Cable axial load measurement device and buckling sensor development

Usalan, Emine Ceren
Axial compression or tension carrying members may need to be monitored for their structural behaviors and/or damage detection. In this thesis, two different types of practical and cost efficient monitoring devices are proposed: The column buckling sensor and the cable tension measuring device. The columns of steel structures are prone to buckling due to their slender nature. The buckling sensor is developed by using strain gauges installed in half Wheatstone bridge and measures the strain level of the most critical section. The strain readings are used to determine the critical buckling condition based on tangent slope of the bending and axial strain graph. The readings are repeated in orthogonal directions for columns with symmetric cross section and the program gives warning when the specified load limit is reached. The buckling sensor is tested on rectangular hollow steel profiles with pin end restraints for both elastic and plastic buckling. The test results, which are compatible with the theory, prove that the buckling sensor works as intended. The cable tension measuring device is developed for measurement of axial load levels in the cables using a low tech sensor without assembling a complicated electronic setup. The device consists of a slender beam with a circular section attached in the mid-span, a laser pointer device at one end and a ruler at the other end for measuring the slope at supports. The beam is clamped to the cable at both ends to bend the beam around the middle circular section. As the slopes at the ends are measured, the bending shape as well as the force at the mid-span can be calculated. The mid-span force and deformed shape of the slender beam and cable can be used to calculate the axial force in the cable. The simplicity and size that permits mobility of the device are its advantages. A prototype is developed and tested for moderately stressed cables and the results are found to be compatible with the analytical studies.


Inelastic seismic response analysis and design of torsionally coupled systems
Kaatsız, Kaan; Sucuoğlu, Haluk; Department of Civil Engineering (2019)
Torsional coupling due to irregular placement of load resisting members and/or uneven mass distribution along a story plan is a very common phenomenon in structural systems. Unsymmetrical-plan buildings with stiffness and/or mass asymmetry behave considerably different compared to regular buildings when they are subjected to earthquake-induced forces. Modern earthquake resistant design related code provisions that employ capacity design principles aim to achieve a certain amount of ductility in the structur...
Form finding and structural analysis of cables with multiple supports
Demir, Abdullah; Polat, Mustafa Uğur; Department of Civil Engineering (2011)
Cables are highly nonlinear structural members under transverse loading. This nonlinearity is mainly due to the close relationship between the final geometry under transverse loads and the resulting stresses in its equilibrium state rather than the material properties. In practice, the cables are usually used as isolated single-segment elements fixed at the ends. Various studies and solution procedures suggested by researchers are available in the literature for such isolated cables. However, not much work ...
Development of a physical theory model for the simulation of hysteretic behavior of steel braces
Çalık, Ertuğrul Emre; Dicleli, Murat; Department of Engineering Sciences (2007)
Bracing members are considered to be effective earthquake-resistant elements as they improve the lateral strength and stiffness of the structural system and contribute to seismic energy dissipation by deforming inelastically during severe earthquake motions. However, the cyclic behavior of such bracing members is quite complex because it is influenced by both buckling and yielding. This thesis presents simple but an efficient analytical model that can be used to simulate the inelastic cyclic behavior of ste...
Seismic behavior and improvement of autoclaved aerated concrete infill walls
Binici, Barış; Canbay, Erdem; Uzgan, Ugur; Eryurtlu, Zafer; Bulbul, Koray; Yakut, Ahmet (Elsevier BV, 2019-08-15)
Performance of infill walls in reinforced concrete (RC) frames is generally questionable under the combined action of in-plane and out-of-plane seismic demands. Despite the vast number of tests investigating the behavior of brick masonry infill walls in RC frames, past research is limited for infill walls made of Autoclaved Aerated Concrete (AAC) blocks. In the first part of the study, six single-bay single-story half-scaled RC frames were tested under the action of in-plane cyclic displacement excursions a...
Drift spectra for inelastic shear frames
Etemadi, Ali; Gülkan, Hakkı Polat; Department of Civil Engineering (2015)
In assessing the damage originating from strong ground motions in building frames, it is necessary to identify properly the post-yield hysteresis degrading behavior of structural components that are well correlated with structural response and in turn, with damage. Likewise, structural damage during the ground motion is due to excessive interstory drift ratio; hence more realistic estimation of interstory drift demands has a significant role in the seismic evaluation of frame buildings. Existing approaches ...
Citation Formats
E. C. Usalan, “Cable axial load measurement device and buckling sensor development,” M.S. - Master of Science, Middle East Technical University, 2015.