Beijing Texida Technology Research and Development Co.

Beijing, China

Beijing Texida Technology Research and Development Co.

Beijing, China
SEARCH FILTERS
Time filter
Source Type

Sun Z.,Nanjing Southeast University | Wu G.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Zhang M.,Beijing Texida Technology Research and Development Co.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2011

The seismic performance of concrete columns reinforced by Steel-FRP (Fiber Reinforced Polymer) Composite Bar (SFCB) is quite different from that of ordinary RC (Reinforced Concrete) columns. Horizontal cyclic loading tests were conducted on concrete columns reinforced by SFCB and ordinary steel bars, separately, with an axial compression ratio of 0.12. Fiber types (basalt and carbon fibers) and steel/fiber ratio of SFCB were the main variable parameters. Test results showed that: (1) compared with ordinary RC column, concrete columns reinforced by SFCB had stable post-yield stiffness, and the load could increase significantly after the yielding of SFCB inner steel bar; (2) due to the post-yield stiffness of SFCB, SFCB reinforced concrete column had less column base curvature demand than ordinary RC column at the same column cap lateral deformation level, and therefore smaller unloading residual deformation could be achieved; (3) the outer FRP type of SFCB significantly influenced the performance of SFCB reinforced concrete columns, and steel-BFRP (basalt FRP) composite bar reinforced concrete columns had better ductility (longer effective length of post-yield stiffness) and smaller unloading residual deformation than steel-CFRP (carbon FRP) composite bar columns under the same unloading displacement.


Shen S.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Yang C.,Nanjing Southeast University | Tang Y.,Nanjing Southeast University | And 2 more authors.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2010

Deformation is in general the most effective indicator of unforeseen damage accumulation, though it is difficult to acquire deformation distribution using traditional "point" monitoring methods. Based on the distributed optical fiber sensing technique of pulse-prepump Brillouin Optical Time Domain Analysis (PPP-BOTDA), an improved conjugated beam method is presented for monitoring the deformation distribution of simply-supported structures and continuous structures. This method is suitable for the combined action of loads and support settlements, extending the application of the traditional conjugated beam method. Another advantage of this method is that the relationship between structural deformation and strain is linear and all calculation parameters can be easily determined without using load or section stiffness. Theoretical and experimental investigations confirm that using this method, the accuracy of deformation monitoring in one span of structure is only related to the accuracy of strain measurements in this span, a characteristics useful for avoiding the influence from strain measurement errors in other spans.


Wu G.,Nanjing Southeast University | Wang H.-T.,Nanjing Southeast University | Wu Z.-S.,Nanjing Southeast University | Wu Z.-S.,Ibaraki University | And 2 more authors.
Journal of Composites for Construction | Year: 2012

An experimental study was conducted to investigate the fatigue behavior of artificially notched steel beams strengthened with four different types of materials tested under equivalent tensile stiffness. These materials include high-modulus carbon-fiber-reinforced polymer (HM-CFRP) plate, high-strength CFRP (HS-CFRP) plate, steel-wire basalt-fiber-reinforced polymer (SW-BFRP) plate, and welded steel plate. Some key parameters, such as material type, the number of HS-CFRP layers, the configuration of HS-CFRP, and the interface treatment of SW-BFRP, are discussed. Compared to the traditional welded steel-plate method, the test results show that the application of a fiber-reinforced composite plate can not only delay crack initiation, decrease the crack growth rate, and prolong the fatigue life, but also reduce the stiffness decay and residual deflection. HM-CFRP exhibited the best strengthening performance; however, SW-BFRP is the optimal strengthening material on the basis of the cost-performance ratio. The fatigue behavior of steel beams can be improved significantly by increasing the layers of strengthening material. SW-BFRP with a rough surface can prolong the fatigue life of steel beams more effectively than SW-BFRP with a smooth surface. The plate configuration has certain effects on the fatigue life. © 2012 American Society of Civil Engineers.


Sun Z.,Nanjing Southeast University | Wu G.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Zhang M.,Beijing Texida Technology Research and Development Co.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2012

Though simulation of the mechanical properties of steel-FRP (fiber reinforced polymer) composite bar (SFCB) with OpenSees, the influences of reinforcement ratio, axial compression ratio, and SFCB post-yield stiffness ratio on the bearing capacity and deformation capacity of SFCB columns, and the maximum and residual deformation responses of SFCB column with different post-yield stiffness ratios under the excitation of three different earthquake waves were studied. The hysterisis behavior of SFCB columns and that of one reference RC (reinforced concrete) column were compared. The results showed: (1) the mechanical properties of SFCB under tensile and cyclic tensile loads could be well simulated by OpenSees based on the mixture rule, during which the steel bar and FRP were modeled separately; (2) with the same reinforcement ratio, the post-yield stiffness and corresponding deformation capacity of SFCB column increased with the increase of FRP content in SFCB; (3) the increase of column axial compression ratio had a negative effect on the post-yield stiffness of SFCB column, and more FRP in SFCB could delay the collapse of SFCB columns caused by the P-δ effect; (4) under the excitation of sever earthquakes of 400 Gal acceleration, SFCB column would exhibit smaller residual displacement than ordinary RC column when the post-yield stiffness ratio of SFCB was larger than 0.15; (5) both the calculation and the experimental results of SFCB columns under horizontal cyclic loading indicated that SFCB column could have smaller residual displacement than RC column, meaning that SFCB column had better post-earthquake reparability.


Wu G.,Nanjing Southeast University | Liu H.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Ren Y.,Beijing Texida Technology Research and Development Co. | Wang H.,Nanjing Southeast University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2012

An experimental study was conducted to investigate the fatigue performance of artificially damaged steel beams strengthened with different externally bonded fiber reinforced polymers, such as high modulus carbon fiber reinforced polymer (high modulus CFRP) plate, high strength CFRP plate, steel wire-basalt fiber composite plate (SBFCP) and welded steel plate. The strengthening effects of different materials on the fatigue performance of steel beams were analyzed, and the influencing factors of the fatigue performance of steel beams were discussed. Experimental results showed that the fatigue life of steel beams strengthened with fiber reinforced polymer was 3.33~5.26 times that of the un-strengthened beams, while the fatigue life of steel beams strengthened with welded steel plate only 1.74 times that of the un-strengthened beams. With the equivalent tensile stiffness of strengthening materials, comparing with welded steel plates, the application of fiber reinforced polymer can substantially postpone crack initiation, reduce crack growth rate and residual deflection of steel beams, prolong fatigue life and improve failure modes. Among the tested strengthening materials, high modulus CFRP plate had the best strengthening effects, and SBFCP was proved to be a strengthening material with the best performance-price ratio. Strengthening material and the interface have considerable influences on fatigue performance.


Yang Y.,Nanjing Southeast University | Wu G.,Nanjing Southeast University | Wu Z.-S.,Nanjing Southeast University | Jiang J.-B.,Beijing Texida Technology Research and Development Co. | Wang X.-B.,CR17BG Construction Engineering Co.
Composites Part B: Engineering | Year: 2015

Because of the inductive impedance caused by steel meshes in traditional reinforced ballastless track slabs, the electrical properties, primarily the rail resistance and inductance, of jointless track circuits are affected by electromagnetic induction between the slabs and the electric current in the rail. This problem results in poor transmission performance throughout the track circuit. Insulating sleeves or cards between the steel meshes have been used to improve the insulation capability of steel meshes in slabs; however, they reduce the bonding performance between the steel bars and concrete. Because of the good insulation properties of fiber-reinforced polymer composite bars (FRPs) and steel-fiber reinforced polymer composite bars (SFCBs), these composite materials have shown potential to overcome this insulation problem. However, the structural performance of the ballastless track slabs reinforced by basalt fiber reinforced polymer composite bars (BFRPs) and SFCBs, which play a key role in the structure and transportation safety, needs to be investigated. In this paper, six ballastless track slabs reinforced with BFRPs, SFCBs, and steel bars were constructed and tested. The following results were obtained. (1) Shear failures were observed for all slabs, both the BFRP and SFCB slabs meet the load level requirements, and SFCBs reinforcements have higher strength utilization compared with BFRPs reinforcements. (2) The bond-quality of SFCBs and BFRPs reinforcements proved slightly poorer than that of the steel bars. Because of the good corrosion resistance of the FRP, the maximum crack width limits can be slightly larger than that of the RC slabs. (3) Bischoff's equation was initially used to calculate the deflection of partially prestressed concrete slabs under service loads. The results demonstrated a good agreement between the theoretical and experimental analysis. (4) Considering the tensile stiffness, the modified ACI equation was used to calculate the slabs' crack width and the theoretical and experimental results showed a good agreement. © 2014 Elsevier Ltd. All rights reserved.


Wu G.,Nanjing Southeast University | Yang Y.,Nanjing Southeast University | Yang Q.,CR17BG Construction Engineering Co. | Jiang J.,Beijing Texida Technology Research and Development Co. | Wu Z.,Nanjing Southeast University
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2014

Steel reinforcements in traditional ballastless track slabs may influence the insulation performance of slabs, exacerbate the track circuit parameters, and in addition the use of insulation sleeves may also impair the bonding performance between the steel bar and concrete. A new type of ballastless track slab reinforced by steel-FRP composite bar (SFCB), which possesses excellent insulation performance, good bonding performance and high elastic modulus, etc, is thus proposed in this study. Insulation performance test of SFCB for ballastless track slab is conducted, and the results show that the rail parameters can be significantly improved. Based on the achieved desirable insulation performance, the experimental study on flexural behavior of SFCB slab is consequently conducted, and results show that SFCB slab has higher ultimate strength, higher energy reserve, and considerably higher displacement ductility than reinforced concrete (RC) slab. The results also show that after the yielding of steel bars, the crack development in SFCB slab may be restrained by the secondary stiffness of SFCB slab. Hence, the proposed SFCB reinforced ballastless track slab is appealing due to its good overall performance, which makes it desirable in engineering practice.


Wu G.,Nanjing Southeast University | Luo Y.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Hu X.,Zhejiang GBF Co. | Zhang M.,Beijing Texida Technology Research and Development Co.
Tumu Gongcheng Xuebao/China Civil Engineering Journal | Year: 2010

Uniaxial and cyclic tensile tests of steel-FRB (fiber reinforced polymer) composite bar (SFCB) products were conducted, with the destruction and damage characteristics observed and the initial stiffness, post-yielding stiffness, yield strength, ultimate strength, unloading stiffness, and residual strain of the specimens measured. Test results showed that the load-strain curve of SFCB was bilinear before fiber fracture and exhibited stable post-yielding stiffness, small residual strain and good recoverability after the reinforcement yielded. Since the theoretical model for the stress-strain curve of SFCB under uniaxial load derived from the mixing rule involves large error for cyclic test data, a Restoring Force Model for the stress-strain curve of SFCB under cyclic load was constructed by statistical analysis of the characteristics of the stress-strain test curve under cyclic tension. The Restoring Force Model could thoroughly display the pattern of the unloading modulus of SFCB degradation under cyclic tensile and the predicted results were in good agreement with experimental data, which proved that the performance of SFCB could be predicted and designed by the proposed model.


Luo Y.,Nanjing Southeast University | Wu G.,Nanjing Southeast University | Wu Z.,Nanjing Southeast University | Zhang M.,Beijing Texida Technology Research and Development Co. | Hu X.,Zhejiang Shijin Basalt Fiber Co.
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2010

Steel-FRP(fiber reinforced polymer) composite bar is a new reinforcement material consisted of inner steel bar and outer longitudinal wrapped FRP. With unique mechanical and anti-corrosion properties, steel-FRP composite bar(SFCB) is promising to be applied to near surface mounted(NSM) strengthening technique. This paper mainly focused on the theoretical analysis on flexural performance of NSM-SFCB strengthened RC beams. Firstly, a predictable method on bearing capacity of NSM-SFCB strengthened RC beams with bending failure mode was proposed based on the plane section assumption and force equilibrium. Secondly, intermediate crack(IC) debonding of the NSM-SFCB strengthened RC beams was theoretically investigated and a debonding differentiating method and bearing capacity calculating method were put forward consequently. At last, the predictable method of ultimate bearing capacity was improved by adopting a debonding strengthen model that both failure modes of bending failure and IC debonding failure can be considered. By comparing the predicted result to the test results, the predictable method was proved valid with good precision.


Sun Z.-Y.,Nanjing Southeast University | Wu G.,Nanjing Southeast University | Wu Z.-S.,Nanjing Southeast University | Zhang M.,Beijing Texida Technology Research and Development Co.
Journal of Composites for Construction | Year: 2011

Steel-fiber-reinforced polymer (FRP) composite bars (SFCBs) are a novel reinforcement for concrete structures. Because of the FRP's linear elastic characteristic and high ultimate strength, they can achieve a stable postyield stiffness even after the inner steel bar has yielded, which subsequently enables a performance-based seismic design to easily be implemented. In this study, lateral cyclic loading tests of concrete columns reinforced either by SFCBs or by ordinary steel bars were conducted with axial compression ratios of 0.12. The main variable parameters were the FRP type (basalt or carbon FRP) and the steel/FRP ratio of the SFCBs. The test results showed the following: (1)compared with ordinary RC columns, SFCB-reinforced concrete columns had a stable postyield stiffness after the SFCB's inner steel bar yielded; (2)because of the postyield stiffness of the SFCB, the SFCB-reinforced concrete columns exhibited less column-base curvature demand than ordinary RC columns for a given column cap lateral deformation. Thus, reduced unloading residual deformation (i.e., higher postearthquake reparability) of SFCB columns could be achieved; (3)the outer FRP type of SFCB had a direct influence on the performance of SFCB-reinforced concrete columns, and concrete columns reinforced with steel-basalt FRP (BFRP) composite bars exhibited better ductility (i.e., a longer effective length of postyield stiffness) and a smaller unloading residual deformation under the same unloading displacement when compared with steel-carbon FRP (CFRP) composite bar columns; (4)the degradation of the unloading stiffness by an ordinary RC column based on the Takeda (TK) model was only suitable at a certain lateral displacement. In evaluating the reparability of important structures at the small plastic deformation stage, the TK model estimated a much smaller residual displacement, which is unsafe for important structures. © 2011 American Society of Civil Engineers.

Loading Beijing Texida Technology Research and Development Co. collaborators
Loading Beijing Texida Technology Research and Development Co. collaborators