FORENSIC ENGINEERINGINVESTIGATION OF STRUCTURAL FAILURE
BY
PROF Dato Dr. SABARUDIN MOHD
E-mail : [email protected]
FAILURE OF STRUCTURESSTRUCTURAL DAMAGESNON-STRUCTURAL DAMAGES1. CLASSIFICATION
STRUCTURAL DAMAGESDESIGN DEFICIENCY
INCORRECT ASSUMPTIONBoundary ConditionJoints and Members ConnectionStructural behaviours
WRONGLY MODELLEDInability of the designer to modelthe structure accuratelySimplified ModelsChange of structural systemsCAN BE CATASTROPHIC
STRUCTURAL DAMAGESDESIGN DEFICIENCY
UNDERESTIMATE OF LOADSError in dealing with live loadsComputer input
OVERESTIMATE OF MATERIAL CAPACITY
FOUNDATION SETTLEMENT
STRUCTURAL DAMAGESCONSTRUCTION ERROR
JOINTS AND MEMBERS CONNECTION
SUBSTANDARD MATERIALS
FABRICATION AND ERECTION
INADEQUATE SITE CONTROL
LACK OF UNDERSTANDING
CHANGE OF USE
GREATER LOADS THAN IT WAS DESIGNED
REMOVAL OF STRUCTURAL MEMBERS
STRUCTURAL EXTENSION
TRIMMING OF STRUCTURAL MEMBERSSTRUCTURAL DAMAGES
FIRE
WEAKENING OF STRUCTURAL MEMBERS
PHYSICAL DAMAGE
IMPACT LOADINGS
VEHICULAR
CRANES
STRUCTURAL DAMAGES
SPECIAL LOADING ( Load Determination can be found elsewhere )
EARTHQUAKE
TEMPERATURE CHANGES
EXPLOSION, BOMBING
FIRE LOADS
FOUNDATION SETTLEMENTSTRUCTURAL DAMAGES
NON-STRUCTURAL DAMAGESTIME DEPENDENT AND USUALLY NON-CATASTROPHICLOSS OF SERVICEABILITY Non-Structural components are not properly functioning,e.g. windows, doors Floors with excessive displacement
FATIGUE Can lead to structural failure, especially at joints andconnections
CREEP Loss of serviceability and can lead to structural failure
NON-STRUCTURAL DAMAGESSHRINKAGE Concrete shortens due to chemical and drying. For concrete with W/C 0.4 0.7, shrinkage strains are between 400 600 X10-6
Shrinkage Strains X 10-6Time of Drying28 days2 yearsW/C = 0.7W/C = 0.4400600
NON-STRUCTURAL DAMAGESSTRESS RELAXATIONDue to temperature, creep, fatigue. Can cause stressredistribution, which may lead to structural failure
LOSS OF PRESTRESSING FORCE Short term and long term, due to creep, stressrelaxation in tendon, efficiency of stress block, maylead to structural failure and can be catastrophic
CORROSION Environmental factors, loss of section, stressredistribution, can lead to structural failure
ABRASIONFloors, columns, piers of marine structures due tovehicular, sand and shingle.