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This paper presents an interpretation technique to quantify the effects of compaction state and matric suction on the undrained shear strength of compacted clay under confined undrained triaxial compression. This novel technique is based on the mathematical frameworks of the 'stress history and normalized soil engineering property' (SHANSEP) method for saturated soil and the 'Barcelona basic model' (BBM) for unsaturated soil. Test data of compacted Calgary till were analyzed and interpreted using the proposed technique. The interpretation technique is very useful in delineating the relative impacts of the factors on the behavioural trends in measured undrained shear strength. It was found that in addition to the initial compacted void ratio and suction, soil structure and failure mode exert significant influence on the undrained shear strength of compacted clay. This technique is attractive to engineering practitioners because the confined undrained compression tests (with no pore-air and pore-water pressure measurement) are much simpler and less time-consuming compared to rigorous laboratory tests on unsaturated soil. Key words: compacted clay, undrained shear strength, suction, soil structure, tensile rupture, strain softening, ductile yielding. Cet article presente une technique d'interpretation permettant de quantifier les effets de l'etat de compactage et de la succion matricielle sur la resistance au cisaillement non drainee de l'argile compactee sous compression triaxiale confinee non drainee. Cette nouvelle technique est basee sur les cadres mathematiques de la methode SHANSEP ([musch less than] stress history and normalized soil engineering property [much greater than]) pour les sols satures et BBM ([musch less than] Barcelona basic model[much greater than]) pour les sols non satures. Les donnees d'essai du till compacte de Calgary ont ete analysees et interpretees a l'aide de la technique proposee. La technique d'interpretation est tres utile pour delimiter les impacts relatifs des facteurs sur les tendances comportementales de la resistance au cisaillement mesuree sans contrainte. Il a ete constate qu'en plus de l'indice des vides initial et de la succion initiale de l'argile compactee, la structure du sol et le mode de defaillance exercent une influence significative sur la resistance au cisaillement non drainee de l'argile compactee. Cette technique est attrayante pour les ingenieurs car les tests de compression confinee non drainee (sans mesure de la pression de l'air interstitiel et de l'eau interstitielle) sont beaucoup plus simples et moins longs que les tests rigoureux en laboratoire sur des sols non satures. [Traduit par la Redaction] Mots-cles : argile compactee, resistance au cisaillement non drainee, succion, structure du sol, rupture a la traction, ramollissement par contrainte, deformation ductile., Introduction The undrained shear strength, [s.sub.u], of saturated soil is one of the key input parameters in total stress analysis for short-term stability and capacity of geotechnical structures (e.g., shallow [...]

The use of modular construction has gained wide acceptance in the industry. For a specific construction facility layout problem such as site precast standardized modular units, it requires the establishment of an on-site precast yard. Arranging the precast facilities within a construction site presents real challenge to site management. This complex task is further augmented with the involvement of several resources and different transport costs. A genetic algorithm (GA) model was developed for the search of a near- optimal layout solution. Another approach using mixed-integer programming (MIP) has been developed to generate optimal facility layout. These two approaches are applied to solve with an example in this paper to demonstrate that the solution quality of MIP outperforms that of GA. Further, another scenario with additional location constraints can also be solved readily by MIP, which, however, if modeled by GA, the solution process would be complicated. The study has highlighted that MIP can perform better than GA in site facility layout problems in which the site facilities and locations can be represented by a set of integer variables. DOI: 10.1061/(ASCE)CO.1943-7862.0000214 CE Database subject headings: Algorithms; Computer programming; Construction sites; Planning. Author keywords: Genetic algorithms; Mixed-integer programming; Facility layout.

SUMMARY Gridlock is defined when traffic comes to a complete halt inducing huge delays. If a work zone on a two-lane two-way highway is set up, in which one of [...]

A simple analytical approximation based on Landau-Ginzburg theory is developed for ferroelectric thin films with continuous and first-order phase transitions. We show that the polarization profile can be conveniently modeled by a power series expansion that allows us to re-express the Landau-Ginzburg free energy as an effective Landau-Devonshire free energy. Simple expressions are obtained for the properties of ferroelectric films. It is found that the calculated properties based on our effective Landau-Devonshire theory are consistent with numerical results from the Landau-Ginzburg theory. [DOI: 10.1119/1.2800353]

In conventional lane-based signal optimization models, lane markings guiding road users in making turns are optimized with traffic signal settings in a unified framework to maximize the overall intersection capacity or minimize the total delay. The spatial queue requirements of road lanes should be considered to avoid overdesigns of green durations. Point queue system adopted in the conventional lane-based framework causes overflow in practice. Based on the optimization results from the original lane-based designs, a refinement is proposed to enhance the lane-based settings to ensure that spatial holding limits of the approaching traffic lanes are not exceeded. A solution heuristic is developed to modify the green start times, green durations, and cycle length by considering the vehicle queuing patterns and physical holding capacities along the approaching traffic lanes. To show the effectiveness of this traffic signal refinement, a case study of one of the busiest and most complicated intersections in Hong Kong is given for demonstration. A site survey was conducted to collect existing traffic demand patterns and existing traffic signal settings in peak periods. Results show that the proposed refinement method is effective to ensure that all vehicle queue lengths satisfy spatial lane capacity limits, including short lanes, for daily operation., 1. Introduction In the past few decades, traffic signal settings at signal-controlled intersections have been optimized using different optimization frameworks, including the stage-based method [1-4], the group-based method [5-12], and [...]

We consider Steiner minimal trees (SMT's) in metrics defined by given orientations. The problem is motivated by wiring considerations of VLSI chips when the wiring direction is not restricted to only horizontal and vertical. In particular, we concentrate on the case when the given orientations form angles of 0 [degrees], 60 [degrees], and 120 [degrees] ([[Lambda].sub.3]-metric) since many interesting results can be obtained which may shed light on other metrics in the family. Specifically, we show that any SMT can be transformed to one with their Steiner points located on the grid points of a multilevel grid, where the number of levels can be quite small. based on this result, we have developed a simulated annealing-based algorithm to generate near-optimal SMT's. Empirical results and comparisons with Euclidean cases are also given. Index Terms - Multilevel grid, orientation metrics, simulated annealing, Steiner tree problem, very large-scale integration.

The switchbox rectilinear Steiner tree problem is to construct an optimal rectilinear Steiner tree interconnecting n terminals on the perimeter of a switchbox without crossing any obstacles inside the switchbox. However, intersecting boundaries of obstacles is allowed. We present an algorithm that computes an optimal switchbox rectilinear Steiner tree in O([F.sub.1](k)n + [F.sub.2](k)) time, where k is the number of obstacles inside the switchbox and [F.sub.1] and [F.sub.2] are exponential functions of k. For any constant k, the proposed algorithm runs in O(n) time. As an immediate extension, we can generate m Steiner trees in O(mn) time, and among them, select the best one.