二次受力CFRP布加固混凝土矩形柱抗压强度计算方法研究

在一次受力下CFRP布加固混凝土矩形柱抗压强度理论公式的基础上,按照叠加原理和强度代换原理推导了二次受力下CFRP布加固混凝土矩形柱抗压强度理论公式,并采用ANSYS软件对CFRP布加固混凝土柱的二次受力性能进行了数值模拟,将试验值与理论值及ANSYS值进行对比,结果基本吻合,证明了理论推导的科学性,为加固工程提供了一定的理论参考．     

基于单调初等函数的缓冲算子构造

在灰色系统缓冲算子公理体系下,将缓冲算子的构建和函数联系起来,利用基本初等函数(指数函数和余切函数)构造了2大类新的缓冲算子,并研究了其特性,最后通过实例验证了所构造的缓冲算子的实用性.解决了冲击扰动系统数据序列建模预测过程中常常出现的定量预测结果与定性分析结论不符的问题.     

丹江口大坝高水头帷幕补强灌浆技术研究

丹江口大坝加高工程帷幕补强灌浆,是在细微裂隙发育且多次复灌并在水库蓄水的高水头条件下进行的,技术环节十分复杂。系统介绍了丹江口大坝在高水头条件下帷幕补强灌浆的难点与特点。为了探求经济有效的灌浆形式和灌浆方式,设计了试验方案,分析了帷幕补强灌浆中不同灌浆形式、不同待凝时间和不同段长的灌浆效果,并进行了水泥浆液扩散试验,研究了丙烯酸盐灌浆工艺的若干关键技术问题。确定了适用于丹江口大坝高水头帷幕补强灌浆特点且经济有效的灌浆形式、灌浆方法和快速施工工艺。     

超长混凝土结构无缝设计研究

结合工程实践,通过合理使用膨胀混凝土和膨胀加强带实现超长钢筋混凝土结构无缝设计,对其进行了初步理论分析和计算,推导出膨胀加强带的计算公式,并以北京地区某幢六层办公用房为例,验证超长混凝土结构膨胀加强带计算的可靠性,为超长混凝土结构设计提供参考。     

浅谈体外预应力在连续刚构桥加固中的应用

以某连续刚构桥为例,从加固效果评价和施工工艺两个方面叙述体外预应力在桥梁加固中的应用。计算表明,桥梁加固前后承载力、应力和挠度都有明显的提升。     

重力式桥台开裂原因的有限元分析与加固措施

本文针对公路上中、小桥台普遍存在的开裂问题,结合实际工程,借助大型通用有限元软件ANSYS对某公铁立交桥斜交U型重力式桥台在侧墙与前墙接缝处开裂的原因进行了分析,且提出了开裂成因和防治办法,供设计、施工参考．     

Numerical analysis of multilayered CFRP retrofitted RC beams with partial interaction

This paper presents a theoretical model to simulate the behaviour of RC beams strengthened with multilayered CFRP matrix allowing for inter-layer slip. An element of the composite beam is assumed to be subjected to a system of forces that satisfy equilibrium and compatibility of deformations. The inter-layer slip is allowed for by relating the differential strain at the interfaces between the CFRP layers and the concrete to the longitudinal shear flow at the corresponding interface through the shear stiffness of the adhesive layer. The basic differential equations are derived in terms of displacement variables and solved numerically using finite differences. The results of the numerical simulation included slip values along the interfaces, maximum slip values, stresses and strains and deflections. The results compare reasonably well with experimental findings.     

Numerical simulation of hypervelocity impact on CFRP/Al HC SP spacecraft structures causing penetration and fragment ejection

A representative carbon fiber reinforced plastic/aluminum honeycomb sandwich panel (CFRP/Al HC SP) spacecraft structure has been modeled in the hydrocode AUTODYN using the state-of-the-art ADAMMO material model [Riedel W, Harwick W, White D, Clegg R. Advanced material damage models for numerical simulation codes. ESA CR(P) 4397, 2003] to study the performance of the structure during impact events that cause perforation and fragment ejection. A new procedure combining a series of existing theoretical methods has been developed and applied to derive a full set of coarse material data. The data set has been implemented in AUTODYN, and the results of the numerical simulation have been compared to experimental impact test data. For impact tests performed near the structural ballistic limit, quantitatively accurate results were obtained over a range of impact velocities and angles. A further increase in the projectile size resulted in significant destruction of the sandwich panel front face-sheet and diversion from the experimental damage measurements. Inspection of the numerical model has shown non-localized propagation of inter-laminar delaminations, possibly caused by an under-prediction of the laminate dynamic inter-laminar tensile strength. The effects of the delamination propagation occur over an extended time scale and were not found to affect the state and trends of the fragment cloud ejected into the satellite interior. Accordingly, experimental trends of fragment cloud dispersion have been qualitatively reproduced.     

碳纤维布与钢板复合加固钢筋混凝土梁抗弯承载力的计算分析

碳纤维布与钢板复合加固钢筋混凝土梁是一种新型的加固方法,作者通过12根试件的试验研究碳纤维布和钢板以及两者复合加固钢筋混凝土梁的破坏特征、受力性能和破坏机理。在试验的基础上,本文分析了混凝土强度、纵筋率、CFRP与钢板的加固量等因素对复合加固梁正截面极限承载力的影响,提出了与现行规范相符合的实用承载力计算公式,并与试验结果进行对比。对比结果表明,计算值与试验值吻合较好,本文建议的实用计算公式对实际工程有一定的参考价值。     

CFRP加固钢结构的现状与展望

碳纤维增强复合材料(CFRP)目前在国内外已广泛用于土木工程领域,特别是在加固混凝土结构中已取得良好效果,但在钢结构加固中尚处于起步阶段.近年来的研究表明,CFRP加固钢结构也显出一定的效果.本文对国内外CFRP加固钢结构的研究现状与进展进行了全面的回顾与展望.