Prestressed I-Beams of 12 m Span Made of Ultra-High Performance Concrete for Construction of Railway Bridges

2014 ◽  
Vol 587-589 ◽  
pp. 1593-1596
Author(s):  
Petr Tej ◽  
Jiří Kolísko ◽  
Petr Bouška ◽  
Miroslav Vokáč ◽  
Jindřich Čech

This paper focuses on research of prestressed I-beams made of ultra-high performance concrete (UHPC), which are designed to be structural elements in small and medium span railway bridges. Prestressed concrete I-beams are designed with ten prestressing cables in the bottom flange. The prestressed beams are laid close together in the actual structure, with panels inserted between them. The entire structure will subsequently become monolithic. At the present time, I-beams made of rolled steel are commonly used as structural elements in this type of structure. The advantage of these types of structures lies in their having low construction height. This paper presents a computer and experimental analysis of loading of UHPC prestressed I-beams. For the purpose of the experiments, three specimens of 12 m span were made. The specimens were subsequently tested in the laboratory in four-point bending tests. The paper presents the process and results of the experiments. Simultaneously with the experiments, computer analyses were created in which optimization of the material and geometric parameters of the beams were carried out. The paper demonstrates the correspondence of the experimental and computer-simulated load test results.

2014 ◽  
Vol 578-579 ◽  
pp. 776-778
Author(s):  
Petr Tej ◽  
Jiří Kolísko ◽  
Petr Bouška ◽  
Miroslav Vokáč ◽  
Jindřich Čech

This paper focuses on research into prestressed I-beams made of ultra-high-performance concrete, which are designed to be structural elements in small and medium span railway bridges. Prestressed concrete I-beams are designed with ten prestressing cables in the bottom flange. The prestressed beams are laid close together in the actual structure with panels inserted between them. The entire structure will subsequently become monolithic. At the present time, I-beams made of rolled steel are commonly used as structural elements in this type of structure. The advantage of these types of structures lies in their having a low construction height. This paper presents a computer and experimental analysis of the loading of UHPC prestressed I-beams. For the purpose of the experiments, several specimens of 7 m span were made. The specimens were subsequently tested in the laboratory in four-point bending tests. The paper presents the process and results of the experiments. Simultaneously with the experiments, computer analyses were created in which optimization of the material and geometric parameters of the beams were carried out. The paper demonstrates the correspondence of the experimental and computer-simulated load test results.


2015 ◽  
Vol 1095 ◽  
pp. 569-572 ◽  
Author(s):  
Petr Tej ◽  
Jiří Kolísko ◽  
Petr Bouška ◽  
Tomáš Bittner ◽  
Veronika Mušutová

This paper focuses on the research carried out on thin plates made of white ultra-high performance concrete reinforced by PVA fibers and 2D textile glass reinforcement. These boards should be used for facades or roof panels. The paper presents a computer and experimental analysis of the loading of thin UHPC plates. For the purpose of the experiments, three specimens of a size of 750 x 125 x 15 mm were made. The specimens were subsequently tested in the laboratory in four-point bending tests. The paper presents the process and results of the experiments. Simultaneously with the experiments, computer analyses were created in which optimization of the material and geometric parameters of the beams were carried out. The paper demonstrates the correspondence of the experimental and computer-simulated load test results.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nasser Hakeem Tu’ma ◽  
Mohammed Naji Hammood ◽  
Rasool Dakhil Mohsin

Abstract The hollow structural elements occupy a great deal of researchers’ interest due to the possibility of losing their weights and maintaining or developing their resistances especially when increasing both compressive and tensile strength of modern materials. The flexural strength based on the forces balance and stain compatibility was derived. Nine beams of Ultra High Performance concrete (UHPC) and conventional reinforced steel bars were casted. Several parameters were taken which are the thickness of the concrete top flange, thickness of the concrete bottom flange, depth of the longitudinal hollow and the ratio of the longitudinal reinforcing steel. By comp aring the practical and theoretical results, the proposed flexural strength provided a safety factor of one-fifth against the experimental collected data. The ultimate flexural force developed up 260 % when increasing the reinforced steel area 4.6 times and 230 % comparing with the solid beam. Many aspect ratios were also mentioned that keep the strength in developing.


2021 ◽  
Vol 13 (9) ◽  
pp. 4895
Author(s):  
Milan Holý ◽  
David Čítek ◽  
Petr Tej ◽  
Lukáš Vráblík

This paper describes the development of an innovative timber–concrete composite bridge system and especially focuses on the evaluation of the load tests of an experimental bridge structure. The load-bearing structure was designed as glue-laminated timber beams connected with only 60-mm-thick precast bridge deck segments made of ultra-high-performance concrete (UHPC). To verify the production details and behavior of the designed structure, we built a full-scale experimental structure and performed a load test. The load test was arranged as a four-point bending test. First, we performed the overall load test until failure. Some bridge deck segments were consequently cut from the structure in order to run further load tests of the bridge deck in the transversal direction. The results of the experiments were evaluated in detail and compared with analytical calculations.


PCI Journal ◽  
2020 ◽  
Vol 65 (6) ◽  
pp. 35-61
Author(s):  
Chungwook Sim ◽  
Maher Tadros ◽  
David Gee ◽  
Micheal Asaad

Ultra-high-performance concrete (UHPC) is a special concrete mixture with outstanding mechanical and durability characteristics. It is a mixture of portland cement, supplementary cementitious materials, sand, and high-strength, high-aspect-ratio microfibers. In this paper, the authors propose flexural design guidelines for precast, prestressed concrete members made with concrete mixtures developed by precasters to meet minimum specific characteristics qualifying it to be called PCI-UHPC. Minimum specified cylinder strength is 10 ksi (69 MPa) at prestress release and 18 ksi (124 MPa) at the time the member is placed in service, typically 28 days. Minimum flexural cracking and tensile strengths of 1.5 and 2 ksi (10 and 14 MPa), respectively, according to ASTM C1609 testing specifications are required. In addition, strain-hardening and ductility requirements are specified. Tensile properties are shown to be more important for structural optimization than cylinder strength. Both building and bridge products are considered because the paper is focused on capacity rather than demand. Both service limit state and strength limit state are covered. When the contribution of fibers to capacity should be included and when they may be ignored is shown. It is further shown that the traditional equivalent rectangular stress block in compression can still be used to produce satisfactory results in prestressed concrete members. A spreadsheet workbook is offered online as a design tool. It is valid for multilayers of concrete of different strengths, rows of reinforcing bars of different grades, and prestressing strands. It produces moment-curvature diagrams and flexural capacity at ultimate strain. A fully worked-out example of a 250 ft (76.2 m) span decked I-beam of optimized shape is given.


Author(s):  
Ariful Hasnat ◽  
Nader Ghafoori

AbstractThis study aimed to determine the abrasion resistance of ultra-high-performance concretes (UHPCs) for railway sleepers. Test samples were made with different cementitious material combinations and varying steel fiber contents and shapes, using conventional fine aggregate. A total of 25 UHPCs and two high-strength concretes (HSCs) were selected to evaluate their depth of wear and bulk properties. The results of the coefficient of variation (CV), relative gain in abrasion, and abrasion index of the studied UHPCs were also obtained and discussed. Furthermore, a comparison was made on the resistance to wear of the selected UHPCs with those of the HSCs typically used for prestressed concrete sleepers. The outcomes of this study revealed that UHPCs displayed excellent resistance against abrasion, well above that of HSCs. Amongst the utilized cementitious material combinations, UHPCs made with silica fume as a partial replacement of cement performed best against abrasion, whereas mixtures containing fly ash showed the highest depth of wear. The addition of steel fibers had a more positive influence on the abrasion resistance than it did on compressive strength of the studied UHPCs.


2021 ◽  
Vol 322 ◽  
pp. 157-162
Author(s):  
Milan Holý ◽  
David Čítek ◽  
Petr Tej ◽  
Lukáš Vráblík

This article presents the results of the experimental development of a unique bridge system consisting of timber beams connected with bridge deck segments made of Ultra-High Performance Concrete (UHPC). The article deals with the production of a full-scale prototype of the timber-concrete composite structure and with an execution of a subsequent load test. The test structure was 3.30 m wide and 10.24 m long and was designed as two beams made of glue laminated timber connected with subtle bridge deck segments with a thickness only 60 mm and with a typical length of 1.50 m. The aim of the production of the test structure was to check some production details and procedures and subsequently to verify the behavior of the composite structure under load by the load test. The load test was performed with a theoretical span of 9.50 m as a four-point bending test to failure. After the overall load test was done, some bridge deck segments were cut from the structure and a load test of the bridge deck in transversal direction were executed to verify the behavior and the load-bearing capacity of the bridge deck segments made of UHPC.


2010 ◽  
Vol 37 (4) ◽  
pp. 511-521 ◽  
Author(s):  
H. Almansour ◽  
Z. Lounis

The construction of new bridges and the maintenance and renewal of aging highway bridge network using ultra high performance concrete can lead to the construction of long life bridges that will require minimum maintenance resulting in low life cycle costs. Ultra high performance concrete (UHPC) is a newly developed concrete material that provides very high strength and very low permeability to aggressive agents such as chlorides from de-icing salts or seawater. Ultra high performance concrete could enable major improvements over conventional high performance concrete (HPC) bridges in terms of structural efficiency, durability, and cost-effectiveness over the long term. A simplified design approach of concrete slab on UHPC girders bridge using the Canadian Highway Bridge Design code and the current recommendations for UHPC design is proposed. An illustrative example demonstrates that the use of UHPC in precast–prestressed concrete girders yields a more efficient design of the superstructure where considerable reduction in the number of girders and girder size when compared to conventional HPC girders bridge with the same span length. Hence, UHPC results in a significant reduction in concrete volume and then weight of the superstructure, which in turn leads to significant reduction in the dead load on the substructure, especially for the case of aging bridges, thus improving their performance.


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