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I.11.61: Full scale tests on moment‐resistant‐frames under cyclic loading
Author(s) -
Avgerinou Stella,
Lignos Xenofon,
Thanopoulos Pavlos,
Vayas Ioannis
Publication year - 2017
Publication title -
ce/papers
Language(s) - English
Resource type - Journals
ISSN - 2509-7075
DOI - 10.1002/cepa.399
Subject(s) - structural engineering , welding , beam (structure) , girder , joint (building) , hinge , moment (physics) , plastic hinge , engineering , full scale , geology , mechanical engineering , physics , classical mechanics
Three large scale tests on two‐story Moment Resistant Frames (MRF) under cyclic loading were conducted in the Laboratory of Steel Structures of NTUA in the frame of the RFCS‐supported project MATCH. Selected joints of the frames were formed with Reduced Beam Sections (RBS), in order to achieve plastic hinge formation away from the welded connections and the heat affected zones. In addition, holes were drilled in the flanges in order to study the crack initiation and crack propagation under large plastic deformations. The experimental set‐up consisted of a rigid test rig frame providing horizontal support to the hydraulic actuator, a base girder on which rested the test frame and a supporting frame, which prevented the out‐of‐plane movement of the test frames. The base girder was attached to the test rig so that no net horizontal force was transferred to the ground. The experimental set‐up was anchored to the Laboratory's strong floor. The test frames were simply supported on the base girder. The test frames were designed with weak beams and strong columns. The beam–to–column joints were realized with all‐around fillet welds. In the two‐bay frames the beams of a selected joint were designed with RBS near the connection regions while the rest of the connection regions were locally reinforced with stiffeners and beam haunches in order to ensure plastic deformation would occur in the selected joint. In the one‐bay frame all beams were designed with RBS sections towards the joints. The distance of the RBS sections from the column faces as well as the geometry of the flange reduction was specified in accordance with the provisions of EN 1998–3. The tests were performed under displacement control using a computer controlled hydraulic actuator. A cyclic load of increasing amplitude was applied according to ECCS provisions while the maximum interstory drift reached was approximately 5%. The actuator's force was applied through a vertical spread beam, which ensured that the load was applied in an inverted triangular pattern, in accordance with the anticipated seismic forces. In the present paper, the design of the test specimens and the experimental set‐up is described in detail, and the preparation and results of the experimental investigations are presented.