The Wilberforce pendulum provides an important qualitative demonstration of coupled harmonic oscillators, but quantitative measurements are not typically performed. The present work examines the dynamics of a simple pendulum comprising a steel spring with attached mass using an ultrasonic motion detector. A series of measurements allowed determination of the coupling constant between the longit...

The fundamental periods of buildings are essential to calculate the design base shear and lateral forces. Most seismic codes specify empirical formulae to estimate the fundamental vibration period of buildings. These empirical formulae are used for both lowand mediumrise buildings. These formulae depend on the building materials (steel, reinforced concrete etc), building types (frame, shear wal...

Steel special moment frames (SMFs) designed per current codes will likely require major repair or be a total loss after design earthquake (DE) shaking. Functional recovery of SMFs can improved by designing to stricter drift limits, improving postyield stiffness, repairability. In this study, FEMA P-58/ATC-138 (beta) was used determine the most effective option for functional recovery. Eighteen ...

This paper reports the findings of research examining the blast resistance of bridge piers that are designed in accordance with current knowledge and specifications to ensure ductile seismic performance. Blast testing was conducted on 1/4 scale ductile RC columns, and nonductile RC columns retrofitted with steel jacketing. The seismically designed RC and steel jacketed RC columns did not exhibi...

response modification factor (r-factor) is one of the seismic design parameters to consider nonlinear performance of building structures during strong earthquake. relying on this, many seismic design codes led to reduce earthquake loads imposed to the structure. the present paper tries to evaluate the r-factors of conventional concentric braced frames (cbfs) and special moment frames (mrfs) in ...

In this paper, an optimization framework is developed for performance-based seismic design of composite moment frames consisting of concrete filled steel box columns and I-shaped steel beams. Material cost of the structure and seismic damage under severe earthquake ground motions are minimized as objective functions. Two design examples are presented to demonstrate the applicability and efficie...

This study deals with performance-based design optimization (PBDO) of steel moment frames employing four different metaheuristics consisting of genetic algorithm (GA), ant colony optimization (ACO), harmony search (HS), and particle swarm optimization (PSO). In order to evaluate the seismic capacity of the structures, nonlinear pushover analysis is conducted (PBDO). This method is an iterative ...

moment-resisting frames have extensive usage in earthquake-prone areas and high ability in energy dissipation.after the earthquake in northridge 1994,kobe 1995 fixed connections of steel structures have shown poor performance and generally they were caught brittle fracture of beam flange weld to the column.in order to remedy to avoid similar situations in future earthquakes,researchers introduc...

some considerable damage to steel structures during the hyogo-ken nanbu earthquake occurred. among them, many exposed-type column bases failed in several consistent patterns, such as brittle base plate fracture, excessive bolt elongation, unexpected early bolt failure, and inferior construction work, etc. the lessons from these phenomena led to the need for improved understanding of column base...