Challenge Journal of Structural Mechanics

1-6

Authors: Mustafa Aytekin

When the settlement of a footing under a structure is estimated by considering the bearing pressure of that footing only, the estimated value of the settlement may not be good enough since the other neighboring footings are going to effect the settlement of the footing under consideration also. Thus, in the settlement estimation of a footing, the effect of neighboring footings must be considered. In this study, impact of adjacent footings is considered on the estimation of elastic settlement of shallow foundations. In the estimation of elastic (immediate) settlement, the Schmertmann’s method that is a very popular method in the elastic settlement estimation of shallow foundations is employed. In order to consider effect of neighboring footings on elastic settlement of main footing in different configurations, a MATLAB script has been generated. Elastic settlements of the various configurations are estimated by the script and several conclusions have been reached.

14-24

Authors: Dejan Erdevicki

This paper will present a design solution for a ductile, tension–only seismic bracing with the use of an energy dissipating ring. This type of bracing behaves very well under seismic loading and has shown, by testing carried out in conjunction with the University of British Columbia, that it can reach very high post elastic drift limits. The presented procedure is a method created by the author and is based on information collected during the research testing program performed by the Civil Engineering Department at the University of British Columbia. The team was led by Professor Carlos Ventura, in collaboration with Dejan Erdevicki from Erdevicki Structural Engineering. The presented design procedure describes the behaviour of the system, the relation between energy, forces, drift limits and capacities of the ring. It also includes geometrical limitations and requirements for the ring element and bracing system, to ensure that target drifts can be achieved. It allows the user to calculate seismic forces and reduction factors based on an energy criterion and the chosen final drift of the structure. For longer period structures, an equal displacement principle was discussed and considered. The procedure can be used for seismic capacity design and is easily adjusted to suit applicable national codes. Ring capacity tables and examples are also included. This ductile, tension–only bracing, with an energy dissipating ring, can be used for new structures, as well as for the retrofit of existing ones. The system is relatively simple and allows for easy replacement of the ring after an earthquake event if needed. The application of the bracing system for buildings, including multi-storey structures, will be discussed.

32-37

Authors: Amaia Martinez, Martin E. Turek, Carlos E. Ventura, Jay Drew

Lock Block Ltd of Vancouver, Canada produces pre-cast concrete products, including their name-sake retaining wall system which uses recycled materials. More recently they have adapted these products to create a system of easy to assemble dome and arch structures. This study aims to evaluate the behavior of these systems when subjected to seismic loading. A program of experimental shake-table testing was undertaken using a small scale arch models. For the tests, a suite of six earthquake records were chosen, including Tohoku 2011, Loma Prieta 1989 and Kobe 1995. The records were time scaled to increase the applied frequencies to the tested models; the accelerations were applied full-scale. For each model, they were tested with increasing intensity until failure occurred; this determined the failure level for each earthquake. For all the cases, the failure mode exhibited the typical four-hinge mechanism. The failure intensity varied with type of earthquake, with impulses being the dominant factor. The study also explored a method of reinforcing the arches, using a steel band over the structure to withstand the tension force, anchored at both ends of the arch. This method performed well to all applied earthquakes.

51-59

Authors: Arcady N. Soloviev, Alexander O. Vatulyan, Sergey N. Shevtsov, Alexander S. Spogakin

For two kinds of defects – delamination and transversal failure in the multilayer composite the damages detection method is proposed. The inverse geometrical problems of crack’s parameters reconstruction were formulated as a sequence of boundary integral equations (BIE). These boundary integral equations were derived on the basis of the principle of works mutuality applied to the problem of the composite specimen stationary oscillations. To solve the integral equations the finite element method, the boundary element method, and the Tikhonov regularization method were used. As complementary information for inverse problems solving the displacement field measured on a mechanical stress free area of the specimen’s surface was served. The numerical examples of the interfacial cracks and transversal failure of the internal layers in the multilayered composite were considered in the framework of two-dimensional elasticity.