Load analysis and structural consideration

• Load and types.
• Structure after load analysis.
• Load transfer.
-Core and load analysis.
-Floorings and types.
-Basement and parking
CONTENT

• Load is the external forces acting on very small area
on a perpendicular point of a supporting structural
element.
LOAD

• GEOPHISICAL
SOURCES OF BUILDING LOADS:
• MAN MADE

DEAD LOAD: (gravity/static load)
Dead load consists of self weight of structure (beam, column, slab & struts etc.) &
equipment permanently attached to structure such as furniture load, home
accessories etc.

LIVE LOAD:
Loads caused by contents of objects within or on a building are called occupancy loads. This
loads includes allowance for the weights of people, furniture, moveable partitions,
mechanical equipment etc.

CONSTRUCTION LOADS
• Structural members may be subjected to loads larger than designed loads during
erection of a building these loads called construction loads
• The weight of floor forms and newly placed slab, which in total may equal twice
the floor load.

TYPES AND EFFECTS OF TEMPERATURE LOAD :
TYPES OF COLUMN EXPOSURE
inside Flange at wall line Partial exposure Full exposure
TYPES AND EFFECTS OF TEMPERATURE-INDUCED MOVEMENT:
COLUMN BENDING:
DIFFERENTIAL MOVEMENT
BETWEEN INTERIOR AND
EXTERIOR COLUMNS.
column temperature may vary from -20 F to
120 F depending on the locality .
expansion
Cold air
contraction
Warm air

WIND LOAD: (dynamic/lateral load)
The mean wind velocity is generally increases with height.
Wind is essentially the large scale horizontal movement of free air. It plays an
important role in design of tall structure because it exerts loads on building.

WIND DIRECTION:
The multidirectional displacement may be
less than It would have been if the same
airflow had encountered the building on
only one face.

Wind pressure:
The wind pressure originates from two
components previously defined : mean velocity
and gust velocity. since static mean velocities are
averaged over longer periods of time, the
resulting wind pressure are also average
pressure and exert a steady deflection on the
building.

SEISMIC LOAD: (dynamic/lateral load)
It is this wave motion that is known as earthquake., It is
apparent that a fault which has suffered from
earthquakes in the past is most likely subject to future
disturbances.
When earthquakes occur, a buildings undergoes
dynamic motion. This is because the building is
subjected to inertia forces that act in opposite direction
to the acceleration of earthquake excitations.
These inertia forces, called seismic loads
Earthquake is one of the destructive events in the world.

When earthquakes occur, a buildings undergoes dynamic motion.

Ground shaking during earthquakes

Different shapes of buildings considered in the present study
Shape:

Circular Shape
Rectangular Shape
Square Shape
Triangular Shape

Lateral , horizontal
and
vertical load transfer
LOAD TRANSFER IN STRUCTURE

Bracing:
It is a device used as a supporting beam in a building that imparts rigidity
and steadies the structure. It is extremely stiff. It helps positioning, supporting,
strengthening or restraining the member of a structural frame.
The basic principles are as follows:
·Vertical K-bracing maybe used along the columns
· Horizontal portal bracing may be applied along the beams .

Braced Frame
• The effectiveness of the system, as characterized by a high ratio of
stiffness to material quantity, is recognized for multistory building in the
low to mid height range.
• Generally regarded as an exclusively steel system because the diagonal
are inevitably subjected to tension for or to the other directions of lateral
loading.
• Able to produce a laterally very stiff structure for a minimum of additional
material, makes it an economical structural form for any height of
buildings, up to the very tallest.
Advantages:
- Girders only participate minimally in the lateral bracing action
- Floor framing design is independent of its level in the structure
- Can be repetitive up the height of the building with obvious economy in
design and fabrication.
Disadvantages:
- Obstruct the internal planning and the locations
of the windows and doors; for this reason,
braced bent are usually incorporated internally
along wall and partition lines, especially around elevator,
stair, and service shaft.
- Diagonal connections are expensive to fabricate and erect

Type of High-Rise Structure
1. Braced Frame
2. Rigid Frame Structure
3. In filled Frame Structure
4. Flat Plate and Flat Slab Structure
5. Shear wall structure
6. Coupled wall structure
7. Wall-frame structure
8. Framed tube structure
9. The trussed tube
10. Tube in tube or Hull core structure
11. Bundled tube structure
12.Core and Outrigger system
13. Hybrid structure

Tubed mega frame
• Vertical tube mega column
• No central core
• That’s why all the load of the building rest on its
perimeter

Load transfer in CCTV Tower China

Outrigger system
• central core with outriggers, connecting
the core to the outer columns.
• the central contains either braced frame of
shear wall.
North east asia trade tower

Infilled Frame Structure
• Infilled serve also as external walls or internal
partitions, the system is an economical way
of stiffening and strengthening the structure.
• Consists of reinforce or steel column and
girder frame with infills of brick work or
concrete block works

Vertical displacement in infill frame structure:

Shear wall
• Concrete wall
• Punches are limited because of torsional and flexural
rigidity
• In most cases lateral loads are carried by shear walls.
Shear wall
• Gravity load and lateral
load are ideally distributed.
• Also shear wall carries all
lateral loads.
Lateral load
Gravity load

Diagrid system
• Here diagrid acts as a rigid shell and
beam for support where rings are
also used.
• lateral loads are introduced
directly to the diagrid structure and
immediately transferred into the
triangulation system these loads are
then handled in a similar manner to
vertical
• Load paths are continuous and
uninterrupted.
• Vertical gravity loads follow the structure of
the tube from top to base along the
diagonal members of said tube.
• Each diagonal can be viewed as
continuous from top of tube to the bottom
of the tube – this is one option for a load to
follow to meet the ground
Rings

Flat plate and flat slab structure
• flat plate is a two-way reinforced concrete
framing system utilizing a slab of uniform
thickness, the simplest of structural shapes
• flat slab is a two-way reinforced structural
system that includes either drop panels or
column capitals at columns to resist heavier
loads and thus permit longer spans.

Tube in tube structure:
Bundle tube
• The inner and
outer tube jointly
resist the gravity
and lateral loads.
Bundle tube structure:
• This system easily
resist the wind pressure
and hold lateral loads.
Tube in tube

Framed tube structure
• Gravity loads are distributed between the tubes and
interior columns or walls
• Lateral loading acts at the perimeter.

STEPS OF FLOORING
• BASE-lay base coat of 100mm
thick in the ratio of cement
concrete 1:8:16 ( 1 part of
cement,8 parts of fine sand &
16 parts of brick blast) or
1:4:8 on compaced earth under
the floor. The base is same for
all types of floors.
• FINISHING: then finishing of
the floor is carried on, for
different flooring materials. As
we will discuss here the
finishing of
terrazzo,brick,stone & cement
concrete floor

-Hard flooring
-Sub flooring
TYPES OF FLOORING
Hard flooring
Hard flooring (not to be confused with
( "hardwood") is a family of
flooring materials that includes concrete or
cement, ceramic tile,glass
tiles, and natural stone products.

Sub flooring
The floor under the flooring is called the subfloor,
which provides the support for the flooring.
Special purpose
subfloors like floating floors, raised floors or sprung
floors may be laid upon another
underlying subfloor provides the structural strength.
Subfloors that are below grade
(underground) or ground level floors in buildings

Basement and parking
Generally basements are common in tall buildings as carparks,
storage of servicesand underground shopping centres. The
Basement Parking space type refers to parking located below
grade within an occupied building.
The main purpose of constructing basements are:
(a) to provide additional space,
(b) as a form of buoyancy raft,
(c) in some cases, basements may be needed for
reducing net bearing pressure by the
removal of the soil.
(d) safe and efficient passage of automobiles as well as
visitors to and from their vehicles
Buoyancy raft

Function and attributes of basement
Additional Structural Requirements:
Below grade extension of the building structure to
accommodate basement parking is required. This
involves additional excavation, structural frame, floor
slabs above, sloped vehicle access ramps, and
basement perimeter walls and partitions separating
parking from other building enclosed areas. Typical
structural floor construction is 4000 PSI 6" concrete
slab with welded wire fabric designed for a live load of
80 LBS/SF, and with a ramp slope of no more than
5.5%.

CORE:
The core of a multistory building that integrates functions and
service needs for established occupants. Such areas are
normally composed of toilet facilities, elevator banks, janitors’
closet, utilities, mechanical facilities, smoke shafts and stair.
25% - 30% of the total circulation area.
Core also known as facade envelope is a spatial element
for load-bearing high-rise building system
• Vertical circulation
• Configuration
• Floor-plate design
• Function of Service Core
• Service core types & placement
• Service Core & Building Economy
• Elevator design & configuration
• Population density
• Traffic analysis
• Quality of ride
• Service-core layout & space
requirements
Core wall

There are two principles of core design arrangement .
the first is providing effective and conveninet vertical
transportation system. The second is creating intact ,
flexible and consistently high quality space that can be
occupied which can be adapted into the structural
system.
Shanghai tower design.
Shenzhen pingan financial center

INTERIOR STRUCTURES
EXTERIOR STRUCTURES

Vertical Circulation
• Cores = service cores = risers
• Contains:
– Elevator shafts.
– Elevator lobbies.
– Main & escape stairways, ramp.
– Riser-ducts.
– Toilets.
– Other service rooms.
• Elevators = MAIN vertical circulation system.
Configuration
At initial design stage, designer DETERMINES:
• Buildable net rentable areas (NRA)
• Gross floor areas (GFA)
• Typical & atypical floor-plates
• Prepare a diagram + propose elevator configuration:
• No. of banks
• No. of stops
• Transfer floor(s)

Function of Service Core
Simply state that service is defined as those part of a building that
consists of the service lift, fire stair , Toilet, service riser duct .
Element of Service :
1. TOILET
2. FIRE STAIR.
3. SERVICE/FIRE ELEVATOR
4. RISER DUCT
1. TOILET
2. PLUMBING
3. DUCTING
4. SERVICE/FIRE LIFT
5. FIRE STAIR

Structure of Core
• If the building structure been
R.C.C , the core structure
should be shear wall. In this
case core structure may not be
steel structure.
steel , the core structure
should be steel structure. In
this case core structure may
be R.C.C structure.
Composite ,the core structure
should be shear wall. In this
case core structure may not be
steel structure

diagonal
connection
vertical connection

Typology of core
1. central core
2. Split core
3. End core
4. Atrium core
configuration
plan
Single tenant
Double tenant
Multiple tenant

Core design
Service Core & Building Economy
• Minimization of material costs
• Optimization of core
geometry
• Minimization of core area
• Minimization of construction
time

POSITION OF CORE:
should be located on the east & west side of the building.
With both cores on hot sides, they provide Buffer zone.
should be on the periphery of the usable floor space. Because--
1. Mechanical lighting
2. Mechanical ventilation
c
v
v
c
v
Cantilevered system
Slabs are
supported by
the core
individually.
Suspended system
c
v
v
c
v
slabs are
suspended at the
top of the core, so
loads of all floor
act from the top of
the core.

central core :
LOAD TRANSFER
core

Service-core layout & space requirements :

Benefits of a peripheral core position:
• No fire-fighting pressurization duct is needed
• Good view out
• Natural ventilation
• Natural sunlight
• A safer building in the event of total power failure
• Solar-buffers & energy savings
Service-core layout & space requirements :
• Elevator car sizes & shapes
• Elevator door types & sizes - common widths 1.1 m or 1.2m
• Elevator shafts - are according to car shapes & sizes, and
door sizes. Sufficient air around cars & counterweights should
be provided to minimize buffeting & air-borne noise during
operation.
• Elevator core & lobby planning - ‘outward facing’ elevators VS
‘inward facing’ elevators.

Department of Architecture
Hajee Mohammad Danesh Science & Technology University

Load analysis and structural consideration

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Load analysis and structural consideration