Experimental investigation of uplift on seismic base isolators /

Download
2014
Erkakan, Evren
Elastomeric rubber bearings reinforced with steel shims, are used to provide structural support in vertical direction and allow horizontal movements for the structure subjected to earthquake and thermal loads. Generally, it is known that tensile stress or uplift may occur when the structure is subjected to strong ground motion or structure have large height-to-width aspect ratio to develop a stability concern subjected to lateral loads. The main focus of this research is to investigate the change in characteristic behavior of bearings under vertical tension load and horizontal load since limited information is available on this combination of loads. For this purpose, four bearings having the same shape factor with different sizes and two other bearings are examined. They are subjected to a series of staged and cyclic loads. Shear modulus values under different vertical loads are calculated according to both TS EN 1337-3 and BS 5400 specifications separately. It is observed that shear modulus decrease with Mullin’s Effect for standard bearings while decreasing in shear modulus of concave edged bearing related to strain amplitude. At the end of study, it can be stated that considerable results are obtained and this pioneering research indicate that bearings can take tension loads while subjected to horizontal loads. Still the subject needs further research and testing.

Suggestions

Experimental Determination of Resistance Characteristics of Support Details Used in Prestressed Concrete Bridge Girders
Baran, Eray; French, Catherine; Schultz, Arturo (American Society of Civil Engineers (ASCE), 2009-09-01)
Static load tests were performed on support details used at the ends of prestressed concrete pedestrian bridge girders to determine the resistance characteristics of girder supports in the direction perpendicular to the longitudinal axis of the girders. The specimens tested represent support details that have also been widely used in prestressed concrete highway bridges in Minnesota and in other states. Two specimens, one representing the free-end detail and one representing the restrained-end detail were s...
Modelling of strengthened hollow brick infills
BARAN, MEHMET; Ozcelik, Ramazan; Sevil, Tugce; Canbay, Erdem (2013-02-01)
Strengthening the existing hollow brick infill walls by bonding high-strength precast concrete panels or applying steel fibre reinforced mortar was found to be an occupant-friendly seismic retrofitting technique for the buildings in use with deficient reinforced concrete structural systems. Both techniques convert the existing non-structural hollow brick infill walls into load-carrying structural members. To verify the effectiveness of the techniques, 20 reinforced concrete frames with hollow brick infill w...
Performance improvement studies of masonry houses using elastic post-tensioning straps
Türer, Ahmet; KORKMAZ, HASAN HÜSNÜ (2007-04-25)
Unreinforced masonry houses are composed of building blocks with weak inter-binding action between them which commonly possess low tensile strength. The principal tensile stresses generated by out-of-plane bending and in-plane shear forces cannot be tolerated well and leads to heavy structural damage and brittle collapse beyond linear capacity of the material. Remedies such as externally applied mesh reinforcement and post-tensioning improves post and pre-cracking performances; however, yielding of reinforc...
Frequency domain optimization of dry friction dampers used for earthquake vibration damping of buildings
Erişen, Zühtü Eren; Ciğeroğlu, Ender; Department of Mechanical Engineering (2012)
There are many active and passive vibration control techniques to reduce the effect of energy on structures which emerges during an earthquake and reduce the displacement of buildings that is caused by ground acceleration. Main advantage of passive vibration control techniques over active vibration control techniques is; no external power or a sensor is required for passive vibration control devices (PVCDs) and it results in lower installation and maintenance costs. However, PVCDs require a predefined optim...
Development of a new seismic isolator named “ball rubber bearing"
Özkaya, Cenan; Caner, Alp; Akyüz, Uğurhan; Department of Civil Engineering (2010)
The experimental research presented in this dissertation aims to develop a new rubber– based seismic isolator type on the basis of the idea that the damping of a conventional annular elastomeric bearing (EB) can be increased by filling its central core with small diameter steel balls, which dissipate energy via friction inside the confined hole of the bearing during their movements under horizontal loads. The proposed bearing type is called “Ball Rubber Bearing (BRB)”. A large set of BRBs with different geo...
Citation Formats
E. Erkakan, “Experimental investigation of uplift on seismic base isolators /,” M.S. - Master of Science, Middle East Technical University, 2014.