Showing papers on "Deck published in 2012"

Stress Analyses and Parametric Study on Full-Scale Fatigue Tests of Rib-to-Deck Welded Joints in Steel Orthotropic Decks

Abstract: Fatigue tests of full-scale orthotropic steel decks were recently conducted to evaluate the fatigue performance of rib-to-deck partial-joint-penetration (PJP) groove welded joints. The test results indicated that rib-to-deck joints are more prone to fatigue cracks in the deck plate than in the rib wall. A shallower weld penetration (for example, an 80% PJP) also appeared to have a slightly higher fatigue resistance than a deeper one (for example, a 100% weld penetration). These PJP welds were also more vulnerable to cracking initiated from the weld toe than from the weld root. Finite-element analyses of the test specimens, using the effective notch stress method, were performed to supplement the laboratory testing and provide additional information on the behavior of these welded joints. The analysis results showed a good correlation with the observed crack patterns. A parametric study also showed that the fatigue resistance of the PJP joint can be significantly influenced by the transverse loading location, deck plate thickness, and the weld penetration ratio. Increasing the deck plate thickness was effective in reducing the stresses, while the rib wall thickness had a little effect. A shallower weld penetration at the PJP joint appeared to have a positive effect in enhancing the fatigue resistance.

Cable-Stayed Bridges: 40 Years of Experience Worldwide

Abstract: PREFACE INTRODUCTION Design fundamentals Design guidelines THE DEVELOPMENT OF CABLE-STAYED BRIDGES Predecessor bridges Cable-stayed bridges with steel deck Cable-stayed bridges with composite deck Cable-stayed bridges with composite deck Special cases ROPES AND CABLES Locked coil ropes Parallel bar cables Parallel wire cables Parallel strand cables Corrosion protection Manufacturing Supervision Cable anchorages Cable dimensioning Dynamic behavior of cables Cable assembly and erection PRELIMINARY DESIGN Analysis of equivalent systems Analysis of overall structural systems Dynamic behavior of bridges Protection against ship collision Calculation examples ERECTION Examples Analysis BUILT EXAMPLES Precast concrete decks: Pasco-Kennewick Bridge, East Huntington Bridge CIP cable-stayed concrete bridge: Helgeland Bridge Steel cable-stayed bridge: Strelasund Bridge Composite cable-stayed bridge: Baytown Bridge Bridges with hybrid decks: Normandy Bridge Series of cable-stayed bridges: Millau Viaduct, Rion-Antirion Bridge PROSPECT LISTS Bridges References Photo credits APPENDIX - 40 YEARS EXPERIENCE IN BRIDGE ENGINEERING WORLDWIDE Personally Bridges in Germany Cable-Stayed bridges abroad New developments resulting from competition participation Checking of bridges Technical Committees and Working Groups Actual projects Conclusion DVD with LECTURE VIDEOS recorded at the Technical University of Dresden

In-service condition assessment of bridge deck using long-term monitoring data of strain response

Abstract: Continuous awareness of the evolution of the structural condition of bridge structures is of great value for bridge owners, as it allows them to make informed decisions regarding the maintenance and management of these public facilities. Structural condition assessment via monitoring has gained in popularity in recent years, because it can provide structural engineers with plentiful information on the structural condition through various sensors. A key issue for successful application of monitoring technologies for condition assessment is how to realize meaningful interpretations of monitoring data. In this study, an approach to structural condition assessment of in-service bridge deck making use of long-term monitoring data of strain response is proposed and applied to the instrumented Tsing Ma Bridge. The proposed method consists of structural assessment at two levels: (1) deck truss component level and (2) deck cross-section level. As long-term monitoring data of dynamic strain under the in-ser...

Influence of Model Parameter Uncertainty on Seismic Transverse Response and Vulnerability of Steel–Concrete Composite Bridges with Dual Load Path

Abstract: This paper uses a fully probabilistic approach to investigate the seismic response of multispan continuous bridges with dissipative piers and a steel–concrete composite (SCC) deck, the motion of wh...

Analysis of Structural Compatibility at Interface Between Asphalt Concrete Pavements and Orthotropic Steel Deck Surfaces

Abstract: Orthotropic steel deck is the most suitable solution for long-span bridges by virtue of its low weight and good mechanical properties. However, this deck shows a lack of adhesion with ordinary paving materials; for this reason special bonding coats are usually applied on the steel surface. Polymer-modified bitumen, asphalt-based mastic, epoxy asphalt, and reinforced asphalt membrane have been used at the interface between the hot-mix asphalt (HMA) course and steel bridge decks. A description of these materials and their construction process is provided. In some extreme situations mechanical reinforcement is necessary to provide adequate bonding between the steel deck and the asphalt pavement. The aim of this study was the laboratory evaluation of the shear properties of smooth and reinforced steel interfaces, which were coated with a polymer-modified bitumen and placed between the steel deck and conventional HMA. A suitable specimen preparation procedure was first defined. Shear resistance was evaluated w...

Vehicle Floor Structure

Abstract: A vehicle floor structure, in which a main structure of the vehicle floor structure is a double deck structure including two sheets of panels formed from a fiber-reinforced thermoplastic composite material; in a region including the double deck structure, each of the panels includes at least two continuous reinforcing structures having a convex open cross-sectional shape; recesses are provided in at least two places of the reinforcing structures; and the panels are joined in such a manner that the reinforcing structures of the respective panels intersect with each other, and that the recesses provided in the reinforcing structures of the respective panels are fitted to each other.

Composite Behaviour of a Hybrid FRP Bridge Girder and Concrete Deck

Abstract: This paper involves experimental investigation onto the composite behaviour of a hybrid FRP bridge girder with an overlying concrete deck. Two types of shear connections were investigated: epoxy resin adhesives alone and epoxy resin combined with steel u-bolts. The results showed that the steel u-bolts combined with epoxy resin provided a more effective connection; hence a full-size specimen was prepared based on this result. Four-point bending test was carried out to determine the behaviour of a full-scale composite hybrid FRP girder and concrete deck. The composite action resulted to a higher stiffness and strength with the hybrid FRP girder exhibiting higher tensile strain before final failure. There was a significant decrease in the compressive strain in the top flange of the FRP girder thereby preventing the sudden failure of the beam. The composite beam failed due to crushing of the concrete followed by shear failure in the top flange and web of the FRP girder.

Fatigue assessment for deck plates in orthotropic bridge decks

Abstract: Since the 1960s, orthotropic deck plates of highway bridges have been built with large coldformed trapezoidal stiffeners supporting a deck plate with a thickness of approx. 12 mm. The maximum cross-beam spacing is approx. 4 m. A number of these bridge decks in The Netherlands suffer from fatigue cracks in the deck plate. First cracks have been observed after about 30 years in service. In one particular movable bridge, the cracks were found after only seven years. In many other countries, this type of crack has not yet been observed. This article provides a fatigue assessment procedure for deck plates. The procedure is calibrated with the conditions and observations in The Netherlands. It gives a fatigue life prediction and takes account of inspection results quantitatively. Although aspects such as the type and thickness of the surface finishes and the traffic load may vary between countries, the principles of the assessment procedure in this article are generally applicable and can be used to identify reasons for differences in fatigue life and to develop strategies for increasing the life

New Bridge Deck Cast onto Corrugated GFRP Stay-in-Place Structural Forms with Interlocking Connections

Abstract: In this study, pultruded glass fiber reinforced polymer (GFRP) corrugated plates, connected together through pin-and-eye connections, were investigated as stay-in-place (SIP) forms for concrete decks. The SIP form completely replaced the bottom layer of reinforcement, whereas a top GFRP mesh was provided. Special attention was given in simulating the details of deck connection to supporting girders. Full-scale deck specimens, including a control deck with conventional steel reinforcement, were cast on concrete supports simulating a girder spacing of 1,780 mm. The 410-mm-wide supports had a rough surface finish along with protruding steel stirrups to simulate the flange of an AASHTO type III girder. An additional cantilevered specimen was tested to examine the feasibility of using SIP forms in deck overhangs at exterior girders. The study also investigated the effects of GFRP plate thickness and bond with concrete on performance. All specimens, except the cantilevered one that failed in flexure, ha...

Transverse post-tensioning arrangement for side-by-side box-beam bridges

Abstract: While side-by-side box-beam bridges have numerous structural advantages, a serious drawback for this type of bridge is the longitudinal deck cracking over the shear keys. These cracks are observed as early as a few years after initial construction, even where transverse post-tensioning is applied. Associated distresses are well documented in the literature. Two hypotheses were established: longitudinal deck cracking in side- by-side box-beam bridges may be mitigated through an optimized transverse post-tensioning arrangement and traffic is not the sole load factor controlling longi- tudinal deck cracking. This broad study, encompassing field observations as well as experimental and numeri- cal investigations, demonstrates that a transverse post- tensioning system can be determined as a function of bridge geometry such that deck cracking due to temperature and traffic loads is mitigated. The recom- mended transverse post-tensioning system is defined by the number of diaphragms and the force applied at each diaphragm.

Rapid Bridge Deck Condition Assessment Using Three-Dimensional Visualization of Impact Echo Data

Abstract: Ultrasonic seismic methods can be used in the condition assessment of bridge decks by evaluating changes in material characteristics and detecting the development of defects and zones of deterioration. The impact-echo method is of special benefit in the evaluation of corrosion-induced deck delamination because of its nondestructive nature and ability to detect delaminated zones at various stages of deterioration: from initial to progressed and developed. The traditional approach in the condition assessment of bridge decks by impact-echo is based on a review of individual test-point records. A new approach based on three-dimensional data visualization is proposed. The developed three-dimensional visualization platform allows for both the advanced presentation and an automated interpretation of impact-echo data. The data presentation is provided in terms of three-dimensional translucent visualizations of reflectors in a bridge deck section and horizontal and vertical cross sections through all distinctive zones, including a zone of delamination. The associated interpretation platform enables the overall assessment of the condition of the deck, through cumulative distributions of reflection intensity of different reflective layers, and the identification of deteriorated zones of the deck to be repaired or rehabilitated in an efficient and intuitive way.

Bridge deck survey with high resolution Ground Penetrating Radar

Abstract: Ground Penetrating Radar applications for structure surveying started to grow in the 1980s; amongst these, initial civil engineering applications included condition assessment of highway pavements and their foundations, with applications to structural concrete focusing on inspection of bridge decks. There are many factors that can cause or contribute to the damage of the top layer of concrete in bridge decks including the corrosion of steel rebar, freeze and thaw cycles, traffic loading, initial damage resulting from poor design and/or construction, and inadequate maintenance. When applied to the analysis of bridge decks, GPR can be successfully used for detecting internal corrosion of steel reinforcement within the concrete deck, which can be an indicator of poor quality overlay bonding or delamination at the rebar level. Therefore, this equipment has the ability to gain information about the condition of bridge decks in a more rapid and less costly fashion than coring and will perhaps yield a more reliable assessment than current geotechnical procedures. However, this application requires suitably designed equipment; for instance, optimization of antenna orientation to take advantage of signal polarization is an important feature for successfully locating reinforcing bars in a time-depth slice. Novel equipment has recently been developed to enable the nondestructive analysis of bridge decks; the IDS RIS Hi-Bright runs two arrays of high frequency sensors featuring a rapid, but very dense data collection, thus dramatically increasing the resolution of the GPR survey. Antenna dipoles in these arrays are deployed to collect two data sets with orthogonal antenna orientations, one with the electric field parallel to the scanning direction (VV), the other perpendicular to it (HH); in this way, the equipment is capable of collecting 16 profiles, 10 cm spaced in a single swath, thus collecting an incredible amount of information. Dedicated data analysis software provides a 2-D tomography of the underground layers and a 3-D view of the surveyed volume. Main output include the determination of pavement and concrete thickness, the detection of moist areas as well as concrete damage and the location of rebars and ducts within the concrete slab.

Decking system with hidden dovetail fastener

Abstract: This present invention relates generally to deck fasteners for securing deck boards together and to a supporting member, and more particularly with a deck fastener which does not protrude from the deck surface.

Structural monitoring of a strengthened orthotropic steel bridge deck using strain data

Abstract: Orthotropic steel bridges have experienced early fatigue cracks at several welded connections in the steel deck plate. One of the possible strengthening systems to enlarge the fatigue life of the e...

Effect of corrosion on the ultimate strength of double hulloil tankers – Part I: stiffened panels

Abstract: Age-related problems especially corrosion and fatigue are normally suffered by weatherworn ships and aging offshore structures. The effect of corrosion is one of the important factors in the Common Structural Rule (CSR) guideline of the ship design based on a 20 or 25 years design life. The aim of this research is the clarification of the corrosion effect on ultimate strength of stiffened panels on various types of double hull oil tankers. In the case of ships, corrosion is a phenomenon caused by the ambient environment and it has different characteristics depending on the parts involved. Extensive research considering these characteristic have already done by previous researchers. Based on this data, the ultimate strength behavior of stiffened panels for four double hull oil tankers such as VLCC, Suezmax, Aframax, and Panamax classes are compared and analyzed. By considering hogging and sagging bending moments, the stiffened panels of the deck, inner bottom and outer bottom located far away from neutral axis of ship are assessed. The results of this paper will be useful in evaluating the ultimate strength of an oil tanker subjected to corrosion. These results will be an informative example to check the effect of ultimate strength of a stiffened panel according to corrosion addition from CSR for a given type of ship.

Structural behavior of bubble deck slab

Abstract: Bubble deck slab is a method of virtually eliminating all concrete from the middle of a floor slab, which is not performing any structural function, thereby dramatically reducing structural dead weight. High density polyethylene hollow spheres replace the in-effective concrete in the centre of the slab, thus decreasing the dead weight and increasing the efficiency of the floor. By introducing the gaps leads to a 30 To 50% lighter slab which reduces the loads on the columns, walls and foundations, and of course of the entire building. The advantages are less energy consumption - both in production, transport and carrying out, less emission - exhaust gases from production and transport, especially CO 2 . The aim of this paper is to discuss about various properties of Bubble deck slab based on the various studies done abroad. Moment, deflection and stress distributions are verified using Finite Element Method (FEM) in SAP2000.

Designing Simply Supported R.C. Bridge Decks Subjected to In-Plane Actions: Strut-and-Tie Model Approach

Abstract: The evaluation of the effects of seismic action on the decks of multi-girder bridges is often neglected by practitioners because it is thought that seismic code prescriptions (i.e., deck elastic behavior and minimum reinforcement) in addition to ultimate limit state reinforcement dimensioning for permanent and variable load, do not justify more accurate analyses aimed at checking and/or optimizing reinforcement layout. With the aim of verifying the reliability of this kind of approach, this article proposes a step-by-step procedure, based on the Strut-and-Tie Model, for the design of R.C. girder bridge decks subjected to in-plane seismic actions. As a first application, the proposed approach is used for a single span girder bridge deck. The influence on the model of geometry and supports of the bridge deck as well as the layout of girders and cross-beams is also investigated.

Automatic landing guide control method for carrier aircraft based on deck motion compensation

Abstract: The invention relates to an automatic landing guide control method for a carrier aircraft based on deck motion compensation, belonging to the technical field of carrier aircraft landing guide and control. An automatic landing guide and control system for a carrier aircraft consists of a guide sub-system mounted on a carrier and a control sub-system mounted on an aircraft. The guide sub-system comprises a tracking radar, a radar stabilizing platform, a high-speed general computer, a display platform, a data code transmitter, a data chain monitor and a flying path recorder; and the control sub-system comprises an autopilot, a data chain receiver, a receiving decoder, an autopilot coupler, an auto-throttle controller and onboard radar equipment. The deck motion information is introduced intothe system, and a deck motion predictor and a deck motion compensation network are arranged so that the carrier aircraft landing path tracks the deck motion path of the carrier, the landing error caused by the deck motion is reduced, and the landing safety is improved.

Self-stabilizing cloud deck based on inertia attitude sensor

Abstract: The invention discloses a self-stabilizing cloud deck based on an accelerometer and a gyroscope, which comprises an inertia attitude sensor, a main control unit, a cloud deck and a cloud deck drive unit, wherein a sensing module comprises the accelerometer and the gyroscope, the cloud deck drive unit comprises a pitch axis steering engine and a transverse roller steering machine, the sensing module is fixed on the cloud deck, the accelerometer and the gyroscope on the sensing module are respectively used for measuring gesture information of the cloud deck, the main control unit is used for fusing a signal of the accelerometer and a signal of the gyroscope by using a weighting algorithm to obtain an optimal gesture angle; and the control unit is used for comparing an expected gesture angle with the optimal gesture angle, figuring out a control quantity of the gesture of the cloud deck, deviating from the expected gesture, by using a control algorithm, and sending the control quantity to the cloud deck drive unit to drive the cloud deck to reach the expected gesture so that the cloud deck is self-stabilized. According to the invention, the accelerometer and the gyroscope are used, thus the cloud deck is better in stability and higher in precision.

Damage Evaluation for Concrete Bridge Deck by Means of Stress Wave Techniques

Abstract: Different from postfailure maintenance in many perspectives, preventive maintenance of civil engineering structures is another highly crucial measure, not only for achieving efficient distribution of limited budget over existent aging infrastructures but also for maximizing their service lifespans. In the context of road bridges, their functional failure often causes serious impact on safety and logistics, which could turn out to be detrimental to the social economy. To appropriately maintain a huge number of aging infrastructures, a strategic maintenance program, facilitating both the global- and local-diagnosis approaches, that is effective in assessing early damage is of high demand. In this study, fatigue damage of concrete bridge decks, which is a common form of deterioration among bridges, was examined by sensitive nondestructive testing methods utilizing propagation of stress waves. Specifically, the fatigue damage process of concrete decks due to repeated traffic loads is visualized by means of active and passive elastic wave techniques, namely the elastic wave tomography and acoustic emission techniques. In the experiment, a full-scale concrete deck was subjected to repeatedly moving wheel load, to induce fatigue damage to the concrete. At three stages of after initial loading, after 10,000 passage and after 20,000 passages of 150-kN wheel loading, the fatigue test was suspended temporarily, and elastic waves were transmitted into the concrete to inspect interior structure with elastic waves' velocity. Applying static load with gradual increment in magnitude, acoustic emission testing was then conducted to extract characteristic acoustic emission (AE) parameters with regard to the intrinsic damage. Promising elastic wave parameters for quantifying the damage, which have been identified through experimental studies, were later verified using in situ deck specimens hewed out from an actual bridge. These experiments showed that by using sparsely arrayed AE sensors for measurement, followed by extracting AE frequency features, global investigation of the integrity of bridge decks could be carried out. Once the area of interest was identified through analysis of AE data, detailed information such as cross-sectional damage could be visualized by employing ultrasonic testing and tomographic reconstruction procedure.