Alireza Khaloo - Department of Civil Engineering, Sharif University of Technology
Mina Haghnezhad - Department of Civil Engineering, Sharif University of Technology,International Campus,Kish Island, Iran

One of the delays which engineers are facing is related to strengthening projects in concrete buildings. The aim of this study was to investigate the causes of delay and its effects on strengthening projects with shear walls and steel bracing through statistical data.To achieve this objective, a list of subjects representing strengthening delays based on available information in the literature and interview with strengthening experts was obtained. A field survey was conducted through a structured questionnaire including owners, contractors, university's professors who have a PhD degree in structural or earthquake engineering, consultant engineers, and supervisor engineers in Mazandaran and Tehran. About 174 respondents participated in the survey. The factors was analyzed by using Relative Importance Index (RII). Ranking of factors and categories was demonstrated according to their importance level on delay. Ten most important causes from a list of 44 different causes and 11 different effects of delay were: (1) delay in finance and payments of completed work by owner, (2) unrealistic contract duration planning, (3) shortage of labor skill, (4) perception of strengthening methods differ amongst stakeholders, (5) inadequate modern equipment, (6) ineffective planning and scheduling of project, (7) inadequate contractor experience, (8) cost of strengthening, (9) contract problems, and (10) unclear strengthening standards criteria. The five important effects of strengthening delays were: (1) dispute, (2) cost overrun, (3) time overrun, (4) increased stress on contractor, and (5) litigation

strengthening, shear wall, steel bracing, delay, causes, effects