scholarly journals In Situ Experimental Study on the Behavior of UHPC Composite Orthotropic Steel Bridge Deck

Materials ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 253 ◽  
Author(s):  
Li Su ◽  
Shilei Wang ◽  
Yan Gao ◽  
Jianlei Liu ◽  
Xudong Shao
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fatigue Cracks ◽  
Steel Bridge ◽  
Orthotropic Steel Deck ◽  
Deck Plate ◽  
In Situ Experiments ◽  
Before And After ◽  
Steel Deck

A novel ultra high performance concrete (UHPC) layer composite orthotropic steel deck was adopted in the construction of a new bridge in China to improve the fatigue performance of the orthotropic steel deck plate and reduce the disease of surface wearing layer. In situ experiments were conducted to study the UHPC layer’s impact on the behavior of the orthotropic steel deck. The test vehicle loads were applied on the deck plate before and after UHPC layer paving, the stresses where fatigue cracks usually occur and the deflections of critical sections were measured. The test results verified that the UHPC composite steel deck system could significantly reduce the stress of the rib-to-deck connection region and the stress at the bottom toe of rib-to-diaphragm weld. In addition, it slightly influenced the performance of U shape rib, girder web-to-deck and diaphragm cutout.

Research of Stress Concentration and Retrofitted Methods for Orthotropic Steel Bridge Decks

2010 ◽  
Vol 163-167 ◽  
pp. 3511-3516 ◽  
Author(s):  
Yan Ling Zhang ◽  
Yun Gang Zhang ◽  
Yun Sheng Li
Keyword(s):  
Stress Concentration ◽  
Stress Distribution ◽  
High Performance ◽  
Bridge Deck ◽  
High Performance Concrete ◽  
Steel Bridge ◽  
Wheel Load ◽  
Orthotropic Steel Deck ◽  
Orthotropic Steel Bridge Deck ◽  
Steel Deck

In this paper, the stress distribution of the orthotropic steel bridge deck in a suspend bridge under local wheel load is analyzed. Some retrofitted methods are introduced, two of which are studied. One is using the concrete paving layer (CPL), and the other is using the sandwich plate system (SPS) to strengthen the orthotropic steel bridge deck. Local finite element models are established by ANSYS; stress distribution of bridge deck is calculated under the designed vehicle load before and after the deck retrofitted by the CPL or the SPS, and the results are compared with each other. The analysis results indicate that, under wheel pressure load, the orthotropic steel deck appears stress concentration; after the deck was retrofitted no matter by the CPL or the SPS, all the stress peaks decrease obviously, and the fatigue resistance of the orthotropic steel deck increases, which indicate that the two methods are effective to retrofit the orthotropic steel bridge deck. Using the CPL method can lead to lower stress concentration than that of using the SPS method, but the concrete paving layer is easy to crack, so, high performance concrete with high tension strength is needed.

scholarly journals Application of PZT Technology and Clustering Algorithm for Debonding Detection of Steel-UHPC Composite Slabs

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2953 ◽  
Author(s):  
Banfu Yan ◽  
Qiqi Zou ◽  
You Dong ◽  
Xudong Shao
Keyword(s):  
Lead Zirconate Titanate ◽  
High Performance ◽  
Clustering Algorithm ◽  
High Performance Concrete ◽  
Fatigue Cracks ◽  
Experimental Tests ◽  
Interfacial Debonding ◽  
Data Set ◽  
Composite Slabs ◽  
Steel Deck

A lightweight composite bridge deck system composed of steel orthotropic deck stiffened with thin Ultra-High Performance Concrete (UHPC) layer has been proposed to eliminate fatigue cracks in orthotropic steel decks. The debonding between steel deck and UHPC layer may be introduced during construction and operation phases, which could cause adverse consequences, such as crack-induced water invasion and distinct reduction of the shear resistance. The piezoelectric lead zirconate titanate (PZT)-based technologies are used to detect interfacial debonding defects between the steel deck and the UHPC layer. Both impedance analysis and wave propagation method are employed to extract debonding features of the steel-UHPC composite slab with debonding defect in different sizes and thicknesses. Experimental tests are performed on two steel-UHPC composite slabs and a conventional steel-concrete composite deck. Additionally, an improved Particle Swarm Optimization (PSO)-k-means clustering algorithm is adopted to obtain debonding patterns based on the feature data set. The laboratory tests demonstrate that the proposed approach provides an effective way to detect interfacial debonding of steel-UHPC composite deck.

Proactive maintenance method for fatigue cracks to steel bridge deck without traffic disruption

2019 ◽  
Author(s):  
Ryo Nakata ◽  
Yukio Adachi
Keyword(s):  
Fatigue Damage ◽  
Fatigue Resistance ◽  
Bridge Deck ◽  
Fatigue Cracks ◽  
New Method ◽  
Steel Bridge ◽  
Traffic Demand ◽  
Deck Plate ◽  
Steel Deck ◽  
Proactive Maintenance

<p>Fatigue damage is a major topic in bridge maintenance. The fatigue damage to steel bridge deck has been dramatically increasing since the first fatigue damage was observed in Hanshin expressway in early 2000s. Insufficient knowledge of bridge fatigue design and unexpected increase of traffic demand and heavy vehicle could be the cause of the fatigue damage.</p><p>Replacement of base pavement course to steel fiber reinforced concrete (SFRC) has been generally used for strengthening of steel decks; however, the countermeasure from the topside of the bridge deck could make serious traffic disruption. Therefore, reactive and proactive maintenance for such steel decks has not been well progressed so far.</p><p>According to the background above, Hanshin expressway has been making an effort on developing new method by strengthening steel deck from the bottom side. The idea of the new method is to enhance fatigue resistance by improving the weld joint between deck plate and U-rib plate. Three potential methods were identified and the effectiveness of those methods was studied in field for making sure of not only fatigue resistance improvement but also field construction.</p><p>This paper will introduce the new retrofit methods for steel deck and describe the effectiveness of those methods.</p>

scholarly journals Debonding Detection of Steel-UHPC Composite Slab Using PZT Technology and Clustering Algorithm

2018 ◽  
Author(s):  
Banfu Yan ◽  
Qiqi Zou ◽  
You Dong ◽  
Xudong Shao
Keyword(s):  
Lead Zirconate Titanate ◽  
High Performance ◽  
Clustering Algorithm ◽  
High Performance Concrete ◽  
Fatigue Cracks ◽  
Clustering Algorithms ◽  
Interface Condition ◽  
Data Set ◽  
Composite Slab ◽  
Steel Deck

A lightweight composite bridge deck system composed of steel orthotropic deck stiffened with thin Ultra-High Performance Concrete (UHPC) layer is developed to eliminate fatigue cracks in orthotropic steel decks. During the construction and operation period of the bridge, the debonding between the steel deck and the UHPC layer may introduce the several issues, such as crack-induced water invasion and distinct reduction of the shear resistance. In the study, an effective and novel non-destructive interface condition monitoring approach using piezoelectric lead zirconate titanate (PZT)-based technologies is proposed to detect interfacial delamination between steel deck and UHPC layer. Experimental tests are performed on several steel-UHPC composite slabs and a conventional steel-concrete composite slab. The thin styrofoam sheets with different sizes and thicknesses are set on different locations of the steel deck as the artificial debondings. The PZT ceramic patches are bonded on the surfaces of the steel deck and UHPC layer as the actuators/sensors. An improved PSO (Particle Swarm Optimization)-K-means clustering algorithms is proposed to obtain the debonding patterns based on the feature data set. The laboratory tests demonstrate that the proposed approach provides an effective and accurate way to detect interfacial debonding of steel-UHPC composite slab.

Fatigue Crack Behavior at Rib-To-Deck Weld Bead in Orthotropic Steel Deck

2014 ◽  
Vol 17 (10) ◽  
pp. 1459-1468 ◽  
Author(s):  
Xiaochen Ju ◽  
Kazuo Tateishi
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Cracks ◽  
Equivalent Stress ◽  
Weld Bead ◽  
Propagation Mechanism ◽  
Mode Iii ◽  
Orthotropic Steel Deck ◽  
Deck Plate ◽  
Steel Deck

One of the typical fatigue cracks observed in orthotropic steel deck is a through-thickness crack which penetrates and propagates along the weld bead. Moreover, according to some reports of the fatigue crack observed in some bridges, the fatigue crack sometimes changes its direction suddenly, and propagates to the rib wall and the deck plate. Such fatigue damage can cause the sudden decrease of stiffness of longitudinal rib. However, the propagation mechanism of the crack has not been investigated clearly. In this study, numerical studies on the through-thickness crack at rib-to-deck weld bead in the orthotropic steel deck were carried out. Finite element model (FEM) of an orthotropic deck with different through-thickness crack at rib-to-deck weld bead was created. In order to identify the propagation behavior of the fatigue crack, stress intensity factors for three deformation modes were estimated by the FE analysis (FEA) and the displacement extrapolation method. Based on the maximum energy release rate (MERR) criterion, the equivalent stress intensity factor and the crack direction were evaluated. From the numerical results, the crack direction change was found to be originated by the Mode II and Mode III deformation near the crack tip due to the out-of-plane bending of the rib wall along the crack.

Strengthening of steel decks for cable-stayed bridge using ultra-high performance concrete: A case study

2020 ◽  
Vol 23 (16) ◽  
pp. 3373-3384
Author(s):  
Lei Wang ◽  
Xiaochao Su ◽  
Yafei Ma ◽  
Ming Deng ◽  
Jianren Zhang ◽  
...  
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fatigue Cracking ◽  
Strengthening Effect ◽  
Steel Bridge ◽  
Ultra High Performance Concrete ◽  
Cable Stayed Bridge ◽  
Local Stresses ◽  
Orthotropic Steel Decks ◽  
Strengthening Method

Fatigue cracking induced by vehicle load is a prevalent problem in orthotropic steel decks. In addition, pavement debonding in steel bridge decks is another familiar issue resulting from low slip resistance in the faying surface between the steel and asphalt concrete. The present study proposed a strengthening method that uses ultra-high performance concrete to stiffen a repeatedly maintained cable-stayed bridge in order to help address these two problems. The existing issues of the real bridge and the corresponding causes were investigated. Following this, an ultra-high performance concrete paving system was designed to improve the stiffness of the orthotropic steel decks. For this paving system, a 45-mm ultra-high performance concrete layer was connected to the deck by welded shear studs. The local stresses at the typical vulnerable fatigue cracking points were determined by means of a finite element model and of a field loading test to evaluate the strengthening effect. The results showed that this strengthening method can prevent the propagation of fatigue cracks. The local stresses of the U-ribs and diaphragms were reduced by 45.4% and 40.0%, respectively. The repaired bridge has sufficient resistance against fatigue cracking based on the in situ observations.

scholarly journals Fluorescence Microscopic Investigations of the Retarding Effect of Superplasticizers in Cementitious Systems of UHPC

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1057 ◽  
Author(s):  
Johannes Arend ◽  
Alexander Wetzel ◽  
Bernhard Middendorf
Keyword(s):  
Molecular Structure ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultra High Performance Concrete ◽  
Adsorption Characteristic ◽  
Beneficial Effects ◽  
Retarding Effect ◽  
Cementitious Systems ◽  
Mixing Water

The adsorption of superplasticizer molecules to particle surfaces in cementitious systems is a very important aspect for the desired liquefaction of pastes and concretes. This way, the comb shaped polymers shield attractive forces between the particles and induce a well-dispersed, homogeneous suspension. These admixtures allow the usage of fine fillers even in combination with low amounts of mixing water, and thus, are the basis for modern high performance concretes. However, the adsorption does not cause beneficial effects only: The polymer covered particle surfaces, especially clinker, are hindered to interact with water, thus hydration is retarded. This is the reason for lower early strength and is very disadvantageous for certain applications. Today it is known that the molecular structure of the polymers, for instance the chain length and charge density, affects the retardation strongly. The complexity and diversity of cementitious systems is the main reason why research in this field is quite empiric and time as well as cost intensive. To investigate the adsorption of superplasticizers in various systems in-situ, a fluorescence microscopic approach was applied: By staining the polymers with fluorescent dye they become localizable and the adsorption quantifiable. This work shows the influence of molecular structure to adsorption characteristic of different polymers and the correlation to the retarding effect of superplasticizers, especially concerning the presence of silica fume, which is indispensable for ultra-high performance concrete (UHPC).

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