Engineering Commons^™

Test Setup Design And Cyclic Evaluation Of Rocking Clt Wall And Floor Restoring Force Lateral System, Aaron Davis Smith

Civil and Environmental Engineering Master's Project Reports

The introduction of the demand for mass timber buildings in areas with seismic hazards has called for new lateral systems. Lateral systems in mass timber building typically utilize a rocking shear wall with post-tensioned rods to provide system re-centering. These post-tensioned rods add axial load to the shear wall and potentially endure long term creep affects. Mass Timber buildings consist of cross laminated (clt) shear walls and floor slabs along with glulam beams. The flexural capacity of the CLT floor slabs along with dead load can provide an alternative source for the restoring force. This project developed a test setup …

Strength Tuned Steel Eccentric Braced Frames, Hosam Abdullah Al-Azzawi

Dissertations and Theses

The primary component in eccentrically braced frames (EBF) is the link as its plastic strength controls the design of the frame as well as the entire building within which it is installed. EBFs are the first part of building design and every other component is sized based on the forces developed in the link. Oversized link elements lead to the use of unnecessary materials and can increase construction costs. Additionally, the advantages of using a continuous member of the same depth for both the link and the controller beam (in terms of the cost and the time) motivates researchers to …

Lateral Deformation Behavior Of Mass Timber Beam To Column Gravity Connection, Tyler James Williams

Civil and Environmental Engineering Master's Project Reports

A beam-to-column connection consisting of glulam beam and column and cross laminated timber floor slab was developed and experimentally evaluated for use in buildings that are expected to undergo earthquake-­­induced lateral drift. The connection utilized a passive gap closure mechanism designed to allow beam rotations during lateral drift while minimizing residual separation between the beam and the column following an earthquake. Full scale cyclic experiments were used to validate the connection’s minimal rotational stiffness and demonstrate low damage performance for lateral drifts exceeding 4.5% drift. The connection exhibited no degradation in gravity load capacity throughout the imposed lateral deformations. An …

Design And Experimental Investigation Of 500kv Current Transformer Seismic Retrofit Utilizing Structure Rocking And Supplemental Damping With Self-Centering, Ilya S. Palnikov

Dissertations and Theses

Electrical substations perform a key role in electrical transmission and distribution; the ability for a substation to remain functional during and after a seismic event contributes significantly to the resilience of the clients supplied. Many legacy components currently installed in the main grid substations were designed with minimal consideration of lateral loads and are not qualified per IEEE693. One of the more critical high-voltage substation components that are vulnerable to earthquake damage is the 500kV freestanding current transformer (CT). The CT is particularly vulnerable due to the slenderness and mass distribution of the component. Current transformers are typically constructed from …

Achieving Operational Seismic Performance Of Rc Bridge Bents Retrofitted With Buckling-Restrained Braces, Ramiro Andrés Gabriel Bazáez Gallardo

Dissertations and Theses

Typical reinforced concrete (RC) bridges built prior to 1970 were designed with minimum seismic consideration, leaving numerous bridges highly susceptible to damage following an earthquake. In order to improve the seismic behavior of substandard RC bridges, this study presents the seismic performance of reinforced concrete bridge bents retrofitted and repaired using Buckling-Restrained Braces (BRBs) while considering subduction zone earthquake demands. In order to reflect displacement demands from subduction ground motions, research studies were conducted to develop quasi-static loading protocols and then investigate their effect on structural bridge damage. Results suggested that subduction loading protocols may reduce the displacement ductility capacity …

Seismic Retrofit Case Study Of Reinforced Concrete Bridges With Buckling Restrained Braces, Michael K. Miotke

Civil and Environmental Engineering Master's Project Reports

Many highway bridges in Oregon have been designed with minimal considerations for seismic hazard and are in need of retrofit. Although buckling restrained braces (BRBs) are not necessarily a new concept, using them to seismically retrofit bridges is. This case study investigates the BRB retrofit concept as compared to traditional retrofit measures for a sample of typical vulnerable bridges in Oregon. The objectives of evaluating these cases were to determine the feasibility of the concept both in terms of performance as well as construction costs. This study builds on the ongoing research at Portland State University into the development of …

Seismic Behavior And Design Of The Linked Column Steel Frame System For Rapid Return To Occupancy, Arlindo Pires Lopes

Dissertations and Theses

The Linked Column Frame (LCF) is a new brace-free lateral structural steel system intended for rapid return to occupancy performance level. LCF is more resilient under a design level earthquake than the conventional approaches. The structural system consists of moment frames for gravity that combines with closely spaced dual columns (LC) interconnected with bolted links for the lateral system. The LC links are sacrificial and intended to be replaced following a design level earthquake. The centerpiece of this work was a unique full-scale experiment using hybrid simulation testing; a combination of physical test of a critical sub-system tied to a …

Seismic Retrofitting Of Existing Structures, Cetin Sahin

Civil and Environmental Engineering Master's Project Reports

This research project will give a brief presentation about earthquake resistant design and the methodology about seismic evaluation and rehabilitation of existing structures. It also provides certain aspects of computer software modeling against seismic loads and shows the necessity of seismic upgrading in a steel moment-frame building.

The seismic evaluation process consists of investigating if the structure meets the defined target structural performance levels. The main goal during earthquakes is to assure that building collapse doesn’t occur and the risk of death or injury to people is minimized and beyond that to satisfy post-earthquake performance level for defined range of …