Engineering challenge in safeguarding and sustainability of architectural heritage Miloš F. Drdácký Institute of Theoretical & Applied Mechanics Institute of Theoretical & Applied Mechanics of the Academy of Sciences of the Czech Republic, v.v.i. ARCCHIP Centre of Excellence (Advanced Research Centre for Cultural Heritage Interdisciplinary Projects) Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007

Safeguarding of architectural heritage Important European Issue Science Engineering Social & Political Matter Environment & Sustainability Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007

Structural heritage values Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Failure of a Gothic vault of St.Francesco church in Assisi (I) Diamond vault in Franciscan Monastery in Kadaň (CZ)

Integrated qualities Aesthetic Functional Technological Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007

Testing of stress distribution in bronze sculpture & inner iron frame National Theatre in Prague St.Trinity Column Olomouc

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Forged hinges with distributed nails & screws (distributed & reduced reaction forces) Structural craft lessons Carpentry door frame with locked corner stiffeners (rigid corner)

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Origin of traces Low work Long felling axe High work Broad axe Examples of carpentry technological traces Log squaring traces left handed carpenter right handed Transparent plastic sheet for trace analysis (below) Traces by left handed carpenter worked above the waist level on a horizontally oriented hewn log

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Rotating crane for roof repair on medieval castle Two way moveable crane for lifting sculptures Proof load tests of timber crane replicas

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Diagnostics & Damage Analysis Imager plate X-ray source X-ray Discovered wood decay & nails, hidden details & fasteners Resistance drilling sound wood cracks decayed area Videoscopy Driven rod penetration Ultrasonics

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Non-standard specimen small sample testing of material characteristics Cutting out wood strands 7x7mm rect. triangle Wood 4.5 mm Core drilling Tension test Compression test Stone & Mortar Bending test - mortar Compression test Shear test Splitting test

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 X-ray Micro-tomography X-ray source Turntable with loading device Medipix detector Calibration carousel Concrete specimen (2x7x13 mm) Principle & set up

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Modeling & testing of climate effects SP01 SP02 SP03 SP04 rain wind Temperature differences on wet surface during cycling 3D laser scanning Simplified FEM Model Process of warming from 5°C to 15°C – surface temperature after 2 hours of heating Failure analysis Stresses in St. Vitus tracery during warming Environmental fatigue

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Lessons from historic materials & development of compatible restoration materials Mortars with fibres Pozzolanic mortars Study of effective stresses in non- compatible filling & original material exposed to real temperature changes Distribution of stresses inside and around filling shaped as truncated pyramid & truncated cone 75 mm thick (above) and as truncated pyramid 15 mm thick (left)

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Testing & modeling of air flow around complex architectural forms Wind tunnel test models & CFD computed velocity streamlines around the tower

Civil Engineering VSU “Lyuben Karavelov”, Sofia, May 15, 2007 Thank you for your attention