A New Energy-Based Structural Design Optimization Concept under Seismic Actions

Abstract

A new optimization concept is introduced which involves the optimization of non-linear planar shear buildings by using gradients based on equivalent linear structures, instead of the traditional practice of calculating the gradients from the non-linear objective function. The optimization problem is formulated as an equivalent linear system of equations in which a target fundamental eigenfrequency and equal dissipated energy distribution within the storeys of the building are the components of the objective function. The concept is applied in a modified Newton-Raphson algorithm in order to find the optimum stiffness distribution of two representative linear or non-linear MDOF shear buildings, so that the distribution of viscously damped and hysteretically dissipated energy, respectively, over the structural height is uniform. A number of optimization results are presented in which the effect of the earthquake excitation, the critical modal damping ratio, and the normalized yield inter-storey drift limit on the optimum stiffness distributions is studied. Structural design based on the proposed approach is more rational and technically feasible compared to other optimization strategies (e.g., uniform ductility concept), whereas it is expected to provide increased protection against global collapse and loss of life during strong earthquake events. Finally, it is proven that the new optimization concept not only reduces running times by as much as 91% compared to the classical optimization algorithms but also can be applied in other optimization algorithms which use gradient information to proceed to the optimum point.

Selecting and Scaling of Energy-Compatible Ground Motion Records

“…The three systems have different yield displacements, equal to 0.052, 0.1, and 0.025 m for the El Centro, the Northridge and the Sakarya target ground motion, respectively. The reader is referred to Papazafeiropoulos et al (2017) for more details about the implementation of the bilinear elastoplastic constitutive model with kinematic hardening and the time integration algorithm that were used in this study. The small ductility value specified for all target ground motions denotes that structures only with slightly nonlinear behavior are considered in this study; for cases of severely nonlinear response the scenarios presented in this study for calculation of the design artificial ground motion is an open research issue.…”

The Effect of Columns Configuration on High-rise Building Using Performance-based Design

“…However, documented poor performance of ordinary moment frames in past earthquakes warned the international community that this structural system required special design and detailing in order to warrant a ductile behavior when subjected to the action of strong earthquakes. Some of these initial efforts were transformed into recommendations that were included in design guidelines in different building codes worldwide as early as the late 1970s [20]. The behavior of the frame against a moment that is subject to gravity and lateral load are shown in Figure 4 and Figure 5 respectively.…”

Optimum Design of RC Footings with Genetic Algorithms According to ACI 318-19

“…Optimization techniques have been successfully used for the design of various reinforced concrete structures [4,5]. Coello et al [6] applied a simple GA for the design of RC elements, where the aim was to minimize the cost of a reinforced concrete rectangular beam based on strength design procedures, while also considering the costs of concrete, steel, and shuttering.…”