Report - PEER - University of California, Berkeley

3.3 Methods of RepairThe method of repair required to restore a component to its original, pre-earthquakecondition, provides a basis for estimating the economic impact of earthquake loading.Information was collected from multiple sources to identify appropriate techniquesfor repairing earthquake damage to RC components and to link these repair methodswith the range of previously identified damage states. The primary referencesconsulted were FEMA 308 Repair of Earthquake Damaged Concrete and MasonryWall Buildings (ATC 1998) and ACI 546R-96 Concrete Repair Guide (ACI Com. 5461996). In addition, the results of previous research by others were used to verify theadequacy of repair methods and to identify which repair methods would be employedfor which damage states (Karayannis 1998, Filiatrault and Lebrun 1996, Tasai 1992,Jara et al. 1989). Additionally, practicing engineers and contractors were consulted toverify linkages between repair methods and damage states (Coffman and Kapur 2003,Runacres 2003, Savage 2003).Review of the relevant sources results in identification of five methods of repairthat would be appropriate for restoring joints to original condition (Table 3). Thesemethods of repair include five basic repair techniques: repair cosmetic finishes, epoxyinject concrete cracks, patch spalled concrete, remove and replace crushed concrete,replace reinforcing steel. Review of the relevant sources also provided a basis forlinking these methods of repair with specific damage states (Table 3). While theprobabilistic framework employed for prediction of economic impact (Eq. 1) wouldsuggest that there should be a probabilistic relationship linking each repair methodwith a set of damage states, there are insufficient data available to calibrate suchmodels.Table 3. Methods of repair for jointsMethod of RepairActivitiesDamageStates0. Cosmetic Repair Replace and repair finishes. 0-21. Epoxy Injection Inject cracks with epoxy and replace finishes. 3-52. Patching Patch spalled concrete, epoxy inject cracks and 6-8replace finishes.3. Replace Concrete Remove and replace damaged concrete, replaces 9-11finishes4. Replace Joint Replace damaged reinforcing steel, remove andreplace concrete, and replace finishes.124. PREDICTION OF REQUIRED REPAIR METHODUsing the experimental data collected as well as the damage states and methods ofrepair identified from the literature, a series of fragility curves were developed for use215