scholarly journals Flexural Behavior of a 30-Meter Full-Scale Simply Supported Prestressed Concrete Box Girder

2020 ◽  
Vol 10 (9) ◽  
pp. 3076 ◽  
Author(s):  
Jianqun Wang ◽  
Shenghua Tang ◽  
Hui Zheng ◽  
Cong Zhou ◽  
Mingqiao Zhu
Keyword(s):  
Prestressed Concrete ◽  
Mechanical Performance ◽  
Compressive Strain ◽  
Full Scale ◽  
Flexural Behavior ◽  
Destructive Testing ◽  
Scaled Model ◽  
Box Girder ◽  
Simply Supported ◽  
Prestressing Tendon

Compared with scaled-model testing, full-scale destructive testing is more reliable since the test has no size effect and can truly record the mechanical performance of the structure. However, due to the high cost, only very few full-scale destructive tests have been conducted on the flexural behavior of prestressed concrete (PC) box girders with girders removed from decommissioned bridges. Moreover, related destructive testing on the flexural behavior of a new precast box girder has been rarely reported. To investigate the flexural behavior and optimize the design, destructive testing of a 30-meter full-scale simply supported prestressed box girder was conducted at the construction site. It is illustrated that the failure mode of the tested girder was fracture of the prestressing tendon, and the corresponding maximum compressive strain in the top flange was only 1456 μ ε , which is far less than the ultimate compressive strain (3300 μ ε ). Therefore, the concrete in the top flange was not fully utilized. A nonlinear analysis procedure was performed using the finite strip method (FSM). The validity of the analysis was demonstrated by comparing the analytical results with those of the full-scale test in the field and a scaled model test in a laboratory. Using the developed numerical method, parametric analyses of the ratio of reinforcement were carried out. The prestressing tendon of the tested girder was increased from four strands to six strands in each duct. After the optimization of the prestressed reinforcement, the girder was ductile and the bearing capacity could be increased by 44.3%.

Creep Effects on Simply Supported Prestressed Concrete Box Girder of High-Speed Railway with Ballastless Tracks

2012 ◽  
Vol 238 ◽  
pp. 733-737 ◽  
Author(s):  
Wang Fang ◽  
Bing Han ◽  
Shao Kun Yang
Keyword(s):  
Prestressed Concrete ◽  
High Speed ◽  
Element Model ◽  
Dead Load ◽  
Box Girders ◽  
Box Girder ◽  
High Speed Railway ◽  
Simply Supported ◽  
Creep Models ◽  
Curing Age

Creep will lead to increasing deflection of prestressed concrete girder, which may induce rails uneven, especially to ballastless tracks in high-speed railways. In this paper, two creep models, CEB-FIP90 and ACI209, were used in a finite element model to analyze influences of creep on simply supported prestressed concrete box girders which are used in high-speed railway in China. Sensitivity analysis was carried on towards curing age, secondary dead load, loading time and prestressing method on deformation of the girder. The results show creep should be controlled in engineering to ensure driving security.

Non Destructive Testing of Low Profile Light Weight Track System

2010 ◽  
Author(s):  
Hassan Al Nageim
Keyword(s):  
Prestressed Concrete ◽  
Traffic Congestion ◽  
Full Scale ◽  
Scale Model ◽  
Light Rail ◽  
Destructive Testing ◽  
Low Profile ◽  
Track System ◽  
Multilayer Beams ◽  
Non Destructive

The paper presents the results of the responses of a concrete trough of a new lightweight rail track system (LR55) to full scale non destructive tasting. The system which is made from three main components; low profile steel rail, elastomeric pad and prestressed concrete trough is developed for light rail transits in cities streets, which can significantly help in improving the traffic flow, reducing the traffic congestion and thus providing opportunities for minimising serious environmental problems such as level of noise, vibration and air pollutions and in this regards it can be considered as environmentally friendly means of transport. A mathematical model was developed where the LR55 track system was treated as multilayer beams on elastic foundations, and the model was then validate experimentally through a series of non-destructive tests on full scale model subjected to a full scale service load specified by the current BS codes of practises.

The Behavior of Reinforced and Pre-Stressed Concrete Beams under Elevated Temperature

2020 ◽  
Vol 47 ◽  
pp. 15-30
Author(s):  
Amr H. Badawy ◽  
Ahmed Hassan ◽  
Hala El-Kady ◽  
L.M. Abd-El Hafez
Keyword(s):  
Reinforced Concrete ◽  
Elevated Temperature ◽  
Prestressed Concrete ◽  
Mechanical Performance ◽  
Concrete Beams ◽  
Load Capacity ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Second Phase ◽  
Prestressed Beam

The behavior of unbounded post tension and reinforced concrete beams under elevated temperature was presented. The experimental work was consisted of two major phases. In the first phase, the objective was studying the mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams respectively were studied. In the second phase, the residual mechanical performance of prestressed beam, prestressed beam with steel addition and reinforced concrete beams under elevated 400oC, for 120 minutes durations. The failure mechanisms, ultimate load capacity, and deflection at critical sections were monitored. The numerical prediction of the flexural behavior of the tested specimens is presented in this paper. This includes a comparison between the numerical and experimental test results according to ANSYS models. The results indicate that the prestressed beam with steel addition and reinforced concrete beams had higher resistance to beams under elevated 400oC than that of prestressed concrete beam in terms of ultimate capacity. It is also shown that the reinforced concrete beams have higher resistance to beams under elevated temperature than that of prestressed beam, prestressed beam with steel addition.

FEM Research on Static Mechanical Performance of Twice Prestressed Composite Curved Beam

2011 ◽  
Vol 243-249 ◽  
pp. 1038-1042
Author(s):  
Fang Fang Wei ◽  
Jin Bo Wang ◽  
Ben Wei Zou ◽  
Hao Sun
Keyword(s):  
Prestressed Concrete ◽  
Composite Structures ◽  
Mechanical Performance ◽  
Curved Beam ◽  
Box Girder ◽  
Bearing Load ◽  
Static Mechanical ◽  
Deformation Stress ◽  
Girder Bridge ◽  
Ordinary Steel

The conception of twice prestressed composite structures (TPCS) was proposed in order to solve great distortion problems in prestressed concrete structures. Through decomposition of the total prestress, we define the 1st stage as one part of the prestress acting on a prefabricated beam, and the 2nd as the other part on a post-pouring structure. This kind of structure could substantially decrease its distortion and enhance the efficiency of prestress, at the same time contributing to flexibly laying the prefabricated concrete. A continuous curved prestressed concrete box girder bridge was modeled with the FEM software ANSYS, taking into account the ordinary steel and prestressed losses. The aim is to analyze the deformation, stress performance, the impacts of the primary prestressed force value on the anti-deforming performance as well as bearing load performance of the twice prestressed composite curved beam. The conclusion could provide a basis for the application and promotion of the structure.

scholarly journals Study on Design of Concrete Box Girder of A Railway Swivel Cable-Stayed Bridge

2021 ◽  
Vol 237 ◽  
pp. 03026
Author(s):  
Yang Liu ◽  
Tenghui Ding ◽  
Qinyun Xie ◽  
Guangli Xu ◽  
Chao Li
Keyword(s):  
Prestressed Concrete ◽  
Mechanical Performance ◽  
Dead Weight ◽  
Box Girder ◽  
Finite Element Software ◽  
Cable Stayed Bridge ◽  
Floating System ◽  
Concrete Box Girder ◽  
The Dead ◽  
Spherical Hinge

A swivel cable-stayed bridge over the existing railway is a span across the existing railway. The recommended scheme for the main bridge is (128 + 388 + 128) m steel mixed composite beam swivel diagonal pull bridge with span. The cables of the diagonal pull bridge are arranged according to the fanshaped central double cable plane, taking into account the mechanical performance and aesthetics. The bridge structure adopts semi floating system. The concrete swivel diagonal pull bridge is adopted in the comparison scheme. The design of the bridge is three spans and (138 + 268 + 138) m prestressed concrete box girder is adopted. The cables are arranged according to the central double cable plane, and the bridge composition adopts the consolidation system. Considering the needs of bridge operation and maintenance in the later stage of the bridge, when the dead weight of concrete diagonal pull bridge is within the ideal range, the concrete swivel diagonal pull bridge can be preferred. In order to calculate the dead weight of the selected bridge, the author uses the finite element software to model the whole bridge and calculate the weight of the bridge. The results show that the dead weight of the concrete swivel diagonal pull bridge is too large, which has exceeded the maximum bearing capacity of the existing spherical hinge. In order to continue to use the concrete swivel diagonal pull bridge scheme, it is necessary to optimize the design of the concrete swivel diagonal pull bridge scheme.

scholarly journals Full-Scale Model Experimental Study of the Flexural Behavior of Hollow Slabs Strengthened by UHPC

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Jinzhi Zhou ◽  
Zihao Wen ◽  
Weiqi Mao ◽  
Chuheng Zhong ◽  
Kangning Wang ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Vibration Frequency ◽  
Prestressed Concrete ◽  
Crack Width ◽  
Full Scale ◽  
Deformation Resistance ◽  
Flexural Behavior ◽  
Scale Model ◽  
Bending Performance ◽  
Load Tests

The hollow slabs strengthened by ultrahigh performance concrete (UHPC) composite beam show many advantages over traditional reinforcement methods. In this paper, full-scale model load tests were carried out on an nonstrengthened prestressed concrete hollow slab and an UHPC-strengthened prestressed concrete hollow slab, comparing the load deflection, crack width, bearing capacity, deformation resistance, and self-vibration frequency of the two. Static loading experimental results indicate that UHPC enhances the overall performance of prestressed concrete hollow slabs by decreasing deflection and crack width and improving bearing capacity. The strengthening effects of UHPC on a prestressed concrete hollow slab’s flexural behavior are also discussed, such as deflection, crack width, bearing capacity, deformation resistance, self-vibration frequency, flexural behavior, and cracking load. Deflection and crack width under a load of 800 kN decreased by 45.8% and 56.3%, respectively, and the initial self-vibration frequency, ultimate bearing capacity, and cracking load increased 19.2%, 21.4%, and 50%, respectively. The plane assumption can be made generally throughout the overall test process while using UHPC strengthening, which significantly constrains crack width and improves stiffness and deformation capacity. The UHPC layer and the prestressed concrete hollow slab were connected by shear studs to produce a good composite action between them, and the bending performance and bearing capacity of the whole structure were clearly improved. In addition to experiments, a validated numerical model is developed to verify the flexural performance of hollow slab strengthened by UHPC.

The first rolling load simulator (ROLLS) for testing bridges in Canada and its application on a full-scale precast box girder

2020 ◽  
Vol 47 (9) ◽  
pp. 1011-1026
Author(s):  
Amir Fam ◽  
Dustin Brennan
Keyword(s):  
Prestressed Concrete ◽  
Load Distribution ◽  
Time Lag ◽  
Element Model ◽  
Full Scale ◽  
Scaling Analysis ◽  
Distribution Method ◽  
Box Girder ◽  
Load Simulator ◽  
Rolling Load

This paper describes the development of a unique rolling load simulator (ROLLS) for testing bridge superstructure with a footprint up to 4 m ×17 m, and its first application to test a full-scale 1220 mm ×900 mm ×16000 mm B900 prestressed concrete box girder. This facility at Queen’s University in Kingston, Ontario, is the first of its kind in Canada. ROLLS can apply cyclic loading in a controlled laboratory environment, under realistic highway scale ‘rolling wheel loads’, in lieu of the conventional ‘pulsating stationary loads’. It has two half-axles of a large tandem, each comprising a dual 1140 mm diameter air-inflated tires spaced at either 1.2 or 2.4 m. Each half-axle can apply up to 125 kN, representing the heaviest half-axle load of the CL-625 design truck of the Canadian Highway Bridge Design Code (CHBDC). The maximum travel range and speed are 14.9 m and 6 m/s, respectively. A case study involving analysis of a bridge with eight adjacent B900 box girders of 27.6 m span was carried out prior to experimentally testing one of the girders using ROLLS. Load distribution analyses were conducted using both (i) a finite element model of the full bridge under various CL-625 truck loading configurations and (ii) the CHBDC load distribution method, and both agreed well. Scaling analysis of the girder load share was then conducted to account for shortening it to 16 m to fit in the laboratory, resulting in two-115 kN ROLLS design loads, 1.2 m apart. Multiple passes were conducted at various loads of 40%–100% of the design load, at speeds of 1–5 m/s to examine the machine and girder behaviours. It was found that the applied load fluctuates by less than 10% of full capacity and a 0.13 s/cycle time lag occurs. The measured girder deflection and elastic strains were 11%–20% lower than predicted theoretically. With the two half-axles assembly spaced at 1.2 m, the apparatus has the ability to complete three million cycles in approximately 4.5 months if ran continuously at 5 m/s.

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