professor emeritus u.s. military academy at west point€¦ · •attacks by vikings, muslims, and...
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Stephen Ressler, P.E., Ph.D.Professor EmeritusU.S. Military Academy at West Point
Introduction
Education: B.S. – U.S. Military Academy at West Point (1979)
M.S.C.E. & Ph.D. – Lehigh University
Master of Strategic Studies – U.S. Army War College
Professional: Commissioned officer, Army Corps of Engineers
Deployments to Somalia and Afghanistan
Professor of Civil Engineering, USMA
Retired from active duty in 2013
Scholarly Interests: Structural engineering
Engineering education
Engineering in the ancient & medieval worlds
HOMEWORK #1:The Great Bridges Scavenger Hunt
• Lecture #3: “A Field Guide to the Great Bridges of Bright Horizons 38 & Times Journeys 17”
• The 18 bridges in this handout will be addressed in the lecture.
• YOUR MISSION: Visit as many of these bridges as possible at our upcoming ports of call.
Win fabulous prizes!
HOMEWORK #2:Discovery Learning
• If you see a particularly interesting bridge that isn’t in the “Scavenger Hunt” handout, e-mail me a photo no later than August 21st.
• I will integrate your bridge into Lecture #3.
My e-mail: sjressler@gmail.com
Stephen Ressler, P.E., Ph.D.Professor EmeritusU.S. Military Academy at West Point
The Medieval Castle
• Private fortified residence of a lord or noble
• Etymology: castrum → castellum → castel→ castle
• Purposes:• Defend key terrain or route
• Pacify and control a region
• Base for offensive operations
• Administrative center
• Symbol of power
Origins
• Breakdown of the Carolingian Empire (late 9th century)
• Attacks by Vikings, Muslims, and Magyars
• Influenced by:
Celtic oppida Roman and Byzantine fortifications
The Walls of Constantinople
The Motte and Bailey Castle
motte
keep(donjon)
bailey
palisade
moat
bridge
palisade
The Motte and Bailey: An Evolving Technology
• Developed in the 10th century
• Closely tied to feudal society
• Easy to build with unskilled labor
• Effective against unsophisticated enemies
• Built throughout France, Holy Roman Empire, British Isles, Denmark, and the Low Countries
• Many local variations
• Timber structures gradually rebuilt in stone
• Became obsolete in the 12th-14th centuries Launceston Castle, Cornwall, England(11th-12th century)
Stimuli for Change
Advances in stone masonry The Crusades
Advances in siegecraft
Medieval Siegecraft
• Treachery
• Investment (blockade)
• Escalade
• Siege towers
• Battering rams
• Artillery (catapults)
• Mining
Medieval Artillery
Ballista
Onager
Trebuchet
Medieval Artillery: How it Worked
Video clip from “Do It Yourself Engineering,” produced by The Great Courses
The New Paradigm: Carrickfergus Castle
The largest and best-preserved Norman castle in Ireland
Carrickfergus Castle
Belfast
AntrimCoast Scotland
Giant’sCauseway
CarrickfergusCastle
NorthChannel
Belfast Lough
Carrickfergus: A Tumultuous History
• 1177 – Castle built by John de Courcy as a base for his conquest of Ulster
• 1204 – de Courcy ousted by Hugh de Lacy acting on behalf of King John
• 1210 – Castle captured by King John; de Lacy exiled
• 1216 – Castle expanded by order of the Crown
• 1226 – Hugh de Lacy returns; further expands the castle
• 1315 – Richard de Burgh implements improvements to gatehouse
• 1315-16 – Siege by Scottish army under Edward Bruce
• 1556-1820 – Major modifications to accommodate artillery and to incorporate the castle with the town walls
Phase I
Phase II
Phase III
Phase IV
PhasesV-X
Carrickfergus: Phases I-IV
Sketchup Model
Let’s build a castle!
The Norman Castle: Major Components
keepinner ward
curtain walls
great hall
middle ward
outer ward
gatehouse
projectingtowers
postern gate
Castle Design: The Big Picture
• Location:• Strategic control of Belfast Lough• Water on three sides; a natural harbor• Spring for water supply
• Concentric design:• Succession of mutually supporting defensive
lines—ditch, gatehouse, towers, curtain walls, inner and outer wards, keep
• Oriented toward the most dangerous approaches
• Adapted to the local terrain
• Projecting towers to cover curtain walls
Defensive Features: Details, Details, Details • Curtain walls:
• Crenellations• Wall walk• Hoardings• Machicolations• Arrow loops
• Gatehouse• Drawbridge• Portcullis• Murder hole
• Keep• Windows• Stairways• Latrines
• Postern Gate
Every detail has a purpose!
Cahir Castle
Curtain Walls: Crenellations & Wall Walk
Embrasures for cannon(added in 16th century)
Hoardings & Machicolations
Carcasonne Cahir Castle
Arrow Loops
Carrickfergus Ferns Castle Ferns Castle
Defensive Features: The Gatehouse
Projectingcirculartowers
Portcullis
Drawbridge
Machicolation
Inward-facingarrow loops
Drawbridge & Portcullis
Murderhole
Roscrea Castle
Trim Castle
Lifting Apparatus
Roscrea Castle Cahir Castle
The Keep
Staircases
Carrickfergus Castle Ferns Castle Cahir Castle
Latrines
The Postern Gate
QUIZ: Siege Methods vs. Defensive Measures
• Investment
• Escalade
• Siege towers
• Battering rams
• Artillery
• Mining
Siege Methods
Sortie
Countermining
Artillery
Defensive & Active Measures
Large supply of food & water Small garrison
High walls TowersMoat Crenellations Machicolations Arrow loops
High walls TowersMoat Crenellations Arrow loops
Thick walls Machicolations
Moat
Moat
Thick walls
Thick walls
Concentricdesign
Sortie
Sortie
Build on bedrock
Towers
Sortie
Variations on a Theme: Trim Castle
Barbican Gate & Battered Walls
Batteredwalls
Barbican Gate
Battered Walls
More Variations
Nenagh Castle, IrelandRoscrea Castle, Ireland
The Castle and Feudal Society
• Local protection from external invaders, following the breakdown of central authority
• A reflection of the persistent medieval struggle between king and aristocracy:
• Royal castles – Used to impose control on the nobility
• Baronial castles – A local hereditary power base, independent of central authority
• Basis for the control of local populations, towns, fields, mills, forests, toll roads
• Garrisoned by the lord’s vassals
• Often enclosed and protected a church
• Served as a stimulus for economic development
“The strong built castles, the weak became their bondsmen.”
Medieval Technological Development
• Warfare as a stimulus for technological development
• The quintessential arms race—castle vs. siegecraft
• Interplay between military and civil technologies
• Increasing complexity and scale →escalating costs → centralization of political power
• Role of disruptive technologies
Carrickfergus in the Gunpowder Era
Questions?
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