Response of Masonry Cavity Cladding under Blast Loading J. Gu, L. Macorini, B. A. Izzuddin Computational Structural Mechanics Group Civil and Environmental Engineering Department Imperial College London

Cladding systems under blast loading Khobar Towers bomb, 1996, Saudi Arabia Quarters for foreign military personnel most of the 19 U.S. servicemen who lost their lives were heavily injured by the high-speed projectiles of the failed exterior cladding Tianjin explosions, 2015, China Civil-Comp Conference, 2015, Prague 1/8

Contents Reduced models of masonry cavity cladding Modelling techniques Responses of the reduced models under blast loading Comparison of the reduced models against a complete model Civil-Comp Conference, 2015, Prague 2/8

Contents Reduced models of masonry cavity cladding Modelling techniques Responses of the reduced models under blast loading Comparison of the reduced models against a complete model Civil-Comp Conference, 2015, Prague 2/8

Masonry cavity cladding Unconfined reduction: Unrestrained side edges Confined reduction: Fully restrained side edges Height: 900mm Length: 1600mm Depth: 102.5mm+80mm+100mm=282.5mm Civil-Comp Conference, 2015, Prague 3/8

Contents Reduced models of masonry cavity cladding Modelling techniques Responses of the reduced models under blast loading Comparison of the reduced models against a complete model Civil-Comp Conference, 2015, Prague 2/8

Modelling techniques Mesoscale description for masonry panels Civil-Comp Conference, 2015, Prague 4/8

Modelling techniques Mesoscale description for masonry panels Partitioning scheme: each panel is modelled as a separate child partition to allow parallel computation. Correlation of panels and wall ties are achieved and realized on the parent level. Civil-Comp Conference, 2015, Prague 4/8 Partition 1 Partition 2

Modelling techniques Mesoscale description for masonry panels Partitioning scheme: each panel is modelled as a separate child partition to allow parallel computation. Correlation of panels and wall ties are achieved and realized on the parent level. Mix-dimensional coupling: master-slave elements are adopted to couple the 6-dof nodes of the beam-column elements with the 3-dof nodes in the mesoscale models. Civil-Comp Conference, 2015, Prague 4/8 Partition 1 Partition 2

Contents Reduced models of masonry cavity cladding Modelling techniques Responses of the reduced models under blast loading Comparison of the reduced models against a complete model Civil-Comp Conference, 2015, Prague 2/8

Unconfined model reduction Concentrated deformation: Deformation is concentrated at lowest bed joints while panels remain relatively undamaged. Civil-Comp Conference, 2015, Prague 5/8

Unconfined model reduction Concentrated deformation: Deformation concentrates at the lowest bed joints while the panels remain relatively undamaged. Brittle failure: With Δt=100ms, when the intensity of the applied deflagration wave is above 40mbar, brittle failure is triggered. Damage increases with intensity Out-of-plane displacements at the top of both panels Civil-Comp Conference, 2015, Prague 5/8

Unconfined model reduction Concentrated deformation: Deformation is concentrated at lowest bed joints while panels remain relatively undamaged. Brittle failure: With Δt=100ms, when the intensity of the applied deflagration wave is above 40mbar, brittle failure is triggered. Damage increases with intensity. Quasi-static response: Prior to brittle failure, blast load is fully transferred to floor system; after brittle failure, transferred blast load drops significantly. Applied and transferred blast loads 40mbar-intensity 80mbar-intensity Civil-Comp Conference, 2015, Prague 5/8

Confined model reduction Negligible deformation of block leaf: Due to the limited load-transferring ability of wall ties and enhanced stiffness, the block leaf experiences very small deformations. Civil-Comp Conference, 2015, Prague 6/8

Confined model reduction Negligible deformation of block leaf: Due to the limited load-transferring ability of wall ties and enhanced stiffness, the block leaf experiences very small deformations. Distributed deformation in brick leaf: Deformation along restrained edges and central vertical line. Civil-Comp Conference, 2015, Prague 6/8

Confined model reduction Negligible deformation of block leaf: Due to the limited load-transferring ability of wall ties and enhanced stiffness, the block leaf experiences very small deformations. Distributed deformation in brick leaf: Deformation along restrained edges and central vertical line. Ductile response: As intensity increases from 100mbar to 600mbar, quasi-static response is observed Out-of-plane displacement at the top of the brick leaf Civil-Comp Conference, 2015, Prague 6/8

Contents Reduced models of masonry cavity cladding Modelling techniques Responses of the reduced models under blast loading Comparison of the reduced models against a complete model Civil-Comp Conference, 2015, Prague 2/8

Verification against complete model Unconfined reduction Confined reduction Complete model 6m W pl1 (N/mm) Confined reduction Civil-Comp Conference, 2015, Prague 7/8

Verification against complete model Unconfined reduction Confined reduction Complete model 6m Confined reduction Civil-Comp Conference, 2015, Prague 7/8

Verification against complete model Unconfined reduction Confined reduction Complete model 6m Confined reduction Civil-Comp Conference, 2015, Prague 7/8

Verification against complete model Applied and transferred blast loads of the complete model Civil-Comp Conference, 2015, Prague 8/8

J. Gu, L. Macorini, B. A. Izzuddin Computational Structural Mechanics Group Civil and Environmental Engineering Department Imperial College London