同济大学：《高层建筑结构》课程教学资源（教案讲稿）Chapter 04 Frame Structures

2015/10/25 Chapter4 4.1 Frame Structures Frame Structures .4.1.1 Types .Steel-C oncrete Fran .Stee Mon .Steel Frame and Concrete core Xiong Haibel,Tongji University,2015 Reinforced Concrete Frame ·Materials tions of beams and columns are moment ·0 ping ratio of RCFrame is ar und 5%; ame is restricted ony 50m. Reinforcement in RC Frame HamCnts 本课件版权归作者所有，仅供个人学习使用，请勿转载。 1

2015/10/25 1 Chapter 4 Xiong Haibei, Tongji University, 2015 Frame Structures 4.1 Frame Structures  4.1.1 Types  Reinforced Concrete Frame (RC Frame)  Steel-Concrete Frame (SRC Frame)  Steel Moment Frame  Steel Frame with braces or dampers  Steel Frame and Concrete Wall  Steel Frame and Concrete core Reinforced Concrete Frame  Materials  Concrete  Reinforce bars  Characteristics  connections of beams and columns are moment support;  Lateral stiffness of RC Frame is lager than steel frame, and less than SRC Frame;  Damping ratio of RC Frame is around 5%;  Cost economic compare to steel frame  The height of RC Frame is restricted only 50m。 钢筋混凝土框架 Reinforcement in RC Frame Connection of rein-bars in joint (plane) 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Steel-Concrete ↓stel-Concrete Frame Frame Materials Steel SRC=S+RC m : Steel-Concrete Frame Steel Moment Frame .Material stee Characteristic ·a 本课件版权归作者所有，仅供个人学习使用，请勿转载。 2

2015/10/25 2 Connection of rein-bars in joint (section) Photos of Connection of rein-bars in joint Steel-Concrete Frame  Materials  Steel  Concrete  reinforcement  Characteristic  Lateral stiffness of SRC Frame is lager than RC Frame;  The Section of beams and columns are smaller than RC frame’s  Better fire-resistant than steel frame  Construction of SRC is complicated Steel-Concrete Frame SRC=S+RC Steel-Concrete Frame Steel Moment Frame  Material  Steel  Characteristic  Good seismic performance  Lateral Stiffness and damping ratio of structure are smaller than RC Frame  Weak in Fire-resistance  Complicated in joint construction 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Steel Frame Steel Frame with braces with braces and Dampers .Material .Material stee .Characteristic menbeedmand eStiess can beobtained fom rameand .Weak in Fire-resistance Steel frame-RCwall .Materials Characteristic the lateral 本课件版权归作者所有，仅供个人学习使用，请勿转载。 3

2015/10/25 3 Steel Frame with braces  Material  Steel  Characteristic  Good seismic performance  Lateral Stiffness can be obtained from frame and braces  Weak in Fire-resistance Steel Frame with braces and Dampers  Material  Steel  Characteristic  Good seismic performance  Lateral Stiffness can be obtained from frame and braces  Better in damping ratio with dampers  Weak in Fire-resistance  同济大学土木大楼  阻尼支撑 Steel frame －RC wall  Materials  Steel  Concrete  reinforcements  Characteristic  Shear walls greatly increase the lateral stiffness and capacity of structures  Steel beam and column joint can be hinge connection, which is easier in construction  Double resistant line of earthquake 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 起州金 Steel tube structure .material .Characteristic esistance 低内保品中 4.1 Frame Structures 4.1.2 failure modes under rare earthquake 取子堪 1.“Strong-Column and Weak-Beam”为 Sourees:China Sou 本课件版权归作者所有，仅供个人学习使用，请勿转载。 g

2015/10/25 4 Steel tube structure  material  steel  Characteristic  Closed columns and deep beam composed to a tube like structures, which greatly increase the general stiffness  Weakness in fire-resistance 4.1 Frame Structures 4.1.2 failure modes under rare earthquake  earthquake vulnerability of RC Frames under “5.12” Earthquake 一、现行设计能实现强柱弱梁吗 1. “Strong-Column and Weak-Beam” ?! Sources: China Southwest Architecture Design Institute Co., Ltd Con’d 现行设计能实现强柱弱梁吗 Sources: China Southwest Architecture Design Institute Co., Ltd Weak Column 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Sources:Chine A 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 5 Con’d 现行设计能实现强柱弱梁吗 Sources: China Southwest Architecture Design Institute Co., Ltd 如何考虑框架、框剪结构中填充墙对整体结构的刚度贡献 Con’d Sources: China Southwest Architecture Design Institute Co., Ltd 如何考虑框架、框剪结构中填充墙对整体结构的刚度贡献 Con’d Sources: China Southwest Architecture Design Institute Co., Ltd Infill walls Disadvantage: inducing damage of structural elements 怎样合理设计框架、框剪结构中的填充墙 Con’d Sources: China Southwest Architecture Design Institute Co., Ltd 建议提高竖向构件的最低配筋水准 Con’d Sources: China Southwest Architecture Design Institute Co., Ltd 箍筋设置问题 Damage regarding to stirrups 建筑材料、施工管理问题 Con’d Sources: China Southwest Architecture Design Institute Co., Ltd 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Key lessons from 5.12 earthquake mnehan oher 广hhord 4.1 Frame Structures 4.1.3 Seismic Grading 4.1.3 Seismic Grading Conceptual Design for structures Seismic Grading for RC Structures Seismic Grading for Steel Structures Seismic grading for reinforced concrete buildings able6.12inGB50011-2010) (Table6.1.2inGB50011-2010) n地 be continued 本课件版权归作者所有，仅供个人学习使用，请勿转载。 6」

2015/10/25 6 十六、重视角柱、加腋梁柱的抗震设计 16. Seismic design of columns, weak points. Key lessons from 5.12 earthquake • Corner columns often behave worse than other exterior and interior columns • Column’s destroy were more occurred and more severe than beam’s. • Complete failure in members detailed for ductility is rare. Therefore all elements must be detailed so that they can respond to strong earthquakes in a ductile fashion. • Non-ductile modes such as shear and bond failures must be avoided. • A high degree of structural redundancy should be provided.  4.1.3 Seismic Grading  Seismic Grading for RC Structures  Seismic Grading for Steel Structures 4.1 Frame Structures 4.1.3 Seismic Grading Conceptual Design for structures  Height  Structural System  Seismic Fortification Intensity Grading  Requirements in Design  Configuration  Calculation  Details Seismic grading for reinforced concrete buildings (Table 6.1.2 in GB50011-2010) Types of structure Seismic fortification intensity 6 7 8 9 Fram structure Height (m) ≤24 >24 ≤24 >24 ≤24 >24 ≤24 Frames 4th 3rd 3rd 2nd 2nd 1st 1st Large span frames 3rd 2nd 1st 1st Wall￾Frame structure Height (m) ≤60 >60 ≤24 25~60 >60 ≤24 25~60 >60 ≤24 25~60 Frames 4th 3rd 4th 3rd 2nd 3rd 2nd 1st 2nd 1st Structural walls 3rd 3rd 2nd 2nd 1st 1st Structural wall structure Height (m) ≤80 >80 ≤24 25~80 >80 ≤24 25~80 >80 ≤24 25~60 Structural walls 4th 3rd 4th 3rd 2nd 3rd 2nd 1st 2nd 1st be continued Types of structure Seismic fortification intensity 6 7 8 9 Frame - supported wall structure Height (m) ≤80 >80 ≤24 25~ 80 >80 ≤24 25~ 80 Struc￾tural walls General 4th 3rd 4th 3rd 2nd 3rd 2nd Streng￾thening 3rd 2nd 3rd 2nd 1stI 2nd 1st Frames that supporting walls 2nd 2nd 1st 1st Framed-tube structure Frame 3rd 2nd 1st 1st Tube 2nd 2nd 1st 1st Tube in tube structure Exterior tube 3rd 2nd 1st 1st Interior tube 3rd 2nd 1st 1st Slab-column￾wall structure Height (m) ≤35 >35 ≤35 >35 ≤35 >35 Columns 3rd 2nd 2nd 2nd 1st Walls 2nd 2nd 2nd 1st 2nd 1st (Table 6.1.2 in GB50011-2010) 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Seismic grading for steel structures 4.2 Calculation (Table8.1.3inGB50011-2010) 4.2.1 3D structure calculation ，3 D finite eler Bullding height s50m >50m Sotware:Sap2000,PKPM ANSYS,ETABS ateral drifts are in dominant 甲 用用 Under vertical loads- -storied Approach st .st HHuH met ron Moment diagram under lateral loads of beam is much larger than that o of column is in the middle of nt is er of 本课件版权归作者所有，仅供个人学习使用，请勿转载。 1

2015/10/25 7 Seismic grading for steel structures (Table 8.1.3 in GB50011-2010) Building height Seismic fortification intensity 6 7 8 9 ≤50m / 4th 3rd 2nd >50m 4th 3rd 2nd 1st 4.2 Calculation 4.2.1 3D structure calculation  3D finite element method  Beams and columns are Beam Elements  Joint can be assumed as moment joint, semi-moment joint and hinge joint  Software: Sap2000, PKPM, ANSYS, ETABS  Natural period and mode shape are very important characteristics of a structure  Lateral drifts are in dominant  Basic requirement：strength capacity of beam，column and joint  Attention to compress ratio of column and reinforcement ratio of beams and columns. 4.2.2 Simplified calculation method for 2D structures 1. Under vertical loads —— storied Approach Calculation Sketch－story independent  Analysis based on no-drift frame structure；  The vertical loads only affect the beams and connected columns;  Base connection of column is fixed, and the joint of beam and column is moment connection. 2. Under horizontal loads (lateral loads) —— Inflection-point Approach  Assumption：  Same drift and Same lateral stiffness of columns in the same floor;  Linear stiffness of beam is much larger than that of connected column;  The inflection-point of column is in the middle of the column. But of the bottom column, the inflection-point is at the 2/3 from the ground；  The inflection-point of the beam is at the center of the beam. 4.2.2 Simplified calculation method for 2D structures Moment diagram under lateral loads inflection-point inflection-point inflection-point 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Calculation Method △ 121 到 inflection-poin D-Valued D=a12 h D-Valued Improved Inflection-point method -D valued method ess of a colun Adjustive factor a<l D Value methods .Attention: 。Only fexu I deformation is kg 本课件版权归作者所有，仅供个人学习使用，请勿转载。 8

2015/10/25 8 Horizontal deformation diagram under lateral loads inflection-point inflection-point inflection￾point Calculation Method m Fj 1k jk jk jk m 1k 2 j jk Fj u 2 u j jk jk m 1k Fj jk V i i V h 12i V h 12i V VV j j           D-Valued 2 c h 12i D   Improved Inflection-point method ——D valued method  D is the lateral stiffness of a column;   is the adjective factor corresponding to the elastic restriction of top and bottom end of a column D-Valued Adjustive factor  1 j j uu D V u n 1j m 1k jk Fj        Attention：  Only flexural deformation is concerned,  Neither axial nor shear deformation is concerned D Value methods 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 Determine the internal forces of lateral- DValue methods force-resisting frames .the shear force of thecom nfloor omlneshoartorcetoreachcolmn 时 长sthe orcdon如eo 4.Shear resistance of members COLUHN ANd OINTe er's section we Design bh≥f(yE,',B.f) 4.Shear resistance of members 4Sher resistance of members Vs⊥0.20gfM) ompressi 27y1020.=5r1/ 本课件版权归作者所有，仅供个人学习使用，请勿转载。 9

2015/10/25 9  the shear force of the k-th column in i-th floor Where Vik is the horizontal shear force induced in column k on i th storey; Dik is relative shear stiffness of column k on i th storey; n i k ik ik ik V D D V   1 (5.7)  n k Dik 1 is summation of relative shear stiffness of total columns on i th story. D Value methods Determine the internal forces of lateral￾force-resisting frames :  Determine flexural stiffness for beam and column;  Calculate D value;  Determine shear force for each column;  Determine the position of the point of contra-flexure in column;  Calculate column moments, then derive the beam moments based on equilibrium of beam to column joint, and distribution of beam stiffness / kl  ik hVM (5.11) )( / ku ik  hhVM (5.12) Design 4.3 Shear resistance of members Members in a Frame: BEAMs, COLUMNs, and JOINTs What's different from beam and column? A member subjected to an axial force of 0.1f c Ag or less can be treated as a beam (Ag = the gross area of the section, f c = design compression strength for concrete). To dirtermin size of a member's section we should: ),,( 0 RE cc bh   fVf • Shear compression ratio : defined as nominal shear stress divided by design compression strength of concrete (cylinder strength), or V/f c bh0 , to quantify a nominal shear stress across a beam section • To ensure that premature diagonal compression failure not occur before the onset of yielding of shear reinforcement, the diagonal compression principal stress should be limited. 4.3 Shear resistance of members For Beam：If ratio of span to depth (跨高比) is greater than 2.5, For Column and Wall：If shear span ratio (剪跨比) is greater than 2, the design shear force should satisfy the following equation: RE cc RE cc cc RE bh fVfV V f bh    0/ .2 /50 .0( 20 ) 1 0 0    4.3 Shear resistance of members 本课件版权归作者所有，仅供个人学习使用，请勿转载

2015/10/25 4.Shear resistance of members strong shear-weak flexure beam P≤015A) v=nMtM +Vo 540 Shear strength of beams th reducton in the V=1.I Miu Ming +Von 5s六0m+125÷) Shear strength of columns 3切 . r=1.2M+M) H 本课件版权归作者所有，仅供个人学习使用，请勿转载。 10

2015/10/25 10 .0( 15 ) 1 bh0 V f cc RE    For Beam：If ratio of span to depth (跨高比) is NOT greater than 2.5, For Column and Wall：If shear span ratio (剪跨比) is NOT greater than 2, the design shear force should satisfy the following equation: .0( 30 ) 1 jjcj RE Vj  hbf   (5.46) For Joint： 4.3 Shear resistance of members To ensure ductile flexural failure and prevent brittle shear failure, a principle of “strong shear—weak flexure” should be followed in seismic design of reinforced concrete beams. Gb n r b l b vb V l MM V    strong shear—weak flexure For beams in grade 1 frames, is 1.3. For beams in grade 2 frames, is 1.2. For beams in grade 3 frames, is 1.1. vb vb vb Gb n r bua l bua V l MM V    1.1 For beams in grade 1 and earthquake intensity 9, the beam and lintel may not be adjusted, but it should satisfy the following requirement. Considering shear strength reduction in the diagonal plan of beam under the repeated reversal loading, the shear strength in diagonal plan should be checked as the follows .0( 42 .1 25 ) 1 0 h0 s A V f bh f sv t yv RE b    ) 1 .1 05 ( 1 0 h0 s A V f bh f sv t yv RE b    Shear strength of beams Principle of strong shear and weak flexure To ensure ductile flexural failure and prevent brittle shear failure n b c t c vc H MM V   (5.37) For columns in grade 1 frames, is 1.5, the others are 1.4 For columns in grade 2 frames, is 1.3. 1.2 For columns in grade 3 frames, is 1.2. 1.1 For columns in grade 4 frames, is 1.1. 1.1 vc vc vc vc Shear strength of columns   n t cua b cua H MM V   2.1 For columns in grade 1 and earhtquake intensity 9, the columns may not be adjusted, but it should satisfy the following requirement. Shear strength of columns 本课件版权归作者所有，仅供个人学习使用，请勿转载