The Effect of Higher Prestress on Concrete Railroad Tie Behavior

Prestressed concrete crossties are used extensively by North American railroads because they offer improved service life and consistent performance. Recent industry trends have encouraged manufacturers to effectively increase concrete ties’ prestressing force to improve their structural performance in flexure and shear. This paper presents the results of linear and nonlinear three-dimensional finite element analyses of typical concrete crossties to study the stress state of crossties at prestress transfer and to identify potential negative consequences of increasing effective prestressing force. The analyses utilize finite-sliding contact with Coulomb friction to model interaction between prestressing strands and adjacent concrete. Variation of several parameters that affect stress state at prestress transfer are considered, including magnitude of prestressing force, stiffness of concrete, crosstie geometry, and strand configuration. The analyses indicate that tensile stresses develop near the ends of the crossties at prestress transfer and their magnitudes increase with decreasing transfer length and increasing prestress force. These tensile stresses may account for widespread longitudinal cracking that has been observed in premature failure of concrete crossties in the last ten years.

Load Analysis of Transversely Prestressed Continuous Concrete Pavement with Oblique-Reinforced

10.4028/www.scientific.net/amm.178-181.1179 ◽

2012 ◽

Vol 178-181 ◽

pp. 1179-1182 ◽

Cited By ~ 1

Author(s):

Hua Cai ◽

Ke Jiang ◽

Jian Miao ◽

Jian Gang Liao

Keyword(s):

Tensile Stress ◽

Prestressed Concrete ◽

Three Dimensional ◽

Plain Concrete ◽

Concrete Pavement ◽

Prestressing Force ◽

Transverse Joint ◽

Load Carrying ◽

Aiming at the problems of the concrete pavement transverse joint, and the characteristics of prestressed concrete pavement and continuously reinforced concrete pavement, a transversely prestressed continuous concrete pavement with oblique-reinforced is presented. ABAQUS software is adopted to establish respectively two three-dimensional finite element models of plain concrete pavement and transversely prestressed continuous concrete pavement with oblique-reinforced for calculating mechanical behavior under the standard load. The results show that, with a concrete pavement slab transversely prestressed, a finite prestressing force exist in longitudinal by bonding among oblique-reinforced and concrete, and there isn’t tensile stress under the load, so the possibility of slab breakage due to tensile stress is low. Due to its excellent performance, in addition its great load-carrying capacity and overall stability, the investigation is valuable for the research of seamlessly prestressed pavement.

Using Externally Bonded CFRP to Repair a PCCP with Broken Wires under Combined Loads

International Journal of Polymer Science ◽

10.1155/2019/8053808 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

Kejie Zhai ◽

Hongyuan Fang ◽

Bing Fu ◽

Fuming Wang ◽

Benyue Hu

Keyword(s):

Prestressed Concrete ◽

Three Dimensional ◽

Soil Pressure ◽

Long Distance ◽

Stress Strain ◽

Wire Breakage ◽

Water Pipelines ◽

Externally Bonded ◽

Prestressed Concrete Cylinder Pipe ◽

Prestressed concrete cylinder pipe (PCCP) is widely used for long-distance water pipelines throughout the world. However, prestressing wire breakage is the most common form of PCCP damage. For some pipelines that cannot be shut down, a new technique for in-service PCCP repair by externally bonding the pipe with layers of carbon fiber reinforced polymer (CFRP) was proposed. A set of three-dimensional finite element models of the repaired PCCP have been proposed and implemented in the ABAQUS software, which took into account the soil pressure, the weight of the PCCP, the weight of the water, and the hydrostatic pressure. The stress–strain features of the PCCP repaired with CFRP of various thicknesses were analyzed. The stress–strain features of different wire breakage rates for the repaired PCCP were also analyzed. The results showed that the strains and stresses decreased at the springline if the PCCP was repaired with CFRP, which improved the operation of the PCCP. It has been found that the wire breakage rates had a significant effect on the strains and stresses of each PCCP component, but CFRP failed to reach its potential tensile strength when other materials were broken.

Comparative Analysis of Several Construction Scheme of a Large-Sized Tie-Arch Aqueduct

10.4028/www.scientific.net/amm.94-96.2350 ◽

2011 ◽

Vol 94-96 ◽

pp. 2350-2354

Author(s):

Shu Zhong Lei ◽

Zhong Xin Wang ◽

Jian Ting Xu ◽

Chi Peng Liu

Keyword(s):

Comparative Analysis ◽

Prestressed Concrete ◽

Three Dimensional ◽

Stability Control ◽

River Diversion ◽

Finite Element Program ◽

Element Program ◽

Stress And Deformation ◽

An aqueduct of larger-span prestressed concrete arch structure for river diversion project is located in coastal areas, and raises difficult questions on deformation and stability control of the construction process due to greater wind load and poor soil. Due to the limited width of bracket erection, this paper put forward five possible construction schemes, and does the comparative analysis using three-dimensional finite element program, and gets the economic and reasonable one. Finally conduct a pressure test after the bracket erection, and verify the analysis results using measured stress and deformation data.

Fatigue Behavior of Prestressed Concrete Beam for Straddle-Type Monorail Tracks

Applied Sciences ◽

10.3390/app8071136 ◽

2018 ◽

Vol 8 (7) ◽

pp. 1136 ◽

Cited By ~ 6

Author(s):

Qianhui Pu ◽

Hanyu Wang ◽

Hongye Gou ◽

Yi Bao ◽

Meng Yan

Keyword(s):

Prestressed Concrete ◽

Concrete Beam ◽

Fatigue Behavior ◽

Three Dimensional ◽

Element Model ◽

Transportation Systems ◽

Traffic Load ◽

Prestressed Concrete Beam ◽

Monorail transportation systems are widely built in medium and small cities, as well as hilly cities, because of their excellent performance. A prestressed concrete track beam is a key load-carrying structural component and guideway subjected to repeated traffic load. The fatigue behavior of the prestressed concrete beam is critical for the safety of the transportation system. This paper presents the results of an experimental study on the fatigue behavior of a prestressed concrete beam in terms of stiffness degradation and strain change. The displacement and rotation of the beam of concrete and reinforcement were examined, respectively. A three-dimensional finite element model was established to help understand the development of the mechanical behavior. No crack was observed throughout the test. Both concrete and bars behaved in their linear-elastic stage throughout the test, and the bond between them performed well.

FINITE ELEMENT ANALYSIS OF THE THERMAL BEHAVIOUR OF SINGLE-DISC CLUTCHES DURING REPEATED ENGAGEMENTS

Tribologia ◽

10.5604/01.3001.0010.7559 ◽

2016 ◽

Vol 266 (2) ◽

pp. 9-24 ◽

Cited By ~ 4

Author(s):

Oday I. ABDULLAH ◽

Laith Abed SABRI ◽

Wassan S. Abd Al-SAHB

Keyword(s):

Finite Element ◽

Thermal Behaviour ◽

Thermal Stresses ◽

Three Dimensional ◽

Finite Element Models ◽

Element Analysis ◽

Premature Failure ◽

Friction Clutch ◽

Most of the failures in the sliding systems occur due to the high thermal stresses, which generated at the interface between the contacting surfaces due to sliding between parts, such as friction clutches and brakes. In this paper, the thermal behaviour of a single-disc clutch is investigated. The surface temperatures of the friction clutch disc will be increased during repeated engagements, in some cases, will lead to premature failure of the clutch disc. In order to avoid this kind of failure, it the surface temperature should be calculated with high accuracy to know the maximum working temperature of the friction system. In this work, the temperature distributions are computed during four repeated engagements at regular intervals (5 s) for the same energy dissipation. Three-dimensional finite element models are used to simulate the typical friction clutch disc.

A three-dimensional finite element model for locally reinforced timber joints made with hollow dowel fasteners

Canadian Journal of Civil Engineering ◽

10.1139/l00-018 ◽

2000 ◽

Vol 27 (4) ◽

pp. 785-797 ◽

Cited By ~ 6

Author(s):

Z W Guan ◽

P D Rodd

Keyword(s):

Finite Element ◽

Failure Mode ◽

Three Dimensional ◽

Ductile Failure ◽

Element Model ◽

Premature Failure ◽

Physical Test ◽

Timber Joint ◽

Strength And Stiffness ◽

Brittle premature failure caused by splitting parallel to the timber grain is a common failure mode in glulam joints made with solid dowel type fasteners. It is thought that this problem can be alleviated by using hollow steel dowels as the fasteners and reinforcing the timber locally in the area of the joint. In this way, by varying the wall thickness of the dowels and the thickness of the reinforcing members, a chosen combination of strength and stiffness should be attainable together with a ductile failure mode. In this paper, three-dimensional nonlinear finite element models are developed to simulate (i) the structural performance of a timber joint made with a single hollow steel dowel and (ii) a moment transmitting joint made with a number of the dowels, each type being locally reinforced by densified veneer wood. The models incorporate suitably defined elastoplasticity and orthotropic elasticity and also allow for large deformations of the joints as well as for frictional contact between the timber and the dowel. They are calibrated against physical test data from joints loaded to failure.Key words: glulam, densified veneer wood, resin injected, hollow dowel fastener, moment transmitting, ductile failure, finite element.

The Characteristic of Prestressed Concrete Pier Seismic Crack

10.4028/www.scientific.net/amm.501-504.1628 ◽

2014 ◽

Vol 501-504 ◽

pp. 1628-1632

Author(s):

Hui Li Wang ◽

Hong Wang ◽

Si Feng Qin

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Prestressed Concrete ◽

Three Dimensional ◽

Element Model ◽

Tensile Zone ◽

Three Dimensional Finite Element ◽

Prestressed Reinforcement

Through three dimensional finite element analyzes, overall cast-in-place prestressed concrete pier seismic crack characteristic is researched. The separation formula finite element model is established by means of bilinear reinforce model and Kent-R.Park concretes model, without considering slip between concretes and. reinforce. It compares and analyzes the seismic crack characteristic between prestressed concrete pier and reinforcement concretes pier. The results show that the prestressed reinforcement can reduce the tensile zone of concrete, put off the appearance of cracks, improved the stiffness of pier, and reduced the top displacement.

ON THE REDUCTION OF PRESTRESSING FORCE NEAR SUPPORTS IN PARTIALLY PRESTRESSED CONCRETE FLEXURAL MEMBERS

Proceedings of International Structural Engineering and Construction ◽

10.14455/isec.res.2018.114 ◽

2018 ◽

Vol 5 (2) ◽

Author(s):

Nazar Oukaili

Keyword(s):

Prestressed Concrete ◽

Load Capacity ◽

Compression Zone ◽

Flexural Members ◽

Tensile Stresses ◽

Prestressing Force ◽

Service Load ◽

Bending Stresses ◽

The Moment ◽

Concrete Section

Straight tendons in pretensioned members can cause high-tensile stresses in the concrete extreme fibers at end sections because of the absence of the bending stresses due to self-weight and superimposed loads and the dominance of the moment due to prestressing force alone. Accordingly, the concrete tensile stresses at the ends of a member prestressed with straight tendons may limit the service load capacity of the member. It is therefore important to establish limiting zone in the concrete section within which the prestressing force can be applied without causing tension in the extreme concrete fibers. Two practical methods are available to reduce the stresses at the end sections due to the prestressing force. The first method based on changing the eccentricity of some tendons by raising them towards the end zone. The second method is based on bond prevention by encasing some of the tendons in plastic sheathing, effectively moving the point of application of prestressing force inward toward midspan for part of tendons. The present study focuses on a proposed third method to reduce the effect of the prestressing force near end supports by using straight strands with limited initial prestressing value in compression zone. New equations were suggested for the cracking moment and the prestressing force which consider the prestressed tendons in compression zone.

Effect of side grooves on the elastic-plastic stress state of fracture toughness specimens—three-dimensional finite element analysis

Engineering Fracture Mechanics ◽

10.1016/0013-7944(82)90019-4 ◽

1982 ◽

Vol 16 (5) ◽

pp. 659-668 ◽

Cited By ~ 13

Author(s):

Imai Yasufumi ◽

Matake Tomokazu

Keyword(s):

Fracture Toughness ◽

Finite Element Analysis ◽

Finite Element ◽

Stress State ◽

Three Dimensional ◽

Element Analysis ◽

Elastic Plastic ◽

Three Dimensional Finite Element ◽

Plastic Stress

The Time to Eliminate the Expansion Joints of Diversion Pipeline in Wanjiazhai Hydropower Station

10.4028/www.scientific.net/amm.733.472 ◽

2015 ◽

Vol 733 ◽

pp. 472-477

Author(s):

Chun Tao Wang

Keyword(s):

Finite Element ◽

Stress State ◽

Three Dimensional ◽

Element Model ◽

Hydropower Station ◽

Expansion Joints ◽

Three Dimensional Finite Element ◽

Hydro Project ◽

Hydropower Stations

At present, many hydropower stations eliminate the expansion joints to solve the pipe leakage problem. It’s very important to control the welding environment temperatures in eliminating the final weld joint of the expansion joints. To address this problem, by adopting three-dimensional finite element model in studying the hydro project of Wanjiazhai, this paper analyzes the stress state of steel pipe in all welding environment temperatures in details and suggests the proper range of welding environment temperatures. Researchers suggest that May is suitable to perform welding.