal value 1.25kg/m3 -shape factor of wind load; thus,1600 -exposure factor for wind pressure. Exposure factor for wind pressure-z ores,lake shores and s.villages,forests s with At a height of 10m yB21 Exposure factor for ind pressure--μz Wind pressure distribution 本课件版权归作者所有，仅供个人学习使用， 请勿转载。 1

2015/10/3 7 For envelop elements： Nominal value w0 — reference wind pressure(kN/m2 ); gz— gust factor at a height of z; s — shape factor of wind load; Z — exposure factor for wind pressure. wk  gz sz  0 Reference wind pressure v0 — Maximum mean wind speed in 10 minutes for flat open ground, at a height of 10m, 50years return period;  — air density, nominal value 1.25kg/m3 thus, For skyscrapers, the v0 shall be adopted with recurrence interval 100years. 2 0 0 2 1  vw 2 0 0 1600 1  vw Exposure factor for wind pressure— Z Field roughness： Category A: sea shores, lake shores and deserts; Category B：open fields, villages, forests; Category C：urban districts in densely￾populated cities; Category D：densely-populated cities with high building urban districts. At a height of 10m, category B:  Z ＝1 Exposure factor for wind pressure— Z Exposure factor for wind pressure— Z Wind pressure distribution 2 0 0 2 1  vw 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 Shape factor for wind pressure Shape factor for wind pressure 音尚 列 苍 aure Dynamic effect factor at a height of z-Bz Gust factor-z ertion mdes shall be nds t tall ca tocofre'wind B.=1+2glnoB.I+R Gust factor-一Pgz Gust factor-Boz 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 8 Shape factor for wind pressure— s Shape factor for wind pressure— s rectangular section high-rise building which is more than 45 m Dynamic effect factor at a height of z — z  marked vibration of high soft structure by wind;  as the extension of structural period, the vibration increase;  more vibration modes shall be considered as to tall building. + 2 z   1 2gI B 1 R 10 z resonance component factor of fluctuating wind background component factor of fluctuating wind peak factor, which is2.5 turbulence intensity at 10 m, surface roughness of catorgy A, B, C, D is 0.12, 0.14, 0.23, 0.39, respectively Gust factor—gz  Considering the complexity of ground wind torrent, gust factor—gz is proposed  Applicable to calculation of fencing structure’s wind load;  Relevant to terrain roughness and height;  adopted with table 7.5.1 (GB 50009) Gust factor—gz Gust factor—gz 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/3 3.3.3 Influences of crosswind 3.3.3 Influences of crosswind Tall Building Bulding yibration by Equivalent later oad 3.3.3 Uncomfortable feeling control 035 -Corner(no damper） caused by wind excitation -Comer with damper) 05g Acceptable 5/w -Center(with damper） 0.05 (mp) 8101 110100 Average Storm No./year 76-story Columbia Towor ith damper Taipei 101- Taipei101 上上 T=2元 Vg 本课件版权归作者所有，仅供个人学习使用，请勿转载。 9

2015/10/3 9 3.3.3 Influences of crosswind Airflow Vortex Tall Building Wind Wind action on Tall Buildings 3.3.3 Influences of crosswind wind Bldg. Vortex Equivalent lateral load Dis. Building vibration by Equivalent lateral load  Tall building under wind load, cross direction wind excitation generated by air eddy current;  unstable air flow; 3.3.3 Uncomfortable feeling control caused by wind excitation Acceleration of wind excitation 0.005g 0.005g～ 0.015g 0.015g～ 0.05g 0.05g～ 0.15g >0.15g body reaction No sensation Have sensation annoying Very annoying unbearable Buildings amax（m/s2） residence, department 0.15 office, hotel 0.25 《Technical specification for concrete structures of tall buildings》 table4.6.6 76-story Columbia Tower with damper Corner ( no damper) Corner ( with damper) Corner ( with damper) sensible Center ( with damper) Acceptable Center ( no damper) Acceleration m/s 2 Average Storm No. /year Taipei 101 —— http://epaper.ce.ntu.edu.tw/vol.21/101d amper-1.html L T 2 g   Taipei 101 —— 本课件版权归作者所有，仅供个人学习使用，请勿转载