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1.
The Externally Bonded Reinforcement (EBR) technique using Carbon Fiber-Reinforced Polymers (CFRP) has been commonly used to strengthen concrete structures in flexure. The use of prestressed CFRP material offers several advantages well-reported in the literature. Regardless of such as benefits, several studies on different topics are missing. The present work intends to contribute to the knowledge of two commercially available systems that differ on the type of anchorage: (i) the Mechanical Anchorage (MA), and (ii) the Gradient Anchorage (GA). For that purpose, an experimental program was carried out with twelve slabs monotonically tested under displacement control up to failure by using a four-point bending test configuration. The effect of type of anchorage system (MA and GA), prestrain level (0 and 0.4%), width (50 mm and 80 mm) and thickness (1.2 mm and 1.4 mm) of the CFRP laminate, and the surface preparation (grinded and sandblasted) on the flexural response were the main studied parameters. Better performance was observed for the slabs: (i) with prestressed laminates, (ii) for the MA system, and (iii) with sandblasted surface preparation. 相似文献
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无粘结预应力楼板新规范设计方法 总被引:2,自引:0,他引:2
赵夕来 《安徽建筑工业学院学报》2005,13(5):12-15,19
目前国内现浇预应力楼板几乎均采用无粘结预应力方案,因而掌握其设计方法无疑具有现实意义。本文根据新规范,系统地介绍了高层建筑无粘结预应力楼板的设计方法,内容包括:设计原理、基本步骤及设计中需要注意的一些问题。 相似文献
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通过对先张法预应力空心梁板施工时容易忽视和发生的几个质量通病产生原因的分析,并结合工程实际和工作体会,粗略探讨了防治这些质量通病的一些措施和方法。 相似文献
5.
On the mechanical behavior of aluminum alloys reinforced by long or short alumina fibers or SiC whiskers 总被引:2,自引:0,他引:2
This study was initiated to examine the dispersion of longitudinal and transverse waves in metal matrix composites in order to obtain the dynamic elastic modulus and to evaluate various models for predicting the composite's macroscopic elastic constants from the properties of its constituents. The materials chosen for this investigation were alumina continuous fibers on the one hand and alumina and SiC short fibers on the other hand, all embedded in an aluminum alloy matrix. In addition, some indications have been obtained experimentally for the acoustoelastic effect in the composite. 相似文献
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为满足装配式建筑节点接缝混凝土抗震性能的需要,以一种自平衡预应力中空棒为研究对象,研究接缝位置短杆件施加预应力的效果。根据力的平衡机理,对结构内部钢棒施加压力使结构外部钢管协调受力拉伸,达到设计预应力后由螺母锁定,将杆件埋入到装配式节点接缝混凝土,浇筑早强灌浆料,待固结达到预定强度释放反力棒,依靠外螺纹结构与混凝土的粘结力自锚实现接缝混凝土施加预应力。力学性能分析方面,研究杆件张拉阶段、静置松弛阶段应力变化及损失情况,验证了杆件张拉完成至放张前应力存储的有效性,通过分析杆件放张后应力分布、预应力损失等参数,验证了杆件应用到节点混凝土后传递应力的机理及有效性,并采用有限元方法分析预应力混凝土构件应力分布规律。研究结果表明预应力中空棒技术作用于装配式节点接缝混凝土具有较高的抗震和耗能能力,对装配式建筑节点混凝土高抗震性能的实现提供了一种新的技术手段。 相似文献
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介绍采用150 mm×150 mm连铸坯、高速线材轧机生产Φ12.5 mm规格预应力82B盘条的试生产情况,对试生产中出现的问题进行分析,并提出了改进意见. 相似文献
9.
The full-range behavior of partially bonded, together with partially prestressed concrete beams containing fiber reinforced
polymer (FRP) tendons and stainless steel reinforcing bars was simulated using a simplified theoretical model. The model assumes
that a section in the beam has a trilinear moment—curvature relationship characterized by three particular points, initial
cracking of concrete, yielding of non-prestressed steel, and crushing of concrete or rupturing of prestressing tendons. Predictions
from the model were compared with the limited available test data, and a reasonable agreement was obtained. A detailed parametric
study of the behavior of the prestressed concrete beams with hybrid FRP and stainless steel reinforcements was conducted.
It can be concluded that the deformability of the beam can be enhanced by increasing the ultimate compressive strain of concrete,
unbonded length of tendon, percentage of compressive reinforcement and partial prestress ratio, and decreasing the effective
prestress in tendons, and increasing in ultimate compressive strain of concrete is the most efficient one. The deformability
of the beam is almost directly proportional to the concrete ultimate strain provided the failure mode is concrete crushing,
even though the concrete ultimate strain has less influence on the load-carrying capacity.
Foundation item: Project (50478502) supported by the National Natural Science Foundation of China 相似文献
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