The present study investigates the force transfer mechanisms for open hoop fiber reinforced plastic (FRP) strips attached at reinforced concrete (R/C) beams with or without anchorage. These open hoop FRP strips are ut...The present study investigates the force transfer mechanisms for open hoop fiber reinforced plastic (FRP) strips attached at reinforced concrete (R/C) beams with or without anchorage. These open hoop FRP strips are utilized in R/C beams that are in need of shear capacity upgrade. This type of retrofitting is necessary for R/C structures designed with less stringent seismic loading conditions than those currently required. For this purpose special unit beam concrete specimens were fabricated and were used to attach open hoop carbon (CFRP) or steel (SFRP) FRP strips with or without anchoring. A novel loading arrangement was utilized to apply the necessary forces to these unit beam specimens together with instrumentation capable of capturing the behaviour of these specimens up to failure. Studying in this way the transfer of forces from the open hoop FRP strips, it could be demonstrated that when this type of retrofitting was accompanied with a properly designed anchoring device, a significant increase in the bearing capacity of the tested specimens was observed. Moreover, the observed failure was that of the fracture of the FRP strips for all such specimens. The highest degree of FRP material exploitation was achieved in the specimen that utilizes a patented anchoring device together with two layers of SFRP strips. Debonding of the FRP strips or failure of the anchoring device results, as was to be expected, in relatively unsatisfactory FRP material exploitation.展开更多
为研究纤维增强复合塑料锚杆锚固料的性质及其工程应用的可行性，对不同配合比的纤维增强复合塑料锚杆锚固料的抗压强度、抗冻、抗渗等参数进行了测试，优选5组配合比，对不同直径的玻璃纤维锚杆和玄武岩纤维锚杆进行了30 cm 深度的锚...为研究纤维增强复合塑料锚杆锚固料的性质及其工程应用的可行性，对不同配合比的纤维增强复合塑料锚杆锚固料的抗压强度、抗冻、抗渗等参数进行了测试，优选5组配合比，对不同直径的玻璃纤维锚杆和玄武岩纤维锚杆进行了30 cm 深度的锚固拉拔试验。试验结果表明：优选的配合比具有较好的施工性，能自密实，达到 C35～C45，F150，P6级别；适量掺加钢纤维或玻璃纤维有利于提高锚固料的抗压强度和锚固性能；试验的纤维增强复合塑料锚杆破坏模式均为拉拔仪与纤维增强复合塑料锚杆接触部位的挤压破坏，表面形状对纤维增强复合塑料锚杆的极限抗拉强度有一定影响，纤维增强复合塑料锚杆单位表面积的极限抗拉强度为4．0～6．5 MPa，可达到工程应用的相关要求。展开更多
Uplift response of symmetrical anchor plates with and without grid fixed reinforced （GFR） reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were ...Uplift response of symmetrical anchor plates with and without grid fixed reinforced （GFR） reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer （FRP） strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.展开更多
文摘The present study investigates the force transfer mechanisms for open hoop fiber reinforced plastic (FRP) strips attached at reinforced concrete (R/C) beams with or without anchorage. These open hoop FRP strips are utilized in R/C beams that are in need of shear capacity upgrade. This type of retrofitting is necessary for R/C structures designed with less stringent seismic loading conditions than those currently required. For this purpose special unit beam concrete specimens were fabricated and were used to attach open hoop carbon (CFRP) or steel (SFRP) FRP strips with or without anchoring. A novel loading arrangement was utilized to apply the necessary forces to these unit beam specimens together with instrumentation capable of capturing the behaviour of these specimens up to failure. Studying in this way the transfer of forces from the open hoop FRP strips, it could be demonstrated that when this type of retrofitting was accompanied with a properly designed anchoring device, a significant increase in the bearing capacity of the tested specimens was observed. Moreover, the observed failure was that of the fracture of the FRP strips for all such specimens. The highest degree of FRP material exploitation was achieved in the specimen that utilizes a patented anchoring device together with two layers of SFRP strips. Debonding of the FRP strips or failure of the anchoring device results, as was to be expected, in relatively unsatisfactory FRP material exploitation.
文摘为研究纤维增强复合塑料锚杆锚固料的性质及其工程应用的可行性，对不同配合比的纤维增强复合塑料锚杆锚固料的抗压强度、抗冻、抗渗等参数进行了测试，优选5组配合比，对不同直径的玻璃纤维锚杆和玄武岩纤维锚杆进行了30 cm 深度的锚固拉拔试验。试验结果表明：优选的配合比具有较好的施工性，能自密实，达到 C35～C45，F150，P6级别；适量掺加钢纤维或玻璃纤维有利于提高锚固料的抗压强度和锚固性能；试验的纤维增强复合塑料锚杆破坏模式均为拉拔仪与纤维增强复合塑料锚杆接触部位的挤压破坏，表面形状对纤维增强复合塑料锚杆的极限抗拉强度有一定影响，纤维增强复合塑料锚杆单位表面积的极限抗拉强度为4．0～6．5 MPa，可达到工程应用的相关要求。
基金supported by the research Grant at UTM,Malaysia(GUP Grant)the project name is"uplift response of symmetrical anchor plates in grid fixed reinforced in cohesionless soil"
文摘Uplift response of symmetrical anchor plates with and without grid fixed reinforced （GFR） reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer （FRP） strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.
