Structural survey and diagnosis of historical constructions - the experience of the Construction Institute

48 Visual assessment of the chimney damages, modification: cut and saturation Vitruvio International journal of Architecture Technology and Sustainability Volume 1 49 aBStraCt 1 CONSTRUCT-LESE, Construction Institute, Faculty of Engineering, University of Porto (IC-FEUP) 2 CONSTRUCT-LESE, Civil Engineering Department, Faculty of Engineering, University of Porto (FEUP) 3 RISCO, Civil Engineering Department, University of Aveiro (UA) 4HEȩSUSTAINABLEȩREHABILITATIONȩOFȩANȩHISTORICALȩCONSTRUCTIONȩCANȩONLYȩBEȩACHIEVEDȩIFȩTHEREȩISȩADEQUATEȩKNOWLEDGEȩ ABOUTȩITSȩSTATEȩOFȩCONSERVATIONȩ4OȩOBTAINȩSUCHȩKNOWLEDGEȩRELIABLEȩSTRUCTURALȩSURVEYȩANDȩDIAGNOSISȩPROCEDURESȩ NEEDȩ TOȩ BEȩ EMPLOYEDȩ !Nȩ OVERALLȩ DEFINITIONȩ OFȩ THEȩ MOREȩ IMPORTANTȩ TECHNICALȩ PROCEDURESȩ THATȩ NEEDȩ TOȩ BEȩ CONSIDEREDȩ ISȩ ADDRESSEDȩ TOȩ PROVIDEȩ GENERALȩ GUIDELINESȩ FORȩ THEȩ STRUCTURALȩ SURVEYȩ ANDȩ DIAGNOSISȩ OFȩ HISTORICALȩ CONSTRUCTIONSȩ!ȩMOREȩDETAILEDȩDESCRIPTIONȩOFȩSOMEȩOFȩTHEȩMETHODSȩISȩTHENȩALSOȩPERFORMEDȩ3EVERALȩCASEȩSTUDIESȩ AREȩTHENȩPRESENTEDȩTOȩILLUSTRATEȩTHESEȩAPPROACHESȩEMPHASIZINGȩTHEȩIMPORTANCEȩOFȩTHEȩTECHNICALȩINSPECTIONȩANDȩ SURVEYȩDATAȩINȩTHEȩREHABILITATIONȩACTIONSȩTHATȩWEREȩDEVELOPEDȩINȩEACHȩCASEȩSTUDY KEYWordS structural survey, structural diagnosis, structural conservation, rehabilitation, historical constructions Structural survey and diagnosis of historical constructions the experience of the Construction Institute Esmeralda Paupério1, Xavier Romão2, António Arêde2, Aníbal Costa3, Humberto Varum2, João Guedes2, Nelson Vila Pouca2 http://dx.doi.org/10.4995/vitruvio-ijats.2016.5269 50 1. INtrodUCtIoN )TȩISȩCURRENTLYȩACCEPTEDȩTHATȩTHEȩHERITAGEȩORȩVERNACULARȩ VALUEȩOFȩANȩHISTORICALȩCITYȩCENTREȩISȩNOTȩDEFINEDȩBYȩTHEȩ VALUESȩOFȩITSȩINDIVIDUALȩCONSTRUCTIONSȩ3MITHȩETȩALȩ ȩ)NSTEADȩTHISȩVALUEȩISȩTHEȩRESULTȩOFȩTHEȩUNIQUEȩ FEATURESȩANDȩINTERACTIONSȩTHATȩCHARACTERIZEȩTHEȩSETȩOFȩ CONSTRUCTIONSȩASȩAȩWHOLEȩ"YȩACKNOWLEDGINGȩTHISȩFACTȩ ANDȩINTEGRATINGȩITȩWITHȩECONOMICȩANDȩSUSTAINABILITY RELATEDȩISSUESȩITȩBECOMESȩCLEARȩTHATȩTHEȩADEQUATEȩ REQUALIFICATIONREHABILITATIONȩOFȩHISTORICALȩCONSTRUCTIONSȩ NEEDSȩTOȩINVOLVEȩEFFORTSȩTOȩMAINTAINȩTHEIRȩCOMPONENTSȩ WHILEȩREDISCOVERINGȩTRADITIONALȩCONSTRUCTIONȩTECHNIQUESȩ TOȩUNDERSTANDȩTHEIRȩPRESERVATIONȩISSUES "YȩSETTINGȩTHATȩONEȩOFȩTHEȩGOALSȩOFȩTHEȩSUSTAINABLEȩ REHABILITATIONȩOFȩHISTORICALȩCONSTRUCTIONSȩSHOULDȩBEȩTOȩ PRESERVEȩTHEIRȩCOMPONENTSȩNAMELYȩTHEIRȩSTRUCTURALȩ ELEMENTSȩASȩMUCHȩASȩPOSSIBLEȩSEVERALȩFACTORSȩMUSTȩ THENȩBEȩINVOLVEDȩTOȩACHIEVEȩTHISȩGOALȩ!CKNOWLEDGINGȩ THEȩNEEDȩTOȩHAVEȩADEQUATEȩKNOWLEDGEȩABOUTȩTHEȩ STATEȩOFȩCONSERVATIONȩOFȩTHEȩCONSTRUCTIONȩANDȩOFȩITSȩ ELEMENTSȩISȩPERHAPSȩTHEȩMOSTȩIMPORTANTȩONEȩ4HROUGHȩ THISȩKNOWLEDGEȩWHICHȩMUSTȩBEȩOBTAINEDȩUSINGȩRELIABLEȩ SURVEYȩOPERATIONSȩTHEȩSTRUCTURALȩCAPACITYȩOFȩANȩEXISTINGȩ CONSTRUCTIONȩCANȩTHENȩBEȩESTABLISHEDȩASȩWELLȩASȩITSȩ LEVELȩOFȩSAFETYȩ4HEȩIMPORTANCEȩOFȩTHESEȩRESULTSȩMAKESȩ THISȩKNOWLEDGEȩINSTRUMENTALȩFORȩTHEȩDECISIONMAKINGȩ PROCESSESȩTHATȩWILLȩDEFINEȩWHICHȩREHABILITATIONȩACTIONSȩ NEEDȩTOȩBEȩUNDERTAKENȩINȩTHEȩCONSTRUCTIONȩ/NLYȩBYȩ HAVINGȩTHISȩKNOWLEDGEȩWILLȩITȩBEȩPOSSIBLEȩTOȩDETERMINEȩ IFȩANDȩWHICHȩCOMPONENTSȩOFȩAȩGIVENȩCONSTRUCTIONȩCANȩ BEȩMAINTAINEDȩ!SȩSUCHȩTHEȩECONOMICȩCOSTSȩOFȩREPAIRȩ ANDORȩSTRENGTHENINGȩOPERATIONSȩTHATȩMAYȩBEȩREQUIREDȩ TOȩREHABILITATEȩAȩCERTAINȩCONSTRUCTIONȩAREȩALSOȩAȩDIRECTȩ CONSEQUENCEȩOFȩTHISȩKNOWLEDGEȩ&ORSYTHȩȩ )NȩTHISȩCONTEXTȩTHEȩCURRENTȩPAPERȩADDRESSESȩSOMEȩOFȩ THEȩMOREȩIMPORTANTȩTECHNICALȩPROCEDURESȩTHATȩNEEDȩTOȩ BEȩCONSIDEREDȩFROMȩTHEȩPOINTȩOFȩVIEWȩOFȩTHEȩSTRUCTURALȩ SURVEYȩANDȩDIAGNOSISȩSTAGESȩINȩORDERȩTOȩOBTAINȩRELIABLEȩ DATAȩSUPPORTINGȩTHEȩSUSTAINABLEȩREHABILITATIONȩOFȩ HISTORICALȩCONSTRUCTIONSȩ!NȩOVERALLȩDEFINITIONȩOFȩTHEȩ PROCEDURESȩINVOLVEDȩISȩFIRSTȩPERFORMEDȩTOȩPROVIDEȩAȩSETȩ OFȩGENERALȩGUIDELINESȩWHICHȩISȩTHENȩFOLLOWEDȩBYȩAȩMOREȩ DETAILEDȩDESCRIPTIONȩOFȩSOMEȩOFȩTHEȩMETHODSȩ3EVERALȩ CASEȩSTUDIESȩAREȩTHENȩBRIEFLYȩPRESENTEDȩTOȩILLUSTRATEȩ ANDȩCOMPLEMENTȩSOMEȩOFȩTHEȩAPPROACHESȩPREVIOUSLYȩ DISCUSSEDȩEMPHASIZINGȩTHEȩIMPORTANCEȩOFȩTHEȩTECHNICALȩ INSPECTIONȩANDȩSURVEYȩDATAȩINȩTHEȩREHABILITATIONȩACTIONSȩ THATȩWEREȩDEVELOPEDȩ4HEȩSELECTEDȩCASEȩSTUDIESȩREFLECTȩ SOMEȩOFȩTHEȩWORKȩTHATȩHASȩBEENȩCARRIEDȩOUTȩOVERȩTHEȩ PASTȩYEARSȩBYȩTHEȩ#ONSTRUCTIONȩ)NSTITUTEȩOFȩTHEȩ&ACULTYȩ OFȩ%NGINEERINGȩOFȩTHEȩ5NIVERSITYȩOFȩ0ORTOȩ0ORTUGALȩINȩ THEȩFIELDSȩOFȩSTRUCTURALȩCONSERVATIONȩREHABILITATIONȩANDȩ STRENGTHENINGȩOFȩHISTORICALȩCONSTRUCTIONSȩ 2. StrUCtUral SUrVEY aNd dIaGNoSIS ProCEdUrES 2.1 GENEral oVErVIEW 4OȩASSESSȩTHEȩSTRUCTURALȩSTABILITYȩANDȩSAFETYȩOFȩ Aȩ GIVENȩCONSTRUCTIONȩADEQUATEȩKNOWLEDGEȩABOUTȩTHEȩ CONSTRUCTIONȩNEEDSȩTOȩBEȩOBTAINEDȩ4OȩENSUREȩTHEȩ SOUNDNESSȩOFȩTHISȩKNOWLEDGEȩAȩSYSTEMATICȩPROCESSȩ MUSTȩBEȩCARRIEDȩOUTȩWHICHȩINVOLVESȩSUITABLEȩDATAȩANDȩ INFORMATIONȩRESEARCHȩPROCEDURESȩTHATȩWILLȩLEADȩTOȩ Aȩ RELIABLEȩDIAGNOSISȩABOUTȩTHEȩSTATEȩOFȩTHEȩCONSTRUCTIONȩ 4HESEȩDATAȩANDȩINFORMATIONȩRESEARCHȩPROCEDURESȩ INVOLVEȩAȩSERIESȩOFȩQUALITATIVEȩANDȩQUANTITATIVEȩ OPERATIONSȩWHEREȩTHEȩLATTERȩAREȩONLYȩPERFORMEDȩIFȩ THEȩFORMERȩAREȩFOUNDȩTOȩBEȩINSUFFICIENTȩTOȩPROVIDEȩ THEȩNECESSARYȩDATAȩ4HESEȩOPERATIONSȩAREȩGENERALLYȩ TERMEDȩSTRUCTURALȩINSPECTIONȩANDȩSURVEYȩPROCEDURESȩ ANDȩINCLUDEȩSITEȩVISITSȩTOȩINSPECTȩTHEȩCONDITIONȩOFȩTHEȩ CONSTRUCTIONȩANDȩITSȩSURROUNDINGSȩANDȩTOȩSURVEYȩTHEȩ RELEVANTȩGEOMETRICȩDATAȩMECHANICALȩPROPERTIESȩOFȩTHEȩ MATERIALSȩSTRUCTURALȩLOADTRANSFERȩMECHANISMSȩANDȩ DAMAGESȩOFȩTHEȩCONSTRUCTIONȩ!LTHOUGHȩAȩTECHNICALȩ INSPECTIONȩINVOLVINGȩJUSTȩAȩVISUALȩASSESSMENTȩISȩSEENȩ TOȩBEȩFUNDAMENTALȩTOȩPROVIDEȩAȩPRELIMINARYȩANALYSISȩOFȩ THEȩCONSTRUCTIONȩITSȩOUTCOMESȩAREȩHIGHLYȩDEPENDENTȩ ONȩTHEȩEXPERIENCEȩANDȩKNOWLEDGEȩOFȩTHEȩANALYSTSȩ THATȩCARRYȩOUTȩTHEȩASSESSMENTȩ4HEREFOREȩITȩISȩALWAYSȩ IMPORTANTȩTOȩINVOLVEȩTWOȩORȩMOREȩANALYSTSȩINȩAȩTECHNICALȩ INSPECTIONȩTOȩALLOWȩFORȩAȩMOREȩINDEPTHȩOBSERVATIONȩ OFȩTHEȩCONSTRUCTIONȩANDȩREDUCEȩTHEȩEXISTINGȩLEVELȩOFȩ UNCERTAINTYȩ&URTHERMOREȩBYȩHAVINGȩMOREȩTHANȩONEȩ ANALYSTȩDOINGȩTHEȩASSESSMENTȩITȩISȩPOSSIBLEȩTOȩDISCUSSȩ THEȩTECHNICALȩVALIDITYȩOFȩWHATȩWASȩOBSERVEDȩANDȩ Vitruvio International journal of Architecture Technology and Sustainability Volume 1 51 SURVEYEDȩTAKINGȩINTOȩACCOUNTȩDIFFERENTȩPOINTSȩOFȩVIEWȩ ANDȩFRAMESȩOFȩREFERENCE !FTERȩGATHERINGȩTHEȩNECESSARYȩINFORMATIONȩABOUTȩTHEȩ CONSTRUCTIONȩTHISȩINFORMATIONȩISȩTHENȩCOMPILEDȩANDȩ ORGANIZEDȩWITHINȩAȩTECHNICALȩINSPECTIONȩREPORTȩTHATȩ WILLȩSERVEȩASȩTHEȩFUNDAMENTALȩINFORMATIONȩTOOLȩFORȩ THEȩSUBSEQUENTȩDEFINITIONȩOFȩTHEȩPOTENTIALȩNEEDȩFORȩ INTERVENTIONSȩ7ITHȩRESPECTȩTOȩTHEȩDAMAGESȩFOUNDȩINȩ THEȩCONSTRUCTIONȩTHEȩREPORTȩUSUALLYȩPRESENTSȩTHEMȩ USINGȩDAMAGEȩMAPSȩ&IGȩȩANDȩDESCRIBESȩTHEIRȩ POTENTIALȩSOURCESȩASȩWELLȩASȩPOSSIBLEȩMEASURESȩTHATȩ MAYȩBEȩREQUIREDȩTOȩREPAIRȩTHEMȩORȩTOȩPREVENTȩTHEMȩ FROMȩSPREADINGȩANDȩINCREASING Humidade Tabique à vistaTabique à vista Destacamento Papel de parede Estuque Destacamento Sujidade Furo Buraco ouFissura Aberta Junta Pavimento Assentamento Granular Desagregação Forte Fissura Madeira Degradação Fuligem Material Falta Empolamento PDA3_1 PDT1_1 PA2_1 PA1_1 1 1 2 2 3 3 4 4 5 5 6 6 Figure 1. Example of a damage map. 2.2 dESCrIPtIoN oF tHE ProCEdUrES 3OMEȩOFȩTHEȩMOREȩRELEVANTȩPROCEDURESȩTHATȩNEEDȩTOȩBEȩ PERFORMEDȩINȩAȩTECHNICALȩINSPECTIONȩAREȩADDRESSEDȩINȩ THEȩFOLLOWINGȩ%VENȩTHOUGHȩNOTȩALLȩOFȩTHEȩPROCEDURESȩ THATȩAREȩDESCRIBEDȩNEEDȩTOȩBEȩINVOLVEDȩINȩAȩCERTAINȩ TECHNICALȩINSPECTIONȩTHEYȩAREȩMENTIONEDȩHEREINȩTOȩ COMMENTȩONȩTHEIRȩUSEFULNESSȩANDȩONȩTHEȩTYPEȩOFȩ MATERIALSȩTOȩWHICHȩTHEYȩCANȩBEȩAPPLIEDȩ4HEȩFOLLOWINGȩ LISTȩOFȩPROCEDURESȩISȩNOTȩEXHAUSTIVEȩBUTȩREPRESENTSȩ 52 WHATȩISȩBELIEVEDȩTOȩBEȩTHEȩBESTȩPRACTICEȩFORȩSTRUCTURALȩ INSPECTIONSȩANDȩSURVEYSȩINȩORDERȩTOȩACHIEVEȩAȩRELIABLEȩ DIAGNOSISȩABOUTȩTHEȩCONSTRUCTIONȩUNDERȩANALYSIS sȩ #HARACTERIZATIONȩOFȩTHEȩOVERALLȩGEOMETRYȩOFȩTHEȩ CONSTRUCTION ȩUSINGȩEXISTINGȩDATAȩORȩUSINGȩSURVEYEDȩ DATAȩOBTAINEDȩFROMȩTRADITIONALȩTOPOGRAPHICȩORȩ PHOTOGRAMMETRICȩTECHNIQUESȩ)NȩTHEȩCASEȩOFȩ CONSTRUCTIONSȩWHEREȩAȩHIGHLYȩDETAILEDȩANDȩRIGOROUSȩ GEOMETRICȩSURVEYȩMAYȩBEȩREQUIREDȩTHEȩUSEȩOFȩLASERȩ SCANNINGȩTECHNIQUESȩCANȩALSOȩBEȩENVISAGEDȩ !ȩ RIGOROUSȩGEOMETRICALȩASSESSMENTȩCANȩOFTENȩLEADȩ TOȩTHEȩIMMEDIATEȩDETECTIONȩOFȩIRREGULARITIESȩSUCHȩASȩ VERTICALȩANDORȩHORIZONTALȩMISALIGNMENTSȩORȩDEVIATIONSȩ OFȩTHEȩSTRUCTUREȩTHATȩCANȩBEȩASSOCIATEDȩWITHȩSTRUCTURALȩ DAMAGEȩORȩANOMALIESȩ"ECKMANNȩANDȩ"OWLESȩ sȩ )DENTIFICATIONȩOFȩTHEȩCURRENTȩSTRUCTURALȩLOAD TRANSFERȩMECHANISMS ȩANDȩPOSSIBLYȩALSOȩOFȩPREVIOUSȩ MECHANISMSȩINȩCASEȩTHEȩCONSTRUCTIONȩHASȩBEENȩ MODIFIEDȩOVERȩTIME sȩ $EFINITIONȩOFȩTHEȩMOREȩIMPORTANTȩELEMENTSȩ OFȩTHEȩ STRUCTURALȩLOADTRANSFERȩMECHANISMSȩANDȩIDENTIFICATIONȩ OFȩTHEIRȩMATERIALS sȩ )DENTIFICATIONȩOFȩALLȩTHEȩDAMAGESȩPARTICULARLYȩ STRUCTURALȩDAMAGESȩANDȩPREPARATIONȩOFȩAȩDETAILEDȩ PHOTOGRAPHICȩRECORDȩ OFȩTHEȩCONSTRUCTIONȩADEQUATELYȩ REFERENCEDȩINȩTHEȩCONSTRUCTIONSȩTECHNICALȩDRAWINGSȩ IEȩAȩDAMAGEȩMAPȩ4HEȩSURVEYȩOFȩTHEȩOBSERVABLEȩ CRACKSȩFOUNDȩACROSSȩTHEȩSTRUCTUREȩALONGȩWITHȩTHEIRȩ SHAPESȩANDȩTHEIRȩWIDTHSȩISȩPARTICULARLYȩIMPORTANTȩTOȩ PERFORMȩAȩPRELIMINARYȩQUALITATIVEȩASSESSMENTȩOFȩTHEȩ CONSTRUCTIONSȩSTABILITYȩANDȩSTRUCTURALȩSAFETYȩANDȩTOȩ IDENTIFYȩPOSSIBLEȩSOURCESȩOFȩINSTABILITYȩ"ECKMANNȩ ANDȩ"OWLESȩȩ!TȩTHISȩPOINTȩTHEȩPOTENTIALȩFORȩ WATERȩINFILTRATIONȩSHOULDȩALSOȩBEȩANALYSEDȩSINCEȩITȩISȩ ONEȩOFȩTHEȩMAINȩSOURCESȩOFȩSTRUCTURALȩDEGRADATIONȩ )NȩCASEȩOFȩAȩCONSTRUCTIONȩWITHȩTIMBERȩFLOORSȩORȩROOFSȩ ITȩISȩIMPORTANTȩTOȩOBSERVEȩANDȩANALYSEȩTHEȩSTATEȩOFȩ CONSERVATIONȩOFȩTHEȩTIMBERȩBEAMSȩASȩWELLȩASȩTOȩ CONFIRMȩTHEȩEXISTENCEȩOFȩNOGGINSȩANDȩTHEIRȩSTATEȩ OFȩCONSERVATIONȩ!NALYSINGȩTHEȩAREASȩWHEREȩTHESEȩ TIMBERȩBEAMSȩAREȩSUPPORTEDȩBYȩTHEȩMASONRYȩWALLSȩASȩ WELLȩASȩTHEIRȩMIDSPANȩDEFLECTIONȩISȩALSOȩCRITICALȩ7HENȩ SURVEYINGȩCONSTRUCTIONSȩWITHȩOLDȩREINFORCEDȩCONCRETEȩ 2#ȩSLABSȩITȩISȩIMPORTANTȩTOȩIDENTIFYȩTHEȩTYPEȩOFȩSLABȩINȩ ORDERȩTOȩUNDERSTANDȩTHEȩMECHANICALȩBEHAVIOURȩOFȩTHEȩ WHOLEȩFLOORȩSYSTEMȩ-ANYȩDIFFERENTȩTYPESȩOFȩ2#ȩFLOORȩ SYSTEMSȩCANȩBEȩFOUNDȩINȩOLDERȩCONSTRUCTIONSȩRANGINGȩ FROMȩGRIDSȩOFȩ2#ȩBEAMSȩTOPPEDȩWITHȩAȩLOWȩTHICKNESSȩ SOLIDȩ2#ȩSLABȩTOȩONEWAYȩRIBBEDȩSLABSȩWITHȩCLAYȩTILEȩ BLOCKȩFILLERSȩ&URTHERMOREȩANALYSINGȩTHEȩDEFLECTIONȩOFȩ THEȩSLABȩANDȩTHEȩCRACKSȩEXHIBITEDȩBYȩTHEȩSLABȩANDȩTHEȩ BEAMSȩISȩALSOȩESSENTIAL sȩ $EFINITIONȩOFȩTESTSȩTHATȩNEEDȩTOȩBEȩPERFORMEDȩ TOȩCHARACTERIZEȩTHEȩMECHANICALȩPROPERTIESȩOFȩTHEȩ MATERIALSȩANDȩTHEȩBEHAVIOURȩOFȩTHEȩSTRUCTUREȩINCLUDINGȩ THEȩFOUNDATIONSȩ4HEȩTESTSȩCARRIEDȩOUTȩFORȩTHEȩMATERIALSȩ OFȩDIFFERENTȩPARTSȩOFȩTHEȩSTRUCTUREȩANDȩFOUNDATIONSȩ AREȩAȩFUNDAMENTALȩPARTȩOFȩTHEȩSURVEYȩPROCEDURESȩ ANDȩDEPENDINGȩONȩTHEȩTESTȩCANȩPROVIDEȩEITHERȩ QUANTITATIVEȩORȩQUALITATIVEȩINFORMATIONȩ4HESEȩTESTSȩ CANȩBEȩPERFORMEDȩONȩMATERIALȩSAMPLESȩCOLLECTEDȩ THROUGHOUTȩTHEȩCONSTRUCTIONȩINȩTHISȩCASEȩTHEȩTESTSȩ AREȩUSUALLYȩDESTRUCTIVEȩORȩSEMIDESTRUCTIVEȩORȩCANȩBEȩ PERFORMEDȩINȩSITUȩINȩTHISȩCASEȩTHEȩTESTSȩAREȩUSUALLYȩNON DESTRUCTIVE )NȩSITUȩTESTSȩUSUALLYȩINVOLVEȩLESSȩINTRUSIVEȩACTIONSȩTOȩ THEȩSTRUCTUREȩANDȩTHEȩRESULTSȩOBTAINEDȩAREȩTYPICALLYȩ QUALITATIVEȩWITHȩTHEȩEXCEPTIONȩOFȩRESULTSȩOBTAINEDȩ FROMȩDYNAMICȩIDENTIFICATIONȩORȩAMBIENTȩVIBRATIONȩTESTSȩ 4HESEȩQUALITATIVEȩRESULTSȩAREȩPARTICULARLYȩIMPORTANTȩ SINCEȩTHEYȩPROVIDEȩ Aȩ PRELIMINARYȩASSESSMENTȩOFȩTHEȩ MECHANICALȩCHARACTERISTICSȩOFȩTHEȩMATERIALSȩ4HISȩTYPEȩ OFȩTESTȩCANȩBEȩUSEDȩTOȩ#ARPINTERIȩANDȩ,ACIDOGNAȩ ȩIȩIDENTIFYȩHIDDENȩSTRUCTURALȩELEMENTSȩSUCHȩ ASȩCOLUMNSȩINTERMEDIATEȩFLOORȩSTRUCTURESȩETCȩIIȩ QUALIFYȩTHEȩMATERIALSȩANDȩTHEIRȩHETEROGENEITYȩACROSSȩ THEȩSTRUCTUREȩIIIȩASSESSȩTHEȩEXTENTȩOFȩMECHANICALȩ DAMAGEȩINȩSTRUCTURESȩWITHȩCRACKEDȩELEMENTSȩIVȩ DETECTȩTHEȩEXISTENCEȩOFȩVOIDSȩANDȩCAVITIESȩVȩEVALUATEȩ THEȩMOISTUREȩCONTENTȩANDȩTHEȩLEVELȩOFȩWATERȩRISEȩBYȩ CAPILLARYȩEFFECTSȩVIȩIDENTIFYȩSURFACEȩDEGRADATIONȩANDȩ VIIȩEVALUATEȩSOMEȩOFȩTHEȩPHYSICALȩANDȩMECHANICALȩ PROPERTIESȩOFȩTHEȩMATERIALSȩ4ESTSȩSUCHȩASȩTHEȩSONICȩTESTȩ THEȩULTRASONICȩTESTȩTHEȩGROUNDȩPENETRATINGȩRADARȩTESTȩ THEȩDYNAMICȩIDENTIFICATIONȩTESTȩTHEȩAMBIENTȩVIBRATIONȩ TESTȩTHEȩ3CHMIDTȩSCLEROMETERȩTHEȩPHENOLPHTHALEINȩP(ȩ INDICATORȩTHEȩRESISTOGRAPHȩTESTȩTHEȩREBARȩDETECTIONȩ TESTȩTHEȩTHERMOGRAPHYȩTESTȩANDȩTHEȩMOISTUREȩCONTENTȩ TESTȩAREȩSOMEȩEXAMPLESȩOFȩINȩSITUȩNONDESTRUCTIVEȩ Vitruvio International journal of Architecture Technology and Sustainability Volume 1 53 TESTSȩ(ELLIERȩȩ3CHULLERȩȩ4HEȩRESULTSȩOFȩ THESEȩNONDESTRUCTIVEȩTESTSȩUSUALLYȩDOȩNOTȩENABLEȩTHEȩ QUANTITATIVEȩCHARACTERISATIONȩOFȩPARAMETERSȩDEFININGȩ THEȩSTRUCTURALȩBEHAVIOURȩOFȩMATERIALSȩ%VENȩTHOUGHȩ SOMEȩOFȩTHEȩTESTSȩPROVIDEȩAȩQUALITATIVEȩDESCRIPTIONȩOFȩ THEȩSTRUCTUREȩEGȩTHEȩGROUNDȩPENETRATINGȩRADARȩTESTȩ AȩVALUEȩFORȩTHEȩGLOBALȩSTIFFNESSȩEGȩTHEȩDYNAMICȩANDȩ AMBIENTȩVIBRATIONȩTESTSȩORȩEVENȩESTIMATESȩOFȩSOMEȩ STRUCTURALȩPROPERTIESȩEGȩTHEȩSONICȩANDȩULTRASONICȩTESTSȩ ASSOCIATEDȩWITHȩEMPIRICALȩCORRELATIONSȩ-IRANDAȩETȩALȩ ȩ-IRANDAȩETȩALȩȩMOREȩRELIABLEȩANDȩDETAILEDȩ DATAȩABOUTȩTHEȩCHARACTERISTICSȩOFȩTHEȩMATERIALSȩNEEDȩTOȩ BEȩOBTAINEDȩUSINGȩTESTSȩTHATȩINVOLVEȩMOREȩINTRUSIVEȩ ANDȩDESTRUCTIVEȩACTIONSȩTOȩTHEȩSTRUCTUREȩ(OWEVERȩTHEȩ LEVELȩOFȩINTRUSIVENESSȩANDȩDESTRUCTIVENESSȩOFȩTHESEȩ ACTIONSȩNEEDSȩTOȩBEȩASȩSMALLȩASȩPOSSIBLEȩINȩORDERȩNOTȩTOȩ INCREASEȩTHEȩGENERALȩLEVELȩOFȩDAMAGEȩOFȩTHEȩSTRUCTUREȩ 4ESTSȩSUCHȩASȩTHEȩCOMPRESSIVEȩTESTȩOFȩCOREDȩSAMPLESȩ THEȩPULLOUTȩTESTȩTHEȩPULLOFFȩTESTȩTHEȩFLATJACKȩTESTȩORȩTHEȩ DILATOMETERȩTESTȩAREȩSOMEȩEXAMPLESȩOFȩDESTRUCTIVEȩANDȩ SEMIDESTRUCTIVEȩTESTSȩ!LMEIDAȩȩ"OSILJKOVȩETȩALȩ Aȩ"OSILJKOVȩETȩALȩBȩ-IRANDAȩETȩALȩ )NȩADDITIONȩTOȩTHESEȩTESTSȩANȩADDITIONALȩREFERENCEȩISȩ MADEȩTOȩTHEȩCASEȩWHEREȩTHEȩPARTICULARȩCHARACTERISTICSȩ OFȩTHEȩSTRUCTUREȩUNDERȩANALYSISȩEGȩITSȩVALUEȩDIFFICULTIESȩ INȩACCESSINGȩTHEȩSTRUCTUREȩDIFFICULTIESȩINȩUNDERSTANDINGȩ THEȩSTRUCTURALȩBEHAVIOURȩTHEȩLOADȩTRANSFERȩMECHANISMSȩ ORȩTHEȩEFFECTIVENESSȩOFȩAȩCERTAINȩSTRENGTHENINGȩSOLUTIONȩ MAYȩREQUIREȩTHEȩCONSTRUCTIONȩOFȩAȩREDUCEDȩSCALEȩ MODELȩ4HISȩMODELȩWILLȩTHENȩBEȩTESTEDȩFORȩAȩSPECIFICȩ LOADINGȩPATTERNȩTHATȩWILLȩREPRODUCEȩTHEȩSCENARIOȩTHATȩISȩ REQUIREDȩASȩREALISTICALLYȩASȩPOSSIBLE %VENȩTHOUGHȩMOSTȩTHEȩREFERREDȩTESTSȩAREȩUSUALLYȩ PERFORMEDȩTOȩDETERMINEȩTHEȩPHYSICALȩANDȩMECHANICALȩ CHARACTERISTICSȩOFȩTHEȩSTRUCTURALȩMATERIALSȩSOMETIMESȩ THEYȩAREȩALSOȩPERFORMEDȩTOȩIDENTIFYȩANDȩCALIBRATEȩ CONSTITUTIVEȩRELATIONSȩTHATȩMAYȩLATERȩBEȩUSEDȩFORȩTHEȩ STRUCTURALȩMODELLINGȩSTAGEȩWHENȩNECESSARYȩ!LMEIDAȩ ETȩALȩȩ/NȩTHEȩOTHERȩHANDȩSTATICȩORȩDYNAMICȩ TESTSȩINVOLVINGȩTHEȩENTIREȩCONSTRUCTIONȩORȩPARTȩOFȩTHEȩ CONSTRUCTIONȩCANȩALSOȩBEȩPERFORMEDȩTOȩVALIDATEȩITSȩ STRUCTURALȩBEHAVIOURȩ4HESEȩTESTSȩCANȩBEȩUSEDȩTOȩ DETERMINEȩTHEȩSTRUCTURALȩBEHAVIOURȩUNDERȩSERVICEȩ LOADSȩBYȩPERFORMINGȩAȩLOADINGȩTESTȩBUTȩCANȩALSOȩBEȩ USEDȩTOȩCOMPAREȩTHEȩEXPERIMENTALȩRESPONSEȩWITHȩTHATȩ OFȩAȩNUMERICALȩMODELȩTOȩPERFORMȩITSȩCALIBRATIONȩ#OSTAȩ ANDȩ!RǾDEȩȩ'UEDESȩETȩALȩȩ!TAMTURKTURȩ ANDȩ,AMANȩȩ"AYRAKTARȩETȩALȩ sȩ $EFINITIONȩ OFȩȩADEQUATEȩ STRUCTURALȩ MODELSȩȩ COMPATIBLEȩWITHȩTHEȩCONDITIONSȩTHATȩWEREȩOBSERVEDȩ INȩTHEȩSTRUCTUREȩANDȩWITHȩTHEȩRESULTSȩOBTAINEDȩFROMȩ THEȩEXPERIMENTALȩTESTSȩIFȩTESTSȩWEREȩPERFORMEDȩ4HISȩ PROCESSȩMUSTȩINVOLVEȩTHEȩCALIBRATIONȩOFȩTHEȩSTRUCTURALȩ MODELȩUSUALLYȩAȩNUMERICALȩMODELȩANDȩTHEȩCAREFULȩ ADJUSTMENTȩOFȩITSȩPARAMETERSȩPOSSIBLYȩUSINGȩSENSITIVITYȩ ANALYSESȩTOȩOBTAINȩANȩADEQUATEȩFITȩBETWEENȩTHEȩ MODELȩRESPONSEȩANDȩTHEȩEXPERIMENTALȩDATAȩ4HEȩ ACTUALȩPURPOSEȩOFȩTHEȩSTRUCTURALȩMODELȩWITHȩRESPECTȩ TOȩTHEȩTYPEȩOFȩRESULTSȩTHATȩWANTȩTOȩBEȩOBTAINEDȩMUSTȩ ALSOȩBEȩCONSIDEREDȩWHENȩDEFININGȩITSȩCHARACTERISTICSȩ SINCEȩITȩMAYȩINFLUENCEȩTHEȩCONFIGURATIONȩANDȩLEVELȩOFȩ DETAILȩOFȩTHEȩSELECTEDȩMODELȩ&ORȩEXAMPLEȩMODELSȩCANȩ BEȩDEVELOPEDȩWITHȩTHEȩPURPOSEȩOFȩREPRODUCINGȩANDȩ INTERPRETINGȩTHEȩSTRUCTURALȩDAMAGEȩTHATȩWASȩOBSERVEDȩ INȩTHEȩSURVEYȩORȩTOȩPREDICTȩTHEȩSTRUCTURALȩRESPONSEȩ UNDERȩLOADINGȩCONDITIONSȩTHATȩDIDȩNOTȩOCCURREDȩ YETȩ!LTERNATIVELYȩMODELSȩCANȩALSOȩBEȩDEVELOPEDȩ TOȩSIMULATEȩTHEȩEFFECTSȩOFȩREHABILITATIONȩANDORȩ STRENGTHENINGȩINTERVENTIONSȩ6ICENTEȩETȩALȩȩ3ILVAȩ ETȩALȩ sȩ $EFINITIONȩOFȩAȩSTRUCTURALȩMONITORINGȩPLAN ȩTOȩ ANALYSEȩHOWȩTHEȩSTATEȩOFȩTHEȩSTRUCTUREȩEVOLVESȩOVERȩ TIMEȩ3TRUCTURALȩMONITORINGȩCANȩBEȩPARTICULARLYȩHELPFULȩ INȩCASESȩWHEREȩTHEȩINFORMATIONȩOBTAINEDȩFROMȩTHEȩ STRUCTURALȩSURVEYȩORȩFROMȩOTHERȩSTAGESȩOFȩTHEȩANALYSISȩ EGȩTHEȩNUMERICALȩMODELLINGȩETCȩISȩINSUFFICIENTȩ TOȩESTABLISHȩAȩFINALȩDIAGNOSISȩ&Uȩȩ+ARBHARIȩ ANDȩ!NSARIȩȩ-ONITORINGȩINVOLVESȩMEASURINGȩ ANDȩCONTROLLINGȩTHEȩTEMPORALȩEVOLUTIONȩOFȩCERTAINȩ PARAMETERSȩSUCHȩASȩLOCALȩANDȩGLOBALȩDEFORMATIONSȩ JOINTȩMOVEMENTSȩTEMPERATUREȩVARIATIONSȩSTRESSȩLEVELSȩ FOUNDATIONȩSETTLEMENTSȩVARIATIONSȩINȩTHEȩUNDERGROUNDȩ WATERȩLEVELȩETCȩ"YȩANALYSINGȩTHESEȩPARAMETERSȩ ITȩISȩTHENȩPOSSIBLEȩTOȩUNDERSTANDȩTHEȩEVOLUTIONȩOFȩ DAMAGEȩOVERȩTIMEȩASȩWELLȩASȩTOȩIDENTIFYȩMOREȩCLEARLYȩ THEȩCAUSESȩOFȩTHOSEȩDAMAGESȩ3UBSEQUENTLYȩTHISȩ ANALYSISȩPROVIDESȩIMPORTANTȩINFORMATIONȩTOȩDEFINEȩTHEȩ STRUCTURALȩDIAGNOSISȩANDȩTHEȩPOSSIBLEȩMEASURESȩTHATȩ MAYȩBEȩREQUIREDȩTOȩMITIGATEȩORȩELIMINATEȩTHEȩSOURCESȩ OFȩDAMAGEȩ#OMMONȩTYPESȩOFȩMONITORINGȩINȩMASONRYȩ 54 STRUCTURESȩINVOLVEȩCONTROLLINGȩTHEȩWIDTHȩOFȩCRACKSȩORȩ JOINTSȩBETWEENȩSTONESȩANDȩTHEȩSTRUCTURALȩROTATIONSȩ ORȩVERTICALȩTILTINGȩ#OSTAȩETȩALȩȩ4HISȩCONTROLȩ CANȩBEȩPERFORMEDȩUSINGȩDIFFERENTȩTECHNIQUESȩBUTȩTOȩ OBTAINȩHIGHȩPRECISIONȩCONTINUOUSȩREADINGSȩELECTRICALȩ DISPLACEMENTȩTRANSDUCERSȩCOMMONLYȩKNOWNȩASȩLINEARȩ VOLTAGEȩDIFFERENTIALȩTRANSDUCERSȩnȩ,6$4ȩAREȩCURRENTLYȩ USEDȩ(OWEVERȩAVAILABLEȩMEASURINGȩTECHNIQUESȩRANGEȩ FROMȩCLASSICALȩPLASTERȩLABELSȩTOȩTHEȩMOREȩSOPHISTICATEDȩ APPROACHESȩTHATȩINVOLVEȩELECTRICALȩSTRAINȩGAUGESȩ CONNECTEDȩTOȩAȩDATAȩACQUISITIONȩANDȩRECORDINGȩSYSTEMȩ %VENȩTHOUGHȩTHEȩPLASTERȩLABELȩTECHNIQUEȩISȩTHEȩSIMPLESTȩ ONEȩITȩONLYȩINDICATESȩIFȩAȩCRACKȩISȩACTIVEȩORȩNOTȩ4HISȩ LIMITATIONȩCANȩBEȩOVERCOMEȩBYȩUSINGȩTELLTALEȩCRACKȩ MONITORSȩORȩEXTENSOMETERSȩ4ELLTALEȩCRACKȩMONITORSȩ AREȩMADEȩOFȩTWOȩTRANSPARENTȩPLATESȩOFȩACRYLICȩPLASTICȩ WITHȩAȩMILLIMETREȩRULERȩWHICHȩOVERLAPȩFORȩPARTȩOFȩTHEIRȩ LENGTHȩANDȩHAVEȩTHEȩABILITYȩTOȩMOVEȩRELATIVEȩTOȩEACHȩ OTHERȩASȩTHEȩCRACKȩOPENSȩORȩCLOSESȩ!NȩEXTENSOMETERȩ CANȩBEȩAȩMECHANICALȩSTRAINȩGAUGEȩATTACHEDȩTOȩTWOȩ SMALLȩMETALȩPLATESȩFIXEDȩTOȩTHEȩSTRUCTUREȩONȩEACHȩSIDEȩ OFȩTHEȩCRACKȩTHATȩRECORDSȩTHEȩEVOLUTIONȩOFȩTHEȩDISTANCEȩ BETWEENȩTHESEȩTWOȩFIXEDȩPOINTSȩASȩTHEȩCRACKȩOPENSȩORȩ CLOSES )NȩORDERȩTOȩMONITORȩTHEȩGLOBALȩDEFORMATIONȩOFȩSTRUCTURALȩ ELEMENTSȩEQUIPMENTȩSUCHȩASȩDEFLECTOMETERSȩCANȩ BEȩUSEDȩ&ORȩMOSTȩCOMMONȩSITUATIONSȩTHEȩUSEȩ OFȩINEXPENSIVEȩSOLUTIONSȩINVOLVINGȩMECHANICALȩ DEFLECTOMETERSȩAREȩSUFFICIENTȩBUTȩDIGITALȩDEFLECTOMETERSȩ AREȩALSOȩCURRENTLYȩAVAILABLEȩ4OȩOBTAINȩHIGHȩPRECISIONȩ CONTINUOUSȩREADINGSȩOTHERȩEQUIPMENTȩCANȩALSOȩBEȩ USEDȩSUCHȩASȩ,6$4SȩVIBRATINGȩWIREȩTRANSDUCERSȩWHICHȩ MEASUREȩTHEȩRELATIVEȩDISPLACEMENTȩBETWEENȩTWOȩ FIXEDȩPOINTSȩTHATȩAREȩAPARTȩUPȩTOȩAȩFEWȩMETRESȩBASEDȩ ONȩTHEȩVARIATIONȩOFȩTHEȩWIREȩTENSIONȩORȩTRANSDUCERSȩ BASEDȩONȩTHEȩGRADIENTȩOFȩTHEȩHYDROSTATICȩPRESSUREȩINȩ COMMUNICATINGȩVESSELSȩ7ITHȩRESPECTȩTOȩTHEȩMONITORINGȩ OFȩROTATIONSȩORȩVERTICALȩTILTINGȩTHISȩCANȩBEȩPERFORMEDȩ WITHȩUNIDIRECTIONALȩORȩBIDIRECTIONALȩCLINOMETERSȩWHICHȩ SHOULDȩBEȩCOMBINEDȩWITHȩTEMPERATUREȩSENSORSȩFORȩ Aȩ BETTERȩINTERPRETATIONȩOFȩTHEȩRESULTSȩ&URTHERMOREȩ TOPOGRAPHICȩMONITORINGȩISȩANOTHERȩTECHNIQUEȩTHATȩ CANȩBEȩUSEDȩTOȩMEASUREȩSTRUCTURALȩDISPLACEMENTSȩINȩ AȩSTRUCTUREȩORȩEVENȩATȩTHEȩELEMENTȩLEVELȩ4HEȩINȩSITUȩ MONITORINGȩANDȩMEASUREMENTȩOFȩFORCESȩORȩSTRESSESȩISȩAȩ LESSȩFREQUENTȩPROCESSȩANDȩALSOȩAȩMOREȩEXPENSIVEȩONEȩ 0OSSIBLEȩTECHNIQUESȩTHATȩCANȩUSEDȩAREȩTHEȩPREVIOUSLYȩ REFERREDȩFLATJACKȩTESTȩORȩLOADȩCELLSȩTHATȩAREȩBASEDȩONȩ ELECTRICALȩSTRAINȩGAUGESȩWHICHȩAREȩABLEȩTOȩPROVIDEȩ NORMALȩSTRESSȩVALUESȩINȩSPECIFICȩAREASȩWHEREȩTHEYȩAREȩ PLACEDȩ4HEȩUSEȩOFȩLOADȩCELLSȩISȩAȩMOREȩEXPENSIVEȩ TECHNIQUEȩANDȩREQUIRESȩAȩDATAȩACQUISITIONȩSYSTEMȩFORȩ THEȩCONTINUOUSȩRECORDINGȩOFȩDATAȩ&ORȩTHEȩMONITORINGȩ OFȩEMBANKMENTSȩORȩFOUNDATIONȩSOILSȩWHICHȩISȩCRUCIALȩ TOȩUNDERSTANDȩTHEȩBEHAVIOURȩOFȩSTRUCTURESȩTHATȩAREȩ FOUNDEDȩINȩTHOSEȩSOILSȩINCLINOMETERSȩAREȩUSUALLYȩUSEDȩ TOȩRECORDȩTHEȩEMBANKMENTȩORȩSOILȩDISPLACEMENTSȩ RELATIVEȩTOȩAREASȩORȩSTIFFȩSOILSȩTHATȩCANȩBEȩUSEDȩASȩFIXEDȩ REFERENCEȩELEMENTS 2EGARDLESSȩOFȩTHEȩTYPEȩOFȩEQUIPMENTȩFOUNDȩTOȩ BEȩMOREȩADEQUATEȩFORȩAȩCERTAINȩMEASUREMENTȩ CAMPAIGNȩTHEȩCORRESPONDINGȩMONITORINGȩPLANȩMUSTȩ BEȩCAREFULLYȩDEFINEDȩTOȩADDRESSȩALLȩTHEȩDAMAGESȩ FOUNDȩINȩTHEȩCONSTRUCTIONȩANDȩTOȩBEȩCOMPATIBLEȩWITHȩ THEȩCURRENTȩSITUATIONȩ4HISȩPLANȩSHOULDȩCLEARLYȩDEFINEȩ THEȩMEASUREMENTȩLOCATIONSȩTHEȩPARAMETERSȩTHATȩ NEEDȩTOȩBEȩMEASUREDȩANDȩTHEȩMOSTȩADEQUATEȩWAYȩTOȩ PERFORMȩTHEȩMEASUREMENTSȩNAMELYȩBYȩCONSIDERINGȩ REDUNDANCYȩANDȩCONTINGENCYȩSCENARIOSȩTOȩACCOUNTȩ FORȩPOSSIBLEȩEQUIPMENTȩFAILURESȩ&INALLYȩITȩSHOULDȩBEȩ NOTEDȩTHATȩINADEQUATEȩORȩEXCESSIVEȩMEASUREMENTSȩDOȩ NOTȩNECESSARILYȩLEADȩTOȩAȩMOREȩOBJECTIVEȩANDȩBETTERȩ ANALYSISȩOFȩTHEȩSTRUCTUREȩSINCEȩITȩINCREASESȩCOSTSȩANDȩTHEȩ ANALYSISPROCESSINGȩTIME 3. CaSE StUdIES 4OȩILLUSTRATEȩTHEȩIMPORTANCEȩOFȩUSINGȩADEQUATEȩ STRUCTURALȩSURVEYȩTECHNIQUESȩTOȩESTABLISHȩANȩOBJECTIVEȩ DIAGNOSISȩABOUTȩTHEȩSTATEȩOFȩCONSERVATIONȩOFȩAȩGIVENȩ HISTORICALȩCONSTRUCTIONȩTHATȩMAYȩTHENȩLEADȩTOȩTHEȩNEEDȩTOȩ PERFORMȩAȩREHABILITATIONȩORȩSTRENGTHENINGȩINTERVENTIONȩ AȩSERIESȩOFȩCASEȩSTUDIESȩAREȩBRIEFLYȩADDRESSEDȩINȩTHEȩ FOLLOWINGȩ4HEȩSELECTEDȩCASEȩSTUDIESȩCOVERȩAȩWIDEȩ RANGEȩOFȩCONSTRUCTIONȩTYPESȩANDȩFOCUSȩTHEȩSPECIFICSȩOFȩ THEȩSURVEYȩTECHNIQUESȩTHATȩWEREȩUSEDȩINȩEACHȩCASEȩTOȩ PROVIDEȩTHEȩRELEVANTȩBACKGROUNDȩTOȩUNDERSTANDȩTHEȩ DECISIONSȩTHATȩWEREȩMADEȩINȩTERMSȩOFȩTHEȩDIAGNOSISȩ 4HEȩFIRSTȩCASEȩSTUDYȩREFERSȩTOȩTHEȩSAFETYȩANALYSISȩFORȩ Vitruvio International journal of Architecture Technology and Sustainability Volume 1 55 DYNAMICȩLOADINGȩWINDȩANDȩEARTHQUAKEȩANDȩTHEȩ STRENGTHENINGȩOFȩAȩSOLIDȩBRICKȩMASONRYȩINDUSTRIALȩ CHIMNEYȩLOCATEDȩINȩTHEȩOUTSKIRTSȩOFȩ0ORTOȩ0ORTUGALȩ ,OPESȩETȩALȩȩ4HEȩCHIMNEYȩISȩCURRENTLYȩ DEACTIVATEDȩBUTȩREMAINSȩASȩANȩIMPORTANTȩEXAMPLEȩOFȩ EARLYȩTWENTIETHȩCENTURYȩINDUSTRIALȩARCHITECTUREȩ4HEȩ ANALYSISȩTHATȩWASȩCARRIEDȩOUTȩSTARTEDȩBYȩPERFORMINGȩ Aȩ DETAILEDȩANDȩRIGOROUSȩSURVEYȩOFȩTHEȩGEOMETRYȩ OFȩTHEȩCHIMNEYȩUSINGȩTERRESTRIALȩLASERȩSCANNINGȩ"Yȩ USINGȩTHISȩTECHNIQUEȩTHEȩGEOMETRICȩDATAȩOBTAINEDȩ FROMȩTHEȩSURVEYȩWASȩABLEȩTOȩREPRESENTȩTHEȩEXACTȩ DEFORMEDȩSHAPEȩOFȩTHEȩCHIMNEYȩ)NȩADDITIONȩ Aȩ Figure 2. Visual assessment of the chimney damages 56 VISUALȩASSESSMENTȩOFȩTHEȩDAMAGESȩFOUNDȩACROSSȩTHEȩ STRUCTUREȩWASȩALSOȩPERFORMEDȩ&IGȩȩ4OȩESTABLISHȩTHEȩ STRUCTURALȩBEHAVIOURȩCHARACTERISTICSȩOFȩTHEȩSTRUCTUREȩ ENVIRONMENTALȩVIBRATIONȩTESTSȩWEREȩPERFORMEDȩTOȩ IDENTIFYȩTHEȩNATURALȩFREQUENCIESȩANDȩVIBRATIONȩMODESȩ OFȩTHEȩSTRUCTUREȩ4HISȩINFORMATIONȩWASȩTHENȩUSEDȩTOȩ CALIBRATEȩTHEȩNUMERICALȩMODELȩTHATȩWASȩDEVELOPEDȩTOȩ SIMULATEȩTHEȩBEHAVIOURȩOFȩTHEȩCHIMNEYȩANDȩANALYSEȩ ITSȩSTRUCTURALȩSAFETYȩ&IGȩȩ"ASEDȩONȩTHISȩASSESSMENTȩ CRITICALȩAREASȩOFȩTHEȩSTRUCTUREȩWEREȩIDENTIFIEDȩWHICHȩ THENȩLEDȩTOȩTHEȩDESIGNȩOFȩAȩSTRENGTHENINGȩSOLUTIONȩ4HISȩ SOLUTIONȩCONSISTEDȩINȩANȩINTERIORȩSTEELȩSTRUCTUREȩWHICHȩ SIMULTANEOUSLYȩSERVEDȩASȩAȩLADDERȩTOȩACCESSȩTHEȩTOPȩOFȩ THEȩCHIMNEYȩFORȩMAINTENANCEȩOPERATIONS %VENȩTHOUGHȩTHEȩUSEȩOFȩNONDESTRUCTIVEȩSURVEYȩANDȩ TESTINGȩTECHNIQUESȩHASȩBEENȩINCREASINGȩINȩTHEȩANALYSISȩ OFȩOLDERȩANDȩHISTORICALȩMASONRYȩSTRUCTURESȩEVALUATINGȩ THEȩMECHANICALȩPROPERTIESȩOFȩTHEIRȩMATERIALSȩUSINGȩ THESEȩAPPROACHESȩISȩSTILLȩCHALLENGINGȩSINCEȩMOSTȩOFȩTHEȩ INFORMATIONȩTHATȩISȩOBTAINEDȩISȩQUALITATIVEȩ4HEREFOREȩ USINGȩDIFFERENTȩTECHNIQUESȩANDȩCOMBININGȩTHEȩDATAȩ OBTAINEDȩFROMȩALLȩOFȩTHEMȩFORȩCROSSCHECKINGȩISȩESSENTIALȩ TOȩGETȩRELIABLEȩRESULTSȩ!SȩANȩEXAMPLEȩOFȩTHISȩTYPEȩOFȩ Figure 3. Modes of vibration of the chimney that were calibrated using the results of the ambient vibration tests. APPROACHȩREFERENCEȩISȩMADEȩTOȩAȩSECONDȩCASEȩSTUDYȩ DEALINGȩWITHȩTHEȩSAFETYȩASSESSMENTȩOFȩTHEȩ#LOCKȩ4OWERȩ OFȩ#AMINHAȩ0ORTUGALȩ3ILVAȩETȩALȩȩ4HEȩSURVEYȩ OFȩTHEȩEXTERIORȩANDȩINTERIORȩGEOMETRYȩOFȩTHEȩSTRUCTUREȩ WASȩCARRIEDȩOUTȩUSINGȩTERRESTRIALȩLASERȩSCANNINGȩWHICHȩ WASȩTHENȩALSOȩCOMBINEDȩWITHȩORTHOPHOTOGRAPHYȩ&IGSȩ ȩAȩANDȩBȩ4HEȩMECHANICALȩPROPERTIESȩOFȩTHEȩSTRUCTUREȩ ANDȩOFȩTHEȩMATERIALSȩWEREȩCHARACTERIZEDȩUSINGȩAMBIENTȩ VIBRATIONȩTESTSȩ&IGSȩȩCȩANDȩDȩANDȩSONICȩTESTSȩ&IGȩ ȩEȩ"ASEDȩONȩTHEȩRESULTSȩOFȩTHEȩSONICȩTESTSȩONEȩTHEȩ WALLSȩWASȩFOUNDȩTOȩHAVEȩSTRUCTURALȩCHARACTERISTICSȩTHATȩ WEREȩDIFFERENTȩTHANȩTHOSEȩOFȩTHEȩREMAININGȩONESȩ4HISȩ STRUCTURALȩVARIABILITYȩWASȩSEENȩTOȩBEȩCONSISTENTȩWITHȩTHEȩ DIAGNOSISȩMADEȩBYȩSTONEȩCONSERVATORSRESTORERSȩTHATȩ BASEDȩONȩTHEȩEXISTENCEȩOFȩSALTSȩONȩTHEȩSURFACEȩOFȩTHATȩ WALLȩCONCLUDEDȩTHEREȩWASȩWATERȩINȩTHEȩFILLINGȩMATERIALȩ OFȩTHEȩWALLȩIEȩBETWEENȩTHEȩINTERNALȩANDȩEXTERNALȩ STONEȩLEAVESȩOFȩTHEȩWALLȩWHICHȩLEDȩTOȩITSȩDEGRADATIONȩ 4HEREFOREȩTHEȩCOMBINEDȩDATAȩOFȩTHEȩTWOȩASSESSMENTȩ TECHNIQUESȩWASȩABLEȩTOȩDETECTȩTHEȩDEGRADATIONȩOFȩ THEȩFILLINGȩMATERIALȩOFȩTHEȩWALLȩWHICHȩTHENȩLEDȩTOȩ RECOMMENDINGȩANȩINTERVENTIONȩINVOLVINGȩTHEȩINJECTIONȩ OFȩAȩCONSOLIDATINGȩGROUT