Reading Report of Tall Building Structure Major: Structural Engineering ID NO: 1130411 Name: 王瑞
1 Reading Report of Tall Building Structure Major： Structural Engineering ID NO： 1130411 Name： 王瑞
Usage of Energy Dissipation Technology in Tall Building Structure Abstract With the developing of tall building structure theory and the application of new material and new technology,the height of high-rise building is increasing and the body type is becoming more complicated,which make it hard to satisfy the seismic requirements with regular structure system only.As a method that can solve the seismic problems properly,the energy dissipation technology has been widely used in design of high-rise building.A brief introduction of energy dissipation echnology and the usage of it in tall building structures are given in this report. [Keyword]seismic design,energy dissipation technology,tall building structure 1 Introduction of energy dissipation technology The theoretical basis of energy dissipation system will be introduced through an example of single-degree of freedom system.The system is composed by a concentrated mass m in the top,a frame without mass to provide the stiffness and a viscous damper to dissipate the seismic energy.Assuming there is no axial deformation in the beams and the columns.The system is presented in Fig.1. 质量 无质量框架 粘滞阻尼器 FigI Single-degree of freedom system The differential equations of motion of this system under harmonic force is mw+c+k=sinwr The steady-state displacement response can be calculated as u(t)=u sin(wt-)=(u)R,sin(w-o) The displacement reaction coefficient can be described as
2 Usage of Energy Dissipation Technology in Tall Building Structure 【Abstract】 With the developing of tall building structure theory and the application of new material and new technology, the height of high-rise building is increasing and the body type is becoming more complicated, which make it hard to satisfy the seismic requirements with regular structure system only. As a method that can solve the seismic problems properly, the energy dissipation technology has been widely used in design of high-rise building. A brief introduction of energy dissipation technology and the usage of it in tall building structures are given in this report. 【Keyword】seismic design, energy dissipation technology, tall building structure 1 Introduction of energy dissipation technology The theoretical basis of energy dissipation system will be introduced through an example of single-degree of freedom system. The system is composed by a concentrated mass m in the top, a frame without mass to provide the stiffness and a viscous damper to dissipate the seismic energy. Assuming there is no axial deformation in the beams and the columns. The system is presented in Fig.1. Fig.1 Single-degree of freedom system The differential equations of motion of this system under harmonic force is '' ' 0 mu cu ku P wt sin The steady-state displacement response can be calculated as 0 0 ( ) sin( ) ( ) sin( ) st d u t u wt u R wt The displacement reaction coefficient can be described as
&-六-oaT0o1a可 From the equations above,the displacement reaction coefficient is becoming smaller with the increase of damping ratio or damp,which means smaller technology.We can take measures to increase the damp of the system to dissipate the seismic energy and thus reduce the dynamic response of structure The energy dissipation technology mainly includes energy dissipation devices like dampers and damping constructions like energy dissipation brace.These devices and constructions can provide additional stiffness and additional damp for the structure to dissipate the seismic energy and reduce the dynamic response under earthquake which reduce the earthquake disaster effectively.These devices can provide high stiffness under the action of wind or small earthquakes.At the same time they can turn into inelastic or yield firstly under severe earthquakes to increase the dampand dissipate the 2 Energy dissipation devices The basic idea of energy dissipation devices is that these devices won't undertake the load directly under normal circumstances but can share part of the load and dissipate the dynamic can reduce the The most common energy dissipation device in use is the damper (Fig.2). Dampers are usually installed in locations like braces,joints between beams and When earthquake happens,the damping force will do work under the relative motion caused by earthquake and dissipate the dynamic energy.This process can translate the inetic energ into heat and reduce the earthouke response The most promnn advantage of dampers is that it won't change the original structure system kind of energy dissipation devices has been widely used in seismic design in China. Fig 2 dampers in structure
3 0 2 2 2 2 0 1 ( ) 1 ( / ) 2( / ) d st n n u R u From the equations above, the displacement reaction coefficient is becoming smaller with the increase of damping ratio or damp, which means smaller dynamic response amplitude. This is the theoretical basis of energy dissipation technology. We can take measures to increase the damp of the system to dissipate the seismic energy and thus reduce the dynamic response of structure [1]. The energy dissipation technology mainly includes energy dissipation devices like dampers and damping constructions like energy dissipation brace. These devices and constructions can provide additional stiffness and additional damp for the structure to dissipate the seismic energy and reduce the dynamic response under earthquake, which reduce the earthquake disaster effectively. These devices can provide high stiffness under the action of wind or small earthquakes. At the same time they can turn into inelastic or yield firstly under severe earthquakes to increase the damp and dissipate the energy [2]. 2 Energy dissipation devices The basic idea of energy dissipation devices is that these devices won’t undertake the load directly under normal circumstances but can share part of the load and dissipate the dynamic energy under certain vertical load, which can reduce the response of the structure [1]. The most common energy dissipation device in use is the damper (Fig.2). Dampers are usually installed in locations like braces, joints between beams and columns, joints between frames and shear walls, bottom chords of trusses and so on [3]. When earthquake happens, the damping force will do work under the relative motion caused by earthquake and dissipate the dynamic energy. This process can translate the kinetic energy into heat and reduce the earthquake response. The most prominent advantage of dampers is that it won’t change the original structure system [4]. This kind of energy dissipation devices has been widely used in seismic design in China. Fig.2 dampers in structure
3 Energy dissipation constructions Energy dissipation construction is a broad concept.The main measure is to improve the energy dissipation capability by certain construction design.To achieve this purpose,we usually prefer bending energy consumption to shear energy consumption or axial energy consumption because of its full hysteresis curve.We can also design to achieve the purpose that some components can enter plastic state to dissipate the dynamic energy thus protect the main structure.Energy dissipation braces.energy dissipation shear wall,energy dissipation joints and connections are main kinds of energy dissipation construction in use. 3.1 Energy dissipation braces (1)Cross energy dissipation brace This kind of brace is based on the theory of HADAS (one kind of hysteretic dampers).It can dissipate dynamic energy through the plastic deformation of steel frames located in the cross position of the brace (2)Friction energy dissipation brace Friction dampers composed by high-strength bolts and steel plates are installed in this kind of brace.It can provide high stiffness without apparent slide under the action of wind or small earthquake.On the other hand it will slide under severe earthquake and reduce the stiffness of structure.The friction in brace can dissipate the energy and reduce seismic response of structure 51. Fig.3 The computational model for friction energy dissipation brace (3)Eccentric energy dissipation brace This kind of brace is often used in steel frame structure.It can dissipate seismic energy through the plastic deformation of eccentric beam section.The eccentric beam
4 3 Energy dissipation constructions Energy dissipation construction is a broad concept. The main measure is to improve the energy dissipation capability by certain construction design. To achieve this purpose, we usually prefer bending energy consumption to shear energy consumption or axial energy consumption because of its full hysteresis curve. We can also design to achieve the purpose that some components can enter plastic state to dissipate the dynamic energy thus protect the main structure. Energy dissipation braces, energy dissipation shear wall, energy dissipation joints and connections are main kinds of energy dissipation construction in use. 3.1 Energy dissipation braces (1) Cross energy dissipation brace This kind of brace is based on the theory of HADAS (one kind of hysteretic dampers). It can dissipate dynamic energy through the plastic deformation of steel frames located in the cross position of the brace. (2) Friction energy dissipation brace Friction dampers composed by high-strength bolts and steel plates are installed in this kind of brace. It can provide high stiffness without apparent slide under the action of wind or small earthquake. On the other hand it will slide under severe earthquake and reduce the stiffness of structure. The friction in brace can dissipate the energy and reduce seismic response of structure [5]. Fig.3 The computational model for friction energy dissipation brace (3) Eccentric energy dissipation brace This kind of brace is often used in steel frame structure. It can dissipate seismic energy through the plastic deformation of eccentric beam section. The eccentric beam
will not yield under the action of wind or small earthquake and can provide enough stiffess The brace will yield under big earthquake and dissipate energy 肉 b)单斜杆型 Fig4 Regular eccentric brace system 3.2 Energy dissipation wall Energy dissipation wall is based on the theory of dampers or install them directly on shear walls or non-bearing walls.It mainly concentrated on the construction measures to deal with the connection parts between walls and frames or the gaps between walls and frames which can control the value of shear force acted on the wall and the deformation capability.These measures can help dissipating the dynamic energy忉 Besides,buckling restrained brace is also one kind of energy dissipation widelyused.For traditional braces,the strength is much smaller than tensile strength and the buckling of braces can badly influence the stiffness,bearing capacity and the earthquake resistant behavior.Buckling restrained brace is composed of both steel and concrete to make sure that the braces will not buckle under compression force.So the compression strength is equal to the tensile strength.The ductility and hysteresis ability are also improved.This kind of braces can dissipate the dynamic energy through the yielding of steel in serious earthquake. 4 Energy dissipation structure systems Many kinds of new structure systems are designed to improve the energy dissipation capability in recent years.Some typical examples will be introduced in this part. 4.1 RC tube in tube structure with friction joints The friction joints in RC tube in tube structure is composed of frame tube,wall tube and the friction joint devices (Fig5).Certain gaps are set up in the slabs conectin the frame tub and wall tube ewhere friction joint devices are installed Under severe earthquakes,the differential movement between the frame tube and the
5 will not yield under the action of wind or small earthquake and can provide enough stiffness [6]. The brace will yield under big earthquake and dissipate energy. Fig.4 Regular eccentric brace system 3.2 Energy dissipation wall Energy dissipation wall is based on the theory of dampers or install them directly on shear walls or non-bearing walls. It mainly concentrated on the construction measures to deal with the connection parts between walls and frames or the gaps between walls and frames which can control the value of shear force acted on the wall and the deformation capability. These construction measures can help dissipating the dynamic energy [7]. Besides, buckling restrained brace is also one kind of energy dissipation constructions widely used. For traditional braces, the compression strength is much smaller than tensile strength and the buckling of braces can badly influence the stiffness, bearing capacity and the earthquake resistant behavior. Buckling restrained brace is composed of both steel and concrete to make sure that the braces will not buckle under compression force. So the compression strength is equal to the tensile strength. The ductility and hysteresis ability are also improved. This kind of braces can dissipate the dynamic energy through the yielding of steel in serious earthquake. 4 Energy dissipation structure systems Many kinds of new structure systems are designed to improve the energy dissipation capability in recent years. Some typical examples will be introduced in this part. 4.1 RC tube in tube structure with friction joints The friction joints in RC tube in tube structure is composed of frame tube, wall tube and the friction joint devices (Fig.5). Certain gaps are set up in the slabs connecting the frame tube and wall tube where friction joint devices are installed. Under severe earthquakes，the differential movement between the frame tube and the