U.S. patent application number 13/395185 was filed with the patent office on 2012-07-05 for structural protection system for buildings.
Invention is credited to Alessandro Balducci.
Application Number | 20120167490 13/395185 |
Document ID | / |
Family ID | 42174615 |
Filed Date | 2012-07-05 |
United States Patent
Application |
20120167490 |
Kind Code |
A1 |
Balducci; Alessandro |
July 5, 2012 |
STRUCTURAL PROTECTION SYSTEM FOR BUILDINGS
Abstract
A structural protection system of buildings is described,
comprising at least one bearing structure (2) connected with at
least one wall of said building (E). The bearing structure (2) is
rigidly connected to the wall of the building (E) and the bearing
structure (2) is a specialized structure comprising an energy
dissipation device (1) adapted to dissipate the energy generated by
the oscillations of the bearing structure due to earth tremor.
Inventors: |
Balducci; Alessandro; (Jesi
(AN), IT) |
Family ID: |
42174615 |
Appl. No.: |
13/395185 |
Filed: |
August 31, 2010 |
PCT Filed: |
August 31, 2010 |
PCT NO: |
PCT/EP2010/062748 |
371 Date: |
March 9, 2012 |
Current U.S.
Class: |
52/167.3 ;
52/167.4 |
Current CPC
Class: |
E04H 9/02 20130101; E04H
9/021 20130101 |
Class at
Publication: |
52/167.3 ;
52/167.4 |
International
Class: |
E04B 1/98 20060101
E04B001/98; E04H 9/02 20060101 E04H009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 10, 2009 |
IT |
MC2009A000195 |
Claims
1. Structural protection system of buildings comprising at least
one bearing structure connected with at least one wall of said
building, wherein said bearing structure is rigidly connected with
the wall of said building, and said bearing structure is a
specialized structure comprising an energy dissipation system
adapted to dissipate the energy generated by the oscillations of
the bearing structure due to earth tremor, characterized in that
the bearing structure has a base and said energy dissipation system
is arranged between the ground and the base of said bearing
structure, the base of the bearing structure being tied to the
ground by means of at least one spherical joint or hinge; wherein
said spherical joint or hinge is arranged on the vertical axis of
the bearing structure and said energy dissipation devices are
arranged in peripheral position with respect to said spherical
joint or hinge.
2. Structural system as claimed in claim 1, wherein said bearing
structure is rigidly connected to the wall of said building by
means of rigid rods having a first end connected to the wall of the
building and a second end connected to said bearing structure.
3. Structural system as claimed in claim 2, wherein that said rigid
rods are arranged according to horizontal planes in correspondence
with the floors of the building and the bearing structure provides
for reinforcement elements arranged according to horizontal planes
in correspondence with the floors of said building.
4. Structural system as claimed in claim 1, wherein the energy
dissipation system is composed of a plurality of energy dissipation
devices comprising an energy dissipation means arranged between two
rigid rods.
5. Structural system as claimed in claim 4, wherein said energy
dissipation device comprises a shock-absorbing element arranged in
parallel position with respect to the energy dissipation means.
6. Structural system as claimed in claim 1, wherein said energy
dissipation devices have a first end tied to the ground and a
second end tied to the base of said bearing structure.
7. Structural system as claimed in claim 1, wherein said energy
dissipation system comprises a lever mechanism adapted to multiply
the travel of said energy dissipation devices during the
oscillation of the bearing structure.
8. Structural system as claimed in claim 7, wherein said lever
mechanism comprises a first lever pivoted at a flange tied to the
ground and a second lever having an end pivoted at the base of the
bearing structure and a second end pivoted at the first lever, in
which the energy dissipation device has a first end pivoted at the
base of the bearing structure and a second end pivoted at the first
lever.
9. Structural system as claimed in claim 1, wherein the bearing
structure is a tower external to the building.
10. Structural system as claimed in claim 1, characterized in that
the bearing structure is a planar frame external to the
building.
11. Structural system as claimed in claim 1, wherein the bearing
structure is a tower situated inside the building.
12. Structural system as claimed in claim 1, wherein the bearing
structure is a column.
13. Structural system as claimed in claim 1, wherein said bearing
structure is composed of multiple overlapped parts tied by a
central hinge around which said energy dissipation devices are
arranged.
Description
[0001] The present patent application for industrial invention
relates to a structural system for seismic protection of buildings.
The structural system according to the invention is especially
suitable for seismic protection of existing buildings, with special
reference to buildings that play an important social role,
classified as strategic buildings (hospitals, schools, barracks,
etc.) and also of new buildings.
[0002] FIG. 1 illustrates a structural system for seismic
protection of buildings according to the prior art.
[0003] A plurality of dissipation devices (1) are installed in
building (E) to be protected, being designed to dissipate the
energy generated by the oscillations of the building due to earth
tremor. According to the different techniques, said dissipation
devices (1) are installed inside the building (E) or outside it on
the walls.
[0004] The building (E) comprises a framework of the bearing
structure. By framework we mean a frame composed of multiple floors
(S) and vertical elements (P), such as pillars or bearing walls, in
order to generate a plurality of spaces (M).
[0005] At least one dissipation device (1) is installed in each
space (M) of said framework, in bracing configuration, preferably
with diagonal direction with respect to the space (M).
[0006] Each dissipation device comprises a dissipation means (1c)
disposed between two rigid rods.
[0007] A first end (1a) of the first rod of the dissipation device
is tied to a portion of angle between the lower floor (S) of the
space and a first lateral wall of the building.
[0008] A second end (1a) of the second rod of the dissipation
device is tied to a portion of angle between the upper floor (S) of
the space and a second intermediate wall of the building.
[0009] Therefore each dissipation device (1) works autonomously and
contributes to compensate wall deformations of each space (M) of
the framework.
[0010] Such a structural system is impaired by a series of
drawbacks due to the fact that the dissipation devices (1) must be
disposed inside the building.
[0011] JP 09 235890 (Kajima Corp.) discloses a reinforcement and
vibration-damping structure for existing buildings.
[0012] The purpose of the present invention is to eliminate the
drawbacks of the prior art by disclosing a structural system that
is able to oppose the oscillations of buildings due to earth tremor
in an efficient and efficacious way.
[0013] Another purpose of the present invention is to provide such
a structural system for seismic protection of buildings that is
versatile and at the same time easy to make, install and
maintain.
[0014] These purposes are achieved according to the present
invention with the features claimed in independent claim 1.
[0015] Advantageous embodiments are disclosed in the dependent
claims.
[0016] According to the invention the building to be seismically
protected is combined with a specialized structure designed to
oppose seismic actions by dissipating energy.
[0017] In case of existing buildings, the specialized structures
can be simply installed in external position, without having to
carry out any works inside the building.
[0018] The specialized structure can consist in a tower or frame or
column with suitably rigidity, connected to the building by means
of rigid rods with two hinges normally disposed at each floor
level.
[0019] Hereinafter, for the sake of simplicity, reference will be
always made to a specialized structure that consists in a
tower.
[0020] The tower is tied at the base with a spherical joint or
hinge. Therefore, the tower is free to oscillate in any direction
around the spherical joint, rotating and pivoting on the joint
(centre of rotation).
[0021] Dissipation devices or dampers are applied around the base
of the tower, which strongly oppose the rotation and oscillation of
the tower, thus suffering movements and dissipating energy by means
of hysteresis cycles.
[0022] To amplify displacements (travel: elongation and shortening)
of the dissipation devices, suitable mechanisms that operate by
means of crank gears can be provided.
[0023] The global dissipation system, which is concentrated at the
base of the tower, can be of any type.
[0024] Therefore, the main function of the tower is to oppose the
effects produced by earth tremor by dissipating energy in the
specialized area where dissipation devices of generic type
(dampers) are installed.
[0025] The re-centering (balancing) of the tower is guaranteed by
the elasticity of the building structure and also by elastic
elements that can be connected in parallel to the energy
dissipation means.
[0026] In new buildings the tower that acts as
seismic-resistant-dissipation element can be inserted inside the
building (for example in the stairwell-elevator area). The
structural system of the invention has several advantages compared
to the known systems.
[0027] Considerable cost reduction is obtained compared to
traditional systems that are made inside the buildings and require
additional works in addition to structural works.
[0028] If the external seismic-resistant-dissipation structure is
of spatial type (tower), it can provide additional usable volume
(enlargement), no longer being an end in itself (of structural type
only) and with lower incidence of the seismic adaptation cost.
[0029] Such a seismic-resistant-dissipation structure can be, for
example, a vertical connection element (stairs, elevator) or
emergency staircase. Reference is made to the frequent installation
of steel emergency staircases outside public buildings, which can
also represent a seismic protection element if designed with the
structural system of the invention.
[0030] Maintenance of dissipation devices can be carried out
without interrupting the use of the building during maintenance
works, consequently reducing the costs caused by the temporary lack
of use.
[0031] The installation of the specialized structure can be carried
out without interrupting the ordinary use of the building to be
protected.
[0032] Dissipation devices are concentrated in a single specialized
area with limited dimensions (tower base), which is consequently
easy to inspect and maintain. For very high buildings the
specialized dissipation area can be also positioned at higher
levels, not only at the base of the tower.
[0033] The dissipation system of the invention guarantees high
efficiency, taking full advantage of the devices, and high efficacy
of the seismic-resistant devices that are concentrated in a single
specialized area compared to the known methods with devices
disseminated on the building, the operation of which is affected by
the uncertain seismic reaction of the building as a whole,
especially due to the presence of non-structural elements (walls in
general, etc.).
[0034] The rigidity of external seismic-resistant structures with
vertical development (tower, frame, column) connected by means of
rigid rods to the building is such that it regularizes the
deformation (horizontal floor displacements) of the building that
is subject to earth tremor, which is generally irregular.
[0035] Complete reversibility of the system is guaranteed because
no alterations are made to the building, as in case of internal
works.
[0036] In case of hospital or school buildings, if the structural
system of the invention has been correctly studied from an
architectural viewpoint, it can provide improved design and
improved operation with the use of additional structures (new
spaces, services, etc.). This is made possible also because of the
high formal flexibility of additional structures (for example, the
tower can have a square, rectangular, polygonal, circular, etc.
shape, can have a constant height or can be tapered
vertically).
[0037] Additional characteristics of the invention will appear
evident from the detailed description below, which refers to merely
illustrative, not limiting embodiments, illustrated in the enclosed
drawings, wherein:
[0038] FIG. 1 is a diagrammatic cross-sectional view along a
vertical plane that shows a structural system for seismic
protection of buildings according to the prior art;
[0039] FIG. 2 is a diagrammatic cross-sectional view along a
vertical plane that shows a first embodiment of the structural
system for seismic protection of buildings according to the present
invention that provides for a specialized structure with
distributed energy dissipation system;
[0040] FIG. 3 is the same view as FIG. 2, except for it shows a
second embodiment of the structural system of the invention with
specialized structure with energy dissipation system concentrated
at the base;
[0041] FIG. 4 is a plan view of the structural system of FIG.
3;
[0042] FIG. 5 is a perspective view of the structural system of
FIG. 3;
[0043] FIG. 6 is the same view as FIG. 3, except for it shows a
different version of the energy dissipation system of FIG. 3, which
provides for a lever mechanism that multiplies the travel of the
energy dissipation device;
[0044] FIG. 6A is an enlarged view of the detail contained in
circle (A) of FIG. 6.
[0045] FIG. 7 is the same view as FIG. 6, except for it shows the
oscillation of the structural system of FIG. 6 during earth
tremor;
[0046] FIG. 7A is an enlarged view of the details contained in
circles (A) and (A') of FIG. 7;
[0047] FIGS. 8 and 9 are two side elevation views that show a
different version of the structural system of the invention,
wherein the specialized structure consists in a planar frame;
[0048] FIG. 10 is a plan view of the structural systems of FIGS. 8
and 9;
[0049] FIG. 11 is a cross-sectional view along a vertical plane
that shows the specialized structure disposed as nucleus inside the
building;
[0050] FIGS. 12 and 12A are two side elevation views that show a
different version of the structural system of the invention,
wherein the specialized structure consists in a column;
[0051] FIG. 13 is a plan view of the structural system of FIG. 12;
and
[0052] FIG. 14 is a perspective view of the structural system of
FIG. 12.
[0053] Now referring to FIG. 2 a first embodiment of the structural
system for seismic protection of buildings according to the present
invention is disclosed.
[0054] The building (E) to be protected comprises a plurality of
levels defined by floors (S) disposed according to horizontal
planes. The structural system of the invention comprises at least
one bearing structure (2) rigidly connected to the building
(E).
[0055] The bearing structure (2) has basically the same height as
the building (E) and is rigidly connected to the building by means
of a plurality of rigid rods (3). The rod (3) is provided with a
first end (3a) tied to a wall of the building (E) and a second end
(3b) tied to the bearing structure (2).
[0056] Advantageously, the bearing structure (2) is provided with a
plurality of horizontal reinforcement elements (S') disposed at the
same height as the floors (S) of the building (E). Advantageously,
the rigid rods (3) are disposed according to horizontal straight
lines on the floors (S) of the building and the corresponding
reinforcement elements (S') of the bearing structure.
[0057] The bearing structure (2) is a specialized structure that
comprises an energy dissipation system adapted to dissipate the
energy of the oscillations suffered by the bearing structure (2)
due to earth tremor.
[0058] It must be noted that the specialized structure (2) is
rigidly connected to the building (E). Therefore the energy
dissipation system of the specialized structure is able to
compensate and damp also the oscillations suffered by the building
(E) during the shocks.
[0059] According to the embodiment of FIG. 2, the specialized
structure (2) is a tower disposed outside the building (E) and the
horizontal reinforcement elements are floors (S') of the tower
disposed between a first vertical wall (2a) facing the building (E)
and a second vertical wall (2b) opposite the first vertical wall
(2a). In this way a vertical row of parallelepiped spaces (V) is
defined in the tower (2).
[0060] One dissipation device (1) is disposed in each space (V) of
the tower (2), in bracing configuration, diagonally, in such a way
to generate an energy dissipation system of the specialized
structure (2) distributed along the entire height of the
specialized structure.
[0061] The dissipation device comprises an energy dissipation means
(1c) disposed between two rigid rods. The energy dissipation means
(1c) can be, for example, a chamber with fluid. A shock-absorbing
element, such as elastic means, spring means or damper can be
disposed in parallel position to the energy dissipation means
(1c).
[0062] In each space (V) the dissipation device (1) comprises:
[0063] a first end (1a) tied to a portion of angle between the
lower floor (S') of the space (V) and the first lateral wall (2a)
of the tower, and [0064] a second end (1a) tied to a portion of
angle between the upper floor (S') of the space (V) and the second
lateral wall (2a) of the tower.
[0065] In the following description identical elements or elements
corresponding to elements that have already been described are
indicated with the same reference numerals, omitting their detailed
description.
[0066] FIGS. 3-5 describe a second embodiment of the structural
system of the invention, wherein the dissipation system is
concentrated at the base of the tower (2).
[0067] In such a case, the base of the tower (2) is tied to a
spherical joint or hinge (4) mounted on a base (B) fixed to the
ground. The vertical axis of the tower (2) passes through the
centre of the spherical joint (4).
[0068] A plurality of dissipation devices (1) is disposed in
peripheral position around the spherical joint (4). Each
dissipation device (1) is provided with a first end (1a) tied to
the base (B) and a second end (1b) tied at the base of the tower.
Advantageously, the tower (2) has a base (20) shaped as overturned
pyramid, wherein the vertex of the pyramid is tied to the spherical
joint (4).
[0069] As shown in FIG. 4, to protect the rectangular building (E),
two specialized structures (2) are sufficient, being disposed in
the long opposite sides of the building, near the opposite angles
of the building.
[0070] The connection system of the tower (2) to the building (E)
comprises four rigid rods (3) in each floor, disposed in
W-configuration with three connection hinges (3a) on the building
(E) and two connection hinges (3b) on the tower.
[0071] As shown in FIG. 5, each tower (2) is damped by eight
dissipation devices (1) disposed at the four angles of the tower
base and along the central lines of the four sides of the tower
base.
[0072] Referring to FIGS. 6, 6A, 7 and 7A, a different version of
the energy dissipation system is described.
[0073] As shown in FIG. 6A, according to this version, each
dissipation device (1) is connected to a lever mechanism (5) to
multiply the travel of the dissipation device (1), i.e.
elongation/shortening of the dissipation device (1) to compensate
the oscillation of the tower (2).
[0074] The lever mechanism (5) comprises two levers (L1, L2). The
first lever (L1) is pivoted in the central point (F1) to a
projection (51) of a flange (50) tied to the base (B). The second
lever (L2) has a first end (La) pivoted at a projection of a flange
(52) tied to the base (20) of the tower and a second end (Lb)
pivoted at one end of the first lever (L1).
[0075] The dissipation device (1) has a first end (1a) pivoted at a
projection of the flange (52) tied to the base (20) of the tower
and a second end (1b) pivoted at the other end of the first lever
(L1).
[0076] In idle state the dissipation device (1) is basically as
long as the second lever (L2) and parallel to the second lever (L2)
in such a way that first lever (L1), second lever (L2), flange (52)
and dissipation device (1) form an articulated quadrilateral that
can oscillate around the fulcrum (F1).
[0077] Referring to FIGS. 7 and 7A, when the building (E) suffers
oscillation due to earth tremor, also the tower (2) that is rigidly
tied to the building (E) suffers oscillation with horizontal
displacement (.delta..sub.o) of the top of the tower. Consequently,
the base (20) of the tower suffers a vertical displacement
(.delta..sub.v) that must be damped and compensated by the
dissipation devices (1).
[0078] If Li is the length of the dissipation device in idle state
and Lf is the length of the dissipation device after compression or
elongation due to oscillation of the tower, the travel of the
dissipation device is determined by the relationship:
.delta..sub.D=|Li-Lf|
[0079] The travel (.delta..sub.D) of the dissipation device is
related to the lever mechanism (5) and vertical displacement
(.delta..sub.v) of the tower base.
(b1) is the distance between the fulcrum (F1) of the first lever
(L1) and the fulcrum (Lb) of the second lever (L2) with the first
lever (L1). (b2) is the distance between the fulcrum (F1) of the
first lever (L1) and the fulcrum (1Lb) of the dissipation device
(1) with the first lever (L1).
[0080] As shown in FIG. 7A, the travel of the dissipation device is
determined by the relationship:
.delta..sub.D=|Li-Lf|=.delta..sub.V*(1+b2/b1)
[0081] If the fulcrum (F1) is in the centre of the first lever
(L1), i.e. (b1=b2), the travel of the dissipation device is:
.delta..sub.D=2*.delta..sub.V
[0082] The elongation or shortening of the dissipation device (1)
will be twice as the vertical displacement (.delta..sub.V) of the
base (20) of the tower.
[0083] Referring to FIGS. 8, 9 and 10, a different version of the
structural system of the invention is disclosed, wherein the
specialized structure is a planar frame (102) composed, for
example, of a reticular framework.
[0084] Also in this case, the dissipation devices (1) can be
disposed at the base of the frame (102). The frame (102) is tied to
the ground by means of a planar hinge (104) instead of a spherical
joint.
[0085] As shown in FIG. 10, to protect a rectangular building, four
frameworks (102) are necessary, being disposed in the four sides of
the building.
[0086] FIGS. 3, 5, 6, 7, 8 and 9 show five-story buildings and
specialized structures (2; 102) provided with energy dissipation
system concentrated only at the base of the structure.
[0087] However, in case of taller buildings, each specialized
structure can be made of multiple overlapped parts that are
mutually tied by means of a central hinge around which the
dissipation devices are disposed. The connection between the
various parts of the bearing structure is exactly made as the
connection of the base of the bearing structure to the ground.
[0088] Referring to FIG. 11, if a new building (E) is built, the
specialized structure (202) can be the nucleus of the building,
that is to say a tower inside the building that is rigidly
connected to the internal walls of the building.
[0089] In such a case, the tower (202) is provided with a
specialized energy dissipation system, such as the systems
described in the aforementioned embodiments.
[0090] Referring to FIGS. 12 12A, 13 and 14, a different version of
the structural system of the invention is described, wherein the
specialized structure is a column (302).
[0091] Also in this case, the dissipation devices (1) can be
disposed at the base of the column (302). The column (302) is
anchored to the ground by means of a spherical joint (4).
[0092] FIG. 12 A shows an embodiment of the present invention in
which the base of the column (302) is a horizontal plane under
which the dissipation devices (1) and relevant multiplier lever
mechanisms (5) are mounted.
[0093] As shown in FIGS. 13 and 14, to protect a rectangular
building, five columns (302) are necessary, being disposed in a row
on the two long sides of the building. The columns (302) are
mutually connected by means of rigid rods (303).
[0094] Numerous variations and modifications can be made to the
present embodiments of the invention by an expert of the field,
while still falling within the scope of the invention as claimed in
the enclosed claims.
* * * * *