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Electric Contact Heating of Concrete
Published in Boris A. Krylov, Cold Weather Concreting, 2020
The design of heating forms with electrically conductive covers differ greatly from the heating formworks where heaters are installed on the back of the deck. The conductive layer is placed in them on the side of the deck that is in contact with the concrete and is well insulated from it. The deck may be made of metal or wood (water-resistant plywood). A layer of electrically conductive polypropylene three mm thick reinforced with polymer pile fabric and protected from the working side with a layer of inert polypropylene 0.5 to one mm thick is laid on an electric insulator. Power is fed to the conductive material by strip electrodes made of brass mesh with openings between one and 2.5 mm and the wire diameter of 0.35 to 0.5 mm, their specific resistance being 5 or 6 × 10-6 ohm.m. The insulator is polyurethane with a density of 40 to 45 kg/m3 (Figure 6.8). The heat insulation layer in this design acts as a layer that ties the heating cover with the structural base of the formwork panel. Electrode power leads protrude from the end of the insulation layer to be connected to a power source.
ASCE 24-14 for Flood Loads
Published in Syed Mehdi Ashraf, Structural Building Design: Wind and Flood Loads, 2018
Typically, buildings are planned in such a manner that decks and patios are located outside the main building. They may be attached to the building or abutting the building or located at a distance from the building. If the deck is attached to the building, the bottom of the deck must be above the BFE or DFE. The foundation of the deck may be below the BFE or DFE but must be capable of resisting the applied loads after erosion and scouring occurs after a flood event. If the deck is below the BFE or DFE, it must be completely independent of the building structure and its foundation. Typically, decks are made of wood or concrete. If they are placed below the BFE or DFE, they should be designed such that they do not convert into a dangerous debris after a flood event.
Planning a Carton or Full-Case Order-Fulfillment Operation
Published in David E. Mulcahy, John P. Dieltz, Order-Fulfillment and Across-the-Dock Concepts, Design, and Operations Handbook, 2003
David E. Mulcahy, John P. Dieltz
Decked or Hand-Stacked Cartons in Standard Pallet Racks The next carton pick position consists of decked or hand-stacked cartons in a standard pallet-rack bay. The decked or hand-stacked cartons in a standard pallet-rack bay method includes the one-deep pallet-rack method and its components, plus a wire- mesh or solid deck in the rack bay. The deck material is metal, wood, pressed board, or plywood. To ensure minimal bowing of the deck material, two to four cross members are placed between the load beams.
Container ships: fire-related risks
Published in Journal of Marine Engineering & Technology, 2021
Frey Gerner Callesen, Maurice Blinkenberg-Thrane, John Robert Taylor, Igor Kozine
Currently, there are no requirements for the installation of fixed fire detection systems above the weather deck of a container ship. The detection of a fire on deck is left to chance. SOLAS1 does not stipulate that fire detectors must be fitted on deck. A fire is only discovered if a perceptible amount of smoke is produced, the fire results in sounds that drown out the ordinary noises of the ship, or if flame is discernible, says H. Hammer the International Union of Marine Insurance Political Forum Chair. (MAREX 2017) Thus, the ship's fire safety above the weather deck relies primarily on visual detection by the crew. The reliability of this method is dependent on the overview/visibility of the containerised cargo from the bridge, weather conditions, location of the container in question (i.e. line of sight to the affected container), general crew rounds, container inspections during voyage and series of other environmental and managerial factors. Due to the increased capacity of the ULCS and the tight stowage of containers, the overview of the containerised cargo is restricted, which may impair the efficiency of this method for detecting fires. Furthermore, this method of detection puts a high responsibility on the crew and simultaneously increases the workload of the individual crew members. The general tendency of reducing manning aboard a ship aggravates this problem.
Prediction of stress spectra under low-period sea states
Published in Ships and Offshore Structures, 2018
Chun Bao Li, Joonmo Choung, Beom-Il Kim
Two seakeeping analysis models with fine panel (FP) and normal panel (NP) sizes were prepared for a 14,000 TEU container ship. Four heading angles and three sea states were applied to two seakeeping models. The NP model-based results were derived assuming that the FP model provides the most accurate results, such as the load RAOs, stress RAOs, and stress spectra. The stress RAOs were taken from six hotspots in way of the deck of the container ship. In total, 72 NP-based stress RAOs were prepared to evaluate the accuracy of the functions, which were used to predict the stress spectrum tails. Three functions were used to predict the stress spectrum tails based on the NP model: exponential function (EF), power function (PF) and rational function (RF). They were used to extrapolate the tails of the NP-based stress RAOs to derive the corresponding stress spectrum tails. Meanwhile, a logarithmic-linear function (LLF) was also introduced to predict the tails for any short-tailed NP-based stress RAOs. The stress spectral parameters (m0, m2) and fatigue damage estimation (D) calculated from the four functions were compared with the values derived from the FP model. The comparisons were used to evaluate the accuracy of each function and select the best function to predict the high-frequency energy from a NP model with the most accuracy.
Comparative study of wind resistance of a 2D stack of featured ocean containers and a 3D forty feet unit
Published in Ships and Offshore Structures, 2020
Hamed Majidian, Farhood Azarsina
New generation of large container ships such as post-Panamax size can load 8 tiers of containers in height, more than 30 rows in length and up to 23 bays along breadth. A fully loaded container ship loads more than 50% of containers above its deck. Consequently, frontal projection areas of such ships above deck level in headwind are about 1000 m2. Generally, in calm sea states, wind resistance comprises 3–5% of total ship resistance (Moonesun 2010), but in container ship with large windage area, wind resistance comprises up to 10% of total resistance (Minsaas and Steen 2008).