GB2264516A

GB2264516A - Earthquake-resistant structure

Info

Publication number: GB2264516A
Application number: GB9204113A
Authority: GB
Inventors: Chit-Sun Cheong; Jian-Heng Lu
Original assignee: LU JIAN HENG; CHINESE BUILDING TECHNOLOGY SE; Chinese Building Tech Services Corp Ltd
Current assignee: LU JIAN HENG; CHINESE BUILDING TECHNOLOGY SE; Chinese Building Tech Services Corp Ltd
Priority date: 1992-02-26
Filing date: 1992-02-26
Publication date: 1993-09-01
Also published as: GB9204113D0

Abstract

An earthquake-resistant high-rise structure has horizontally placed sliding plates 1 to divide the super-structure into a plurality of independent rigid structures Rs, each of which is connected to its upper or lower independent rigid structure with long bolts 3 and nuts 2. The recess/hole for the long bolts is filled with rubber filler which acts as a buffer elastic isolator. Further, elastic recovery devices such as steel springs are installed between each independent rigid structures Rs and the rigid core structure which can be in the form of a lift shaft, or shear wall. <IMAGE>

Description

METHOD AND DEVICE OF EARTHQUAKE RESISTANT & NERGY REDUCTION FOR HIGH-RISE STRUCTURES FIELD OF THE INVENTION This invention relates the method and device of earthquake resistant and energy reduction for high-rise structures (hereafter termed as MDERER). The method and device fall within the scope of the building or civil engineering. It is applicable to multi-storey and high-rise buildings or any other type of high-rise structures. Its main function is to resist or absorb earthquake energy while the structure is under earthquake loading and to reduce energy while the structure is under horizontal loading (e.g. wind load).In general, the invention reduces energy through friction generated from relative movements whilst the structure is subjected to any type of superimposed horizontal loading.

BACKGROUND OF THE INVENTION A building usually consists of three major portions i.e. the foundation, the sub-structure and the super-structure. All loading of the building transfers from the super-structure to the sub-structure and eventually to the foundation. When the traditional high-rise building is under earthquake loading or wind loading, the dynamic response of the high-rise building will have the following behaviour: l.When the structure is under earthquake loading only, the resonance effect due to the dynamic response and the interaction of the super-structure, the sub-structure, the foundation and the foundation soil produces an exceptionally large shear to the structure and causes damage or even failure.The structure fails, in accordance with many studies, due to inadequate connection between the super-structure and the sub-structure, and/or betwwen the sub-structure and the foundation, and/or failure of subsoil.

2.When the structure is under wind loading, the accumulated wind load induces very large shear force to the structure. The structure is required to be very rigidly designed to withstand the strong shear induced.

3.When the structure is under both earthquake and wind loading, the resonance effect will induce extremely large shear.

It is generally noted that it is virtually impossible to analyse the stress distribution diagram for case 1 and 3.

However, the stress distribution for case 2 can be determined.

It is, therefore, necessary for contemporary design of the high-rise structure to be in a very rigid state and consequently increase the building investment.

Mr. Lu Jien-heng, one of the inventors of the MDERER, has disclosed the "Building Earthquake Resistant Device (BERD)" (China Patent Application No. 87100151.9) and the "Building Earthquake Elimination Device (BEED)" (China Patent No.

1036424). The BERD and BEED are devices used to increase earthquake resistance in respect of a sub-structure and foundation. However, the BERD and BEED have no energy reduction effect when the super-structure is subjected to horizontal loading. The cross sectional area of the structural components and the amount of reinforcement increase with the increase of the total height of the structure. It is necessary to resolve the earthquake resistance and the enery reduction problem for the multi-storey building or high-rise structure so as to reduce the complexity of the stress distribution and subsequently reduce the building investment.

The object of this invention is to resolve the above mentioned problems and provide a method and device to resist earthquakes and reduce energy for all kinds of high-rise structures.

SUMMARY OF THE INVENTION The method of this invention is to divide the super-structure into two or more independent rigid structures that vertically interact with each other by using one or a plurality of sliding plate(s). Any two adjacent independent rigid structures shall be connected by means of long bolts at a number of locations.

Washers shall be placed between the independent rigid structure and the long bolts or nuts. An additional resilient liner shall be placed between the independent rigid structure and the nut. The clearance between the bolt and the recess hole (for placing the bolt) shall be closely filled with buffer elastic isolators.

Further, the core structure i.e. the shear wall, the lift shaft or any other similar structure shall be designed as an integral rigid structure and shall not be divided by the sliding plate.

Elastic recovery devices shall be installed between the independent rigid structures and the core structure. These devices shall be used to absorb part of the energy and to assist the independent rigid structures to recover to their original position.

The device of this invention is characterized in that it includes one or a plurality of sliding plate(s), a plurality of long bolts, a plurality of nuts, a plurality of washers, a plurality of resilient liners, a plurality of buffer elastic isolators and a plurality of elastic recovery devices.

The said sliding plate(s) is(are) used to divide the structure into two or more independent rigid structures. The said independent rigid structure is connected to its vertically adjacent (upper or lower) independent rigid structure by means of long bolts and nuts The said long bolts and nuts shall be complete with washers. The said buffer elastic isolators shall be placed between the long bolt and the independent rigid structure at the recess hole for the bolt.The clearance between the bolt and the recess hole shall be closely filled with buffer elastic isolators. The said elastic recovery device shall be installed between the core structure and the independent rigid structures.

The said sliding plate shall be made with high strength PTFE or any other anti-corrosive high-strength material. The washer shall be a rubber washer or of any other similar material like nylon, etc. The said buffer elastic isolators shall be of rubber or any other similar material. The said elastic recovery device shall be a steel spring or of any other material having a similar character.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A detailed description of the MDERER now will be illustrated with reference to the following drawings.

Fig. 1 shows the elevation (front view) of a high-rise building using the device of the present invention.

Fig. 2 is the elevation (cross sectional) view of the high-rise building showing parts of the device of the present invention.

Fig. 3 shows the elevation and the cross section of a high-rise building that is build with a core structure. It also shows elastic recovery devices that are installed between the core structure and the independent rigid structures.

Fig. 4 is;a top view corresponding to Fig.3.

Fig. 1 shows the high-rise building employing the device of the present invention. The sliding plates defined as part of the device divide the entire structure into four independent rigid structures Rsl, Rs2, Rs3 and Rs4. These four independent rigid structures form the superstructure of the building. The building also includes the sub-structure 4 that transfers the horizontal loading to the foundation 5.

Fig. 2 shows that there are two vertically interacted independent rigid structures Rsi and Rs(i+l). Between these two structures, parts of the device of the present invention, i.e. the sliding plate 1, long bolts & nuts 2, and the buffer elastic isolators 3, for example, rubber fillers, are installed.

Fig. 3 shows a typical core structure which is designed to take the residual horizontal loading from the independent rigid structure after part of the horizontal loading energy is released through relative movement between the independent rigid structures. The core structure 7 can be a lift shaft, shear wall or any other similar structure. The elastic recovery devices, which are parts of the device of the present invention, are installed between the core structure and the independent rigid structures which are divided as shown in FIG.1. The sliding plate can be made with high strength PTFE and can also be made with any other anti-corrosive highstrength material.

The core structure is one of the essential elements of the device of the present invention. As illustrated in Fig. 3, the core structure can be in the form of a lift shaft, a shear wall or any other similar structure within the building. The core structure must be rigidly designed as an integral unit and shall not be divided by any sliding plate. In order to absorb the horizontal loading energy and provide the recovery effect, elastic recovery devices shall be installed between the core wall and the independent rigid structures. One end of the elastic recovery device shall be anchored into the wall of the core structure and the other end anchored into the independent rigid structure. As shown in Fig. 3, the elastic recovery devices 6 are connected to the core wall 7 and also to the independent rigid structure Rsi.The elastic recovery devices can be made by steel spring or any other elastic material that can provide the similar effect.

When a high-rise structure is subjected to horizontal loading e.g. wind load, each independent rigid structure has a tendency of incurring relative movement between the adjacent independent rigid structures. Any movement incurred will induce friction and hence part of the energy will be released. When movement of the independent rigid structures continues, buffer elastic isloators, e.g., the rubber filler, will be compressed and the long bolts will be subjected to bending which again will absorb part of the remaining energy. All the horizontal loads that act upon the independent rigid structures will be transferred into energy and released through friction loss when there is relative movement between the independent rigid structures or stored as potential energy when the rubber filler is compressed or the long bolts are bent.Due to the fact mentioned-above, the oscillation of the high-rise building will be reduced to a minimum.

The high-rise structure that employs MDERER differs fundamentally in its mechanical response from the conventional high-rise structure. The conventionally designed structure restrains the energy generated from the horizontal loading acting upon the structure, therefore the structure has to be very rigidly build. A small portion of the energy can be released through oscillation of the building and the remaining energy restrained within the structure and transferred to the foundation. When the horizontal force continues to be applied to the structure, like earthquake loading, the resonance effect will cause failure to the structure. This newly developed method and device i.e. the MDERER releases the energy generated from horizontal loading and reduces the possibility of damage to the structure.

The main function of the MDERER is achieved through the following: -the sliding plate(s) 1 as shown in Fig. 1 divide(s) the structure into a plurality of independent rigid structures and allow each independent rigid structre to have relative movement so as to release energy through friction loss; and -the long bolts and nuts 2 as shown in Fig. 2, the buffer elastic isolators 3 as shown in Fig. 2 and the elastic recovery device 6 shown in Fig.3 also absorb (reduce) part of the energy.

The thickness of the sliding plates are determined in accordance with the loading of each independent rigid structure.

The diameter and the material used for the long bolts and the thickness of the buffer elastic isolator, e.g. the rubber filler and the rigidity of the elastic recovery devices are main factors in considering the ability in absorbing the energy. These factors are determined according to the horizontal loading taken by each independent rigid structure and the permissible relative movement of each independent rigid structure. As each independent rigid structure is structurally independent, the stress distribution of each independent rigid structure, when subject to external loading, depends upon the layout and the size of the structure's members and also depends upon the number and the layout of the bolts. Hence the design of the independent rigid structures is simplified and each independent rigid structure can have a different layout as required. Further, the bolts transfer only vertical loads to the next independent rigid structure and no bending is required to be considered, this makes the stress distribution within the entire structure very simple. The utilization of the columns becomes more effective and reduces the dead weight of the structure. Also, structural analysis becomes simple and accurate and the behaviour of the structure can be predicted.

The device of the present invention is applicable to any type of high-rise structure or multi-storey building. The device can be used in conjunction with the BEED and BERD which are patented in China and will increase the ability of the structures to resist earthquake and wind load.

Claims

Claim

l.An earthquake resistant and energy reduction method that is applicable to multi-storey buildings, high-rise buildings or any other high-rise structures, characterized in that one or a plurality of sliding plate(s) are used to divied the superstructure into two or more independent rigid structures that interact vertically with each other, that any two adjacent independent rigid structures shall be connected by long bolts at a number of locations, that washers shall be placed between the independent rigid structures and the long bolts and nuts, additional resilient liner is placed between the independent rigid structure and the nut, and that the clearance between the bolt and the recess hole (for placing the bolt) shall be closely filled with buffer elactic isolators.
2.The earthquake resistant and energy reduction method as claimed in claim 1, characterized in that the core structure of said high-rise structure, which can be in the from of lift shaft or shear-wall or any other type of similar structure is designed as an integral rigid structure that bears the horizontal loading and is not divided by sliding plate(s).
3.The earthquake resistant and energy reduction method as claimed in claim 2, characterized in that the elastic recovery devices are installed between said core structure and said independent rigid structures, one end of the device is connected to said core structure and the other end to said independent rigid structure.
4.The earthquake resistant and energy reduction method as claimed in claim 3, characterized in that said elastic recovery device comprises a steel spring or any other elastic material made into a device that has the similar function of the spring.
5.An earthquake resistant and energy reduction device applicable to multi-storey buildings, high-rise building or any other type of high-rise structures, characterized in that said device includes one or a plurality of sliding plate(s), a plurality of long bolts, a plurality of nuts, a plurality of washers, a plurality of resilient liners, a plurality of buffer elastic isolators and a plurality of elastic recovery devices, said sliding plate(s) dividing the structure into two or more independent rigid structures, said independent rigid structures being connected to its vertically adjacent (upper or lower) independent rigid structures by means of long bolts and nuts, said bolts and nuts having washers and resilient liners being added at the nut end, the clearance between said long bolt and the recess hole of said independent rigid structures being filled with buffer elastic isolators, said elastic recovery devices being installed between said independent rigid structures and said core structure.
6.The earthquake resistant and energy reduction device as claimed in claim 5, characterized in that said sliding plate is made of high strength PTFE
7.The earthquake resistant and energy reduction device as claimed in claim 5, characterized in that said sliding plate is made of any other anti-corrosive high strength elastic material.
8.The earthquake resistant and energy reduction device as claimed in any of claim 1-7, characterized in that said liner is made of rubber or any other kind of elastic material e.g.

Nylon.
9.The earthquake resistant and energy reduction device as claimed in any of claim 1-7, characterized in that said buffer elastic isolator is made of rubber or any other kind of material that has high elastic property e.g. Nylon.
1O.The earthquake resistant and energy reduction device as claimed in any of claim 5-7, characterized in that said elastic recovery device is made of steel spring or any other type of elastic material made into the device that has the similar function of a spring.
ll.An earthquake resistant and energy reduction method that is applicable to a high rise structure comprising: at least two adjacent independent rigid structures and connecting means for interconnecting any two adjacent structures so as to permit relative movement therebetween.
12.An earthquake resistant and energy reduction method as in claim 11 wherein the connecting means comprises at least one linkage attachable to each structure.
13.An earthquake resistant and energy reduction method as in claims 11 and 12 wherein the connecting means comprises at least one rigid linkage connected to each structure on resilient buffer members.
14.An earthquake resistant and energy reduction method as in claim 11 or claim 12 including at least one resilient isolating member disposed in a recess found in the structure and surrounding each connecting means.
15.An earthquake resistant and energy reduction method as in claims 11 to 14 wherein the connecting means is a bolt.
16.An earthquake resistant and energy reduction method as in claim 11 wherein two adjacent structures are separated by one or more sliding plates made of an anticorrosive high strength elastic material.
17.An earthquake resistant and energy reduction method as in claim 11 including a core structure constituting an integral rigid structure that bears loading in the direction of movement of the plates.
18.An earthquake resistant and energy reduction device which is applicable to a high rise structure comprising at : least two adjacent independent rigid structures and connecting means for interconnecting any two adjacent structures so as to permit relative movement therebetween.
19.An earthquake resistant and energy reduction device as in claim 18 wherein the connecting means comprises at least one linkage attachable to each structure.
20.An earthquake resistant and energy reduction device as in claims 18 and 19 wherein the connecting means comprises at least one rigid linkage connected to each structure on resilient buffer members.
21.An earthquake resistant and energy reduction device as in claim 18 or 19 including at least one resilient isolating member disposed in a recess found in the structure and surrounding each connecting means.
22.An earthquake resistant and energy reduction device as in claims 18 to 21 wherein the connecting means is a bolt.
23.An earthquake resistant and energy reduction device as in claim 18 wherein two adjacent structures are separated by one or more sliding plates made of an anticorrosive high strength elastic material.
24.An earthquake resistant and energy reduction device as in claim 18 including a core structure constituting an integral rigid structure that bears loading in the direction of movement of the plates.
25.A high-rise structure comprising at least two adjacent independent structures, and connecting means for interconnecting any two adjacent independent structures so as to permit relative movement therebetween.