This study investigates impacts of the 2001 World Trade Center attack on critical infrastructure systems in the New York City metropolitan area. Of particular interest are the physical or logical connections—also known as interdependencies—among these systems, and the impacts of the attack on them. This study extends knowledge about the behavior of complex and interdependent infrastructures sys...

Current American design provisions treat unstiffened elements under stress gradients as if they were uniformly compressed for effective width calculations. Australian, British, and European design provisions allow accurate calculation of the elastic buckling coefficient, however, the same effective width equation for compressed elements is used for elements with stress gradients. In all cases, ...

The morphology shape and texture of dust fractions of five Apollo lunar soils and a lunar dust simulant, JSC-1Avf, was studied using scanning electron microscopy. Shape aspect ratio and complexity of particles was described based on the two-dimensional projection images. The distributions of aspect ratio and complexity of particles are reported. It was determined that the Apollo lunar dust part...

This research effort focuses on the evaluation of existing design standards for cold-formed steel stud walls and the development of retrofit wall systems. Full-scale wall systems are tested under uniform static pressure using a vacuum chamber. The resistance functions obtained are used to model the dynamic behavior of the walls and to predict performance under blast conditions. This paper focus...

An empirical model is developed to predict daily maximum stream temperatures for the summer period. The model is created using a stepwise linear regression procedure to select significant predictors. The predictive model includes a prediction confidence interval to quantify the uncertainty. The methodology is applied to the Truckee River in California and Nevada. The stepwise procedure selects ...

A revised procedure for the design of steel plate shear walls is proposed. In this procedure the thickness of the infill plate is found using equations that are derived from the plastic analysis of the strip model, which is an accepted model for the representation of steel plate shear walls. Comparisons of experimentally obtained ultimate strengths of steel plate shear walls and those predicted...

In this paper, we study the progressive collapse of three-dimensional framed structures made of reinforced concrete after the sudden loss of a column. The structures are represented by elastoplastic Euler-Bernoulli beams with elongation-rotation failure threshold. We performed simulations using the discrete element method considering inelastic collisions between the structural elements. The res...

Basin configuration and equipment design govern whether rectangular secondary clarifiers will experience problems of inadequate sludge transport capacity. The operating factors to be considered, other than peak flows which may be severe, are the potential for sludge bulking and the higher mixed liquor suspended solids concentrations and solids retention times employed for biological nutrient re...

The modeling of statistical size effect of concrete structures that fail at crack initiation is studied, with special attention to the interaction between the autocorrelation length and the size of the failure zone. The mechanical failure of concrete is modeled by a network of axial springs with degrading stiffness. The heterogeneity of concrete is idealized by spatial variation of the tensile ...

Fuzzy project scheduling has interested several researchers in the past two decades; about 20 articles have been written on this issue. Contrary to stochastic project-scheduling approaches that are used by many project schedulers, and even if the axiomatic associated to the theory of probabilities is not always compatible with decision-making situations, fuzzy project-scheduling approaches that...