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UNIVERSITY OF BEDFORDSHIRE: TECHNICAL STUDIES
f (STRESS) = P (force) / A (area)
SUMMARY
• Structural Systems in Nature
• Structural Systems in Architecture
• Forces in Architecture:
• Fundamental Principles:
Live and Dead Loads
Equilibrium
Newton’s Laws of Motion
Forces Acting on a Body
Stress
Strain
Elastic and Plastic Deformation
Stiffness and Flexibility
• Column and Beam: Origins and Architecture
• Beams:
• Columns:
Transfer of Loads
Turning Moments
Bending
Deflection
Shear
Buckling
Effective Height
Eccentric Loading
UNITS: N/mm2 (1 Pascal (Pa) = 1 N/m2)
STRAIN = Change in size (∆L)
Original size (L)
UNITS: % or decimal
YOUNG’S = Stress
Strain
MODULUS
UNITS: N/mm2 (Pa)
A stiff material has
a high Young’s
Modulus; a flexible
material has a low
Young’s Modulus
Turning moment = w (force) x
UNITS: Nm
L (lever arm)
NEWTON’S LAWS OF MOTION
1.
A body remains at rest or in motion with a constant velocity in a straight line unless an external force acts on it
2.
Force (Newton) = Mass (kg) x Acceleration (m/s2) (Gravity on earth = approx. 10m/s2)
3.
For every force acting on a body, the body exerts a force having equal magnitude in the opposite direction
[INTRODUCTION TO STRUCTURAL PRINCIPLES, BEAMS AND COLUMNS : SUMMARY]
Pete Silver and Will McLean, Introduction to Architectural Technology (London: Laurence King, 2008)
Francis D.K.Ching , A Visual Dictionary of Architecture (New York: Van Nostrand Reinhold, 1997)
Derek Osbourn , rev. Roger Greeno, Mitchell’s: Introduction to Building, 2nd ed. (Harlow: Longman, 1997)
Jack Stroud Foster and Roger Greeno, Mitchell’s: Structure & Fabric, Part 1, 7th ed. (Harlow: Prentice Hall, 2007)
Jack Stroud Foster, Raymond Harington and Roger Greeno , Mitchell’s: Structure & Fabric, Part 2, 7th ed. (Harlow: Pearson Prentice Hall, 2007)
Alan Everett, rev. C.M.H. Barritt, Mitchell’s: Materials, 5th ed. (Abingdon: Routledge, 2013)
Peter Burberry, Mitchells: Environment and Services, 8th ed. (Harlow: Longman, 1997)
Alan Blanc, Mitchell’s: Internal Components (Harlow: Longman, 1994)
Michael McEvoy, Mitchell’s Building Series: External Components (Abingdon: Routledge, 2014)
Yvonne Dean, Mitchell’s Building Series: Finishes, 4th ed. (Abingdon: Routledge, 2014)
Yvonne Dean, Mitchell’s: Materials Technology (Harlow: Longman, 1996)
J. B. McKay, McKay’s Building Construction (Shaftesbury: Donhead, 2005); also available as separate volumes
Sophie Pelsmakers, The Environment Design Pocketbook (London: RIBA, 2012)
Charlotte Baden-Powell, Jonathan Hetreed and Ann Ross, Architect’s Pocket Book, 4th ed. (Oxford: Architectural Press, 2011)
Matthys Levy and Mario Salvadori, Why Buildings Stand Up: The Strength of Architecture(London: W.W. Norton, 1990)
Matthys Levy and Mario Salvadori, Why Buildings Fall Down: How Structures Fail (London: W.W. Norton, 1992)
Austin Williams, Shortcuts: Book 1: Structure and Fabric (London: RIBA, 2008)
Austin Williams, Shortcuts: Book 2: Sustainability and Practice(London: RIBA, 2008)
[RECOMMENDED READING: BOOKS]
LECTURE 1:
INTRODUCTION TO STRUCTURAL PRINCIPLES, BEAMS AND COLUMNS
LECTURE 2:
LOAD-BEARING WALLS AND STRUCTURAL OPENINGS
LECTURE 3:
TRUSSES, FRAME STRUCTURES AND SLABS
LECTURE 4:
COMPLEX STRUCTURAL SYSTEMS
LECTURE SERIES 1: STRUCTURE AND FORM
Architects’ Journal
[RECOMMENDED READING: MAGAZINES / SERIES]
Architects’ Working Details (Architect’s Journal/EMAP)
Detail magazine
[RECOMMENDED READING: MAGAZINES / SERIES]
LOAD-BEARING WALLS
Transfer of loads
Crushing
Eccentric Loading
Buckling
Overturning
f (stress) = P (force) / A (area)
UNITS: N/mm2 (1 Pascal (Pa) = 1 N/m2)
[FUNDAMENTAL PRINCIPLES: STRESS]
Compressive
stress
distributed
Compressive
stress increases
towards the base
Battered wall
WALLS: TRANSFER OF LOADS
Vertical wall
1. Closely spaced beams/loads:
even distribution of loads
2. Opening in the wall:
increase loading around edges of window
WALLS: TRANSFER OF LOADS
3. Wider spaced beams/loads:
more uneven distribution of loads,
especially at head of wall
4. Very widely spaced beams/loads:
very uneven distribution of loads at head
and base of wall
5. Very widely spaced beams/loads:
pilasters used to carry load
WALLS: TRANSFER OF LOADS
• Loads should usually be concentrated in the middle third of the horizontal
section of the column to prevent tensile stresses developing
[COLUMNS: ECCENTRIC LOADING]
• Crushing is caused by
over-stressing a
material and is avoided
by adequate thickness
at all points to keep the
stresses within the safe
compressive strength
of the material.
WALLS: CRUSHING AND ECCENTRIC LOADING
• Eccentric loading
increases the
compressive stress in
the wall on the loaded
side and decreases on
the other, causing
bending in the wall.
• The greater the slenderness ratio, the greater
the tendency for a wall/column to buckle.
WALLS: BUCKLING
[COLUMNS: BUCKLING]
The tendency for a wall
to buckle relates to its
stiffness.
Methods to reduce
buckling in a wall:
- limit height
- increase thickness
- buttresses
- intersecting walls
- intersecting floors/roof
- reduce loads
WALLS: BUCKLING
WALLS: BUCKLING
WALLS: OVERTURNING
resultant force
within area of
buttresses
WALLS: OVERTURNING
WALLS: OVERTURNING - BUTTRESSES
WALLS: OVERTURNING - BUTTRESSES
WALLS: OVERTURNING - BUTTRESSES
Notre Dame Cathedral, Paris, 14th century
WALLS: OVERTURNING - BUTTRESSES
STRUCTURAL OPENINGS
Greek and Roman Architecture
Lintels
Arches
STRUCTURAL OPENINGS: GREEK AND ROMAN ARCHITECTURE
STRUCTURAL OPENINGS: LINTELS
Active force/load
Transfer of load to supports
Reaction
STRUCTURAL OPENINGS: LINTELS
Reaction
STRUCTURAL OPENINGS: ARCHES
Catenary Curve
The shape assumed by a hanging
chain or cable when supported
only at its ends.
Parabola
The shape assumed by a hanging
chain or cable when a vertical
load is uniformly distributed
across it’s width. It is almost
identical to a catenary curve (but
not quite)
STRUCTURAL OPENINGS: ARCHES
STRUCTURAL OPENINGS: ARCHES
STRUCTURAL OPENINGS: ARCHES
STRUCTURAL OPENINGS: ARCHES
St Chapelle, Paris, 13th century
Antoni Gaudi, Catenary Model
Antoni Gaudi, Casa Mila, Barcelona, 1910
Antoni Gaudi, Catenary Model
Antoni Gaudi, La Sagrada Familia
Cathedral, Barcelona, 1882-2026
Antoni Gaudi, Catenary Model
Richard Hawkes, Arched Eco House, 2009
Grand Designs video link
Sheffield Winter Gardens, Pringle Richards
Sharratt Architects and Buro Happold
(Structural Engineers), 2003
SUMMARY
• Load-Bearing Walls
-Transfer of loads
- Crushing
- Eccentric loading
- Buckling
- Over-turning
• Structural Openings
-Lintels
- Arches
LOAD-BEARING WALLS AND STRUCTURAL OPENINGS: SUMMARY