1. Department of Civil and Architectural Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, Al-Khoud 123, Muscat, Sultanate of Oman
2. Ministry of Labour, P.O. Box 413, PC 100, Muscat, Oman
3. Department of Civil and Environmental Engineering, Manhattan College, 4513 Manhattan College Parkway, Riverdale, NY 10471, USA