SEISMIC DESIGN OF STRUCTURE

Transcription

1 SEISMIC DESIGN OF STRUCTURE PART I TERMINOLOGY EXPLANATION Chapter 1 Earthquake Faults Epicenter Focal Depth Focus Focal Distance Epicenter Distance Tectonic Earthquake Volcanic Earthquake Collapse Earthquake Large Reservoir-Induced Earthquake Body Wave and Surface Wave P wave and S Wave Peak ground motion, duration of motion and frequency content, PGA Earthquake Magnitude and Intensity Modified Mercalli Intensity Scale (MMI) Chapter 2 Site Category for building seismic design Classification of soil Equivalent shear wave of soil Subsoil and Foundation Natural subsoil Pile foundation Adjusted design value of seismic bearing capacity of subsoil Soil Liquefaction and Liquefaction Index Chapter 3 Dynamic Response of Structure Dynamic Equilibrium Harmonic Loading Response Spectra SDOF and MDOF Free Vibration and Impulse Motion Damped Structure and Undamped Structure Resonance Generalized-Coordinate

2 Rayleigh s Method Earthquake Response Mode Shapes and Frequencies SRSS and CQC Seismic Effect Coefficient Response-Spectrum Analysis Chapter 4 Building Configuration Building Symmetry Configuration Regularity and Irregularity Vertical setback Seismic Joints Failure mode Nonstructural Components Chapter 5 Earthquake Design Philosophy Exceed probability of 10% in 50 years Structural Frame System Structural Wall System Dual System Seismic Grading for structure Equivalent-lateral Force Procedure Dynamic Analysis Procedure Response-spectrum Modal Analysis Time-history Analysis D-value Method Moment Distribution Method Plastic Moment Redistribution Load Combinations Limitation of Axial Compression Ratio Limitation of Shear Compression Ratio Diagonal Shear Resistance Effective Width of Beam-column Joints Elastic Story Drift Cantilever Structural Wall Span Depth Ratio Chapter 6 Multi-story masonry building Multi-story masonry building with framed one/two stories Multi-story masonry building with multi-row column of inner frame

3 Equivalent wall stiffness Ordinary brick and hollow brick Clay brick walls with horizontal reinforcement Wall with small size concrete block Maximum Height to width of building Seismic transverse shear wall Constructional Column Ring Beam Horizontal seismic effect Coefficient Chapter 7 Moment Resisting Frame Braced Frame Structure Frames with Shear Wall Tube Structure Frames with Tube Belt Structure Expansion Joint Plastic hinge mechanism CBF and EBF Second order moment P-Delta effect Slenderness ratio of column Width-thickness ratio of plate in beam and column Butt Welt Frame bent and rigid frame Brace system Chapter 8 Seismic Control Seismic base isolation Sliding Isolation Friction Pendulum System (FPS) Restoring Force Rubber Bearing Lead Bronze Slider Seismic Energy Dissipation Supplement damping hardware Hysteretic Damper Unbonded Steel Brace Velocity-dependent Damper Active Control and Passive Control Hybrid Control

4 PART II QUESTIONS Chapter 1 1. How many sorts of earthquakes depending on the focal depth and the courses of earthquake respectively? 2. What are the main features of an earthquake acceleration record, and what roles are they in seismic design? 3. What differences between earthquake magnitude and intensity, and which index is used in seismic design of building? 4. What earthquake design philosophy is accepted in China? How to realize these ideas in seismic design? Chapter 2 5. How many categories are classified in seismic design according code for seismic design of building(gb )? And what factors are dependent on? 6. Description briefly the steps of calculation of natural fundamental seismic capacity. 7. Briefly introduce the phenomena of soil liquefaction How to determine the liquefaction Index? 8. What damages may be occurred on ground surface and buildings? 9. How to mitigate of soil liquefaction hazard? Chapter Description briefly the steps of Mode Analysis Method in calculation of earthquake action of seismic design of building. 11. Why the additional horizontal seismic action applied top of building should be considered in Base Shear Method? 12. How many methods are normally accepted in calculation of earthquake response? 13. Introduce briefly about the numerical integration for calculation of earthquake response. 14. What is the generalized-coordinate approach? 15. What are generally included in response analysis of a MDOF system? 16. What similarities and differences in the calculation between static analysis and dynamic analysis respectively? 17. What is the Base Shear method? And what assumption should be considered? 18. What is the seismic effect coefficient curve? Chapter In building configuration, what main factors should be consideration? 20. Why design characteristic of redundancy and detailing connection should be considered carefully in seismic design of building? 21. What is a desirable aspect of building configuration? 22. In summary, what are main factors of the optimum seismic configuration? 23. Why torsion irregularity in plan should be restricted strictly?

5 24. In Chinese Code for Seismic Design of Buildings, what additional requirements are specified if irregularities defined is large than limit? 25. What requirements should be take into consider in general seismic structural system? 26. What effects of nonstructural components on structural system? Chapter Introduce briefly about the principle of strong column-weak beam, and How to realize it in column design? 28. Introduce briefly about the principle of strong shear and weak flexural. 29. Introduce briefly about the principle of strong joints and weak member. And how to design beam-column joint? 30. Indicate what main failure modes for cantilever structure. 31. What basic assumption and analytical models for dual system? 32. What is the limitation on cross-section dimensions of framed beams? 33. What is the limitation of axial compression ratio of column in frame structure with seismic grade 1? 34. What is the limitation of story drift for reinforce concrete frame structure system and shear wall system respectively in site of intensity grade VII? 35. Why the boundary elements should be set in a structure wall? Chapter How many main structural types of masonry buildings? And what are they? 37. What are the design criteria for multi-story masonry? 38. What configuration of structural system of multi-story masonry building with framed first one/two stories is it? 39. What is the principle for the distribution of horizontal seismic action? 40. Indicates the calculation steps in calculation of multi-story building. 41. What are building height limitation, numbers of stories and minimum thickness for the multi-story with ordinary brick in site intensity VII respectively? 42. Why the location dimension limitation should be considered in seismic design for multi-story masonry building? 43. Why reinforce concrete constructional column and ring beam should be set in multi-story brick building? 44. What is the value of horizontal seismic effect coefficient in site of intensity grade VII, grade VIII and Grade IX? Chapter What are mechanical properties of structural steel in seismic design? 46. What are normal failure modes for steel structure and steel members? 47. Indicate briefly about requirements for arrangement of steel structure system. 48. What is the height limitation and height-width ratio for steel structure with braced frame system in site of earthquake intensity grade VII? 49. What is the idea failure mode for braced frame system?

6 50. Why several lines against earthquake attack should be set in seismic design? 51. In beam-column joint, which one is suggested in seismic design, column through type or beam through type? 52. What is basically assumption for single story large span workshop in calculation of earthquake action? 53. What is the guidance for distribution of earthquake load in longitudinal direction of steel workshop? Chapter What is the concept of active control and passive control in building seismic design respectively? 55. How many types for isolation system? And what are their differences with each other? 56. How many kinds of damper are used in increasing damping ratio of building structure? 57. What effect of increasing damping ratio of building structure? 58. What differences are in force-displacement relationship for hysteretic damper and velocity-dependant damper? 59. Briefly introduce the applications of one type of damper. 60. Briefly introduce the applications of one type of isolator.

7 PART III CALCULATION AND SEISMIC DESIGN Exercise 1 The soil profile at a site is shown in table 1. Determine the appropriate soil type. Table 1 Data of soil exploration at site Bottom depth of soil layer Thickness of soil (m) layer (m) Soil profile name Shear-wave (m/s) Soft Clay Very soft silty clay Sand Fine sand Gravelly sand 550 Exercise 2 A three-story reinforce concrete frame section is shown in Figure 1. Two columns have same cross with b=0.30m and h=0.45m and the height for every floor is same as 3.3 meters. The mass of every floor is concentrated at floor, and with same value as 12000kg for 1st floor and 2nd floor, and 6000kg for 3rd floor. The modulus of concrete is E=2.5*1010Pa. Please determine the Mode Shapes, Periods and Participation Factors of this three-story Frame. 6000kg 12000kg 12000kg Figure 1 Sketch for calculation Exercise 3 A 5-story reinforce concrete building is located at site of category III which design seismic in group 1. The seismic zone of intensity for design is Ⅶ. After dynamic analysis for this building, five modes and corresponding periods, participating factor are given and shown in Figure 2. The damp ratio of this frame is Calculate the standard horizontal seismic actions at each story under frequent-occurring earthquake by base shear method 2. Calculate the standard horizontal seismic actions at each story under frequent-occurring earthquake by mode analysis method. 3. Compare two results and briefly introduce the effect of additional horizontal seismic action applied at the top of the building in base shear method.

8 MODE 1 MODE 2 MODE 3 MODE 4 MODE kg kg kg kg kg Period: T1=0.691s r1= T2=0.201s T3=0.117s T4=0.188s T5=0.078s r2=0.204 r3=0.064 r4=0.025 r5=0.007 Figure 2 Five modes and corresponding periods Exercise 4 Seismic design of a 5-story reinforce concrete frame A 5-story office building, structured in reinforce concrete frame, located in Shanghai. Seismic zone of intensity for design is VII, site of category IV and design seismic in group 1. The strength of concrete for beams and columns is grade C30; main longitudinal reinforcing bars are steel grade HRB335, transverse or stirrup reinforcing bars are HPB235. The plane and section of the structure are shown in Figure 3. Check seismic resistance of the axis 1 frame in transversal direction. 1. Calculate lateral seismic actions under frequent-occurring earthquake (the fundamental period of frame is 0.6sec). 2. Drawing figures of seismic force, story shear forces and moment. 3. Calculate elastic story drift and make the drift diagram All beam cross G1=6000kN All column cross G1=9000kN G1=9000kN All column cross G2=9000kN G1=10000kN Figure 3 Plane and section of the building, and the model for analysis

9 Exercise 5 seismic design of a six-story masonry building The six-story masonry, height of first story is 3.85 m (from foundation), and other story is 2.8m high. Structural plan is seen as fig 4. The floors and roof are pre-cast cored slabs. The material of the upper stories is the multi-hole brick and the grade is MU10; and the mortar grade is M10 in first story, M7.5 in second and third story, M5 in others. Dimensions of the doors and windows are seen as Fig 4. Seismic intensity is Ⅶ, and design earthquake is in group Ⅱ, at site of categoryⅡ. The representative values of gravity loads of stories are: G6= kN, G5 = kN, G4 = kN, G3 = kN, G2 = kN, G1 = kN 1. Calculation of horizontal seismic action. 2. Check seismic capacity of walls in axis 5 and between axis A and axis E. Figure 4 Structural plan of the masonry building

10 Exercise 6 seismic design of a single-story steel workshop A single-story steel workshop with one bay is located at site of categoryⅡ with design earthquake in group I. And the Seismic intensity is Ⅶ. The calculation model is shown in Fig.5. The two steel columns are same as H450*50*12*20 and the moment of inertia I=5.315*10 8 mm The steel property is Q235 with E N/mm, Please calculate the standard value of horizontal seismic action of this workshop and check the capacity of this column under frequently occurred earthquake. Figure 5 Sketch for a single story workshop with one bay