Grand Avenue Traverse: Uniting Accessibility, Utilities and Economy Into a New Experience

<p>The Grand Avenue Pedestrian Bridge spans 85m from a park and residential neighborhood to a developing waterfront district that is 24m below. The bridge carries sewer, storm, and water utilities over rail lines and a highway while passing under power lines. The bridge’s east landing is on a landslide prone steep slope. On the west the bridge lands on a new concrete stair and elevator tower that rests on soil that is regularly infil- trated with seawater.</p><p>The design concept uses the constraints of the project to create a unique moment that is both utilitarian and unexpected. By sloping the truss to drop 4.8% towards the west, a set of accessible ramps are created on the top, side, and interior of a box-truss style bridge. Traversing 7m of elevation through accessible paths allowed the design team to minimize the height of the elevator and therefore moment into the foundations, critical for a site that is seismically active and located in seawater infiltrated soil.</p><p>Material choices for the bridge and throw barrier were based on considerations of durability and mainte- nance. Weathering steel is used for the primary truss members, painted steel for members located under the deck, and bare aluminum panels with a custom CNC cut perforation form the guardrail and throw barrier. All of the elements come together as a unified experience.</p>

Residual Strength Prediction of Aluminum Panels with Multiple Site Damage Using Artificial Neural Networks

Multiple site damage (MSD) cracks are small fatigue cracks that may accumulate at the sides of highly loaded holes in aging aircraft structures. The presence of MSD cracks can drastically reduce the residual strength of fuselage panels. In this paper, artificial neural networks (ANN) modeling is used for predicting the residual strength of aluminum panels with MSD cracks. Experimental data that include 147 unique configurations of aluminum panels with MSD cracks are used. The experimental dataset includes three different aluminum alloys (2024-T3, 2524-T3, and 7075-T6), four different test panel configurations (unstiffened, stiffened, stiffened with a broken middle stiffener, and bolted lap-joints), many different panel widths and thicknesses, and the sizes of the lead and MSD cracks. The results presented in this paper demonstrate that a single ANN model can predict the residual strength for all materials and configurations with high accuracy. Specifically, the overall mean absolute error for the ANN model predictions is 3.82%. Furthermore, the ANN model residual strength predictions are compared to those obtained using the most accurate semi-analytical and computational approaches from the literature. The ANN model predictions are found to be at the same accuracy level of these approaches, and they even outperform the other approaches for many configurations.

Stamp Forming: A Comparison in the Use of Draw Beads and Blank Holder Force for Producing Aluminum Panels

An investigation was performed examining the effects of draw beads and blank holder forces on local forces in various regions of a stamp forming process that produced oval aluminum panels. The results showed that provided there was sufficient blank holder forces to prevent wrinkling, the regions with draw beads were affected more by draw bead height than by blank holder force. However, at the die ends, away from the draw beads, blank holder force had more of an effect than the draw beads did with respect to local forces. Additionally, the draw bead height effects at the die end were not directly related but had to be interpreted based upon the effect on strains within the flange region at the die ends. This study may be especially useful for researchers in the automotive sector who are particularly interested in aluminum panel forming.

Improvement of lng carriers’ structures

Представлены результаты разработок, направленных на повышение надежности и экономической эффективности судов для перевозки сжиженного природного газа (СПГ) за счет рационализации конструкции и технологии строительства. Целью данной работы является поиск архитектурно-конструктивных и технологических решений для газовоза с вкладными ёмкостями, обеспечивающих (по сравнению с известными решениями) повышение прочности и надежности грузовой емкости для транспортировки и хранения сжиженного газа, уменьшение вероятности нарушения ее герметичности, сокращение затрат на строительство газовоза и его продолжительности. Для достижения этой цели выполнены следующие работы: · проанализированы различные виды традиционных архитектурно-конструктивных решений для судов-газовозов; · выявлены преимущества и недостатки традиционных решений; · предложены принципиально новые архитектурно-конструктивные решения; · описаны особенности работы предложенных конструкций в составе судна и обоснована их эффективность. Для совершенствования газовозов предложены следующие новые технические решения: · ёмкость для транспортировки и хранения СПГ в виде многослойной термоизолированной оболочки предлагается выполнять из полых алюминиевых панелей, образующих совместно с набором и переборками прочную конструкцию ёмкости с не менее чем двумя герметичными барьерами; · теплоизоляцию емкостей предлагается выполнять из многослойных полых податливых панелей из полимерного композиционного материала (например, из стеклопластика); · установку прочных конструкций емкостей выполнять с деформированием элементов теплоизоляции и с образованием натяга в соединении этих конструкций с теплоизоляцией; · строительство судов-газовозов предлагается осуществлять путем параллельного изготовления корпуса судна, прочных конструкций грузовых емкостей и конструкций теплоизоляции, а затем производить монтаж на корпусе крупных блоков теплоизоляции в отсеках судна, после чего производить вставку прочных конструкций емкостей в отсеки судна. Results of developments for LNG carriers’ reliability and cost efficiency increase owing to structure and construction technology rationalization are presented. The aim of this paper is search for architectural-and-structural and process engineering solutions for LNG carriers with containment systems that provide (in comparison with familiar solutions) strength and reliability increase for a containment system for liquefied gas transportation and storage, decrease of its seal failure probability, reduction of cost for LNG carrier construction and its duration. To achieve this aim, the following was completed: · various types of conventional architectural-and-structural solutions for LNG carriers were analyzed; · advantages and disadvantages of conventional solutions were identified; · fundamentally new architectural-and-structural solutions were proposed; · specific features of proposed structures operation in a LNG carrier were described and their effectiveness was proved. The following innovative technologies were proposed for LNG carriers: · containment systems for liquefied gas transportation and storage in the shape of a multilayer thermally insulated shell are supposed to be produced from hollow aluminum panels that form a strong containment system structure using a framing and bulkheads, with at least two leakproof barriers; · the containment system thermal insulation is expected to be manufactured from multilayer hollow compliant panels from a polymeric composite (for example, fiberglass); · strong containment system structures will be installed with deformation of thermal insulation elements and with forming tightness in these structures connection with the thermal insulation; · It is intended to construct LNG carriers through parallel manufacturing of a vessel hull, strong containment systems and thermal insulation structures and then install large thermal insulation units in the hull in vessel compartments, after that insert strong structures of the containment systems into the vessel compartments.