NEW INTEGRATED KNOWLEDGE BASED NIKER APPROACHES TO THE PROTECTION OF CULTURAL Grant Agreement n° HERITAGE FROM EARTHQUAKE-INDUCED RISK 244123 Deliverable 3.2 Critical review of retrofitting and reinforcement techniques related to possible failure Due date: June 2010 Submission date: December 2010 Issued by: POLIMI WORKPACKAGE 3: Damage based selection of technologies Leader: POLIMI PROJECT N°: 244123 ACRONYM: NIKER TITLE: New integrated knowledge based approaches to the protection of cultural heritage from earthquake-induced risk COORDINATOR: Università di Padova (Italy) START DATE: 01 January 2010 DURATION: 36 months INSTRUMENT: Collaborative Project Small or medium scale focused research project THEME: Environment (including Climate Change) Dissemination level: PU Rev: FIN NEW INTEGRATED KNOWLEDGE BASED NIKER APPROACHES TO THE PROTECTION OF CULTURAL Grant Agreement n° HERITAGE FROM EARTHQUAKE-INDUCED RISK 244123 1 INTRODUCTION ......................................................................................................................... 3 1.1 Description and objectives of the workpackage .................................................................... 3 1.2 Objective and structure of the deliverable ............................................................................. 3 2 GENERAL REMARKS ................................................................................................................ 5 2.1 Repair criteria ........................................................................................................................ 6 2.1.1 General - Selection of optimal solutions .......................................................................... 6 2.2 Compatibility of the intervention ............................................................................................ 9 2.2.1 Traditional technique ....................................................................................................... 9 2.2.2 Modern techniques ........................................................................................................ 12 3 IMPROVEMENT OF MASONRY QUALITY AND EQUILIBRIUM ............................................ 16 3.1 Strengthening of masonry walls .......................................................................................... 16 3.1.1 Grout injection ................................................................................................................ 16 3.1.2 Jacketing by R.C. plaster ............................................................................................... 22 3.1.3 Structural Repointing (Deep repointing) ........................................................................ 25 3.1.4 Bed-Joint Reinforced Repointing ................................................................................... 39 3.1.5 Anti-expulsion tie-rods ................................................................................................... 43 3.1.6 Insertion of artificial headers .......................................................................................... 44 3.1.7 FRP/SRP/SRG application ............................................................................................ 45 3.1.8 Confinement for columns and pillars ............................................................................. 47 3.1.9 Vertical stiffening of earthen building elements ............................................................. 49 3.1.10 Others ............................................................................................................................ 50 3.2 Local repair of cracks or of decayed portions ...................................................................... 51 3.2.1 Local Dismantling and Reconstruction (“scuci-cuci”, i.e. “unstitch-stitch”) ..................... 51 3.2.2 Grout injection of cracks ................................................................................................ 53 3.2.3 Bed Joint Reinforced Repointing ................................................................................... 57 3.2.4 FRP/SRP/SRG application ............................................................................................ 57 3.2.5 Crack stitching and anchoring ....................................................................................... 57 3.2.6 Others ............................................................................................................................ 60 3.3 Stability improvement .......................................................................................................... 61 3.3.1 Enlargement .................................................................................................................. 61 3.3.2 Buttresses ...................................................................................................................... 62 4 IMPROVEMENT OF SUB-ASSEMBLAGE CONNECTIONS ................................................... 66 4.1 Lack of connection between walls ....................................................................................... 66 4.1.1 Tie beams ...................................................................................................................... 67 4.1.2 Tie-rods .......................................................................................................................... 71 4.1.3 Hysteretic dissipation anchor ......................................................................................... 75 Damage based selection of technologies D3.2 1 NEW INTEGRATED KNOWLEDGE BASED NIKER APPROACHES TO THE PROTECTION OF CULTURAL Grant Agreement n° HERITAGE FROM EARTHQUAKE-INDUCED RISK 244123 4.2 Lack of connections between walls and Floors/roof ............................................................ 77 5 OPTIMIZATION OF VAULT PERFORMANCE ......................................................................... 80 5.1 Direct interventions (applied to vaults) ................................................................................ 80 5.1.1 Local Dismantling and Reconstruction (“scuci-cuci”) ..................................................... 80 5.1.2 Grout injection of the cracks .......................................................................................... 80 5.1.3 Structural Repointing (Deep repointing) ........................................................................ 80 5.1.4 Bed Joint Reinforced Repointing ................................................................................... 80 5.1.5 FRP/SRP/SRG application ............................................................................................ 80 5.1.6 Use of extrados R.C. jacketing ...................................................................................... 82 5.1.7 Reducing the loads from extrados infilling ..................................................................... 83 5.1.8 Extrados stiffening elements, mainly in barrel vaults (“frenelli”) .................................... 83 5.2 Indirect interventions (supporting masonry stability) ........................................................... 83 5.2.1 Insertion of the tie-rods and confinement ...................................................................... 83 5.2.2 Buttresses ...................................................................................................................... 84 6 SEISMIC IMPROVEMENT OF WOODEN FLOORS ................................................................. 86 6.1 Improvement interventions through the use of wood (IPM) ................................................. 87 6.1.1 Orthogonal or diagonal planking .................................................................................... 87 6.1.2 Only wood technique - Timber flange connected by dowels to main beams, (Modena et al., 1997c) ................................................................................................................................. 88 6.2 Improvement interventions through the use of a reinforced concrete cooperating slab ...... 89 6.2.1 The Turrini - Piazza (1983) method ............................................................................... 90 6.2.2 The Alessi, Lamborghini, Raffagli (1989) system .......................................................... 90 6.2.3 The Tampone (1992) system ......................................................................................... 91 6.3 Improvement interventions through the use of steel elements ............................................ 92 6.3.1 Metallic plates ................................................................................................................ 92 6.3.2 Metallic diagonals .......................................................................................................... 92 6.3.3 Intervention using metallic plates and diagonals (Gattesco et al., 2007) ....................... 93 6.4 Improvement interventions through the use fibro-reinforced composite materials .............. 94 6.4.1 Intervention using FRP, (Angotti et al., 2005) ................................................................ 95 6.4.2 Intervention using GFRP, (Borri 2004b) ........................................................................ 96 6.5 Final remarks ....................................................................................................................... 96 6.5.1 Available experimental procedures and analytical and numerical models .................... 96 7 IMPROVEMENT