Deck Components Research Articles

Seismic fragility and vulnerability assessment of a multi-span irregular curved bridge under spatially varying ground motions

Multi-span reinforced concrete (RC) curved box-girder bridges are commonly designed to facilitate traffic flow at highway interchanges. The Aksemsettin Viaduct (henceforth, A Viaduct for brevity) in Istanbul, Turkey, is an eleven-span interchange bridge with a total length of 596.8 m. Located in a high seismicity zone, the A Viaduct is designed with a curved deck, multiple bearings that have different isolation mechanisms at different bents and directions, ten rectangular columns with unequal heights, and a mix of pile foundations and spread footings. The significant length of the viaduct crossed by eleven spans also makes it susceptible to varying ground motion excitations at different foundations. To evaluate the effects of the degree of modeling detail and analysis complexity on the estimated seismic performance, the present study conducts a comprehensive fragility assessment of the specimen viaduct under various ground motion excitation schemes. First, a three-dimensional finite element model is developed with detailed simulations for the deck, columns, bearings, foundations, and abutment components. To enable different ground motion excitations at each foundation, 57 sets of spatially varying ground motions are simulated by considering the realistic surface topography and soil stratigraphy at the bridge site. Cyclic pushover analyses are performed along multiple loading directions to develop the direction-dependent capacity limit state models for hollow rectangular columns. Subsequently, a demand-capacity ratio method is utilized to develop reliable fragility models for bridge columns. Component- and system-level fragilities of the A Viaduct are then assessed under uniform versus multi-support excitations, vertical motions, and ground motions with varying incidence angles. To further capture the seismic damage discrepancies of the same components at different locations, seismic repair cost ratios of the A Viaduct are assessed when subjected to uniform and multi-support excitations. This study highlights the significance of considering multi-support excitations to achieve more realistic seismic fragility and loss estimates for multi-span long curved highway bridges.

Interference of cracking and drilling on opposite side of steel deck components

Fatigue cracking and drilling on one side of component will weaken local stiffness and cause stress redistribution to aggravate cracking on the opposite side. By conducting fatigue tests and numerical simulation of typical details in steel decks, the influence of cracking and drilling on the stress characteristics of weld toe, local base metal, stop-hole and crack-growth ability on the opposite side of components was analyzed. The results demonstrate that the stiffness-based interference effect of fatigue cracking and drilling can be relieved by raising component dimensions. The fastest stress increment at the weld toe on one side of diaphragm-to-rib welded joints occurs as the crack on the opposite side of the U-rib propagates within 20 mm, which can be treated as the maintenance occasion for new initiated cracks. The crack growth will be aggravated after drilling on the opposite side of components, which will also conversely weaken the crack-arresting effect of stop-holes. Drilling shall be simultaneously applied on both sides of bilaterally cracked components. Drilling with the hole center right at the crack tip will lead to the largest stress increment on the other side, which shall be avoided. The hole diameter has greater impact than hole locations, while an early evaluation of local stress shall be conducted on the other side when adopting large holes.

Automatic evaluation of rebar spacing and quality using LiDAR data: Field application for bridge structural assessment

This paper proposes a framework to automatically quantify the quality of rebar placement in the field to improve construction quality and long-term durability of the bridge structures. In this study, three-dimensional point clouds of a concrete bridge construction site were acquired using a mobile LiDAR scanner. Additionally, two algorithms, including projection algorithm and slicing algorithm, were developed to automatically extract the bridge rebar locations for layout quantification at the global level, bin level, and local level. Subsequently, LiDAR extracted rebar placement quality was compared to design drawings to investigate the effectiveness. This study also evaluated the quality of other concrete deck components, which include formwork panels and the contact surface between rebars and anchor bolts. The research revealed that the proposed framework can inform the rebar placement quality in the field prior to concrete pour, providing a permanent record of the bridge deck quality for future inspections and assessments.

Thermal Behaviour of Rebars and Steel Deck Components of Composite Slabs under Natural Fire

Most of the studies involving composite slabs under fire follow the standard fire scenario described by the ISO 834 curve, disregarding the cooling-phase. However, recent studies show that this phase is equally important, as it can lead to the collapse of the structure. Therefore, the present research carried out a parametric study, using numerical models, validated through experimental tests, to evaluate the thermal behaviour of the composite slabs components under natural fire. The results showed that the maximum temperatures in the reinforcement bars occur during the cooling-phase, reaching temperatures up to 300% higher than at the heating-phase, on the steel deck occur at the end of heating, and that the concrete thickness above the steel deck influences the temperature of these components. Also, during the cooling-phase, a “heat bubble” effect is observed on the ribs of the composite slabs, where the reinforcement bars are normally placed. These results highlight the importance of considering different natural fire scenarios, in the structural performance and safety of composite slabs, since during the cooling-phase there is still heat transfer between the elements, which can lead to slab failure. New parameters are proposed to find the temperature of each component for different fire ratings.

Developing Bridge Deterioration Models Using an Artificial Neural Network

The condition of a bridge is critical in quality evaluations and justifying the significant costs incurred by maintaining and repairing bridge infrastructures. Using bridge management systems, the department of transportation in the United States is currently supervising the construction and renovations of thousands of bridges. The inability to obtain funding for the current infrastructures, such that they comply with the requirements identified as part of maintenance, repair, and rehabilitation (MR&R), makes such bridge management systems critical. Bridge management systems facilitate decision making about handling bridge deterioration using an efficient model that accurately predicts bridge condition ratings. The accuracy of this model can facilitate MR&R planning and is used to confirm funds allocated to repair and maintain the bridge network management system. In this study, an artificial neural network (ANN) model is developed to improve the bridge management system (BMS) by improving the prediction accuracy of the deterioration of bridge decks, superstructures, and substructures. A large dataset of historical bridge condition assessment data was used to train and test the proposed ANN models for the deck, superstructure, and substructure components, and the accuracy of these models was 90%, 90%, and 89% on the testing set, respectively.

Infrared thermography detection of delamination in bottom of concrete bridge decks

Infrared thermography (IRT) has been widely used in detecting the subsurface delamination of bridge deck. However, IRT inspection on delamination zones of the bridge deck which have limited exposure to direct solar radiation (e.g., the bottom surface of the bridge deck) is rather challenging due to the relatively low thermal contrast (∆T) development in these zones. Therefore, the purpose of this study is to conduct a series of experimental studies in conjunction with numerical modeling for investigating the effectiveness of IRT in delamination detection of bridge deck components which are normally not exposed to direct solar radiation. Specially, the effects of different environmental conditions, thickness of bridge deck, and defect characteristics on the absolute thermal contrast (∆T) development were systematically investigated. The results show that IRT can effectively detect the subsurface delamination of concrete bridge deck located in regions that are not exposed to the direct solar radiation. In addition, the development of detectable thermal contrast (>0.5°C) is much dependent on the rate of change in ambient temperature with a suitable detection period between 8 am and 4 pm. Furthermore, it shows that the value of ∆T increases with the increase of bridge deck thickness and delamination size.

Prestressed bridge deck responses to blast loads

Bridges are critical to most transportation systems, especially in times of crisis; however, as highly visible and accessible structures, they are also potential targets for terrorist attacks. An understanding of the performance of bridges subjected to blast loads is of critical importance to prevent progressive collapse of such structures that could lead to a catastrophic loss of life. The current research focuses on investigating the behaviour of bridge decks under blast loads from various explosions. The bridge in this investigation is the Sheikh Saad Bridge in Wassit Province, Iraq, whose deck is made of simply supported spans with two types of prestressed concrete girders. Both spans were accurately modelled using the finite element software Abaqus/Explicit, and both concrete and steel mechanical material properties were modified to match the properties under high strain rate conditions of the blast analysis. The latest element deletion technique of the built-in Concrete Damaged Plasticity (CDP) model (available since Abaqus 2019) was used to provide a realistic simulation of concrete damage and spalling. The model was separately subjected to various explosive charges placed at different locations above or below the bridge deck in order to determine the influence of size and location of blast on the bridge superstructure, detailed results and the relevant conclusions are thus presented. Overall, the modelling managed to successfully simulate the blast load response and the cracking propagation within the damaged deck components.

Potential Application of Green Composites for Cross Arm Component in Transmission Tower: A Brief Review

Recently, advanced technologies exploit materials from nonrenewable resources such as petroleum, natural gas, metal ores, and minerals. Since the depletion of these resources and environmental issues, it has brought attention to researchers to progress in the development of biodegradable materials from green composites. Most biofibres and biopolymers are obtained from agricultural waste products either from stem, leaf, stalk, or fruit. Nowadays, green composites with well-regulated life span have been widely discussed in numerous fields and applications. Some studies have shown that biofibres and biopolymers have comparable mechanical, thermal, and physical properties with glass fibre and other synthetic polymers. Thus, researchers are progressively narrowing down the development of green composite materials in many high strength applications, such as house deck and automotive components. This review focuses on the background of green composites (natural fibres and biopolymers), the manufacturing processes, potential applications in cross arm structures, and testing evaluations. This article also focuses on the specific current cross arm configurations and the pultrusion process to form squared hollow section beams. Many open issues and ideas for potential applications of green composites are analysed, and further emphases are given on the development of environmentally friendly material structures. Hence, the article is expected to deliver a state-of-art review on manufacturability and perspectives of natural fibre reinforced biopolymer composite cross arms for transmission towers.

Experimental Investigation of Novel Corrugated Steel Deck under Construction Load for Composite Slim-Flooring

Trapezoidal-shaped thin-walled metallic profiled sheets are used in composite floor construction to enable rapid construction and reduce reinforcement and formwork requirements in concrete casting. However, relevant literature reported the early failure of steel sections due to the buckling and shear of existing trapezoidal and re-entrant decking profiles. There are also limitations regarding design rules for composite flooring systems. Current work aims to develop a new type of composite top-hat section for possible use in composite slim-floor construction. Sinusoidal metallic corrugated sheets that are widely used in building construction were utilized and a new bending technique was used to produce deck components, in which transverse corrugations were introduced along the main direction of the corrugated profile. This paper investigates the structural response of these new sections for several loading and support conditions using a pilot experimental scheme. The developed top-hat sections demonstrated considerable resistance to bending as well as buckling through effective stress re-distributions under considered construction stage loading for single span and continuous span conditions. Currently available design equations recommended by Australian Standards for a similar type of corrugated decks were used to predict the design strength and to compare it with those obtained experimentally. It was concluded that the expressions proposed by the code were inadequate for single span loading cases and would require modifications before being applied to the new profile.

Terahertz time domain spectroscopy and imaging application for analysis of sandwich panel with embedded fibre Bragg grating sensors and piezoelectric transducers

Sandwich structures are commonly used in many objects, e.g. deck components in bridge deck panel. Safety requirements result in development of structural health monitoring (SHM) systems that are implemented into sandwich structures. Such systems based on different types of sensors that can be embedded into the structure. The paper presents THz time domain spectroscopy and imaging application for internal structure analyses of a sandwich panel with glass fibre reinforced polymer skin and polyurethane foam fulfilment. In the adhesive bond between skin and fulfilment, an array of fibre Bragg grating (FBG) sensors and piezoelectric (PZT) transducers was embedded. The analyses were focused on detection and localisation of embedded sensors and transducers and their influence on THz wave propagation. The analysis contains differences in THz wave parameters, like refractive index and absorption coefficient and image analyses. Methods that allow to detect and localise of transducers and fibre optics with FBG sensors as well as damage (debonding between GFRP skin and foam fulfilment in sandwich structure) were proposed.

Preparation and properties of flame‐retardant damping polyurethane and its application in floating deck

Flame‐retardant modified polyurethane (PU) damping layers were prepared using the combination of expandable graphite (EG), aluminum hydroxide, and phosphorus‐nitrogen flame‐retardant HF600B. The mechanical, thermal, damping, and flame retardancy properties of PU damping layer and the sound insulation, vibration damping, and fire resistance of the deck components were studied systematically. The results revealed that the incorporation of flame retardant depressed the mechanical performance in general, and there was no significant change in damping property. At the same time, the residual char ratio of damping layer increased obviously with the addition of HF600B, the vertical burning rating was upgraded from V‐2 to V‐0 and passed the low flame test of marine materials. The A60 fire test showed that the floating deck system with damping layer had a maximum temperature rise of 75°C on the backfire surface during the test, which is much lower than 180°C required in the A60 grade fire resistance and has good fire resistance. Sound insulation test of the deck components showed that only a 2 mm damping layer increased the average sound insulation by 3 dB, especially in the low‐frequency range by about 8 dB. The vibration test showed that the damping effect of the floating damping deck system on the steel plate surface and the dressing surface is increased by 1.1 and 4.0 dB in the range of 10–200 Hz, 9.2, and 4.7 dB in the range of 200–1,500 Hz, respectively. POLYM. ENG. SCI., 59:2136–2147, 2019. © 2019 Society of Plastics Engineers

Structural performance of Nissibi cable-stayed bridge during the main and aftershocks of Adıyaman-Samsat earthquake on March 2, 2017

The structural performances of long span cable-stayed bridges having different elements such as pylons, stayed cables and decks are very sensitive to earthquake ground motions due to their highly statically indeterminacy. Therefore, responses of pylon, cable and deck components of long span cable-stayed bridges should be continuously monitored to prevent structural damages. The present study aims to investigate the responses of pylons, stayed cables and deck components of Nissibi cable-stayed bridge during the main (Mw = 5.5) and aftershocks (Mw = 3.5-4.4) of Adiyaman-Samsat (Turkey) earthquake on March 2, 2017. Firstly, the properties of structural and fixed monitoring systems of Nissibi bridge are introduced, and active faults and earthquake zoning maps of Adiyaman, acceleration records and shake map of main and aftershocks of the earthquake are presented. Then, responses of the pylon, deck and cable elements during the main and aftershocks are obtained using the data taken from the fixed bridge monitoring system. The forces in cables and accelerations in the two pylons and deck are evaluated and compared with each other.

Designing bridges for manufacture and assembly: joining technologies for precast concrete components

In this article, Charlotte Murphy, winner of the Institution's Pai Lin Li Travel Award 2017, discusses her research into joining techniques for precast concrete bridge deck components in the USA, and considers what lessons could be applied in the UK to facilitate the use of off-site manufacturing.

Diaphragm effectiveness of precast concrete structures with cladding panels under seismic action

The seismic performance of precast frame structures strongly depends on the mechanical devices connecting both structural and non-structural elements. Following recent post-earthquake field observations of unintended seismic interaction of the cladding panels with the frame structure, the seismic design of the cladded system is currently being critically examined by the scientific community. Design solutions involving a controlled cladding–structure interaction have been proposed to address this problem. However, the frame–panel interaction may draw high stresses into the roof diaphragm, as a consequence of the stiffening of the external frames only. This paper presents a parametric study based on linear and non-linear dynamic analyses investigating different levels of interaction among frames, panels, and diaphragm system. The results show how the deck and cladding connections influence the seismic behaviour of the structure. Innovative fastening systems aimed at enhancing the seismic performance of the structure are proposed based on the use of dissipative connection devices inserted into both cladding and deck components.

Hygrothermal aging effects on axial behaviour of pultruded web–flange junctions and adhesively bonded build-up bridge members

Premature local failure of web/flange junctions of the majority of unstiffened commercially produced pultruded fiber-reinforced polymer composites profiles is inescapable due to lack of fiber continuity at the resin-dominated junction zones. This paper focuses on evaluating both short- and long-term behavior of such junctions when subjected to axial tensile stresses. In this study, the axial mechanical behavior of web/flange junctions of pultruded bridge deck components before and after hygrothermal aging effect is investigated. In the experimental phase, axial tensile tests were performed on six different types of pultruded web–flange junctions to assess axial characteristics of each web/flange junction type. In order to evaluate the hygrothermal behavior of such junctions, axial tensile tests were conducted on web/flange junction specimens that were exposed to both fresh water and artificial seawater environments at temperatures of 40℃, 60℃, and 80℃. Several controlling parameters affecting both strength and stiffness of pultruded fiber-reinforced polymer junctions were identified and discussed that include: (i) Junction's web and flange thicknesses, (ii) fillet radius, and (iii) variation of hygrothermal exposure environments. Results of this study indicated that the axial tensile capacity of a pultruded profiles is increased as the thickness of both web and flange increases. Also, it was found that the larger fillet radius of the pultruded fiber-reinforced polymer profile may contribute to a larger axial tensile capacity of pultruded profiles. However, due to variable size and geometry of the resin-rich junction zones and the common manufacturing defects in the form of folded fabric and other fibers misalignment effects, it is difficult to generalize the preceding results. Experimental results also showed that the degradation of web/flange junctions axial tensile strength increases when junctions are exposed to higher temperatures. Also, it was found that the axial tensile characteristics for junctions specimens exposed to freshwater environment are slightly different than those that were exposed to artificial seawater environments.

Study on seismic performance enhancement in bridges based on factorial analysis

The seismic performance of bridges depends on the ductile behavior of its column, as the deck and other substructural components except pile foundations are normally designed to be elastic to facilitate bridge retrofitting. Codes such as AASHTO, Caltrans, IRC: 112 etc. give guidelines for the seismic performance enhancement of columns through ductile detailing. In the present study, a methodology for the seismic performance enhancement of bridges is discussed by using a “Parameter-Based Influence Factor” (PIF) developed from factorial analysis. The parameters considered in the factorial analysis are: percentage of longitudinal reinforcement (Pt), compressive strength of concrete (f′c), yield strength of steel (fy), spacing of lateral ties (S) and column height (H). The influence of each parameter and their combination on the limit states considered is estimated. Pushover analysis is used to evaluate the capacity of columns, considering shear failure criteria. A total of 243 (35 combinations) analysis results are compiled to develop ‘PIF’ used in the performance enhancement process. The study also encompasses other sub-objectives such as evaluating the discrepancies in using the Importance Factor (I) in designing bridges of varied functional importance; and estimating the aspect ratio and slenderness ratio values of bridge columns for its initial sizing.

Allowable slope change of approach slabs based on the interacted vibration with passing vehicles

The slope change of an approach slab can induce a “bumping” effect to passing vehicles, magnify the vehicle impact on the bridge, and accelerate the deterioration of the bridge deck and other components. The allowable slope changes recommended in previous studies, which are usually based on the survey results of ride comfort only, are usually inconsistent. In this study, a three-dimensional vehicle-road-bridge interaction model is developed to study the interaction between passing vehicles and the road and bridge. By fully considering three important aspects, i.e., vehicle's running safety, vehicle users' comfort, and the impact on the bridge, an allowable slope change for approach slab is then proposed based on the recommended limits on the three indexes according to relevant codes. The proposed allowable slope change is considered more rational than previously recommended values and could be used as a reference for engineering practice.

Single Objective Optimization Research of a Bulk Carrier Structure

The purpose to optimize the ship structure is to obtain the minimum weight and the maximization of economic benefit. The way is to change the ship size, structure form, whole or partial structure layout under the condition of meeting the requirements of mechanical properties. The whole ship structure optimization model is established. Optimization is carried out by means of the Optimtoolbox in MATLAB, with the total mass of the ship as objective function, the requirements of the specification and the natural frequencies as constraint conditions. With sensitivity analysis,the thickness of bottom plate, deck, keelson, side keelson, superstructure bulkhead, hatch coaming and other components are selected as design variables. The results show that through optimization, better ship lightweight effect is obtained under the premise of guarantee hull structure strength, stiffness and dynamic characteristics. The bulk carrier structure is optimizaed.

Analysis of the Fatigue Stress on Welded Joints of the U-Rib in an Orthotropic Steel Deck

With the improvement in the quality of steel materials, the issue of fatigue cracking has become more important for steel bridges than the failure of the material itself. In this study, the Pelikan-Esslinger method was used to determine the fatigue stress of an orthotropic steel deck. A parametric study was then conducted with the steel deck components as the parameters. Based on the results, the effect of the diverse components of the steel deck on the fatigue stress was analyzed.

Mathematical Logarithmic Model for Predicting Noise of Simply-Supported PC-Box Girder in High-Speed Railway

When a train runs across a bridge, vibration energy is transmitted from the track structure into the bridge deck and other components which act as different size of ‘sounding boards’. These ‘sounding boards’ also radiate noise, namely, re-radiated noise, which results in ‘hot spots’ in noise maps for bridge sections. Based on the field tests on the noise of 32m double line simply-supported PC-box girder serviced in Chengdu-Dujiangyan High-speed Railway (CDHR) in China, mathematical logarithmic equation for predicting the equivalent A-weighed noise level (LA,eq) is proposed. Predicted results are compared with field ones and the non-parametric tests including two-related samples Wilcoxon and two-independent samples Kolmogorov–Smirnov are carried out, indicating satisfactory results and verifying the reliability of theoretical model. Analysis shows that equivalent A-weighed noise level detects no significant difference between the model predictions and the field measurements at the confidence level of 95%.