Conventional Deck Research Articles

Ultimate Strength Behaviour and Optimization of Laser-Welded Web-Core Sandwich Panels under In-Plane Compression

In pursuit of more efficient load-bearing solutions for ship deck panels of Very Large Crude Carriers exposed to vertical hull girder bending forces, laser-welded web-core sandwich panels are considered as an alternative to conventional stiffened panels. The primary goal is to identify a lighter steel sandwich structure capable of matching the ultimate strength of conventional counterparts. Utilizing non-linear finite element analysis, the ultimate strength of conventional decks subjected to uniaxial compression is assessed. Attention is then shifted to laser-welded sandwich panels, with a detailed examination of how various design parameters influence their performance. Specifically, four key design aspects of unidirectional vertical webs, including face thickness, web thickness, web height, and web spacing, are optimized to strike a balance between weight and strength through structural optimization techniques combined with the response surface method. Ultimately, a comparison is drawn between the ultimate strength of these innovative steel sandwich panels and their conventional, stiffened counterparts. The findings reveal that web-core sandwich panels, when employed as an alternative, result in a notable reduction in hull weight, thereby showcasing the potential for a more efficient and sustainable approach in the maritime industry.

Experimental study and numerical modelling of a novel two-way steel-concrete composite slab

This study proposes a new innovative two-way steel-concrete composite slab system. The experimental work investigates the structural capacity, shear behaviour and two-way load distribution of the proposed composite slabs consisting of a new profiled steel deck and concrete. The innovative deck is developed by providing 90° bends in corrugated steel sheets to form hat sections, which then are placed on a corrugated base sheet in the perpendicular direction. Five composite slabs were tested under uniform loading, in which three slabs contained shear studs, and the remaining two were tested without shear studs. The slabs failed by flexural failure and shear bond failure, and the composite slabs with and without studs showed comparable load-carrying capacity and two-way action. The unique geometry of the deck profile provides good longitudinal shear capacity in the main direction. The slip is absent in the main longitudinal direction of the slab due to the corrugated top-hats. The provided shear studs further complement the role of the top-hats by resisting interface shear failure in the perpendicular direction. Therefore, the new deck type can be used effectively in two-way composite slabs for shear and load capacity by reducing the quantity of additional shear connectors, which is a significant advantage of the proposed deck compared to conventional deck types. A finite element (FE) model of the composite slabs with and without shear connectors is developed and validated against the experimental results and then used to investigate the slab's performance in two-way load distribution.

Multibody dynamic analysis of float-over installation based on active multi-dimensional motion compensation equipment

Float-over technology has been gaining attention for its cost-effectiveness and ability to handle heavier loads. However, wave-induced motions during the installation of offshore platform topsides can pose challenges for the barge and interfere with the load-transferring process. To address this issue, this paper proposes a new active motion compensation equipment (MCE) that can replace the conventional Deck Supporting Unit (DSU) to enhance the load-transferring operation. The study develops a multibody dynamic model of the motion-compensated float-over (MCFO) system and introduces a Jacobian matrix to describe the interaction between the topside and barge due to the MCE's altered connection properties. Numerical simulations are conducted for the specific mating process of MCFO with MCE and DSU equipped, respectively. The analysis considers the motions of the barge and topside, as well as the corresponding loads of the Leg Mating Unit (LMU). Results show that the proposed MCE can compensate for most of the wave-induced motion of the barge, reducing the duration and scale of slamming during load transferring. The proposed MCE can thus improve operational feasibility in harsh sea states and presents a profitable attempt at active compensation mode.

Role of fat on the quality and shelf-life of gluten-free bread baked by Ohmic heating and conventional deck oven

The addition of fat to gluten-free (GF) bread can influence several quality attributes, such as texture and starch retrogradation. Therefore, the aim of this study was to investigate the influence of different fats on GF bread properties using two different baking methods (conventional and ohmic heating), in order to understand how these affect the physical bread quality, the formation of amylose-lipid complexes and its effect on crumb firming behavior. Fats (coconut, rapeseed, butter, and palm) with different physico-chemical properties, and physical state (solid, liquid) were tested in standard GF bread formulations. Results showed that fat significantly improved crumb pore uniformity. Crumb texture and pasting properties were mostly influenced by the type of fat, storage time and baking method. Staling was delayed in all breads added with fat due to the formation of amylose-lipid complexes, which were highest with palm fat and were usually higher when baked by ohmic heating.

Experimental and Finite Element Study of a Novel Two-Way Corrugated Steel Deck System for Composite Slabs

This paper investigates the structural performance of a new two-way profiled steel decking system for steel-concrete composite slabs. Several studies have investigated steel decking for steel-concrete composite slabs and focused on utilising the conventional deck as a one-way floor system. The newly developed deck consists of top-hat sections formed by bending corrugated sheets at 90°, which are attached to a corrugated base sheet. The deck is designed for improved composite and two-way action contributed by its unique geometry due to corrugations in the transverse and longitudinal directions. This paper experimentally tested a novel steel decking geometry under construction stage loading. It was in the absence of concrete to establish the deck’s suitability for construction and contribution towards loading capacity and performance for future use as a two-way composite slab. Ultimate load, two-way action, and failure modes were identified. A finite element model was also developed, and parameters assessed that could influence the performance when the deck is potentially used in the composite stage. It was concluded that, while increasing the thickness of the corrugated base sheet significantly affects the load-carrying capacity, the thickness of the top hats has no significant impact. Improved load transfer with two-way behaviour is observed when the bottom flanges of the top hats are continuously connected to the bottom flanges of the adjacent top hats to form a deck. This contrasts with the concept deck, where individual top hats are attached to a corrugated base sheet. In this case, decks with a corrugated base sheet perform 54% better in ultimate load capacity than decks without a corrugated base sheet.

Efisiensi Pemilihan Pelat Baja pada Rehabilitasi Gedung Bertingkat terhadap Biaya dan Waktu (Studi Kasus Gedung Operasi RSUD Kota Langsa)

Increasing the use of space in the multi-storey buildings is self-requirement for the owner in making the most of function of the building. The Langsa City Hospital Operating Building with structural height of +10 meters and has two floors, with the existing part of the 2nd floor not fully designed a closed room. Currently, according to the owner's request, the function of this building is being utilized to be used as a first-floor room as an operating room, while the second floor is intended as a storage room and hall. Based on that, it is necessary to estimate against the appropriate and efficient method of slab work so that to be sure the project objectives are achieved. This paper aims to analyze the comparison between the use of steel deck and conventional deck to the study sites based on cost and time. The research method used begins with collecting field data, calculating the budget plan referring to the Work Unit Price Analysis (AHSP) contained in the contract document, then estimating the implementation time using the labor coefficient according to the 2016 AHSP. The results showed that there was a difference in the budget for the two deck slabs of Rp. 28,616,000. In addition, in terms of the duration of the completion of the work, the difference between the calculation of the estimated implementation of the conventional deck work and the realization of the implementation of the steel deck is 39 working days. Based on the results obtained, the use of steel deck is cheaper and more time efficient than the use of conventional deck. So that the selection of the use of steel deck at the study site is appropriate because it can save costs and time.

Analysis of Adhesive Joints in a GFRP Bridge Deck under Bidirectional Bending Due to Traffic Wheel Loads

Glass-fiber-reinforced polymer (GFRP) decks have been widely used in the rehabilitation and construction of bridges as a replacement for conventional deck materials, such as steel, concrete, and wood. In this study, an analysis method for checking the local safety of joints in adhesively connected GFRP decks under bidirectional bending due to traffic wheel loads is newly presented. This method can be applied for designing and evaluating the joints of other FRP decks. The orthotropic material properties of the deck were approximately assumed according to the test results and previous research. Three-dimensional solid elements were used to simulate the local behavior of the adhesive and deck substrates at the joints. Global deflections of the deck and local deformations of the adhesive were evaluated for serviceability. The local stresses in the adhesive and deck substrate are evaluated at the joint to check for local failure modes of the joint under serviceability and ultimate limit states. The analysis results indicate that local failures of the adhesive and deck substrate at the joint occurred. Recommendations for avoiding these local failures and performing more precise analysis are suggested.

Recent developments in the prefabricated bridge deck systems

Bridge deck systems developed using conventional materials like concrete and steel have low strength-to-weight ratios; take long time to install; are prone to premature deterioration due to corrosion, especially in humid environment; and have high maintenance needs. Therefore, prefabricated deck systems developed using modern materials are the need of the time. These deck systems are lightweight, easy to install, have low maintenance cost and have long life. Such deck systems have wide application, especially in movable bridges. This study summarizes the current state of knowledge on modern/lightweight bridge deck systems including aluminum, fiber-reinforced polymers (FRPs), ultra-high-performance concrete (UHPC) and Hybrid systems. Main findings and recommendations drawn by various researchers on the basis of experimental work and computer-aided analysis are presented. Prefabricated bridge deck systems developed using these materials mostly satisfy the strength and serviceability requirements, and have potential to replace the conventional deck systems. The primary objective of this study was to support researchers, highway engineers, consultants and contractors in the field of bridge engineering to get an outline of recent researches on prefabricated bridge deck systems.

A new deck arch bridge and a study on its mechanical properties by FE and experiment methods

In this study, a new type of deck arch bridge was proposed based on the triangle stability principle, and its mechanical properties were tested. The new deck arch bridge—named the superposed truss arch bridge—consists of main arches, auxiliary arches, a girder, and web members. These components adopt steel structures and are connected into a series of triangles to form a superposed truss structure. The new structural system design retains the advantages of the truss and arch structure. Additionally, the rise-span ratio of the main arch can be smaller in the new system design, so the rise height is smaller, which can decrease construction difficulty. The underlying mechanical principles of the new bridge were explained. A new type of railway deck arch bridge with a 650 m span was designed, and the finite element method was used to analyze its stiffness, strength, stability, and dynamic properties and the corresponding effects of the arch-axis coefficient, rise-span ratio, and span length on the mechanical properties. An experiment was carried out on a new deck arch bridge and a conventional deck arch bridge with the same span (10 m) to compare their performance. The results showed that the new deck arch bridge exhibited good mechanical properties while being inexpensive and easy to construct, which makes it suitable for high-speed railway bridges.

Non-Destructive Evaluation of Closure Joints in Accelerated Bridge Construction using a Damage Etiology Approach

In accelerated bridge construction (ABC), prefabricated bridge deck elements are merged using “closure joints.” Because of the cast-in-place nature of closure joints that are expected to go into service rapidly and problems observed for some types of closure joints, there have been some concerns about their long-term durability. This has necessitated the need for monitoring the condition of ABC closure joints using non-destructive testing (NDT) methods. Closure joints contain unique features and details that sets them apart from conventional deck panels. This requires a special treatment of closure joints when it comes to selecting the appropriate NDT technique for their health monitoring. A clear guideline for selecting an applicable NDT method for various types of closure joints has not been developed yet. For this purpose, an investigation was carried out in the Accelerated Bridge Construction University Transportation Center (ABC-UTC) at Florida International University. This paper summarizes the result of this investigation. It includes reviews of all relevant NDT methods for applicability to ABC closure joints and efforts for categorizing closure joints according to joint features that affect the use of NDT. Since the applicability of NDT methods heavily depend on the type of expected anomaly to be detected and its root causes, all potential defects and types of damage were identified and investigated using a damage sequence tree (DST). Consequently, damage etiology for ABC closure joints were established using fault tree analysis (FTA). Finally, a quantitative statistical survey was used to substantiate the selection of the NDT methods that were most applicable to the health monitoring of ABC bridges containing closure joints. The results presented in this paper can be used by bridge owners and consultants as an effective and practical guide for the selection of NDT methods for monitoring the health of ABC closure joints.

Span Length Variance Effect on the Fatigue Life of FRP Bridge Deck

Fiber reinforced composite materials have the merits of light weight and durability for bridge deck and are estimated to be superior in economy to conventional deck materials considering the life-cycle cost of bridge. In this study, fatigue tests were conducted for the span lengths of 2.0 m and 2.5 m in order to investigate the change trend of fatigue characteristics of composite material deck according to the change in the span length. The result showed that the fatigue life rapidly reduces to about 25% when the span increases by 25%. However, considering that the fatigue performance safety margin was approximately 1.6 times more than the design axle load of the DB-24 design truck load in Korea, even at the span of 2.5 m, it is judged that the FRP decks being considered can be effectively used at a span length of 2.5 m.

Low-Cracking, High-Performance Concrete Bridge Decks

Cracks in concrete bridge decks provide easy access for water and deicing chemicals that shorten the life of the deck, and field surveys show that the problem has become progressively more severe since at least the 1980s. A two-phase, 10-year Pooled Fund study to minimize cracking in bridge decks is now under way. Twenty bridge decks have been constructed in the program to date. Comparison with conventional decks shows that the techniques embodied in low-cracking, high-performance concrete (LC-HPC) bridge deck specifications have been highly successful in reducing cracking in bridge decks. The results also show that high-slump high-strength concretes result in greater cracking in bridge decks than low-slump, moderate-strength concretes and that concrete temperature control and early application of curing counteract the negative effects of casting concrete under high-temperature conditions. Early owner and contractor buy-in is needed for successful LC-HPC bridge deck construction, and top performance requires the adherence to all aspects of the specifications.

Structural Behavior of FRP Composite Bridge Deck Panels

Fiber-reinforced polymer (FRP) composite bridge deck panels are high-strength, corrosion resistant, weather resistant, etc., making them attractive for use in new construction or retrofit of existing bridges. This study evaluated the force-deformation responses of FRP composite bridge deck panels under AASHTO MS 22.5 (HS25) truck wheel load and up to failure. Tests were conducted on 16 FRP composite deck panels and four reinforced concrete conventional deck panels. The test results of FRP composite deck panels were compared with the flexural, shear, and deflection performance criteria per Ohio Department of Transportation specifications, and with the test results of reinforced concrete deck panels. The flexural and shear rigidities of FRP composite deck panels were calculated. The response of all panels under service load, factored load, cyclic loading, and the mode of failure were reported. The tested bridge deck panels satisfied the performance criteria. The safety factor against failure varies from 3 to 8.

In-Field Performance of the Modified Beam-in-Slab Bridge: A Replacement Option for Low-Volume Bridges

Managers of most low-volume roads (LVR) face a deteriorating bridge population, and replacement is frequently the most cost-effective solution. With more structures needing replacement than available funds to do so, low-cost alternatives that are constructible in-house are a desirable option. The modified beam-in-slab bridge (MBISB) is one such alternative that has been developed specifically for LVRs. The MBISB system consists of longitudinal steel stringers that support a transverse concrete arched deck. Composite action is obtained by using an alternative shear connector (ASC) rather than shear studs. Other than nominal transverse reinforcement, which is part of ASC, MBISB requires minimal additional reinforcement—approximately 70% of that required in conventional decks. Two demonstration bridges—MBISB 1, 50 ft (15.24 m) long and 31 ft (9.45 m) wide, and MBISB 2, 70 ft (21.34 m) long and 32 ft (9.75 m) wide-saved the bridge owner slightly more than 20% of the cost of conventional bridge systems. Field ...

A parametric study for the structural behaviour of a lightweight deck

Lightweight structures are increasingly used for high-speed ships. Research of fatigue and stability of the highly stressed thin plate structures is an ongoing activity, which produces valuable information for the structural engineers. One topic that should be an integrated part of these studies is the dynamic behaviour of lightweight deck structures. When the deck structures are made extremely lightweight, the natural frequencies of the structures as such may increase while the loaded decks will most likely deflect more than conventional decks do. It is then expected that the natural frequencies of the decks will decrease and new problems of vibration and damping will appear. There is concern for resonance with propeller blade frequencies but also with the wave responses of these high-speed ships. The subject of this paper is to study the static and dynamic behaviour of a lightweight ship deck. A theoretical model was made in order to study the interaction between the car and the deck. The model indicates that the car chassis is a significant part of the problem and influences the solution. A finite element model of the ship deck was generated and special parameters, such as material of the panels, numbers and locations of loaded cars were studied. The speed of running cars on the deck during loading and the frequencies of the propeller excitation were varied in order to understand their influences on the structural response. Based on the results from finite element analysis obtained, it is shown how a conventional steel structure is improved by introducing lightweight material. The structural behaviour is significantly influenced from both a static and dynamic point of view.

Comparison of the fatigue behaviors of FRP bridge decks and reinforced concrete conventional decks under extreme environmental conditions

This paper summarizes the results of the fatigue test of four composite bridge decks in extreme temperatures (-30°C and 50°C). The work was performed as part of a research program to evaluate and install multiple FRP bridge deck systems in Dayton, Ohio. A two-span continuous concrete deck was also built on three steel girders for the benchmark tests. Simulated wheel loads were applied simultaneously at two points by two servo-controlled hydraulic actuators specially designed and fabricated to perform under extreme temperatures. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the deck was subjected to a total of ten million cycles. Quasi-static load-deflection and load-strain responses were determined at predetermined fatigue cycle levels. Except for the progressive reduction in stiffness, no significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

Punt da Suransuns Pedestrian Bridge, Switzerland

The Punt da Suransuns is a stress-ribbon bridge with a span of 40 m carrying a footpath across the Hinterrhein river through the Viamala gorge. Its deck is constructed with slabs of Andeer granite, which are prestressed over rectangular steel bars. Compared with a conventional deck, this prestressing increases the stability considerably.In 1996, the Veia Traversina (a footpath following a historic Roman trail) was opened, with the Traversiner Steg being the first stage of the walkway through the Viamala. For its continuation through the southern part of the gorge, a new path needed to be constructed between the Wildener Brucke and Rania, crossing the Hinterrhein north of the Viamala bridge that carries the national A13 highway across the gorge.

Slime molds, ascidians, and the utility of evolutionary theory

This game is about discovering generality in biology. How so? Let’s give the face values on the cards biological interpretations. An ace represents genes and molecules underlying biosynthetic pathways of great antiquity, the kings mechanisms of transcription and translation, the queens regulatory or signaling molecules. The cards comprising the stacked deck correspond to events that arose early in the history of life. The conventional deck, with its deuces and treys, represent taxon-specific biological features, say, the morphologies of antelope horns, the variety of social insect castes, or the polyp polymorphisms of siphonophores. A winning hand is a general finding, one germane to all or a large fraction of extant organisms.

Flutter Stability of Very Long Suspension Bridges

As longer suspension bridges are being built and planned around the world, many feasibility problems arise. Experiences related with preliminary studies on the Gibraltar Bridge are presented. Flutter is considered to be the main feasibility problem for a very-long-span bridge, and it is analyzed in this paper for span lengths ranging from 1,600 to 6,000 m. As conventional deck designs present unacceptably low critical velocities, several alternative suspension schemes are analyzed to determine their qualities to prevent flutter instability. These systems use a variable number of main cables (from one to four) and hangers arranged in such a way as to produce the highest stiffening effects on the statical system. Flutter is analyzed by means of a multimodal finite-element-based method, and critical conditions are defined by observation of the U-f diagrams. The crossed-hangers system is chosen as the simplest way to improve flutter stability, although the results of this study indicate that it is useful only for very long spans.

Sensory Quality and Energy Use for Baking of Molasses Cookies Prepared with Bleached and Unbleached Flour and Baked in Infrared, Forced Air Convection, and Conventional Deck Ovens

ABSTRACTCookies were prepared with bleached and unbleached flour, two formulas, and baked in institutional deck, infrared and convection ovens to determine the effects on sensory qualities and energy for baking. Sensory qualities were evaluated by a trained panel and energy use with meters. Flour significantly (p<0.05) affected all characteristics except width of cracks; oven, all characteristics except top‐grain score and number of cracks; and formula, all textural and most appearance but no flavor characteristics. Values were generally highest with bleached flour and the convection oven. Energy use in baking was greatest in the convection oven (p<0.05).