Prestressed Wire Ropes Research Articles

Seismic Performance Analysis of Concrete Columns Reinforced with Prestressed Wire Ropes Embedded in Polyurethane Cement Composites

In order to improve the seismic performance of reinforced concrete (RC) columns, a reinforcement technology using prestressed steel wire ropes embedded in polyurethane cement composite material is proposed. Four concrete columns reinforced with different materials were subjected to a combination of axial compression and horizontally repeated loading tests (one of which was not reinforced, while the remaining three were reinforced with prestressed steel wire rope, polyurethane cement composite material, and prestressed steel wire ropes embedded in polyurethane cement composite material). The experimental results show that the ductility and energy dissipation capacity of reinforced concrete columns after reinforcement are significantly improved. After strengthening with prestressed steel wire ropes embedded in polyurethane cement composite material, the ultimate horizontal displacement and energy dissipation capacity of reinforced concrete columns were significantly improved, which were 69% and 3.2 times higher than those of unreinforced columns, respectively.

Static Load Test Analysis of T-Beam Bridge Shear Strengthening by Prestressed Steel Wire Rope Embedded in Polyurethane Cement (PSWR-PUC)

Many bridges suffer from aging and deterioration problems and need to be strengthened. PSWR-PUC is an emerging structural strengthening technology that enhances the load-bearing capacity of concrete bridges by embedding prestressed steel wire ropes into polyurethane cement. This paper focuses on investigating the shear reinforcement effectiveness of PSWR-PUC. Firstly, the composition of PSWR-PUC is introduced. Subsequently, two T-beam bridges in similar service condition are selected, and shear strengthening schemes involving PSWR-PUC and externally bonded steel plates are devised. Lastly, static loading tests are conducted, and the deflection and strain data of the two bridges before and after reinforcement intervention are analyzed. The results indicate that both strengthening methods improve the bridge load-carrying capacity. However, compared to the bridge strengthened with the externally bonded steel plate method, the deflections in the bridge strengthened with PSWR-PUC decreased by 36.8% and 42.1%, the strains decreased by 18% and 23%, and the shear stiffness was improved to a greater extent. These results verified that the PSWR-PUC strengthening method is effective for improving structural capacity and performance. This study will contribute to an in-depth understanding of the performance characteristics and application scope of PSWR-PUC shear strengthening technology, and it provides a scientific basis and guidance for practical engineering applications.

Automatic detection of defects in pre-stressed multi strand wires using hall effect sensor

Pre-stressed wire ropes are the steel-reinforced cables used in bridges to carry loads and to prevent the bridges from displacements. Steel strands are of different orientations and with arbitrary number of wires within it. This strands twisted one over the other to form the steel ropes, which plays a major role for supportive purpose and any defects in the strand wires leads to failure of the rope and the structures which it supports. So it became essential to inspect periodically, to ensure the safety operation. But, the challenges are that the ropes are at the non-accessible and non-demandable locations, thereby the common inspection methods are limited. So in this research, inspection of wire ropes had done by using a robot with Hall Effect sensor. This developed robot has to be allowed to pass over the cable and the detector detects the defects, if any based on the flux variations at the broken steel strands. The experimentation results proved that the developed robot is at par in detection and it can be used to detect the defects for various applications.

Numerical studies on the influence of selected construction features and road conditions on the performance of road cable barriers

Cable barriers are commonly used on Polish roads, including motorways and local roads. Their main elements are pre-stressed wire ropes, which are usually anchored at two ends in concrete blocks buried in the soil. In this work numerical studies concerning the influence of selected construction features and parameters of the vehicle motion on the performance of cable barriers were performed. Numerical simulations are a useful tool to conduct such analyses that is now being used more and more. The calculations were carried out by using finite element code of LS-DYNA.

Observation of ultrasonic guided wave propagation behaviours in pre-stressed multi-wire structures

Ultrasonic guided wave (UGW) is a promising technique for nondestructive testing of pre-stressed multi-wire structures, such as steel strand and wire rope. The understanding of the propagation behaviours of UGW in these structures is a priority to applications. In the present study, first the properties of the UGW missing frequency band in the pre-stressed seven-wire steel strand is experimentally examined. The high correlation between the observed results and the previously published findings proves the feasibility of the magnetostrictive sensor (MsS) based testing method. The evolution of missing frequency band of UGW in slightly tensioned steel strand is discussed. Two calibration equations representing the relationship between the missing band parameters and the tensile force are given to derive a new tensile force measurement method, which is capable of measuring an incremental of stress of approximately 3MPa. Second, the effects of tensile force on the UGW propagation behaviours in three types of complicated steel wire ropes are alternatively investigated based on the short time Fourier transform (STFT) results of the received direct transmission wave (DTW) signals. The observed inherent missing frequency band of the longitudinal mode UGW in the pre-stressed steel wire rope and its shifting to a higher frequency range as the increases of the applied tensile force are reported for the first time. The influence of applied tensile force on the amplitude of the DTW signal and the unique UGW energy jump behaviour observed in a wire rope of 16.0mm, 6×Fi(29)+IWRC are also investigated, despite the fact that they cannot yet be explained.

The Analysis of Slab and Beam Floor with Pre-stressed Wire Rope Reinforcement

The paper presents calculations of monolith slab and beam floor with pre-stressed wire rope reinforcement. The numerical modeling of the slab is performed with PC “Lira-SAPR 2013”. The paper describes finite elements used in calculations, the conditions of the slab reinforcement, concrete and wire rope reinforcement connections. The calculation results are shown as stress isofields in concrete and steel elements of the slab. The paper also estimates pre-stressed wire rope reinforcement efficiency when used in slab and beam floor. The authors compare stress and strain condition of typical monolith slab and beam floor with reinforcement bars and slab and beam floor with wire rope reinforcement while changing intermediate slab thickness. The results are presented as a finite element model of monolith slab and beam floor with pre-stressed wire rope reinforcement and with untensioned reinforcement.

Fire Resistance Performance of High-Strength Concrete Columns Reinforced with Pre-Stressed Wire Ropes

In this study, the fire resistance performance of high-strength concrete columns was evaluated to see the influence of lateral confinement reinforcement with wire ropes for improving ductility, fire resistance reinforcement with fiber cocktail and load ratio. For this, loaded fire test was conducted under ISO834 standard fire condition. The axial ductility of the 60MPa high-strength concrete column reinforced with pre-stressed wire ropes was improved and its fire resistance performance was also improved by 23% compared with its counterpart without wire ropes. The appropriate load for the 60MPa concrete column reinforced with wire ropes was found to be 70% of design load. The fire resistance performance of the 100MPa high-strength concrete column reinforced with pre-stressed wire ropes and fiber-cocktail was improved as much as 4 times compared with that reinforced with tie bars only. The appropriate load for the 100MPa columns was found to be less than 70% of design load in order for the columns to secure required fire resistance performance.

와이어로프를 적용한 고강도 철근콘크리트 기둥의 내화공법 및 하중비에 따른 내화성능에 관한 연구

60 MPa급, 100 MPa급 고강도 철근콘크리트 기둥에 대하여 횡구속력 보강공법(와이어로프)과 내화보강공법(Fiber-Cocktail) 적용 유무 및 하중비에 따른 내화성능을 평가하기 위하여 표준화재 재하조건에 내화실험을 실시하였다. 실험결과 60 MPa급 고강도 콘크리트 기둥의 경우 와이어로프를 적용함으로써 화재시 축방향의 연성이 향상되며, 내화성능은 23 % 이상 향상되는 것으로 나타났다. 또한 와이어로프를 적용할 경우 하중은 설계하중의 70 % 수준이 적정하다고 판단된다. 100MPa급 고강도 콘크리트 기둥에 와이어로프와 Fiber-Cocktail을 적용할 경우 띠철근만을 적용한 경우보다 내화성능이 4배 이상 향상되는 것으로 나타났으며, 100MPa급 고강도 콘크리트 기둥에 내화성능을 확보하기 위해서는 하중은 설계하중의 70 % 미만으로 설정하는 것이 적정하다고 판단된다. The fire resistance test has been conducted under the standard fire & loading conditions to evaluate fire resistance performance, according to applying to methods of the lateral confinement reinforcement by prestressed Wire Rope and fire resistance reinforcement by Fiber-Cocktail and load ratio for high strength concrete column. The test result, for 60 MPa high-strength concrete column, It was indicated that applying to the wire rope has improved axial ductility in the fire condition, and fire resistance performance has been enhanced by more than 23 %. In addition to this, in case of applying the wire rope to 60 MPa high-strength concrete column, load can be judged that about 70 % of designed load is appropriate. If the Wire Rope and Fiber-Cocktail is applied to 100 MPa high-strength concrete column, It was shown that the fire resistance performance was enhanced by 4 times as much as applying only hoops.

60 MPa급 고강도 콘크리트 기둥의 내화공법 유형별 화재거동 및 전열 특성에 관한 실험적 연구

본 연구는 60 MPa급 고강도 철근콘크리트 기둥에 와이어로프를 적용할 경우 표준화재 재하조건에서 내화성능에 미치는 영향 및 고강도 콘크리트의 내화성능 향상을 위하여 폴리프로필렌 섬유(Polypropylene Fiber)와 강섬유(Steel fiber)를 하이브리드한 섬유(Fiber-Cocktail)를 폭렬저감재로 첨가하여 내화성능의 향상방안을 제시하고자 한다. 실험결과 띠철근을 적용한 경우 147분의 내화성능을 확보하였으며, 와이어로프를 적용한 경우 180분의 내화성능을 확보하는 것은 가능하였지만 주철근의 온도가 고강도 콘크리트의 내화성능 관련 고시에서 제시하고 있는 평균 <TEX>$538^{\circ}C$</TEX>, 최고 <TEX>$649^{\circ}C$</TEX>를 초과하는 것으로 나타났다. 하지만 와이어로프 및 Fiber-Cocktail을 모두 적용한 경우 내화성능은 180분 이상을 확보할 수 있는 것으로 나타났다. In this study, we intend to propose a method for improving fire resistance performance by adding Fiber-Cocktail made by hybridizing steel fiber and Polypropylene fiber as the materials for reducing explosion to enhance the fire resistance performance of high-strength concrete and the effect on the fire resistance performance under standard fire loading conditions, in case of applying pre-stressed wire rope to 60 MPa high-strength reinforced concrete column. According to the test result, in case of applying hoops, the fire performance for 147 minutes has been secured and the wire-rope for 180 minutes. However, it was shown that the temperature of the main reinforcement exceeded <TEX>$538^{\circ}C$</TEX> in average, <TEX>$649^{\circ}C$</TEX> at maximum specified in the notices related to fire resistance performance of high strength concrete. However, in case of applying both of wire-rope and fiber-cocktail, it was shown that the fire performance for more than 180 minutes has been secured.

In-plane seismic performance of unreinforced masonry walls strengthened with unbonded prestressed wire rope units

This study proposes a practical strengthening technique for enhancing the in-plane shear strength and ductility of unreinforced masonry (URM) walls using the unbonded prestressed wire rope units. Six full-scale strengthened URM walls and an unstrengthened URM wall were tested under constant axial load and cyclic lateral loads to explore the significance and limitations of the developed seismic strengthening procedure. The main variables investigated were the aspect ratio of walls, and the spacing and configuration of the prestressed wire ropes. The ductility of the walls tested was evaluated using the work damage indicator calculated at each loading step from the hysteretic loops. In addition, shear transfer capacities of masonry and wire ropes were identified based on the statistical fitting of test data for URM walls compiled from the literature and 45° truss analogy, respectively, in order to propose simple equations for shear strength of the URM walls strengthened with the developed wire rope units. Test results showed that the proposed strengthening procedure was highly effective in enhancing the in-plane shear strength and ductility of URM walls and controlling crack propagation along head and bed mortar joints. The shear strength and work damage indicator increased with the decrease of the spacing of wire ropes, showing that the inclined wire ropes were more capable of enhancing ductility than vertical wire ropes. The crack resistance capacity and stiffness of URM walls were also improved due to the additional axial compression force provided from the prestressing force applied to the wire ropes. The shear capacities obtained from the proposed simple equations were in good agreement with the test results, indicating that the mean and standard deviation of the ratios between measured and predicted shear capacities were 1.14 and 0.13, respectively.

Study on the Method for Calculating Shear Strength of RC Beams Strengthened with Externally Prestressed Wire Rope

Through shear test data analysis of 13 RC beams Strengthened with externally prestressed wire rope, shear failure mechanism was elaborated, and shear bearing capacity of reinforced beams were not only calculated respectively by truss -arch model and other simplified calculation methods, but also were compared with test data. Based on the result of comparation, shear capacity calculation method of RC beam Strengthed with externally prestressed wire rope was discussed. The analysis results show that the mechanism of the wire rope shear externally prestressed reinforced concrete beams against the shear is similar with stirrups inside beam. When the shear span ratio is less than 2.7, the static average ratio of the truss-arch model shear capacity caculation value and tested value is 1.02, and standard deviation statistics is 0.07. In another word, calculation value agree with experimental value. When the shear span ratio is larger than 2.7, the calculation value is bigger than test.

Test Study on the Resisting Shear Strengthening Effect with External Pre-Stressed Wire Rope

The resisting shear strengthening technology of existing reinforced concrete bridges as an important research topic in the field of old bridges, play an important significance to improve the mechanical properties of old bridges and reduce security incidents. Based on comparative test analysis on two basic beams and twelve reinforced concrete beams strengthened with external pre-stressed wire rope, the influence of the shear strengthening effect was studied systematically caused by the original beam design parameters and the spacing of wire rope, in the meantime the strengthening mechanism was analyzed. Research results showed that the shear capacity of the strengthened beams was improved, because the development of cracks was not only effectively limited, but also stirrup strain was reduced, and yield load was put off. Along with the increasing of the ratio of original beams longitudinal reinforcement and the ratio of stirrup ,and the concrete grade, as well as the decreasing of spacing of external wire rope, the stirrups strain were decreasing and the shear capacity of strengthened beams increased. With the spacing of external wire rope decreasing, the diagonal crack resistance of the strengthened beams increased. The research results can provide reference for the design and research on shear strengthening of bridges.