Fail-safe optimization of viscous dampers for seismic retrofitting

This paper presents a new optimization approach for designing minimum-cost fail-safe distributions of fluid viscous dampers for seismic retrofitting. Failure is modeled as either complete damage of the dampers or partial degradation of the dampers' properties. In general, this leads to optimization problems with large number of constraints. Thus, the use of a working-set optimization algorithm is proposed. The main idea is to solve a sequence of relaxed optimization sub-problems with a small sub-set of all constraints. The algorithm terminates once a solution of a sub-problem is found that satisfies all the constraints of the problem. The retrofitting cost is minimized with constraints on the inter-story drifts at the peripheries of frame structures. The structures considered are subjected to a realistic ensemble of ground motions, and their response is evaluated with time-history analyses. The transient optimization problem is efficiently solved with a gradient-based sequential linear programming algorithm. The gradients of the response functions are calculated with a consistent adjoint sensitivity analysis procedure. Promising results attained for 3-D irregular frames are presented and discussed. The numerical results highlight the fact that the optimized layout and size of the dampers can change significantly even for moderate levels of damage

Structural design optimization

Guest Editorial, Special Issue on Structural Design Optimization, Advances in Structural Engineering, An International Journal, 2007, Vol. 10, No.6

Material studies related to lunar surface exploration. Volume 1 - Lunar soil mechanics and soil properties Final report, 6 Mar. 1967 - 30 Jun. 1968

Lunar soil mechanics and properties for structural engineering aspects of lunar spacecraft landings and surface exploratio

Nanomaterials in Structural Engineering

Development of structural engineering, daring structures with record spans or heights, meets two serious obstacles—the limitations of traditionally used materials and the need of continuous monitoring of new structures subjected to complex loads, including those of dynamic nature. Considering the responsibility for the life of people and the budget of new structures, the need of constant monitoring is inevitable. This is why structural engineers seek for new solutions; among them, smart structures based on self-monitoring materials seem to be one of the most attractive proposals. It is still an unexplored area, but current research shows a high potential of the use of composites reinforced by carbon-based nanomaterials as self-sensing structural materials. Nanomaterials also influence other important features of structural materials, such as microstructure, mechanical, and transport-related properties. In this chapter, we present the state of art of the use of nanomaterials in structural engineering in various areas including mechanical and electrical properties as well as issues referring to durability

Nonlinear mathematics in structural engineering

Accepted versio

Practical application of CFD for wind loading on tall buildings

This paper is concerned with assessing the scope of appicabiity for computational fluid dynamics(CFD) in the field of structural engineering, with a particular reference to tall buildings. Modern design trends and advances in engineering materials have encouraged the demand for taller and more slender structures. This pattern induces inherent structural flexibility; these cases exceed the limitations of the quasi-static method offered by current codes of practice. Wind tunnel testing is the traditional solution for such dynamically sensitive structures. However, even this scaled modelling approach is clouded by some uncertainties, including scaling the Reynolds number and assuming damping values for the aeroelastic model. While CFD cannot be used as a replacement for wind tunnel testing, there are results within the literature to suggest it has the potential to act as a complimentary tool - provided it is used within its capabilities. The paper outlines the various turbulence models that are available and summarises the extent of their application in a practical structural engineering sense. It also details the user-defined criteria that must be satisfied and discusses the potential for simplified models in tall building CFD analyses, with a view to promoting more efficient and practical solutions

Advanced ceramic in structural engineering

The work deals with "Advanced Ceramics in Structural Engineering”. Throughout this work we present the different types of ceramic that are currently in wider use, and the main research lines that are being followed. Ceramics have very interesting properties, both mechanical and electrical and refractory where we can find some of the most interesting points of inquiry. Through this work we try tounderstand this complex world, analyzing both general and specific properties of differenttypes of advanced ceramics. It also discusses the advantages and disadvantages of their use compared to other materials, and we will make some conclusions about all the work.Ingeniería Industria

Inverse Problems in Structural Engineering

When it is possible to determine governing equations, shapes and sizes of the domains, boundary and initial conditions, material properties of structures, and internal sources and external forces or inputs, then the analysis determining the unknown field is considered mathematically or numerically solvable. This issue compiles excellent articles, most of which are very meticulously performed reviews of the available current literature