Advance earthquake resistance techniques project

ADVANCED EARTHQUAKE RESISTANT TECHNIQUES
Page | 1
INTRODUCTION
Throughout history, we've built impressive structures and cities only for them to
encounter the forces of nature. Earthquakes are one of the Earth's most destructive forces-
the seismic waves throughout the ground can destroy buildings, take lives, and costs
tremendous amounts of money for loss and repair. According to the National Earthquake
Information Center, there is an average of 20,000 carthquakes each year September 20,
2017, a magnitude 7.1 rocked Mexico's capital city and killed approximately :-16 of them
being major disasters. On 230 people. As with the case with other earthquakes, the
damage was not caused by the quake itself but by the collapse of buildings with people
inside them, making earthquake-proof buildings a must.Over the past few decades,
engineers have introduced new designs and building materials to better equip buildings to
withstand earthquakes. Read on to learn how earthquake-proof buildings are designed
today

Page | 2
How earthquakes impact buildings
1. Create a flexible foundation
 Strong foundation for an earthquake resistant home
 Designing from the ground down
 Designing foundation to suit the risk
 Large steel reinforced floating slabs
 Steel reinforced grade beam slabs
 Pinned to stable rock formation
2. Counter forces with damping
 Vibrators forces with damping
 Pendulum power
 Damping effect on structural response
 Types of dampers
3. Shielding in buildings
 Electromagnetic shielding
 Lionizing radiation shielding
 Radiation shielding with high density concrete
 Radiation protection in buildings
 Radiation shielding for construction
 Radiation shielding walls
 Radiation shielding doors
 Radiation shielding windows
4. Reinforce the building’s structure
 Earthquake resistant materials
 Innovative materials
 What is a shear wall and how does it protect your buildings?
 When are shear wall required?
 Shear wall v/s load-bearing wall

Page | 3
How earthquakes impact buildings
Before we look at the features, it’s important to understand how earthquakes impact man-made
structures. When an earthquake occurs, it sends shockwaves throughout the ground in short rapid
intervals in all different directions. While buildings are generally equipped to handle vertical forces
from their weight and gravity, they cannot handle side-to-side forces emitted by quakes.
This horizontal load vibrates walls, floors, columns, beams and the connectors that hold them together.
The difference in movement between the bottom and top of buildings exerts extreme stress, causing the
supporting frame to rupture and the entire structure to collapse.
How to make a building earthquake proof
 Placement of shear wall
 Shear wall material
 Shear wall construction with steel plate and wood
 Types of lateral force-resisting systems in commercial buildings
 Moment frames
 Braced frames

Page | 4
To design an earthquake-proof building, engineers need to reinforce the structure and counteract an
earthquake’s forces. Since earthquakes release energy that pushes on a building from one direction, the
strategy is to have the building push the opposite way. Here are some of the methods used to help
buildings withstand earthquakes.
1. Create a flexible foundation
One way to resist ground forces is to “lift” the building’s foundation above the earth. Base isolation
involves constructing a building on top of flexible pads made of steel, rubber, and lead. When the base
moves during the earthquake, the isolators vibrate while the structure itself remains steady. This
effectively helps to absorb seismic waves and prevent them from traveling through a building.
Strong Foundations For An Earthquake Resistant Home

Page | 5
Unfortunately earthquakes are a part of life in New Zealand. Geonet estimates that there are around 250
earthquakes felt each year. Most are small enough to cause very little damage, however there are
unexpected large quakes which can be extremely damaging.
For the health and safety of the population, lessons about house and building design need to be learnt
from the earthquakes of the past, especially the big event in Christchurch, and more recently Kaikoura.
These big event quakes can also show seismic engineers which technologies are effective in the event of
earthquake.
When structural engineers and architects design buildings, either high rise or residential houses within a
seismically active area, they design with two key goals. The number one priority, is to keep the building
intact long enough to allow the occupants to escape to safety, in the event of a major earthquake. A
secondary priority of the design, is to enable the structure to remain functional and habitable if a small
earthquake strikes.
Designing from the ground down
As most buildings sit on foundations, which contact the earth, the design, preparation and construction
of a building’s foundation is of prime importance within a seismic region. Experience has shown that
the ground works for a building, can contribute to a building surviving a quake. If a building is
constructed on loose or filled-in soil, there is more likelihood of it sliding off its foundation. When it is
constructed on solid, firm ground or even better bedrock, a structure is more likely to remain intact
through an earthquake.
Before constructing a building’s foundations, it is important to prepare the ground surface. Removing
any loose soil, and digging down onto firm compacted soil is a basic level of preparation. If there is a
risk of a moderate earthquake, sinking piles onto solid bedrock, will provide the structure with more
stability.

Page | 6
Designing foundations to suit the risk
Depending on the level of seismic activity, within a region, there are a number of foundation styles
which may be used. There are four basic types of foundation used in earthquake prone areas. Ranging
from the basic floating slab, through to deep piled structures. The decision of which one to use, should
be made in conjunction with an architect after studying the regional building code. As expected, the
construction costs increase with the level of complication, and security.
Large steel reinforced floating slabs
This is often the standard type of flooring in brick, and often timber framed modern buildings. It
consists of a footing under the load bearing walls, ideally the footings should extend in depth to exceed
the frost depth for the area. Then a foundation wall, which is poured around the entire foot print of the
building. Once this wall is set, a large steel reinforced slab of concrete, which covers the entire floor
area of the structure is created. Each stage of the construction needs to set and cure, before the next
section is poured, this curing time is usually about a week.

Page | 7
Steel reinforced grade beam slabs
In areas where more earthquake activity may occur it is possible to provide greater reinforcement to a
slab floor, to provide more anchorage, and more stability to the structure. After the foundation of the
floor is cured, a structural steel or steel reinforced concrete sill is created to provide additional support to
the flooring of the building. These grade beam foundations work very well on houses with non-
traditional footprints, like hexagonal structures. The size and design pattern of the graded beams will
need to be calculated by an architect, based on the structure, and the level of the earth movement
anticipated in the geographical region. Although more expensive than a floating slab, it is cheaper than
the more expensive ground work options.
Pinned to stable rock formations
Where greater stability is required due to frequent or moderate sized earthquakes, it is essential to pin
the foundation of the house to a stable rock formation. This is achieved by locating, a bedrock
formation, and building the footings directly onto the rock. Where the depth is too great to clear the
overriding soil, sink the reinforced concrete piles onto the rock base, then build the footings of the house
or other structure on the footings, to achieve a stable and strong build.
Deep anchored pedestal structures

Page | 8
In areas with high seismic activity, structures require high levels of stability. This stability is achieved
by developing a deep anchored foundation with a small foot print, and then building the house on a
pedestal. Reinforced piles are driven or poured, to a great depth, to anchor the structure into the ground.
Instead of creating a footing for the entire footprint of the building, a very strong, reinforced and
compact pedestal is built above the surface of the ground. This pedestal, then supports the entire
structure, through the central core. The floor, walls and the roof are all anchored to the central pedestal,
producing a very stable structure.
About foundation of earthquake-resistant building
 it is necessary to reduce the connections of foundations with the soil – the source of seismic
effects;
 side faces of the foundations in contact with the soils accumulate (contribute to an increase the
value) horizontal seismic effects on the foundation, leading to its displacement. In this
connection, it is advisable leave an air gap to reduce these effects;
 reducing friction between the base of the foundation and the soils reduces the transmission of
horizontal seismic effects on the foundation and at exceeding of the friction resistance
contributes to the slippage of the seismic wave under the foundation;
 protection of the foundation by a trench is effective and depends on the depth, size and location
of the trench closer to the building, from wave length, type of foundation.
It is known, a foundation is the supporting part of a structure that transmits the loads from the structure
to the foundation soils. Due to seismic loading, foundations can experience a reduction in bearing
capacity and increase in settlement. Two sources of loading must be taken into consideration: inertial
loading caused by the lateral forces imposed on the structure, and kinematic loading caused by the
ground movements developed during the earthquake.
Generally, a properly designed and performing foundation system should
 support the mass of the structure without excessive settlement;
 transfer large lateral earthquake loads between the structure and the ground
 resist earthquake - induced overturning forces;
 resist both transient and permanent ground deformations without inducing excessive

Page | 9
 displacements in the structure or in-plane distortions in elements supported by the structure.
A design earthquake is a theoretical earthquake event that modern building designers use to check the
resilience of a new structure. It is impossible to create a completely earthquake-proof structure.
However, a building may be engineered to withstand a design earthquake or at least behave in a
predictable way if a design earthquake should occur. The above discussion suggests that there are many
aspects which require research and development efforts, especially in order to achieve optimal designs.
A degree of seismic resilience can be achieved by applying a sound understanding of structural
engineering and construction principles to the structural elements and system that make up the building.
2. Counter Forces with Damping
You might be aware that cars have shock absorbers. However, you might not know that engineers also
use them for making earthquake-resistant buildings. Similar to their use in cars, shock absorbers reduce
the magnitude of shockwaves and help buildings slow down. This is accomplished in two ways:
vibrational control devices and pendulum dampers.
Vibration control devices
The first method involves placing dampers at each level of a building between a column and beam. Each
damper consists of piston heads inside a cylinder filled with silicone oil. When an earthquake occurs, the

Page | 10
building transfers the vibration energy into the pistons, pushes against the oil. The energy is transformed
into heat, dissipating the force of the vibrations.
Pendulum power
Another damping method is pendulum power, used primarily in skyscrapers. Engineers suspend a large
ball with steel cables with a system of hydraulics at the top of the building. When the building begins
the sway, the ball acts as a pendulum and moves in the opposite direction to stabilize the direction. Like
damping, these features are tuned to match and counteract the building’s frequency in the event of an
earthquake.
Damping Effect on Structural Response
Damping increasing reduces structural response ( acceleration and displacement) damping effect at low
frequency (close to zero) have no effect on spectrum amount and at high frequency, it has low effect on
response acceleration. Figures 1 and 2 show the most effect of damping increasing in the frequency of
0.3 to 2.5 seconds.

Page | 11
Types of Dampers
Dampers are classified based on their performance of friction, metal (flowing), viscous, viscoelastic;
shape memory alloys (SMA) and mass dampers. Among the advantages of using dampers we can infer
to high energy absorbance, easy to install and replace them as well as coordination to other structure
members.(journal,2006).
Friction Dampers

Page | 12
In this type of damper, seismic energy is spent in overcoming friction in the contact surfaces. Among
other features of these dampers can be classified as avoiding fatigue in served loads(due to the non-
active dampers under load) and their performance independent to loading velocity and ambient
temperature. These dampers are installed in parallel to bracing (journal,2006).
In figure , rotational friction dampers are shown. Because of very simple behavior and easy to install
and make, this type of damper is converted to one the most common types of friction dampers.(
Warn,2004)

Page | 13
PVD Damper
It is another type of friction damper and due to ease to installation, is one of the most widely used
damper in structures( Warn,2004). PVD damper can be used to create necessary damping for flexible
structures, such as bending steel frame or to provide effective damping to relative stiffness of
structures(Naeim,1995). PVD damper is designed to installation where displacement can generate
necessary damping such as installation of metal skeleton brace or concrete moment frame.
The first building which was designed by Iranian designer and by using PVD damper of Robinson
company and it was a building with private owner in and with 164/5 squares meters area and it will be
built in 6 floors. This building is located in Rey. The floor is about 112 square meters. And its main
skeleton is a type of steel and screws and nuts type. In this building, the retrofitting new technology is
used for earthquake called seismic dampers system. The numbers of PVD dampers are 12 damper of
100 KN. Another high-rise building was designed in northern Tehran with 19 dampers of 350, 600, 850
KN PVD of Robinson company by another designer which are in ordering stage.

Page | 14
In equipment and dependent dampers on the lead such as lead rubber bearings and lead dampers which
are used as the best and most successful protective equipment for different structures against earthquake.
And they are invented in New Zealand country by Rabinson company at DSIR physics and engineering
laboratory. And they have been used as the best dampers extensively in last 30 years. PVD damper are
designed based of lead plastic deformation such as lead rubber bearing. For rubber lead bearing, the
created damping force by lead is less than elastic force related to rubber, while for PVD, damping force
of lead is much greater than rubber elastic force. Now, PVd is used as an effective damper on many
bridges, towers, buildings. The advantages of PVD damper include(Hwang et al.,1994):
1. PVD damper acts effectively on low displacements. For example, one 1MN PVd damper can acts
effectively for 0.5 mm to 5 mm displacement.
2. PVD damper requires no maintenance and does not have any lubrication or winder components.
3. PVD damper behavior is like the behavior of a metal damper.
Pall Friction Damper
Another type of friction damper is Pall friction damper. (figure 1-2-1-2). This damper includes a bracing
and some steel plate with friction screws. And they should be installed in the middle of bracing. Steel
sheets are connected to each other by high strength bolts and they have a slip by a certain force, to each
other.

Page | 15
Metallic Dampers (submission)
In this damper, transferred energy to the structure is spent to submission and non-linear behavior in used
element in damper. In these dampers, metal inelastic deformation is used such as for formability metals
such as steel and lead for energy dissipation. In all conventional structures, energy dissipation is based
on deformation of steel members after the submission.
In braces, using submission metallic dampers is more common. These dampers are often created by
some parallel steel plates. And in combination with a bracing system, they undertake the role of

Page | 16
absorption and energy dissipation. This part of bracing can acts as a fuse in structure. And by focusing
on nonlinear behavior prevent non-linear behavior and damage in other major and minor structure parts.
X-shaped metal dampers have a significant performance. Massive submission on steel volume,
providing Hysteretic damping and extraordinary energy dissipation are unique features of this type of
damper. These dampers have a high lateral stiffness, in addition to providing damping. So, they were
entitled as Added Damping And Stiffness (ADAS).

Page | 17
These dampers are installed between head chevron tracings and floor beams. And by good connections,
these dampers can be installed in concrete frames
Lead Injection Damper (LED)
This damper is made of a two-chamber cylinder, piston and lead inside piston. And by piston moving
during earthquake, lead moves from larger chamber to smaller chamber. And with plastic deformation,
the kinetic energy is wasted as heat. In figure 1-1-2-3, the longitudinal section of lead damper injection
is shown(Saiidi et al.,1999).
Shape Memory Alloy (SMA)[14]
Shape Memory alloy (SMA) are created from metals which have the following properties:
1. their flexibility is very similar to the flexibility of the rubber piece.
2. after applying many deformation, they can back to their original state, by heating.

Page | 18
The alloy of nickel and titanium has good resistance to corrosion, in addition to have these properties.
Viscous Dampers
In this damper, by using viscous fluid inside a cylinder, energy is dissipated. Due to ease of installation,
adaptability and coordination with other members also diversity in their sizes, viscous dampers have
many applications in designing and retrofitting

Page | 19
This type of dampers are connected to the structure in three ways:
 damper installation in the floor or foundation ( in the method of seismic isolation)
 connecting dampers in stern pericardial braces
 damper installation in diagonal braces.
In connecting dampers on the floor or foundation of structures, we can use a combination of dampers
with isolators.

Page | 20
3. Shield building from vibrator
Instead of just counteracting forces, researchers are experimenting with ways buildings can deflect and
reroute the energy from earthquakes altogether. Dubbed the “seismic invisibility cloak”, this innovation
involves creating a cloak of 100 concentric plastic and concrete rings in and burying it at least three feet
beneath the foundation of the building.
As seismic waves enter the rings, they are forced to move through to the outer rings for easier travel. As
a result, they are essentially channeled away from the building and dissipated into the plates in the
ground.
Shielding in building
Shielding is used in buildings to protect people and equipment from the effects of other nearby items.
Shielding is most often used in medical/dental buildings and research laboratories due to the specialty
equipment and compounds used in those types of facilities. Architects working in the healthcare and
institutional sectors will need to understand the various kinds of shielding available
Shielding can be used to protect the contents of a room or object (prevent something from getting in) or
it can be used to protect everything outside a room (prevent something from getting out). For instance,
passersby should be protected from the radioactive materials in a laboratory storage room (prevent

Page | 21
something from getting out). Or, a sensitive piece of equipment may want to be protected from radio
waves entering the space and affecting test results (prevent something from getting in).
There are two main types of shielding used in medical and research buildings: electromagnetic shielding
(including radio frequencies and magnetic fields) and ionizing radiation shielding (including x-rays and
radioactive material). Each category requires the use of different materials to prevent harmful exposure
Electromagnetic Shielding
Electromagnetic shielding in buildings generally protects sensitive devices from external interference. In
some cases, it can also be used to keep an object's field contained so that it doesn't interfere with other
objects or equipment. Electromagnetic interference (EMI) comes in many forms such as radio
frequencies, magnetic fields, and electrical fields. An expert in EMI shielding should design the
shielding systems due to the complexity involved.
Shielding from electromagnetic interference is usually accomplished passively by using metal sheets
such as copper, aluminum, steel, or metal alloys. Copper is usually used to protect equipment from radio
frequency and electrical interference, but aluminum and steel also work. Steel plate or silicon steel are
usually used to keep magnetic fields from extending further out into the environment.
Copper Shielding Installed on Walls and Ceiling

Page | 22
There are also active shielding options where a compensation system continuously measures the
electromagnetic fields of a space and generates balancing fields that counteract the harmful fields. Due
to their cost and need for regular maintenance, active systems are reserved for situations where passive
systems prove inadequate.
It is important that all six sides of a room are properly shielded because electromagnetic fields extend in
all directions and are not "line-of-sight" like ionizing radiation. It is also critical that all penetrations in
the shield are properly protected using filters or waveguides. Filters prevent electrical cables and wires
from transmitting EMI into a space. Waveguides prevent air ducts and water pipes from transmitting
EMI into a space.
The most challenging EMI to shield against is quasi-static DC field interference. This occurs when
large, moving metal objects pass through the earth's magnetic field and generate a ripple of DC fields,
which can affect sensitive equipment such as MRI machines or electron microscopes. Such interference
can be caused by trucks, cars, or buses passing too close to sensitive equipment. Since vehicles tend to
be far enough away to not be a problem, the biggest culprit for quasi-static DC field interference are
elevators, which are generally dispersed throughout medical and research facilities. The best way to
avoid this problem is to keep elevators far enough away from sensitive equipment. An engineer,
physicist, or equipment manufacturer can help determine the separation required.
Ionizing Radiation Shielding
Humans must be protected from ionizing radiation to prevent serious health risks. Radiation in
healthcare and research facilities often comes in the form of x-rays or tracer elements used during
diagnostic procedures. It is also found during radiation therapies, such as treatments for cancer. Rooms
that are used for certain diagnostic imaging procedures or for radioactive treatments are shielded to keep
the radiation from escaping and compromising nearby people.
There are three ways of protecting from ionizing radiation: (1) Time - allow the radiation to decay; (2)
Distance - keep the radiation away from humans; (3) Absorption - shield humans with a material that
absorbs the radiation. Time and distance are fairly self-explanatory, so we will focus on absorption, also
known as shielding.

Page | 23
It is critically important that a physicist design ionizing radiation shielding. Different types of
radiation will interact with various shielding in different ways. In fact, it is possible to make radiation
more lethal if the wrong type of shielding is used. However, the basic premise is to increase the level of
shielding, the mass and thickness of the shielding material should be increased.
The most common way that ionizing radiation is stopped is by providing a lead shield. This is easily
seen in a dentist office where a patient wears a lead apron and the technician moves behind a lead-lined
wall during an X-Ray. Since X-Rays are fairly low-dose radiation, they can be stopped with a thin lead
shield. Higher doses of radiation may require a room to incorporate lead-lined drywall, lead-lined
plywood, or lead bricks

Page | 24
Radiation shielding with high density concrete
Walls, ceilings and floors containing magnadense radiation shielding concrete protect against ionizing
radiation due to the high density.
Radiation protection in buildings
High density concrete radiation shielding guarantees that people can work safely in buildings where
ionising radiation occurs. Typical buildings that require this radiation shielding material are:

Page | 25
As you are aware, the construction of these types of building needs to meet certain specifications.
Fortunately, LKAB Minerals can advise you in choosing an aggregate with the right density,
specification, quality and consistency, which is key for effective shielding of radiation in buildings.
How does high density concrete block radiation?
Concrete shielding reduces the intensity of radiation depending on the thickness and density of the
concrete structure. Moreover, with a higher density material, you can reduce the radiation faster.
Therefore, our customers use MagnaDense as a concrete aggregate in the concrete formulation to
achieve densities of up to 4.0 t/m³. Contrary, standard concrete typically has a density of up to 2.4 t/m³.
As a result, MagnaDense concrete gives full protection but uses less space.

Page | 26
Different construction solutions
Ultimately, there are several construction solutions for using the high density aggregate MagnaDense to
build a radiation-protected room or bunker to provide the right degree of defence:
 Standard heavy concrete walls: Walls made of high density concrete which contains MagnaDense.
 “Sandwich” walls: As the name of this solution indicates it involves a layer of compacted MagnaDense
between two (mostly) pre-fabricated walls which act as a lost formwork.
 Modular high density concrete blocks: Radiation shielded walls are built using blocks made of heavy
concrete and MagnaDense. We have published a news article with a detailed business case with
information about this particular method.

Page | 27
Advantages of using MagnaDense as a radiation shielding material
We often get asked what advantages MagnaDense heavyweight concrete can bring to a radiation
shielding project. However, there is not one reply that fits all. You will see that depending on your
project one or more of these benefits may apply:
 More weight, less volume; less excavation/transportation/reinforcement and time for construction
 Good radiation shielding characteristics
 Increased weight for a given volume
 Reduced risk of cracking due to the high heat retention of MagnaDense which results in a lower peak in
heat of hydration
 Space-saving; thinner walls
Making and handling heavy concrete
In general, building a radiation shielding wall is usually not an everyday job for most companies.
Fortunately, heavy concrete can be produced using standard construction equipment. Of course, it is
important to understand that the weight of MagnaDense will have an influence on the equipment you
use. Moreover, you can use your equipment effectively to handle a heavy concrete just as you can for
ordinary concrete. Luckily, we can help you select the aggregate size you need to create the right density
of concrete for your project.
Radiation Shielding for Construction
Radiation shielding construction materials are made from solid lead or contain a layer of laminated lead
sheeting to stop the penetration of harmful radiation. We provide shielded building materials for
medical, nuclear, and other industries requiring radiation shielding. The sheet lead used in our walls and
doors meets or exceeds Federal Specification QQL-201 F Grade C and ASTM B749-03 Standard

Page | 28
Specification for lead and lead alloy strip, sheet and plate products. All our leaded glass meets or
exceeds Federal Specification DD-G-451. Construction projects completed using our radiation shielding
buildings materials include:
 Custom size neutron doors and lead-lined walls for medical testing facilities
 Oversized sliding vault doors for Radiation Therapy Vaults
 Extra-large leaded x-ray glass for medical imaging rooms which maximizes patient visibility by the
technician
Read our case studies or view our featured projects to learn more about radiation protection in
medical imaging, radiation therapy, laboratories, and testing facilities.
Radiation Shielded Walls
Our lead sheeting, lead lined plywood, and lead lined sheetrock all come in varying sizes and
thicknesses to meet your needs. We offer all the standard building materials required for constructing
any type of radiation shielding walls, including lead-lined plywood, lead-lined sheetrock, lead
bricks, lead angles, and lead cutout and penetration shielding products.
Radiation Shielded Doors
Radiation shielded wood doors come in wood veneer and plastic laminate options. We also provide 16-
gauge steel, ready-to-install lead-lined door frames in standard and custom sizes. In addition, we offer
lead lined hollow metal doors with lead lined frames. Ask us about our neutron shielding doors for the

Page | 29
highest level of radiation protection. Choose the lead thickness that meets your shielding requirements.
Doors are available with or without a leaded glass window.
Radiation Shielded Windows
Our radiation-shielded frames and glass provide the protection you need without sacrificing visibility.
Standard sizes for leaded windows range from 8”x10” to 108”x54”. We also provide lead-lined mullion
frames and telescoping frames made to match your wall thickness.

Page | 30
4. Reinforce the building’s structure
To withstand collapse, buildings need to redistribute the forces that travel through them during a seismic
event. Shear walls, cross braces, diaphragms, and moment-resisting frames are central to reinforcing a
building.
Shear walls are a useful building technology that helps to transfer earthquake forces. Made of panels,
these walls help a building keep its shape during movement. Shear walls are often supported by diagonal
cross braces. These steel beams have the ability to support compression and tension, which helps to
counteract the pressure and push forces back to the foundation.
Diaphragms are a central part of a building’s structure. Consisting of the floors of the building, the roof,
and the decks placed over them, diaphragms help remove tension from the floor and push force to the
vertical structures of the building.
Moment-resisting frames provide more flexibility in a building’s design. This structure is placed among
the joints of the building and allows for the columns and beams to bend while the joints remain rigid.
Thus, the building is able to resist the larger forces of an earthquake while allowing designers more
freedom to arrange building elements.

Page | 31
Earthquake-Resistant Materials
While shock absorbers, pendulums, and “invisibility cloaks” may help dispel the energy to an extent, the
materials used in a building are equally responsible for its stability.
Steel and Wood
For a building material to resist stress and vibration, it must have high ductility — the ability to undergo
large deformations and tension. Modern buildings are often constructed with structural steel — a
component of steel that comes in a variety of shapes that allow buildings to bend without breaking.
Wood is also a surprising ductile material due to its high strength relative to its lightweight structure.
Innovative Materials

Page | 32
Scientists and engineers are developing new building materials with even greater shape retention.
Innovations like shape memory alloys have the ability to both endure heavy strain and revert to their
original shape, while fiber-reinforced plastic wrap — made by a variety of polymers — can be
wrapped around columns and provide up to 38% greater strength and ductility.
Engineers are also turning to natural elements. The sticky yet rigid fibers of mussels and the
strength-to-size ratio of spider silk have promising capabilities in creating structures. Bamboo
and 3D printed materials can also function as lightweight, interlocking structures with limitless
forms that can potentially provide even greater resistance for buildings.
Over the years, engineers and scientists have devised techniques to create some effective
earthquake-proof buildings. As advanced the technology and materials are today, it is not yet
possible for building to completely withstand a powerful earthquake unscathed. Still, if a
building is able to allow its occupants to escape without collapsing and saves lives and
communities, we can consider that a great success.
What is a Shear Wall and How Does it Protect Your Building?

Page | 33
Shear wall definition: Shear walls (shear panels) protect a home or building from becoming warped or
distorted when attacked by horizontal (lateral) forces during an intense wind event, hurricane, or seismic
event.
For many years, builders constructed shear walls with wood or steel framing. However, today builders
have a better alternative shear wall material ﹘ Insulated Concrete Forms (ICFs). ICFs provide more
protection against lateral loads from earthquakes and severe winds than wood or steel framing. ICFs also
provide quicker and easier construction and more energy efficiency, durability, and indoor
environmental quality than framed-shear walls.
When Are Shear Walls Required?
Most homes and buildings in high-wind and earthquake-prone regions require exterior shear walls.
However, larger houses and high-rise structures also need interior shear walls to protect against lateral
wind and seismic forces.
Shear Wall V/s Load-Bearing Wall
When choosing between a bearing wall vs. a shear wall, you must consider how prone the region is to
lateral loads and the height of the building.
 Shear wall structural systems resist lateral loads (horizontal forces acting on a structure) of wind
and seismic activity, carrying the compression loads (vertical forces) from the weight of the
building components (beams, girders, etc.) down to the foundation.
 Load-bearing walls only carry the compression loads down to the foundation but lack bracing, so
they do not resist lateral loads.
How Do Shear Walls Work?
Ideally, the shear wall details and design includes walls on all sides of the building, extending its entire
height. Long walls are more robust than short walls, and solid walls are better than walls with openings
(windows, doors, etc.).

Page | 34
In addition, the design of a shear wall should ensure that the building can survive severe sideways (in-
plane) forces (racking and shear) without being damaged or bent out of position. In addition, to provide
earthquake resistance in low-rise structures, builders must sufficiently anchor the shear wall by
installing steel reinforcing bars that extend across the joint between the walls and the foundation.
Placement of Shear Walls
The shape and placement of the shear wall will considerably influence the structure's behavior.
Structurally, shear walls work best in the center of each half of the building, placed symmetrically
around the structure’s central axis. However, architects find this challenging since shear walls take up so
much space. Often, you will find shear walls around stairwells, elevator shafts, or windowless walls.
How to Build a Shear Wall
Construction of a shear wall includes materials and design that enhance a structure’s stiffness, strength,
and ductility in order to withstand lateral forces from severe winds and earthquakes. In most U.S towns
and cities, Chapter 16 of the International Building Code and Chapter 6 of the International Residential
Code provide a construction guide for designing and constructing shear walls.
How to Identify a Shear Wall
Shear wall construction drawings identify a shear wall by a solid line with a thinner line indicating a
covering of sheathing.
Shear Wall Material
You can use any structural material to build a shear wall; however, the strength of the material must
equal or exceed the surrounding structural material. Three common shear wall materials include steel
plates, wood, and ICFs.
Steel plate shear walls consist of vertical steel infill plates one story high and one bay wide connected to
the surrounding columns and beams. When installed in one or more bays for the full height of a
building, the plates form a stiff cantilever wall. Often used to strengthen existing 4 to 8 story buildings.

Page | 35
Shear Wall Construction with Steel Plates
The steel plate shear wall composition includes a thin steel web plate bounded by and attached to a rigid
beam supported at either end by stiff columns (portal frame). The rigid joints between the beam and
columns permit the transfer of the bending force in the beam to the columns.
Wood shear walls contain relatively low strength and stiffness compared to steel or reinforced concrete,
making them suitable for lightweight construction. A seismic-resistant wood wall requires several long
or many shorter shear walls.

Page | 36
Shear Wall Construction with Wood
Wood shear walls consist of attaching sheathing (plywood or OSB) to wood frames.
Constructing wood shearwalls can become labor intensive and has additional costs for
some mechanical connectors and fasteners. Builders fasten the sheathing to the framing
with nails sized and spaced according to an engineer's specifications. Finally, they
mechanically attach the sheathing to the foundation walls with metal connectors and/or
metal cross-strapping.
Reinforced, cast-in-place, concrete shear walls (like those built with ICFs) are a highly reliable shear
wall material for medium to heavy construction. ICF shear walls achieve all the vital properties of
earthquake resistance. The strength of concrete resists compression forces, and the reinforced steel

Page | 37
manages the lateral forces. The reinforced concrete shear walls' high level of ductility allows architects
to design with shorter wall lengths compared to other materials.
TYPES OF LATERAL FORCE-RESISTING SYSTEMS IN COMMERCIAL BUILDINGS
Every structure must be designed and constructed to withstand lateral loads and horizontal loads.
Structures are braced against lateral and horizontal forces in several ways. Bracing is installed
perpendicular to the direction of the potential force. Bracing is often installed in every direction because
forces can come from every direction.
The most common bracing methods for resisting lateral forces in commercial buildings include moment
frames, shear walls, and braced frames. These are vertical elements that transfer lateral loads, including
wind, seismic forces, and stability forces through floor or roof diaphragms to the building’s foundation.
They help keep a structure from blowing over or collapsing.
Moment Frames
Steel moment frames are vertical frames consisting of traditional beams and columns that are typically
connected by bolts and/or welds. They are more flexible than shear walls and brace frame structures.
The rigid connection points permit the frame to resist lateral loads through the flexural strength
(bending) and continuity of its beams and columns, such that moments are transferred from beams to
columns at the connection points. A moment frame will not move laterally without bending the beams
or columns. The three main types of connections are bolted, welded, and proprietary, and there are

Page | 38
several variations of each. Concrete frames are also commonly considered moment frames because of
their similar continuity.
Moment frames have several applications in single-story and multi-story commercial buildings, but
they’re used primarily in low-rise buildings. Moment frames allow for larger openings and small wall
sections while still supporting required loads and resisting various forces.
Some of the typical applications include:
 structural steel buildings;
 large building entryways;
 walls with large openings; and
 tuck-under parking.

Page | 39
The three types of moment frames include ordinary moment frames (OMF), intermediate moment
frames (IMF), and special moment frames (SMF).
Braced Frames
Braced frames are common in steel construction. They use diagonal and/or triangulated steel beams or
cables to resist lateral forces. Resistance is provided by vertical bracing or horizontal bracing. Vertical
bracing between structural columns transfers lateral forces to ground level. Horizontal bracing at each
floor or the roof transfers lateral forces to the vertical bracing, and then it’s transferred to ground level.
However, the floor system is usually a sufficient diaphragm without the need for additional steel
bracing. Braced frames are suitable for multi-story buildings in the low- to mid-rise range.
The two main types of braced frames are concentric bracing and eccentric bracing. Concentrically
braced frames are typically triangulated and connected at the endpoints of other framing members
(joints) to develop a truss. A few common configurations include a cross-brace (X-brace), inverted V-
brace (chevron brace), and a single diagonal brace. Eccentrically braced systems utilize diagonal braces
with one or two ends deliberately offset to the supporting member such that the bracing isn’t centered.
The gap between the offset bracing is referred to as the structural fuse region, and it’s designed to
dissipate a lot of energy during an earthquake event.

Page | 40
Inspecting Moment Frames, Shear Walls, and Braced Frames in Commercial
Buildings
Moment frames, shear walls, and braced frames perform well in areas in high seismic and wind activity,
but defects and other damage may arise from those occurrences. Municipal building departments
typically perform inspections after any seismic activity to identify unsafe buildings. An engineering firm
may also perform the inspection. Commercial property inspectors should refer to their documentation if
their client opted to have the research portion of an inspection completed. Inspectors may also choose to
ask building owners, occupants, and others with sufficient knowledge of the property about whether it’s
known if the building experienced strong storms, earthquakes, or the like during the interview portion of
the inspection.

Page | 41
Results and discussions
The proposed constructive solution of the foundations of seismic resistant buildings is confirmed by the
results of tests of sandy soils at the base of a rigid stamp with dynamic (seismic) load, by construction
experience, and the results of a survey of the load-bearing structures of rigid buildings after strong
earthquakes. The construction of rigid buildings with foundations, in according with the proposed
design scheme, will allow to exclude horizontal seismic impact on the vertical walls of the foundations
(due to the absence of clamping), and therefore horizontal seismic tremors on the buildings are also
excluded.

Advance earthquake resistance techniques project

Recommended

Recommended

More Related Content

Similar to Advance earthquake resistance techniques project

Similar to Advance earthquake resistance techniques project (20)

Recently uploaded

Recently uploaded (20)

Advance earthquake resistance techniques project