Influence of increasing differential settlement under columns on a RC frame response considering different support conditions

Document Type : Original Article

Authors

1 Department of Civil Engineering, Faculty of Engineering, University of Kashan, Kashan, Iran

2 Department of Civil Engineering, Faculty of Engineering and Technology, Alzahra university, Tehran, Iran

Abstract

Natural hazards and human activities bring about overall or local ground subsidence. Predicting the effects of large differential settlement on response of structural frames, especially in congested urban areas, is a main issue in design process as inadvertence can lead to irrecoverable human and financial losses. In order to better understand the consequences of the subsidence phenomenon on the superstructure, a three dimensional reinforced concrete (RC) moment frame designed according to the current Iranian codes of practice is analyzed due to six separate nonlinear analysis cases considering three locations for the increasing differential settlements (under corner, exterior, and interior columns) as well as two support conditions (fixed and flexible); Various results including change in pattern of bridging beam bending moments, axial force redistribution in columns, and also maximum tolerable elastic and inelastic settlements are evaluated. Based on the findings of the numerical models, although cases with the settlement imposed under an interior column have the least vertical downward displacement at formation of first plastic hinge in a beam compared to corresponding cases, the highest capacity to bear differential settlement occurs due to one of the cases of a corner column location. Moreover, formation of plastic hinges and redistribution of axial forces in first-story columns are highly affected by the modeled support conditions.

Keywords

Main Subjects


[1] Camos, C., Molins, C. and Arnau, O. (2014). Case study of damage on masonry buildings produced by tunneling induced settlement. International Journal of Architectural Heritage: Conservation, Analysis, and Restoration, 8(4), 602-625.
[2] Laefer, D., Ceribasi, S., Long, J. and Cording, E. (2009). Predicting RC frame response to excavation-induced settlement. Journal of Geotechnical and Geoenvironmental Engineering, 135(11), 1605-1609.
[3] Son, M. and Cording. (2011). Responses of Buildings with Different Structural Types to Excavation-Induced Ground Settlements. Journal of Geotechnical and Geoenvironmental Engineering, 137(4), 323-333.
[4] Arapakou, A. and Papadopoulos, V. (2012). Factors Affecting Differential Settlements of Framed Structures. Geotechnical and Geological Engineering, 30(6), 1323-1333.
[5] Ren, C. and Yan, B. (2015). Experimental research of the influence of differential settlement on the upper frame structures. In: 3rd International Conference on Mechanical Engineering and Intelligent Systems (ICMEIS 2015). Yinchuan: ATLANTIS press, 539-544.
[6] Zhu, M., Gary, T. and Bachus, R. (2012). Assessment of a building settlement and the litigation process-a case study. In: 6th Congress on Forensic Engineering. San Francisco: Technical Council on Forensic Engineering of ASCE, 1318-1327.
[7] Bazan,M. (2008). Response of Reinforced concrete elements and structures Following Loss of Load Bearing Elements. Ph.D.theseis , Northeastren University, USA.
[8] Sasani, M. and Sagiroglu, S. (2008). Progressive Collapse Resistance of Hotel San Diego. Journal of Structural Engineering, 134 (4), 478-488.
[9] Lahri, A. and Garg, V. (2015). Effect of Differential Settlement on Frame Forces - A Parametric Study, International Journal of Research in Engineering and Technology, 4(9), 453-464.
[10] Lin, L, Hanna, A. and Tirca, L. (2015). Structural Response to Differential Settlement of Its Foundations . Journal of Civil Engineering Research, 5(3), 59-66.
[11] Pachenari, A., Pirayande, E. and Pachenari, Z. (2017). Assessment of a RC frame response to differential settlements in various column locations. In: 10th Natioanl Congress on Civil Engineering (10NCCE). Tehran: Sharif University of Technology.
[12] Regulations, I. N. B. (2013). Loads on buildings, Ministry of Rood & Urban Development (in persian)
[13] Regulations, I. N. B. (2013). Design and Implement of Reinforced Concrete Buildings, Ministry of Rood & Urban Development (in Persian)
[14] SAP2000®, “Linear and Nonlinear Static and Dynamic Analysis and Design of Three-Dimensional Structures,” Computers and Structures Inc., Berkeley, CA, 1997.
[15] BHRC (Building and Housing Research Center., (2014). Iranian Code of Practice for Seismic Resistant Design of Buildings. Standard No. 2800, 4th edition. Tehran: BHRC.
[16] Management and Planning Organization. (2007). Instruction for Seismic Rehabilitation of Existing Buildings: No. 360. Tehran: Office of Deputy for Technical Affairs.