Construction Of Superstructures Research Articles

Thermoelastic Stress Analysis of Composite Finger Joints

The marine industry at present employs the use of aluminium extrusions in the construction of decks and superstructures that could be replaced with pultruded glass reinforced plastic (GRP) profiles. The length of the pultruded section is limited and therefore, efficient and economic jointing techniques must be developed that can withstand the loads applied to ship structures. This paper evaluates a novel means of adhesively bonded connection for GRP structures known as a finger joint. Various joint geometries are examined, load displacement behaviour is established and Thermoelastic Stress Analysis (TSA) is used to provide the full field stress distribution over the joint. The results of the TSA are compared with the load displacement behaviour. It is shown that by increasing fingertip angle there is a decrease in load carrying capacity, a decrease in shear stress and an increase in stress concentration factor at the finger joint tip.

Stress analysis of finger joints in pultruded GRP materials

Pre-formed composite components have the potential to provide an economical alternative to traditional construction techniques for the manufacture of ship structures. The marine industry at present employs the use of aluminium extrusions in the construction of decks and superstructures that could be replaced with pultruded glass-reinforced plastic (GRP) profiles. The length of the pultruded section is limited and therefore, efficient and economic jointing techniques must be developed that can withstand the loads applied to ship structures. This paper evaluates finger joints in GRP components manufactured from material that models pultruded construction. Various joint geometries are examined, load displacement behaviour is established and thermoelastic stress analysis (TSA) is used to provide the full field stress distribution over the joint. Calibration techniques are described for the TSA. The results of the TSA are compared with the load displacement behaviour. It is shown that by increasing fingertip angle there is a decrease in load carrying capacity, a decrease in shear stress and an increase in stress concentration factor at the finger joint tip. The results from the experimental work were used to validate a numerical model that provides data for initial joint optimisation.

Enabling stability analysis of tubular reactor models using PDE/PDAE integrators

We discuss the construction of computational superstructures enabling time-dependent process simulation codes to perform stability, continuation and bifurcation calculations—tasks in principle not accessible to them—directly. The basis of the approach is the so-called Recursive Projection Method of Shroff and Keller (SIAM Journal of Numerical Analysis 31). We discuss its implementation and performance for the detection of different types of bifurcations (with emphasis on Hopf bifurcations) as well as slight modifications appropriate for index 1 partial differential/algebraic equations (PDAE) simulators. Tests that help discriminate between physical and numerical (spurious) bifurcations detected in the process are discussed and illustrated through the standard example of a tubular reactor with a single irreversible exothermic reaction.

Integral Abutment Bridges: Current Practice in United States and Canada

Integral abutment bridges have been gaining popularity among bridge owners as cost-effective alternatives to bridges with conventional joints. They reduce initial construction costs and long-term maintenance expenses, improve seismic resistance, and extend long-term serviceability. New York has been building them since the late 1970s, with a wide variety of details, and they have been performing well. For further improvement of New York’s design practice, a comparative survey was undertaken across North America, focusing on design and construction of both substructures and superstructures. In all, 39 states and Canadian provinces responded, including 8 who said they had no experience with these bridges. Responses are analyzed and summarized in this report. Overall, integral abutment bridges are performing as well as, if not better than, conventional bridges, but no uniform national standards exist for their design. Design practices and assumptions concerning limits of thermal movement, soil pressure, and pile design vary considerably among responding agencies. These decisions are based largely on past experience. Validity of these assumptions needs investigation by testing and analysis to ensure efficient and reliable design.

New Class of Microporous Materials: Porous Metal Phosphonate Thin Films

AbstractSolid state metal phosphonates (M(O3P-R-PO3) or M(O3P-R)2 (M = metal)) have layered structures where the metal atoms lie in planar sheets and the intervening R groups take up the interlamellar space. Microporous metal phosphonates can be prepared by reaction of the metal with a mixture of large and small phosphonates (M(O3P-LARGE)x(O3P-SMALL)2-x. The larger group acts as a pillar that holds the layers apart. Void spaces result from the presence of the smaller groups. The porous nature of these solids make them potential candidates for applications as sensors, size- and shape- selective catalysts, and chromatographic materials. Metal diphosphonates (M(O3P-R-PO3) can also be prepared one layer at a time on a surface, resulting in the construction of interesting superstructures that are not accessible through the solid state synthesis. For example, these superstructures can contain different components in sequential layers and may have applications in energy conversion, vectorial electron transport, and NLO devices. The preparation of microporous thin films would combine the desirable potential applications of the porous solids with the interesting parallel superstructures that can be prepared from the thin film assemblies. We report our progress toward the construction of microporous metal phosphonate thin films. The two methods that are currently being developed include: 1) phosphonate exchange of pre-assembled films, and 2) co-deposition of different large and small phosphonates during film assembly.

ELEVATED SECTION OF THE WEST GATE FREEWAY, SOUTH MELBOURNE, AUSTRALIA. PART 2: DESIGN AND CONSTRUCTION OF SUBSTRUCTURE AND SUPERSTRUCTURES.

ELEVATED SECTION OF THE WEST GATE FREEWAY, SOUTH MELBOURNE, AUSTRALIA. PART 2: DESIGN AND CONSTRUCTION OF SUBSTRUCTURE AND SUPERSTRUCTURES.

Final Report on Specifications for Bridge Design and Construction for Design and Construction of Steel Highway Bridge Superstructures

These specifications cover the design of fixed span bridges and require first-class design, material, and workmanship, subject to the approval of the Engineer.

On the Construction and Erection of Iron Piers and Superstructures for Railway Bridges in Alluvial Districts

On the Construction and Erection of Iron Piers and Superstructures for Railway Bridges in Alluvial Districts