Building irregularity issues and architectural design in seismic areas

Abstract

When designing buildings in seismic areas, choices of the architectural designer heavily influences seismic structural performances. Namely, building morphology may lead to complex seismic responses as it occurs when building plan and elevation become irregular. Typical irregularities are due to architectural, functional and distribution constraints, thus leading to plan or vertical or combined plan/vertical irregularities. A frequent plan-wise irregularity arises when earthquake resistant structures, such as cores and shear walls, are concentrated on one side of the building plan, while vertical irregularity often arises from the presence of soft stories especially located at the ground level or, less frequently, at an intermediate level. In the last decades, some trends in architectural design, such as Deconstructivism and other contemporary theories, worked in pursuing architectural solutions based on the concept of "deconstruction" in place of "construction", favoring non-rigid schemes, non-regular shapes and, more generally, avoiding geometric rules and classical canons of symmetry and regularity. In this paper the above issues are investigated with the goal of assessing effects of irregularity conditions, introduced by the architectural design, on the building seismic performances with the aim at not forbidding the designer ambitions but at making him aware of the effects of his architectural choices.

Parametric analysis on external dissipative link system for seismic protection of low rise r.c. buildings

“…In this sense, structural irregularity has a relevant role. In fact, structural response is significantly affected by geometric and material irregularity [4,5]. A relevant intervention should consider mechanical irregularity, particularly the high dispersion in concrete resistance [6].…”

“…As the link stiffness decreases, the maximum displacements of the existing structure are expected to increase. (4) Maximum actions on the existing structure; The proportion of seismic action absorbed by the existing structure and by the bracing system is controlled. In particular, the percentage of the shear at the base (see Fig.…”

“…For the analyses carried out, the variation of the parameters (1-5) is considered and studied. (4) Optimization of the retrofitting system. Once a type of link has been established, by evaluating the decrease in the actions transmitted to the bracing system, it is possible to optimize the profiles of the retrofitting system.…”

Out-of-Plane Seismic Response of Masonry Façades Using Discrete Macro-Element and Rigid Block Models

“…When the connections between walls or, more in general, between vertical and horizontal structural elements do not guarantee a box-type behavior, the out-of-plane failure mechanisms represent the main source of seismic vulnerability of the building. Irregular buildings, where torsional modes increase the seismic demand in specific parts, are also vulnerable to out of plane modes [1] [2]. Simplified models [3] generally do not account for the in and out-plane behavior in a unique numerical model, being based on numerical strategies that accounts for in-plane walls behavior only.…”

Stochastic Assessment of Rocking Masonry Façades Under Real Seismic Records

“…Indeed, usually the connections between vertical elements and horizontal diaphragms and vertical walls are poor and the box-type behavior is not guaranteed. Also building irregularities could activate torsional modes that might cause a concentration of seismic demand in specific parts of the building [1,2]. The traditional tie-rods, generally used for improving the OOP behavior of masonry walls [3][4][5][6][7], strongly increase the safety level of masonry constructions under dynamic actions.…”