IJE TRANSACTIONS A: Basics Vol. 32, No. 10, (October 2019) 1395-1406 Please cite as: O. Kumbhar, R. Kumar, P. L. Panaiyappan, E. Noroozinejad Farsangi, Direct Displacement-Based Design of RC Elevated Water Tanks Frame Staging, International Journal of Engineering (IJE), IJE TRANSACTIONS A: Basics Vol. 32, No. 10, (October 2019) 1395-1406 International Journal of Engineering Journal Homepage: www.ije.ir Direct Displacement Based Design of Reinforced Concrete Elevated Water Tanks Frame Staging O. Kumbhar a , R. Kumar a , P. L. Panaiyappan a , E. Noroozinejad Farsangi* b a Visvesvaraya National Institute of Technology, Nagpur, India b Faculty of Civil and Surveying Engineering, Graduate University of Advanced Technology, Kerman, Iran PAPER INFO Paper history: Received 05 July 2019 Received in revised form 04 September 2019 Accepted 12 September 2019 Keywords: Water Tank Direct Displacement-Based Design Force Based Design Seismic Hazard Level Staging Lifeline ABSTRACT Elevated water tanks supported by the reinforced concrete (RC) Staging are classified as inverted pendulum structures. These are considered as structures of high post-earthquake importance and should remain functional after the seismic events. National codes of various countries recommend Force-Based Design (FBD) procedure for water tank staging, which does not ensure nonlinear performance level for a given hazard. Therefore, it becomes necessary to design these structures with a performance-based design approach like Direct Displacement-Based Design (DDBD). Many design engineers consider that the behavior of frame staging of the elevated water tank is similar to the building's frame and generally adopt the same design principles for both types of structures. However, the seismic behavior of the building frame is significantly different from frame staging due to the absence of diaphragm action at the bracing level and concentrated mass at the top level only. Therefore, it may not be rational to utilize the same DDBD procedure of the building's frame for the design of frame staging of the elevated water tanks. The present study proposes some modification in existing DDBD procedure (used for the design of frame building) based on the nonlinear time history analysis of twenty meters high RC frame staging with four different configurations. The modifications are proposed in terms of inelastic displacement profile, design displacement, effective height, and effective mass calculation. Further, the performance of the same RC frame staging designed using the proposed DDBD procedure has been assessed using nonlinear static and dynamic analyses to verify the suitability of proposed modifications. doi: 10.5829/ije.2019.32.10a.09 1. INTRODUCTION 1 In highly populated countries like India, the most economical method for water distribution is to use a combined pumping and gravity system. In this method, the water is stored in large overhead water tanks by pumping and distributed by means of gravity (Figure 1(a)). Even moderate damage to water tanks can make it non-functional leading to additional chaotic condition after an earthquake. Therefore, water tanks are categorized as lifeline structures that must be designed to withstand the seismic forces with minimal damage and remain functional even after a major seismic event. Generally, elevated water tanks are classified based on support conditions, construction materials, and capacity. Nowadays, construction of tall RC water tanks on frame staging has become a common structure in rural and *Corresponding Author Email: noroozinejad@kgut.ac.ir (E. Noroozinejad Farsangi) urban India. Similarly, this type of water tanks is also popular in many countries viz. Iran [1-2], New Zealand [3], Chile [4] and Turkey [5]. These structures are classified as small, medium, large and very large water tanks based on their capacities [6]. It has been evidenced from past earthquakes that several elevated water tanks were significantly damaged or failed due to ground shaking [7-14]. The elevated water tank provides potable water and water to subdue building fires, which failure of them may lead to inconvenience in post-earthquake life functioning’s. Moreover, the failure of water tanks during an earthquake would lead to a catastrophe and loss of human lives and properties. In order to mitigate these post-earthquake consequences, it is essential to ensure the safety of water tanks against seismic loads to remain serviceable even after these events. Therefore, various Indian national