Steel Deck Plate Research Articles

Beamforming: a spatial de-noising approach for civil structural health monitoring

In the civil structural health monitoring fields, monitored data suffer from noise and sensor faults. In practice, redundant sensors are usually deployed to monitor structural condition to obtain more accurate and robust information. This paper proposes a beamforming-based spatial filtering method to improve the data quality by using the information redundancy within sensor networks. Data pre-processing is first implemented, including missing data imputation and thermal response separation. Subsequently, short-term Fourier transform is used to transform the measured time sequences into time–frequency domain to obtain more useful features. Finally, signals in the time and frequency domain are processed using the beamforming algorithm. In the beamformers, a linear filter is applied to suppress noise signals, which is formulated as a constrained optimization problem. Herein, interior point algorithm is used to optimize the allocation of the linear filter, wherein the objective function is to minimize the power of the noise component at the beamformer output. The effectiveness of the proposed method is verified by using signals from strain gauges installed on steel deck plates of the 3rd Nanjing Yangtze River Bridge. Results through the case study show that signals after spatial filtering have a satisfactory de-noising, which indicates the effectiveness of the proposed beamforming algorithm. We believe that the proposed beamforming algorithm has substantial potential applications, such as providing high quality data source for further investigations.

Fatigue resistance of rib-to-bimetallic steel deck welded joints in orthotropic steel bridge decks

The stainless-cladding techniques have been applied in the top plate of the orthotropic steel decks in the high-speed railway steel bridges to improve the corrosion and wear resistance. The rib-to-deck (RD) welded joint with the stainless-clad bimetallic steel deck plate becomes a new critical fatigue detail. This study firstly examines the fatigue performance of this full-scale new RD joint through six high-cycle constant-amplitude fatigue tests and two beach-mark tests under eccentric over-rib loading. The structural hot-spot stress at the weld toe on the deck plate is obtained by strain gauges and the linear extrapolation method for each RD specimen before the cyclic loading. Experimental results indicate that five RD specimens suffer from the toe-deck failure modes, while the rests encounter root-deck cracking. The fatigue strength of these new RD joints satisfies the FAT100 hot-spot stress S-N curve based on the IIW design recommendation. Numerical simulation is further conducted to investigate the effect of different cracking modes and welding technologies on the fatigue crack propagation behavior of this new RD joint. Root-deck cracking mode shows weakly higher fatigue resistance than the toe-deck failure case. Using the double-side welds between the U-rib and deck plate, and the thickened-edge U-rib technology can slightly enhance the fatigue life in terms of toe-deck cracking mode in contrast with the traditional single-side groove welds. Experimental and numerical validation quantify the excellent fatigue performance of this new RD joint in comparison with the other types of RD welded joints.

Fatigue analysis of orthotropic steel-ultra-high-performance fiber-reinforced concrete (UHPFRC) composite deck considering accelerated deterioration and self-healing of fractured ultra-high-performance fiber-reinforced concrete in surface water condition

In this study, an orthotropic steel bridge deck overlaid with ultra-high-performance fiber-reinforced concrete (UHPFRC) is investigated using the finite element analysis. The composite bridge deck which is undergone moving-wheel load is examined under environmental surface water conditions. Two phases, i.e., Phases 1 and 2, are considered for the material model of the UHPFRC with stagnant water. In Phase 1, mechanical recoveries of the tensile strength and reloading stiffness are considered for the cracked UHPFRC caused by the autogenous self-healing behavior. In Phase 2, under the moving-wheel load, the crack bridging stress degradation in reinforced overlayer accelerates due to the closing–opening actions of surface cracks in water. In both phases, the deformation behaviors of the steel deck plate and UHPFRC overlayer are numerically examined. The results of the current numerical model agree with the experimental data in terms of the strain tendency, wherein the strain range of the steel deck plate and UHPFRC overlayer decreases in Phase 1 and progressively increases in Phase 2. Therefore, it can be asserted that, under the surface water condition, scenarios considering two phases of the material model of cracked UHPFRC, have governed the strain behaviors of the tested composite bridge deck.

Experimental Investigation on Fatigue Improvement of Orthotropic Steel Bridge Deck Using Steel Fiber Reinforced Concrete

AbstractThe high-performance topping concrete overlay would significantly reduce the fatigue stresses at susceptible details of orthotropic steel deck (OSD) and effectively improve the fatigue performance. Full-scale fatigue tests and numerical simulations were carried out to quantify the effects of steel fiber reinforced concrete (SFRC) topping pavement in reducing the OSD fatigue stresses based on a practical bridge design. Fatigue stress of the OSD critical details was measured from tests and cracking was observed in the SFRC overlay. Both an innovative pre-pump-pulse Brillouin optical time domain analysis (PPP-BOTDA) distributed optical fiber sensor and strain gauges were also used to measure the stress at OSD fatigue-prone details, including the crossbeam cut-out, rib-to-deck weld, rib-to-crossbeam weld and splice of U-rib. The corresponding three-dimensional (3-D) finite element model was then established and verified by the test results, and used to conduct a parametric study to obtain a quantitative expression of fatigue stress reduction factor, in terms of relative elastic modulus and thickness of overlay and steel deck plate. The proposed quantitative model of the fatigue stress reduction effect can guide the cost-effective design of composite bridge deck.

Flexural behavior and crack width prediction of UHPC-steel strip composite decks under sagging moments

The UHPC-steel strip composite deck is a novel technique for strengthening in-service orthotropic steel decks with numerous fatigue cracks penetrating the steel deck plate. However, the anti-cracking behavior of the new composite decks under sagging moments is still unclear and formulas for prediction of the crack width at the bottom surface of the UHPC layer is unavailable. In this study, the flexural behavior of the UHPC-steel strip composite deck under sagging moments was investigated through a series of experimental tests. In the tests, the width of the steel strips and the thickness of the UHPC layer were considered as the two primary parameters. The responses of the UHPC-steel strip composite specimens, including the load–deflection curve, failure mode of the specimens, interfacial slippage, and nominal cracking stress of UHPC, were systematically analyzed and discussed. The test results indicate that the specimens with steel strips possessed a better anti-cracking performance compared to that of the specimens without steel strips. This phenomenon implies that the steel strips should impede the initiation and propagation of cracks in UHPC. Moreover, an increase to the width of the steel strips could reduce the average crack spacing and maximum crack width of UHPC. Further, theoretical formulas were proposed to calculate the maximum crack width at the bottom surface of the UHPC layer. The theoretical results obtained via the proposed formulas agreed well with the test results, confirming that the proposed analysis method should be suitable for the UHPC-steel strip composite deck. So the proposed method could be utilized to calculate the crack width at the bottom surface of the UHPC layer under sagging moments.

Fatigue evaluation of the rib-deck weld in OSDs considering the effect of asphalt-steel interface bonding property

The interface bonding layer is usually adopted to connect the asphalt surfacing and steel deck plate; however, the effect of interface bonding conditions on fatigue performance of rib-deck welds still remains unclear. In this study, comprehensive finite element analysis was carried out to clarify the effect of interface bonding conditions. Parametric analysis was conducted to investigate the effect of Poisson’s ratio and elastic modulus of asphalt surfacing, and the interface bonding condition on fatigue performance of rib-deck welds, so is the coupled effect of elastic modulus and interface bonding condition. Taking into account the time-variant temperature and traffic volume, the accumulated fatigue damages in rib-deck welds were compared and analysed. Results show that the simulation of the interface bonding condition is reliable, as convinced by bending tests. The interface bonding condition and the elastic modulus of asphalt surfacing, which are both sensitive to the temperature, considerably affect the fatigue performance of rib-deck welds. The fatigue damage of rib-deck welds is underestimated if the interface bonding behaviour is not considered.

Deflection Test of Wire-Integrated Steel Deck Plates with Various End Details

This experimental study was conducted to evaluate the deflection performance of wire-integrated steel deck plates with various end details subjected to cumulative gravity loads. In general, when deck plates are installed in the Republic of Korea, vertical bars are mounted at the ends of the wire-integrated deck plates. However, this process can extend the construction time, thus incurring additional costs. Consequently, this study aimed to examine the structural performance of a deck plate when a lattice foot-rather than a vertical bar-is installed at the end of it. A total of nine specimens were prepared; the experimental variables included the end details, height of the lattice truss girder, and structure type. To evaluate the deflection performance, the cumulative gravity load (as a construction load) and a concrete self-weight were applied to the specimens, and the deflections of each specimen were measured. In the experimental results, the deflection values of the specimen with vertical bars were 0.9~6.1 mm, while those for the specimen without vertical bars were 0.8~5.0 mm. This means that a lattice foot exhibits better deflection performance than conventional end details. Additionally, the deflection of the specimens satisfied the deflection limits required in the relevant standards.

Monitoring and Simulation Study on Shrinkage Behaviour of Steel-UHPC Composite Deck

Combining an Ultra-High Performance Concrete (UHPC) layer with an orthotropic steel bridge deck by stud connectors could enhance the fatigue performance of a deck system because of the improved system stiffness. However, UHPC is featured by significant early-term shrinkage owing to the material composition. Inappropriate constraints introduced by stud connectors may result in a high risk of UHPC cracking, leading to unexpected safety and durability issues. This study investigated the early-term shrinkage behaviour of a steel-UHPC composite bridge deck by conducting an 80-day shrinkage monitoring test at first. The monitoring results showed that the UHPC hardening process lasted for over 44 h, and the maximum UHPC shrinkage under constraint in the composite deck was only 120 μϵ, while the shrinkage induced compressive stress on the steel deck plate reached 36 MPa. Meanwhile, qualitative simulation and parametric analysis works were carried out to investigate structural dimension effects on shrinkage behaviour of the composite bridge deck in detail. According to the analysis results, the UHPC shrinkage and the induced stress on the steel deck plate had obvious uneven distribution feature. And stud spacing was found as a sensitive factor to shrinkage constraint extent compared with rebar spacing and stiffener thickness. Therefore, a rational stud spacing and design suggestions for practical applications were discussed in addition.

Shrinkage effect and mechanical performance of steel-ultra-high performance concrete composite deck under negative bending action

Shrinkage effect can result in damages in steel-UHPC composite decks. And these damages may even cause mechanical performance degradations. The details are critical to deck design practice and evaluation theory establishment while not being clearly understood. In this study, static shrinkage monitoring and negative bending tests on two full-scale segmental composite deck specimens (D12 and D16) were sequentially conducted. 12-mm- and 16-mm-diameter reinforcements were respectively embedded in the specimens. Simulation and parametric analysis were executed as well for further understanding. The 90 days static shrinkage monitoring results showed the maximum induced compressive strains on reinforcements of D12 and D16 were 559 με and 328 με. The maximum compressive strains on steel deck plates were 80 με and 82 με. It indicated shrinkage effect cannot be ignored. The bending test results showed the UHPC tensile strain maximums were 1458 με and 1149 με in the two specimens when the maximum UHPC crack width was 0.10 mm. Moreover, the simulation analysis results also showed that the model with 90 days shrinkage effect had a 16% lower bending secant stiffness at the load level equivalent to allowable UHPC crack width. And the reduction increased to nearly 40% when the crack width reached 0.10 mm. In addition, the parametric analysis showed that a strain-hardening feature could be favorable to delay the UHPC damage evolution compared with a strain-softening one with relatively lower tensile strength. These results provided important support to the design practice of steel-UHPC composite decks.

Static and fatigue performance of steel bridge decks strengthened with air-cured UHPC

Adding a thin layer of ultra-high performance concrete (UHPC) onto the steel deck plate is an effective approach to improve the fatigue performance of orthotropic steel decks (OSDs) through increasing structural stiffness and load-carrying capacity, but a wide industrial acceptance of the approach is hindered by heat curing of UHPC. In this study, air-cured UHPC with low shrinkage was adopted to fabricate the cast-in-situ topping layer for the composite decks. Experiments were carried out to investigate the structural behavior of the composite decks under static and fatigue loading. Experimental results showed that (1) UHPC with relatively high strengths and low shrinkage could be manufactured without any special curing regime; and (2) the composite decks had enough mechanical strengths and fatigue resistance to withstand service loads. Finite element analyses were performed to determine the contribution of air-cured UHPC on the fatigue performance of OSDs. Finally, a hot spot stress reduction factor was introduced to assess the long-term effectiveness of air-cured UHPC in improving the fatigue performance of OSDs. Results suggested that UHPC cracking and the associated degradation in structural stiffness had limited effects on the fatigue behaviors of composite decks.

Design and experimental study of a replaceable steel-UHPC composite bridge deck

This paper proposes a prefabricated orthotropic steel-UHPC composite bridge deck consisting of standard units, which could be assembled conveniently in-situ to avoid the traditional complicated steaming curing of UHPC with high temperature. The standard unit can also be replaced separately under conditions of failures or local damage. This composite bridge deck can thus convincingly mitigate the fatigue problem in the orthotropic steel deck and also the pavement damage in traditional steel bridges. A parametric study of the composite bridge deck is performed together with the PBL shear connector to determine a reasonable design of the deck structure. The effects of some key structural parameters, such as the UHPC layer thickness, the steel deck plate thickness, the spacing and stiffness of the open rib, and the size of the PBL shear connectors, are carefully studied by the finite element model analysis. Based on the determined deck design, a full-scale experiment study is further executed to investigate and demonstrate the performance of the proposed structure. Results show that the failure mode of the structure is the yielding of stiffening ribs, while the UHPC panel under a tensile state works well. Moreover, as a new cement-based composite material, UHPC exhibits the improved tensile strength and a strong ability to limit the width of cracks after the test load is removed.

Experimental Study of the Factors Influencing the Performance of the Bonding Interface between Epoxy Asphalt Concrete Pavement and a Steel Bridge Deck

The bonding between pavement and a steel bridge deck is a key component affecting the structural integrity of steel deck pavement and delamination is a major cause. The bonding interface of steel deck pavement was systematically investigated to evaluate the interactive influences of factors, such as the air void of the asphalt concrete pavement, the surface roughness of the steel deck, the thickness of the zinc-rich epoxy primer, and the waterproof bonding membrane, on the bond strength of the pavement interface, through simulated loading, brine immersion, pull-off, and interface observation experiments. The results show that a low air void (<3.0%) was a necessary condition for the corrosion resistance and bonding reliability of the steel deck pavement structure, and a zinc-rich epoxy primer provided an additional guarantee for corrosion resistance of the steel deck pavement; additionally, the combination of steel deck plate roughness in the range of 120–140 μm and zinc-rich epoxy primer thickness in the range of 80–110 μm led to a high bond strength, which was also conducive to the corrosion resistance of the steel bridge plate. The steel deck pavement structure should be designed through combinatorial optimization of multiple factors to create an integrated waterproof and anticorrosion bonding system.

Welding-induced Residual Stresses in U-Ribs of a Steel Bridge Deck

To calculate the welding-induced residual stresses in U-ribs of the steel deck plate and conduct quantitative analysis of influential factors, the U-ribs of steel deck plate of Xinghai Bay Bridge was taken as the research object. In the ABAQUS finite element software, the local models of U-ribs of steel deck plate were established. Nodal body force loads, i.e., heat generation rate, of the double ellipsoidal heat source models were applied via the compiled subsidiary Dflux program. The welding process of the v-groove welds was simulated, to obtain the residual stresses distribution in the top plate and U-rib plates. The influence of thickness of top plate and angle of welding groove on the residual stresses in the U-ribs were studied. The results show that the welding-induced residual stresses calculated by the numerical method proposed in this paper agree well with the experimental data. The maximum residual stresses in the top plates and the U-rib plates all occur near the welds, which exceeds the yielding limitation of the material. As the thickness of top plate increases, the maximum values of residual stresses in the top plates and U-ribs increase. However, with the increase of groove angle, the maximum values of residual stresses in the top plates and U-rib plates decrease.

Impact resistance of steel materials to ballistic ejecta and shelter development using steel deck plates

The destruction caused by ballistic ejecta from the phreatic eruptions of Mt. Ontake in 2014 and Mt. Kusatsu-Shirane (Mt. Moto-Shirane) in 2018 in Japan, which resulted in numerous casualties, highlighted the need for better evacuation facilities. In response, some mountain huts were reinforced with aramid fabric to convert them into shelters. However, a number of decisions must be made when working to increase the number of shelters, which depend on the location where they are to be built. In this study, we propose a method of using high-strength steel to reinforce wooden buildings for use as shelters. More specifically, assuming that ballistic ejecta has an impact energy of 9 kJ or more, as in previous studies, we developed a method that utilizes SUS304 and SS400 unprocessed steel plates based on existing impact test data. We found that SUS304 is particularly suitable for use as a reinforcing material because it has excellent impact energy absorption characteristics due to its high ductility as well as excellent corrosion resistance. With the aim of increasing the structural strength of steel shelters, we also conducted an impact test on a shelter fabricated from SS400 deck plates (i.e., steel with improved flexural strength provided by work-hardened trapezoidal corrugated plates). The results show that the shelter could withstand impact with an energy of 13.5 kJ (2.66 kg of simulated ballistic ejecta at 101 m/s on impact). In addition, from the result of the impact test using the roof-simulating structure, it was confirmed the impact absorption energy is further increased when artificial pumice as an additional protective layer is installed on this structure. Observations of the shelter after the impact test show that there is still some allowance for deformation caused by projectile impact, which means that the proposed steel shelter holds promise, not only structurally, but also from the aspects of transportation and assembly. Hence, the usefulness of shelters that use steel was shown experimentally. However, shelter construction should be suitable for the target environment.

Analytical and Measured Effects of Short and Heavy Rail Cars on Railway Bridges in the USA

The overall number of railcars recorded in the North American railcar fleet from 2010 to 2015 increased about 5%; the number of all 130 tonne (286,000 lb) gross weight railcars (heavy axle load (HAL) railcars) increased 19%. The increase in shipments in short railcars increases the loading on railway bridges, especially the 12.8-m railcars, commonly used to ship sand and cement, which is approximately a 25% increase in load per unit length compared to 16.2-m coal cars. Significant differences between maximum effects of shorter railcars and common 16.2-m railcars were predicted in analysis for bridge spans longer than 18.3 m. The differences were more prominent on spans 24.4 m and longer. This study presents analytical and measured effects of freight railcars on a two-span truss bridge, with spans of 61 m and 33.5 m, and a 35-m riveted steel deck plate girder (DPG) bridge. The investigation confirmed that short railcars cause higher load effects on main bridge components: the 35-m riveted steel DPG has 28% higher stresses at mid-span, while in the truss, the difference in stresses depends on the location of the member and ranges from 15 to 35%.

Flexural Strength of Composite Deck Slab with Macro Synthetic Fiber Reinforced Concrete

In this research, flexural performance was evaluated using macro-synthetic fiber-reinforced concrete (MFRC) in structural deck plates. Material tests were performed to evaluate the mechanical properties of the MFRC, and the flexural strength evaluation was conducted in two experiments, positive and negative moment tests. In the material test results, compressive strength and modulus of elasticity of the MFRC were increased compared with normal concrete. Flexural tensile tests showed that, after achieving maximum strength, the deck plates had sufficient residual strength until fracture. Structural tests showed that flexural strength and cracking load of all specimens increased according to macro synthetic fiber dosage. According to the experimental results, we proposed a flexural strength model of a steel deck plate containing macro synthetic fiber. The model showed greater accuracy than the current standard compared with the experimental results. In addition, since it was confirmed that the MFRC steel decks had greater flexural stiffness until yielding, it will be necessary to quantitatively evaluate the effect of MFRC on the effective flexural stiffness of steel decking in future studies.

Perencanaan Struktur Komposit Baja-Beton Dengan Metode Lrfd (Load And Resistance Factor Design) Ruang Kelas Lantai Iii Smk Pariwisata Labuan Bajo – Flores – Ntt

Planning a steel-concrete composite structure using the LRFD (Load and Resistance Factor Design) method is a method that clearly takes into account the boundary conditions, various load factors, and resistance factors, where in this case the resistance factor is needed to maintain the possible lack of structural strength, while the factor load is used to anticipate the possibility of an overload that is formulated. This planning uses a composite structure that is focused on profile steel beams, steel deck plates, and composite columns. Dead and live loads are calculated based on the Indonesian loading regulations for 1983 buildings, while earthquake loads are calculated based on the earthquake resistance planning procedure for building and non-building structures as stipulated in SNI 1762-2012. The steel-concrete composite structure itself is calculated based on the specifications for the design of steel structure buildings using the LRFD method as stated in SNI 03-1729-2002. The structural analysis in the form of the magnitude of the force acting on the building was carried out using the SAP2000 application while the analysis of the feasibility of using the dimensions of the composite structure based on the SNI used was done manually. From the planning results, the dimensions of beam and column cross-sections for each floor plate 1, 2 and 3 are B1 250/250, B2 250/175, B3 300/150, and K1 350/350. The use of steel decks on floor plates 1, 2, and 3 uses shear connectors (studs) with a diameter of 19 mm with 40, 20, and 25 shear connectors, respectively. The joints used in the main and child beams on floors 1, 2, and 3 respectively use 19 mm diameter bolts with 4 bolts, 2 bolts, and 4 bolts respectively, while the connections to columns and beams use diameter bolts 20 mm with the number of bolts 8 pieces.

Behavior of stiffened deck plates under hydrocarbon fire

Hydrocarbon fire accidents in offshore deck structures are of serious concern due to the confined environment of offshore oil drilling and production platforms, which limits the escape routes. One of the major structural components that are highly affected during fire accidents is the deck plates. The deck plates are usually designed as stiffened plates with high strength steel. The increase in temperature during fire changes the mechanical properties of steel significantly, which may result in strength and geometric instability of the structure. The present study aims to investigate the behavior of a stiffened steel deck plate under different hydrocarbon fire scenarios using sequential thermal and structural analyses using Ansys. The stress distribution and deformation of the plate in time scale are presented, discussing the highly affected region concerning the source of the fire. The fire rating for the steel deck under hydrocarbon fire is also suggested for different fire scenarios considered in the study. It was observed that the deformation of the deck plate varies to the area of deck plate in direct contact with fire, boundary conditions of the plate, and the area of steel plate with elevated temperature beyond which the mechanical properties of steel are highly affected. Also, the numerical investigations of the deck plate under the combined action of mechanical load and hydrocarbon fire had shown an increased deformation in the deck plates, which in turn reduces the fire rating of the plate under all fire scenarios. The effect of creep strain at high temperature on the response of the steel deck plate is also studied for the different fire loading cases.

Dynamic properties of a steel–UHPC composite deck with large U-ribs: Experimental measurement and numerical analysis

Steel–ultra-high-performance concrete (UHPC) composite decks, which are composed of thin steel– UHPC layers and large U-ribs, are an innovative bridge deck system. In this study, experimental and numerical approaches were combined to investigate the dynamic properties of a steel–UHPC composite deck. A large-scale steel–UHPC composite deck specimen was fabricated and tested under hammer impacting. The effects of the impact force characteristics on structural vibrations and noise were evaluated, and the vibration transmission characteristics in the deck were explored. The experimental results revealed that the steel–UHPC composite deck with large U-ribs exhibited complicated dynamic properties in different frequency bands. A finite element (FE) model was built and validated through comparison with the experimental natural frequencies and frequency responses. FE analysis was then used to compare the steel–UHPC composite deck with two other bridge deck systems (a conventional orthotropic steel deck and a steel–concrete composite deck). The numerical results indicated that the thin UHPC layer guaranteed the stiffness of the steel deck plate in the low-frequency range. At frequencies above 200 Hz, the vibration energy of the conventional orthotropic steel deck was approximately 0.45 times that of the steel–UHPC composite deck. Two countermeasures for reducing vibration (i.e., adjusting the crossbeam spacing and filling the large U-ribs with plain concrete) were found to be effective. Based on the simulation results, filling the U-ribs with plain concrete was the most effective approach and reduced the vibration energy by an average of 285% in the center frequency range of 63–1600 Hz.

Design method for steel deck plates under quasi-static patch loads with allowable plastic deformations

Plastic deformation of plates in steel deck structures under heavy vehicle or helicopter wheel loads is common in ships and offshore structures, and is therefore of significant interest to designers of ro-ro/cargo ships, helicopter-carrying ships and offshore platforms. To provide insight into the plastic deformation of plates, the nonlinear elasto-plastic response of stiffened steel plates loaded quasi-statically by a central rigid rectangular indenter is investigated both experimentally and numerically. The numerically-determined stiffened plate permanent deflections compare well with those obtained experimentally. The concept of applying the elasto-plastic method to the design of deck plates under wheel patch loads is introduced, and the design principle of wheel patch loaded plating is studied together with the design criteria. A simple design formula to determine plating thickness is proposed based on an acceptable level of permanent set. Ship-mounted helideck plating design cases are given to illustrate the elasto-plastic method, and comparisons are made between the thicknesses derived using the proposed design formula and those found from Lloyd's Register (LR), Bureau Veritas (BV) and DNV-GL rule requirements.