Thermal Experiment of a Reinforced Approach Pavement for Semi-Integral Abutment Jointless Bridge

2013 ◽  
Vol 639-640 ◽  
pp. 183-190 ◽  
Author(s):  
Xue Fang Zhan ◽  
Xu Dong Shao ◽  
Guo Li Liu
Keyword(s):  
Crack Width ◽  
Load Transfer ◽  
Influence Factor ◽  
Scale Model ◽  
Maximum Temperature ◽  
Integral Abutment ◽  
Average Reference ◽  
Approach Slab ◽  
Jointless Bridges ◽  
Highway Pavement

Semi-integral abutment fully jointless bridges, which connecting the main girder, the approach slab and the reinforced approach pavement all together and eliminating all the deck expansion joints and also the approach reinforced pavement joint is studied. As we know, the temperature variation is the key influence factor of the basic performance of the fully jointless bridges. When the temperature drops, the cracks appeared along the reinforced approach pavement. In the paper, emphasisis primarily made on simulating the temperature drops. A 28m full scale model stretching experiment simulating the temperature drops has been carried out in laboratory. After the experiment simulation we found that:(1)The crack width of approach pavement distribute uniformly at the pre-cut joints and their crack widths ranged mainly between 0.2mm and 0.8mm and the mean crack width was 0.37mm when the maximum stretch length at the end of the approach slab reached 9.87mm, which was within AASHTO and the Chinese highway pavement specification allowable value; (2)the load transfer capability coefficient at the third pre-cut joint with the maximum crack width (0.97mm) was 84%,which also satisfied the allowance of Chinese highway pavement specification. So this reinforced approach pavement is safe to connect semi-integral abutment bridge for the temperature length of 45m with the maximum temperature decrement of =20 ºС from the average reference construction temperature.

Design and Performance of Jointless Bridges in Ontario: New Technical and Material Concepts

2000 ◽  
Vol 1696 (1) ◽  
pp. 109-121 ◽  
Author(s):  
Iqbal Husain ◽  
Dino Bagnariol
Keyword(s):  
Economic Benefits ◽  
Integral Abutment ◽  
Expansion Joints ◽  
Actual Performance ◽  
Approach Slabs ◽  
Approach Slab ◽  
Jointless Bridges ◽  
Integral Abutment Bridge ◽  
Existing Bridges ◽  
Deck Slab

It is well recognized that leaking expansion joints at the ends of bridge decks have led to the premature deterioration of bridge components. The elimination of these maintenance-prone joints not only yields immediate economic benefits but also improves the long-term durability of bridges. In Ontario, Canada, “jointless” bridges have been used for many years. Recently, the use of two main types of these bridges has increased dramatically. The first type is an “integral abutment” bridge that comprises an integral deck and abutment system supported on flexible piles. The approach slabs are also continuous with the deck slab. The flexible foundation allows the anticipated deck movements to take place at the end of the approach slab. Control joint details have been developed to allow movements at this location. The second type is a “semi-integral abutment” bridge that also allows expansion joints to be eliminated from the end of the bridge deck. The approach slabs are continuous with the deck slab, and the abutments are supported on rigid foundations (spread footings). The superstructure is not continuous with the abutments, and conventional bearings are used to allow horizontal movements between the deck and the abutments. A control joint is provided at the end of the approach slab that is detailed to slide in between the wing walls. Some of the design methods and construction details that are used in Ontario for integral and semi-integral abutment bridges are summarized. A review of the actual performance of existing bridges is also presented.

Influence of Traffic Load on the Crack Widths of Full Jointless Bridges

2016 ◽  
Vol 847 ◽  
pp. 401-406
Author(s):  
Xue Fang Zhan ◽  
Yu Hui Zhang
Keyword(s):  
Crack Width ◽  
Influence Factor ◽  
Traffic Load ◽  
Lab Experiments ◽  
Jointless Bridges ◽  
Small Cracks ◽  
Crack Widths ◽  
Original Crack

Traffic load not only increases the original crack widths of the reinforced approach pavement of full jointless bridges, but also generates the development of new small cracks. Using lab experiments, this paper mainly studies the influence of traffic load on the crack width of the approach pavement of full jointless bridges. The results show that the load of traffic not only increases the crack width, but also increases the vertical settlement. In order to control the crack width we need to consider the influence of the traffic load. And the traffic load influence factor here we choose to be equal to 1.45.

Research on Friction between Grade Flat Approach Slab and Sliding Material in Jointless Bridges

2019 ◽  
Author(s):  
Yufeng Tang ◽  
Bruno Briseghella ◽  
Junqing Xue ◽  
Peiquan Zhang ◽  
Fuyun Huang ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Life Cycle Cost ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Element Model ◽  
Expansion Joints ◽  
Approach Slab ◽  
Jointless Bridges ◽  
Friction Function ◽  
The Mathematical Model

<p>The application of jointless bridges has been increasing year by year, because it could reduce the life‐cycle cost and improve the riding comfort. The approach slab in jointless bridges does not only have the function of road transition which is the same as the approach slab in bridges with expansion joints, but also transfer and absorb the deformation produced by the thermal expansion and contraction of the girder. The Grade Flat Approach Slab (GFAS) horizontally placed on the subgrade is one of the most common types of the approach slab in jointless bridges. The material placed between GFAS and subgrade should be able to properly slide to reduce the stress in GFAS. The friction coefficient between GFAS and sliding material is an important parameter affecting the mechanical behavior of GFAS in jointless bridges. In this paper, the tests of GFAS with different sliding materials subjected to horizontal displacement were conducted to obtain the corresponding friction coefficients (from 0.34 to 0.68). The mathematical model of bilinear spring could be adapted to simulate the friction function between GFAS and different sliding materials. One Deck‐Extension Bridge (DEB) that is one type of jointless bridges was chosen as a case study. The finite element model was implemented by using Midas‐Civil software. The influence of GFAS with different sliding materials on the mechanical properties of DEB under temperature variation was investigated. It can be concluded that the influence of the friction coefficient between GFAS and sliding material on the bending moment of DEB should be taken into account.</p>

Numerical analyses on mechanical performance of flat buried approach slab and soil deformation

2021 ◽  
Author(s):  
Junqing Xue ◽  
Dong Xu ◽  
Yufeng Tang ◽  
Bruno Briseghella ◽  
Fuyun Huang ◽  
...  
Keyword(s):  
Finite Element ◽  
Tensile Stress ◽  
Parametric Analysis ◽  
Mechanical Performance ◽  
Element Model ◽  
Soil Deformation ◽  
Longitudinal Deformation ◽  
Expansion Joints ◽  
Approach Slab ◽  
Jointless Bridges

<p><br clear="none"/></p><p>The vulnerability problem of expansion joints could be fundamentally resolved using the concept of jointless bridges. The longitudinal deformation of the superstructure can be transferred to the backfill by using the approach slab. The flat buried approach slab (FBAS) has been used in many jointless bridges in European countries. In order to understand the mechanical performance of FBAS and soil deformation, a finite element model (FEM) was implemented in PLAXIS. Considering the friction between the FBAS and soil, the buried depth, the FBAS length and thickness as parameters, a parametric analysis was carried out. According to the obtained results and in order to reduce the soil deformation above the FBAS, it is suggested to increase the friction between the FBAS and sandy soil, and the buried depth of FBAS. Moreover, it should be paid attention to the vertical soil deformation and the concrete tensile stress of FBAS in pulling condition.</p>

scholarly journals Tension Force Estimation in Axially Loaded Members using Wearable Piezoelectric Interface Technique

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 47 ◽  
Author(s):  
Joo-Young Ryu ◽  
Thanh-Canh Huynh ◽  
Jeong-Tae Kim
Keyword(s):  
Axial Force ◽  
Load Transfer ◽  
Estimation Method ◽  
Tension Force ◽  
Scale Model ◽  
Force Estimation ◽  
Cable Structure ◽  
Transfer Capability ◽  
Axially Loaded ◽  
The Relationship

Force changes in axially loaded members can be monitored by quantifying variations in impedance signatures. However, statistical damage metrics, which are not physically related to the axial load, often lead to difficulties in accurately estimating the amount of axial force changes. Inspired by the wearable technology, this study proposes a novel wearable piezoelectric interface that can be used to monitor and quantitatively estimate the force changes in axial members. Firstly, an impedance-based force estimation method was developed for axially loaded members. The estimation was based on the relationship between the axial force level and the peak frequencies of impedance signatures, which were obtained from the wearable piezoelectric interface. The estimation of the load transfer capability from the axial member to the wearable interface was found to be an important factor for the accurate prediction of axial force. Secondly, a prototype of the wearable piezoelectric interface was designed to be easily fitted into existing axial members. Finally, the feasibility of the proposed technique was established by assessing tension force changes in a numerical model of an axially loaded cylindrical member and a lab-scale model of a prestressed cable structure.

scholarly journals Effects of Out-of-plane Brace-to-chord Angle on Multiplane CHS X-joints Behavior Under Brace Compression

2019 ◽  
Author(s):  
Bida Zhao ◽  
Ke Li ◽  
Chengqing Liu ◽  
Dengjia Fang ◽  
Jianguo Wu
Keyword(s):  
Load Transfer ◽  
Influence Factor ◽  
Experimental Tests ◽  
Hollow Section ◽  
Out Of Plane ◽  
Transfer Pattern ◽  
The Common ◽  
Circular Hollow Section ◽  
Numerical Parametric Study ◽  
Layered Lattice

Multiplanar CHS X-joints, different from the common uniplanar CHS X-joints, usually with a relative small out-of-plane brace-to-chord angle (OPBCA) for appealing architectural appearance in the single layered lattice structures. In order to study the effects of OPBCA on the static behavior of circular hollow section (CHS) X-joints under brace axial compression, experimental tests and numerical parametric study on the ultimate capacity and load transfer pattern of the CHS X-joints were carried out. The numerical analysis results had good consistent with experimental tests in terms of the capacity and fail mode of the X- joints. OPBCA changes the load transfer pattern to more load at the up saddle point from the same load at the up and bottom saddles in uniplanar X-joints, and more obvious for the X-joints with lager OPBCA. OPBCA is also unfavorable to the capacity, especially the X-joints with relative large brace-to-chord diameter ratio and in-plane brace-to-chord angle. Then an equation considering the OPBCA influence factor, extended the capacity prediction formulae of uniplanar X-joints in the current specifications to the multiplanar X-joints, is also established; and the equation has been validated favorably.

scholarly journals Laboratory Characterization of The Load Transfer-Crack Width Relation for Innovative Short Concrete Slabs Pavements

2020 ◽  
Vol 15 (1) ◽  
pp. 232-250 ◽  
Author(s):  
Mauricio Pradena ◽  
Lambert Houben ◽  
Andrés César
Keyword(s):  
Structural Design ◽  
Crack Width ◽  
Load Transfer ◽  
Plain Concrete ◽  
Design Methods ◽  
Transfer Efficiency ◽  
Concrete Slabs ◽  
Concrete Pavements ◽  
Load Transfer Efficiency ◽  
Reduced Scale

Aggregate interlock is the dominant load transfer mechanism in non-dowelled Jointed Plain Concrete Pavements, as the innovative short concrete slabs. Although the Load Transfer Efficiency of this pavement innovation is based on that mechanism, the structural design methods do not relate the Load Transfer Efficiency by aggregate interlock with its direct cause, which is the Crack Width under the joints. The objective of the present article is to characterise in the laboratory the Load Transfer Efficiency−Crack Width relation for innovative short slabs Jointed Plain Concrete Pavements. Additionally, as an alternative to large-scale laboratory tests to study the Load Transfer Efficiency, a practical test on a reduced scale is proposed. The results confirmed that short slabs Jointed Plain Concrete Pavements with high-quality aggregates are able to provide adequate Load Transfer Efficiency (above 70%) without dowels bars. Based on the laboratory results, complemented with previous field data, a Load Transfer Efficiency−Crack Width curve is proposed and made available for structural design methods of short slabs Jointed Plain Concrete Pavements. Finally, the laboratory test on a reduced scale is useful to develop specific Load Transfer Efficiency−Crack Width relations using standard equipment available in traditional concrete laboratories.

Comparison of Thermal Test Using Slice Model and Half-Scale Model of Shipping Package

2018 ◽  
Author(s):  
Kyoung-Sik Bang ◽  
Seung-Hwan Yu ◽  
Ju-Chan Lee ◽  
Woo-Seok Choi
Keyword(s):  
Nuclear Power ◽  
Single Layer ◽  
Temperature Limit ◽  
Full Scale ◽  
Scale Model ◽  
Maximum Temperature ◽  
Thermal Tests ◽  
Neutron Shielding ◽  
Thermal Test ◽  
Thermal Integrity

KORAD-B/II shipping packages are used to transport C4 concrete packages that are temporarily stored at the HANUL nuclear power plant. These packages must therefore satisfy the requirements prescribed in the Korea Nuclear Safety Security Commission Act 2014-50, the IAEA Safety Standards No. SSR-6, and US 10 CFR Part 71. These regulatory guidelines classify a KORAD-B/II shipping package as a Type B package, and state that this type of package must be able to withstand a temperature of 800 °C for a period of 30 min. It is desirable to conduct a test using a full-scale model of a shipping package when performing tests to evaluate its integrity. However, it is costly to perform a test using a full-scale model. Therefore, to evaluate the thermal integrity of a KORAD-B/II shipping package, thermal tests were conducted using a slice model. For comparison purposes, a thermal test was also carried out using a half-scale model. In the first thermal test using a slice model, the maximum surface temperature of the cask body was higher than the permitted maximum temperature limits owing to incomplete combustion. In the second thermal test using a slice model and in the thermal test using a half-scale model, the maximum temperature of the cask body was lower than the permitted maximum temperature limit. Therefore, the thermal integrity of the KORAD-B/II shipping package could be considered to be maintained. The temperature results from the thermal test using a slice model were higher than those of the thermal test using a half-scale model. Therefore, the effect of flame on a single-layer shipping package without neutron shielding, such as the KORAD-B/II shipping package, seems to be affected by the reduction in the time rather than the size reduction.

scholarly journals Seismic Performance of Various Piles Considering Soil–Pile Interaction under Lateral Cycle Loads for Integral Abutment Jointless Bridges (IAJBs)

2020 ◽  
Vol 10 (10) ◽  
pp. 3406
Author(s):  
Fuyun Huang ◽  
Yulin Shan ◽  
Ahad Javanmardi ◽  
Xiaoye Luo ◽  
Baochun Chen
Keyword(s):  
Energy Dissipation ◽  
Plastic Hinge ◽  
Reinforcement Ratio ◽  
Effective Length ◽  
Deformation Capacity ◽  
Integral Abutment ◽  
Concrete Pile ◽  
Jointless Bridges ◽  
Pile Interaction ◽  
Energy Dissipation Capacity

The flexural pile foundation is used in integral abutment jointless bridges (IAJBs) in practical engineering to effectively dissipate the horizontal reciprocating deformation induced by the ambient temperature or earthquake loadings. Various types of flexural piles including the H-shaped steel pile (HP), prestressed concrete pile (PC), prestressed high-strength concrete pile (PHC) as well as the reinforcement concrete pile (RC) have been implemented in IAJBs. However, there is a lack of comprehensive studies on the flexural deformation and seismic performances of these piles. In order to investigate and compare their mechanical behaviors and seismic performances, a low-cycle pseudo-static test on several different types of piles was carried out. The test results indicated that the plastic hinge location of piles moved to a deeper pile depth with the increase of reinforcement ratio, buried pile depth and prestressing level, which led to better pile–soil interaction. The crack resistance of a concrete pile was improved as the reinforcement ratio and prestressing level increased. Moreover, the rectangular pile had a better soil–pile interaction and energy dissipation capacity than the circular pile. The inflection point of the pile deformation shifted deeper as reinforcement ratio, buried pile depth and prestressing level increased, which improved the effective length and horizontal deformation capacity of piles. The H-shaped steel pile showed a better elastic-plastic deformation capacity, ductility and energy dissipation capacity as compared to the concrete pile. Moreover, the pile having a higher bearing ratio sustained larger lateral loads whereas the surrounding soil was subjected to higher loads. Finally, new seismic design criteria of three-stage seismic fortification and five damage level for the concrete piles of IAJBs were proposed.

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