STRUCTURAL DESIGN OF PSUEDO-DYNAMIC TESTING FACILITY PROPOSED AT IIT ROORKEE

Abstract

The Department of Earthquake Engineering, IIT Roorkee is developing a large-scale structural testing facility to test the full scale structures like bridge piers, multi-storey reinforced concrete and masonry buildings. It is addressed as "Pseudo-Dynamic (PsD) Structural Testing Facility" though it is designed for other testing applications as well. This dissertation comprises of the analysis and design of the civil/structural part of the proposed PsD Testing Facility. Strong Floor and Reaction Wall (Reaction Structure) are the two major components of the test facility. The Laboratory Building which will house the facility is a 21 m tall industrial type of structure which is to be roofed by steel trusses and to be equipped with 40 Ton capacity overhead crane. A Literature Review has been carried out to study the various existing large-scale structural testing methods and facilities worldwide. Four alternative structural systems (RC, Steel-RC Composite, Precast Pre-Stressed Concrete and Cast in-situ Pre-Stressed Concrete) have been considered in the preliminary design and it has been finalized to carry out the detailed design for Cast in-situ Pre-Stressed Concrete construction by considering constructability and economy. The Reaction Structure is configured with L-shaped solid Reaction Wall (2 m thick and 13 m high) and box type Strong Floor. (4.2 m overall depth and 14.5 m x 12.5 m plan area). The Reaction Wall has been designed as a partially pre-stressed member for 10 MNm/m. The Strong Floor has been designed asa Reinforced Concrete member for the factored moment due to the bridge pier specimen. Two bench mark test specimens — (i) four storey full scale RC building, and (ii) three bridge piers under simultaneous testing, have been considered as the governing criteria to design and evaluate the performance of Reaction Structure. The four storey RC specimen building has been designed for upper bound of static and seismic forces and the capacity has been estimated from Nonlinear Static Pushover Analysis, considering the effect of flange in beam members. Yield forces due to the testing of three bridge piers simultaneously, as considered in the design of similar PsD facility (ELSA) at Italy, have also been considered in design and evaluation of the proposed facility. The Structure has been modeled in SAP 2000 with and without considering the flexibility of soil medium to estimate the various response quantities (deflections, settlements, soil pressure, stresses, and dynamic characteristics) due to bench mark specimen loading. It has been observed that the stresses and deflections are within the limits.