Lec 1 Design of RC Structures For Lateral Loads

Higher Studies
Diploma, Master of Science in Structural Engineering

Feb. 2017 – May 2017
Assc. Prof. Dr. Nasser. El-Shafey

Course teaching topic by - Dr. Nasser. El-Shafey:
1. Types of applied vertical and lateral Loads on reinforced concrete
buildings.
2. Introductions to Earthquake ( Theories of how earthquake formed
,classifications of earthquake, earth tectonic plates, faults and ground
movements, methods of measuring earthquake, earthquake waves,
history of some severe earthquakes occurs in the history)
3. Structural systems used to resist earthquakes (moment resisting
frames, shear wall, cores,…)
4. Structural damages due to earthquake.
5. Simplified model response spectrum method ( lateral force
distributions on building, center of mass & center of rigidity,
symmetrical & unsymmetrical shear walls or cores, symmetrical &
unsymmetrical rigid frames, torsion effect, drift of structures due to
seismic)
6. Distribution of wind loads on R.C. buildings.
7. Coupled shear walls (behavior, distribution of lateral loads, stresses
on each wall )
8. Distributions of lateral loads on building resisting by both shear
wall & rigid frames.
At the end of this course
the attendees should be able to:
1. Chose suitable structural systems to resist earthquakes (moment resisting
frames, shear wall, tube in tube,…)
2. Define different structural damages due to earthquake .
3. Distribute lateral forces (seismic) using response spectrum method for

buildings resisted by either symmetrical or unsymmetrical shear walls,
rigid frames, or both and coupled shear walls including torsion effect, drift
of structures )
4. Calculate wind loads and its distributions on buildings.
5- Check (sliding, overturning and drift) for the concrete buildings.
6- Complete calculations for Design and detailing of different structural
resisting concrete elements (shear walls, rigid frames and coupled shear
walls to resist lateral loads).
Method of Assessment Percentage of total

Written examination (closed Book exam) 70%
Assignments (15%) , quizzes(15%) 30%
Knowledge and Understanding
 Design straining actions for different structural elements.
 Behavior of concrete structural elements.
 Types of damages and cracking in different structural

concrete elements.
 Design of different concrete sections, columns and walls

under different straining actions.
List of References:
1. Lecture notes .
2. “Earthquake damage to structures ”, By : Mark Yashinsky ( Structural
Engineering handbook).
3. “Seismic design of building to Euro code 8 ” By Ahmed El-Ghazouli
Local books of Concrete structures.
4. “Some concepts in Earthquake Behavior of Buildings” C.V.R Murty,
Rupen Goswaml
5. The Egyptian code of practice for design and construction of
concrete structure.
6. The Egyptian code of practice for load calculation.
Loads on buildings
All structural elements must be designed for all loads anticipated to act during
the life span of such elements. These loads should not cause the structural
elements to fail or deflect excessively under working conditions.
Main vertical load
Dead loads (D.L)
•Weight of all permanent construction.
• Constant magnitude and fixed location.
Examples: Weight of (Walls, Floors, Roofs, Ceilings, Stairways, Partitions,
Fixed Service Equipment )
Live Loads (L.L) according to building uses (2 : 5 KN/m2).
Wall Loads according to own weight of wall intensity (15 : 18 KN/m3).
These types of loads consider as a main loads for any types of buildings
Secondary Load
 Wind loads.
The wind load is a lateral load produced by wind pressure. It is a type of dynamic load
that is considered static to simplify analysis. The magnitude of this force depends on the
shape of the building, its height, the velocity of the wind in which the building exists.
 Seismic loads (Earthquakes loads).
The earthquake load is a lateral load caused by ground motions resulting from
earthquakes. The magnitude of such a load depends on the mass of the structure and the
acceleration caused by the earthquake.
Earth pressure.
water pressure loads.
Impact loads.
These loads consider secondary load for the ordinary low rise buildings, but
for high rise buildings or special buildings, these loads consider main loads
Vertical deflection (sag) Lateral deflection (sway)
Dead, Live, etc. Wind or

earthquakes
Lateral Load
Performance-Based Design:
Control displacements within acceptable
limits during service loading, factored
loaded, and varying intensities of
environmental loading Wind Loads Earthquakes loads
Loads and load combinations
For members subject to live loads:
U = 1.4 D + 1.6 L Where,
D = Dead Loads L= Live Loads
- For members subject to either wind load, W or seismic load, S the
ultimate load shall be taken equal to the greater value obtained from the following two
equations:
U = 0.8 (1.4 D + 1.6 L + 1.6 W)
U = 1.12 D + a L + S Where,
S = Ultimate seismic loads.
a = A factor that accounts for the effects of the sustained live loads on the
structure during seismic activities.
a = 1/4; for residential buildings
a = 1/2; for public buildings including, schools, hospitals, garages, theatre halls,
commercial and office buildings
a = 1 ; for structures subject to loads acting for a long duration of time which
include but are not limited to, silos, bins, water tanks, libraries, storage buildings
Internal Forces
• The internal strength of the entire structure
must be = or > the total forces applied on the
building
• The ability to withstand all forces depends on
the structural component’s dimensions and
the solidity and elasticity of the material.
• Internal forces :
• Compressive and Tensile Forces
According to Newton’s Third Law, forces
act in pairs. In structural terms, tensile
force pulls a structural element apart while
compressive force compresses it.
• Torque
If opposing forces are applied at different
points, a structural element may become
twisted. Internal forces in a structural element
Egyptian Code of practice
 The Egyptian Code of practice require that in addition to the vertical
loads, buildings designed to resist lateral loads (wind or earthquake
loads).
 Lateral loads may or may not affect the design of structures according
to buildings heights.
 In working stress design method, if seismic or wind loads are
considered, then the allowable stresses may be increased by 15%.
 Wind loads and seismic loads should not be combined.(only, the
higher of the two load case is to be considered)
What is a High-Rise Building ??
 A building whose height creates different conditions in the design,
construction, use than those that exist in common buildings of a certain
region and period.”
• “A Structure because of its height, is affected by lateral forces due to wind
or earthquake actions to an extent that they play an important role in the
structural design.”
■ Why Tall Building (Advantage)??
• Business activities need to be as close to each other.
• It forms prestige symbols, distinctive land marks, hotels and commercial city centers.
• High cost of land and limited space.
■ Disadvantage of Tall Building ??
• Putting intense pressure on the available land space .
• Increase the risk, safety hazards and constitute an easy target in case of war or
terrorism.
STAGES OF HIGH RISE building DESIGN
■ Design Process
Architectural Structural MEP
Preliminary Structural Design Based on

Concept Design
Vertical Loads Plus an allowance for Lateral
Loads Based mainly on EXPERIENCE
Accurate Modeling and Analysis Based on

Final Design Final Layout and All Possible Loads and
Development of Final LAYOUT DRAWINGS
Final Design Calculations and the

Working Design Development of Working Drawings by
Cooperation with CONTRACTORS
Lateral Load Resisting Elements
• Vertical Elements:
• Moment-Resisting Frames.
• Walls – Bearing walls / Shear Walls.
• “Dual” System (Frame + Wall).
• Tube System.
• Tube in Tube system
• Bundled-Tube System.
• Floor / Diaphragm.
• Foundation – various types
Moment-Resisting Frames
 Moment-resisting frames are structures having the traditional beam-
column framing, carrying gravity loads that are imposed on the floor
system.
 The floors also function as horizontal diaphragm elements that
transfer lateral forces to the girders and columns. In addition, the
girders resist high moments and shears at the ends of their lengths,
which are, in turn, transferred to the column system. As a result,
columns and beams can become quite large.
■ Moments resisting frames

Consist of beams and
columns in which bending of
these members provides the
resistance to lateral forces.
Basic Behavior
Frame Lateral Load Systems
Flat plate-column frame:
Beam-column frame:
Elevation
Shear Wall Lateral Load Systems
Shear deformations
Shear wall Edge column generally govern
Elevation
Interior gravity frames

 The elevator shafts, stairwells necessary for access in a high rise and
must be protected by fire walls, as demanded by fire safety regulation.
 Shear wall with its highly resistance to shear stress, are highly suitable
for assuming the shear forces that arise through lateral loads.
Dual Lateral Load Systems
Type 3 – Cumulative Drift
+ =
Shear deflection profile Flexural deflection profile Combined deflection profile

Type 1 Frame Only Type 2 Core Only Type 3
The total deflection of the interacting shear wall and rigid frame systems
is obtained by superimposing the individual models of deformation
Core Structure System
The framed-tube structure has its
columns closely spaced around
the perimeter of the building,
rather than scattered throughout
the footprint, while stiff spandrel
beams connect these columns at
every floor level
Tube-in-tube system
Framed-tube system
Dewitt chestnut
• The lateral resistant of the framed-tube structures is

provided by very stiff moment-resistant frames that
form a “tube” around the perimeter of the building.
• The basic inefficiency of the frame system for reinforced

concrete buildings of more than 15 stories resulted in
member proportions of prohibitive size and structural
material cost premium, and thus such system were
economically not viable.
• The frames consist of (2-4m) between centers, joined by

deep spandrel girders.
• Gravity loading is shared between the tube and interior

column or walls.
Bundled-tube system Braced-tube system
BUNDLED TUBE SYSTEM
The concept allows for
wider column spacing in the
tubular walls than would be Sears Tower, Chicago.
possible with only the Burj Khalifa,
exterior frame tube form. Dubai.
The spacing which make it
possible to place interior
frame lines without seriously
compromising interior space
planning.
High Rise Example
1.Sears Tower
Nine Bundled Tubes,
each 25 m wide with no columns
between core and perimeter.
Location: Chicago
No of Stories: 108
Construction Year: 1974
Height: 442 m
Outrigger-braced system
■ Tallest twenty high rise in the world
CHALLENGES IN THE DESIGN OF HIGH RISE BUILDINGS
10/28/2009
■ High Rise Example (Burj Dubai)
This is the tallest Man

Made Building in the
world with a predicted
height of 818m.
■ High Rise Example (World Trade Center)
534 meter to tower

top 610 meter to pyramid
top 670 meter to comm. tower
Structural Systems for Tall Buildings
Makkah Clock Royal Tower
Burj khalifa
Taipei 101
Petronas Towers
International Commerce Center
Wills Tower Kingkey Finance Nanjing
Greenland
Tower Financial
Center
■Construction Challenge Modern Shuttering
■Design Challenge
Ductile Detailing
Using Advanced Control Techniques

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Higher Studies

Diploma, Master of Science in Structural Engineering

Assc. Prof. Dr. Nasser. El-Shafey

3. Distribute lateral forces (seismic) using response spectrum method for

Method of Assessment Percentage of total

 Behavior of concrete structural elements.

 Types of damages and cracking in different structural

 Design of different concrete sections, columns and walls

Dead, Live, etc. Wind or

Preliminary Structural Design Based on

Accurate Modeling and Analysis Based on

Final Design Calculations and the

■ Moments resisting frames

Interior gravity frames

Shear deflection profile Flexural deflection profile Combined deflection profile

• The lateral resistant of the framed-tube structures is

• The basic inefficiency of the frame system for reinforced

• The frames consist of (2-4m) between centers, joined by

• Gravity loading is shared between the tube and interior

This is the tallest Man

534 meter to tower

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