Fibre phantom generation using FibreSimulator: an open-source Python tool.

This study focuses on the tensile behavior of fiber-reinforced polymer (FRP) composites in a concrete-based alkaline environment. Because basalt/glass FRP (BFRP/GFRP) composites exhibit relatively poor alkaline resistance compared with carbon FRP (CFRP) composites, a rubber toughening modification method has been proposed to mitigate microcracking and decrease the diffusion of the alkaline solution in the resin matrix. Different proportions of liquid rubber toughening agents were added into the epoxy resin, on the basis of which different FRP composites were made and then subjected to tensile tests after alkaline exposure. Test results indicated that the rubber toughening modification approach can significantly reduce the tensile strength degradation of the BFRP and GFRP composites in the alkaline solution. Moreover, no degradation of the elastic modulus for the FRP composites was observed. The weight gain and microstructure of the FRP composites were also investigated before and after the alkaline exposure to determine the corrosion mechanisms of the FRP composites in the alkaline environment and interpret the mechanical test results.

23 - Non-destructive evaluation (NDE) of composites: using fiber optic sensors

Fiber-reinforced polymer (FRP) composites have gained increasing recognition and application in the field of civil engineering in recent decades due to their notable mechanical properties and chemical resistance. However, FRP composites may also be affected by harsh environmental conditions (e.g., water, alkaline solutions, saline solutions, elevated temperature) and exhibit mechanical phenomena (e.g., creep rupture, fatigue, shrinkage) that could affect the performance of the FRP reinforced/strengthened concrete (FRP-RSC) elements. This paper presents the current state-of-the-art on the key environmental and mechanical conditions affecting the durability and mechanical properties of the main FRP composites used in reinforced concrete (RC) structures (i.e., Glass/vinyl-ester FRP bars and Carbon/epoxy FRP fabrics for internal and external application, respectively). The most likely sources and their effects on the physical/mechanical properties of FRP composites are highlighted herein. In general, no more than 20% tensile strength was reported in the literature for the different exposures without combined effects. Additionally, some provisions for the serviceability design of FRP-RSC elements (e.g., environmental factors, creep reduction factor) are examined and commented upon to understand the implications of the durability and mechanical properties. Furthermore, the differences in serviceability criteria for FRP and steel RC elements are highlighted. Through familiarity with their behavior and effects on enhancing the long-term performance of RSC elements, it is expected that the results of this study will help in the proper use of FRP materials for concrete structures.

Strengthening concrete using phosphate cement-based fiber-reinforced inorganic composites for improved fire resistance

Long-term performance of 15-year-old full-scale RC beams strengthened with EB FRP composites

FRP-strengthened RC slabs anchored with FRP anchors

This paper provides a review of research being conducted at The University of Hong Kong (HKU) on the strengthening of concrete, metallic and timber construction materials with externally bonded fibre-reinforced polymer (FRP) composites. The motivation of such research is to enhance our understanding of the interfacial behaviour between the FRP and the three different substrate materials via FRP-to-concrete, -metal, and-timber joint tests. Of the three substrate materials, concrete has clearly experienced the most research activity to date by the wider research community, followed by that of metal and then that of timber. In order to progress the extensive knowledge base of FRP-to- concrete behaviour, research at HKU is aimed at enhancing the bond strength of the FRP via the addition of anchorage. The anchor of choice is the so called FRP anchor and its effectiveness in anchoring FRP flexural strengthening applied to reinforced concrete (RC) slabs is also presented. For the metal and timber substrate materials, HKU research is more focused at this stage on understanding the influence of key fundamental variables affecting interfacial behaviour such as FRP geometry, surface preparation and substrate material characteristics.

This paper presents an experimental study on the shear behavior of RC members fully wrapped with polyethylene terephthalate (PET) fiber-reinforced polymer (FRP) composites, which are a new type of FRP material characterized by a much larger rupture strain (LRS) compared with conventional FRPs (i.e., made of carbon, glass, and aramid fibers). A total of 10 PET fully-wrapped RC beams, which were designed to fail in shear and with different shear-span to effective-depth ratios, transverse reinforcement ratios and shear strengthening ratios, were tested under 4-point bending loads. The overall load-deflection responses and the shear deformation of the beams as well as the strain development of the transverse steel reinforcement and the FRP jackets were carefully observed. Based upon the extensive strain measurements, the shear contributions by concrete, FRPs, and transverse reinforcement are differentiated. It was found that the use of PET FRP composites as the jacket material of RC members could shif...

The present study intends to investigate the effect of temperature on cumulative fatigue damage of laminated fibre-reinforced polymer (FRP) composites. The effect of temperature on fatigue damage is formulated based on a previously proposed residual stiffness fatigue damage model. The fatigue strength of FRP composite laminates is also formulated to have temperature dependent parameters. The research work is divided into three main parts; the first part reviews the fatigue damage mechanism is fibre-reinforced composites based on stiffness degradation. The recent residual stiffness of Varvani-Shirazi was used as the backbone structure of damage analysis in this thesis. This model is capable of damage assessment while the effects of maximum stress, stress ratio and fibre orientation of FRP composites were recognized. The Varvani-Shirazi damage model was further developed to assess fatigue damage of FRP composites at various temperatures (T). Inputs of the damage model are temperature dependent parameters including Young's modulus (E), ultimate tensile strength(ðult) and fatigue life (Nf). As the next part of the proposed analysis, the temperature dependency of each parameter is formulated, and the relations of E-T and ðult-T are substituted in the Varvani-Shirazi fatigue model. Finally, all terms and equations are evaluated with the experimental data available in the literature. Six sets fatigue data were used in this thesis to evaluate fatigue of FRP specimens. The predicted results were found to be in good agreement with the experimentally obtained data. The proposed fatigue damage model was found promising to predict the fatigue damage of unidirectional (UD) and women FRP composites at different temperatures. Temperature dependant parameters of Young's modulus, ultimate tensile strength, and S-N diagram were also found to be responsive when used of UD, cross-ply, and quasi-isotropic FRP laminates.

Geometric calibration of all-sky cameras using sun and moon positions: A comprehensive analysis

Experimental study of seismic behavior of partially corrosion-damaged reinforced concrete columns strengthened with FRP composites with large deformability

The International Institute for FRP in Construction (IIFC) was formed in 2003 with a mission to advance the understanding and application of fiber–reinforced polymer (FRP) composites in civil infrastructure. Since 2005, IIFC has enjoyed a fruitful association with ASCE via co-sponsorship of the Journal of Composites for Construction (JCC). Therefore, it is fitting that this present JCC issue commemorates the 10th anniversary of IIFC. This is the third special IIFC issue published by JCC; the first two issues were in April 2007 (“Recent International Advancements in FRP Research and Application in Construction”) and April 2011 (“In Honor of Professor Urs Meier”). The flagship events of IIFC are undoubtedly its biannual worldwide and Asia-Pacific regional conference series, which are known as FRP Composites in Civil Engineering (CICE) and Asia-Pacific Conference on FRP in Structures (APFIS), respectively. These conferences are held in alternating years at differing locations around the world: CICE in 2001 (Hong Kong), 2004 (Adelaide), 2006 (Miami), 2008 (Zurich), 2010 (Beijing), and 2012 (Rome); and APFIS in 2007 (Hong Kong), 2009 (Seoul), 2012 (Sapporo), and 2013 (Melbourne). CICE 2014 will be held in Vancouver and CICE 2016 in Hong Kong.This special issue of JCC has been timed for release prior to CICE 2014. IIFC also co-sponsors other international conference series and workshops. To better disseminate knowledge to the wider community, IIFC makes the proceedings of most IIFC official and supported events available on its website (http://www.iifc-hq.org) for free download. IIFC publishes a newsletter and all copies are also held on the IIFC website. The newsletter commenced in 1993, and for its first 10 years, was known as FRP International. IIFC also runs several working groups that offer tangible benefits such as educational resources, state-of-the-art reports, conference special sessions, and journal special issues. IIFC recognizes excellence in the form of several awards, namely, IIFC Medal, Distinguished Young Researcher Award, President’s Award, Lifetime Achievement Award, conference best paper awards, and IIFC fellowships. The IIFC website contains lists of all award recipients over the years, in addition to far more information than can be contained in this editorial. IIFC is a dynamic organization that has been positively influenced by numerous individuals over the years. It is governed by an Executive Committee, which is overseen by an Advisory Committee. The Council is populated by up to 40 elected leading figures in the field from around the world, plus members of the Advisory Committee. At present, 21 countries are represented on these three committees and several of these leading figures also serve on the Editorial Board of JCC. This special issue contains 18 invited papers contributed by members of these committees and their collaborators, addressing a diverse range of topics that are representative of the breadth of activity in the field. More specifically, the papers are of an experimental, analytical, and numerical nature and address: • FRP for strengthening concrete; namely, prestressed FRP plates, strips, and rods (two papers), confinement (one paper), FRP patch anchors (one paper), limits to the application of FRP for repair (one paper), near-surface mounted FRP (one paper), cementitious bonding agents (three papers), and large strain capacity FRP (one paper); • FRP for strengthening timber (one paper), steel (one paper), and masonry (one paper) construction materials; and • FRP for new construction; namely, hybrid FRP tendons (one paper), FRP bars (two papers), FRP beams (one paper), and stay-in-place structural forms (one paper). There is plenty of work still to be done in the field. In particular, more systematic and in-depth research is required on the long-term behavior of both FRP structures and FRP strengthened structures to substantiate the common claim that such structures have superior durability over other structures. Innovative combinations of FRP with either traditional construction materials or new materials to produce new structural members and forms will have an important role in designing the next generation of high-performance and sustainable structures. There is no doubt that the conversion of research findings into workable design guidelines and standards for use by design engineers is critical in widening the applications of FRP in civil construction. The contributions of numerous individuals are acknowledged in the preparation of this special issue. The authors of the papers in this issue are thanked for preparing high-quality manuscripts. Professor Charles E. Bakis, Editor-in-Chief of JCC, is thanked for handling the paper review process and ensuring maintenance of the high JCC standard. Professor Bakis is also supported by Ms. Renee Lindenberg and a large team of reviewers; their contributions are all acknowledged. The idea of an IIFC 10th anniversary special issue was positively received by Professor Lawrence C. Bank, IIFC President, and by the members of the Executive Committee following discussions after CICE 2012. For that, they are all thanked for their support. Finally, all members of IIFC, past and present, are thanked for their various contributions over the years, which have enabled IIFC to move into its second decade on a sound and positive footing.

Fiber-reinforced polymer (FRP) composites have emerged as promising next-generation materials for advanced structures in civil engineering. Notwithstanding the recent progress, the unsatisfactory mechanical properties and problematic long-term stability in the alkali environment remain daunting challenges toward their large-scale practicability. In this study, we address such limitations by a dual modification method, in which first ethyl cellulose (EC) is incorporated into the matrix and then the FRP composite is dipped in a dilute poly(dimethylsiloxane) (PDMS) solution. The FRP composite exhibited enhanced flexural strength by 23.4% and increased flexural modulus by 23.5% compared to those of the pristine basalt fiber-reinforced polymer (BFRP). Such an eminent performance is mainly attributed to the bridging effect of EC. As confirmed by the DMA characterization, the incorporation of EC greatly increased the cross-linking density and improved the thermal stability. Additionally, the FRP composite had a stable performance in the alkali environment tests. Tuning the amount of ethyl cellulose was found to have a profound effect on the mechanical performance and aging behavior in the alkali solution. This study establishes a practical approach to fabricating FRP composites with long-term stability in alkali environments.

This research explores the development of curved archi¬tectural components from a specific type of sheet material: thermoformable PET foam manufactured from recycled plas¬tic bottles. The principal goal is to develop structural sandwich panels—made by stiffening foam with fiber-reinforced poly-mer (FRP) composites—that are both three-dimensional and materially efficient. Our research examines how waste can be reduced by molding 3D components from flat sheets of recycled material rather than carving them from new blocks of foam. After an overview of historical and contemporary uses of FRP construction by architects, this paper examines the benefits of thermoforming and explores techniques for creating curvilinear structural elements from PET foam that can be heated and formed in wood molds. The initial prototypes discussed are small in scale and limited to components heated in a conventional oven. To overcome size limitations, a custom oven is built to heat standard, 4 ft. x 8 ft. rectangular sheets. The research next illustrates the architectural potential of larger curved FRP sandwich panels; a full-scale prototype is built to test the process from start to finish. Taking the form of a pavilion called Hot.PET, this self-supporting, lightweight structure is made from three large, multi-layered sandwich panel elements. Installed on a college campus, the prototype serves as the focal point and info station for an agricultural demonstration garden fertilized with biosolids—a type of recycled compost. The thermoformed panels used to construct the pavilion incorporate the equivalent of 38,000 .5-liter recycled PET bottles.

When exposed to environmental conditions, fibre-reinforced polymer (FRP) composites are prone to material degradation. The environmental reduction factor in different structural codes reflects the significant effect of the long-term durability of FRPs in aggressive environments. Traditional prediction methods rely on oversimplified premises, which may result in erroneous errors. Due to its proficiency in dealing with complex non-linear structural problems, machine learning (ML) offers a unique potential to increase the predictability of structural engineering factors. This can be attributed to the recent advancements in ML techniques, which leverage their robustness when handling large datasets, as well as the increased processing power that facilitates more efficient data analysis. This article reviews the current implementation cases and capabilities of ML algorithms in overcoming the shortcomings of conventional models for predicting the durability performance of FRP systems. According to the literature, it was found that the efficiency of ML approach varies significantly depending on the quality and comprehensiveness of the database. While various researcher-employed algorithms generally yield accurate predictions for retaining mechanical properties in FRP composites with minor errors, sensitivity analysis highlights varied impacts of variables when using different datasets or machine learning algorithms. This variance may arise from factors like inadequate or low-quality datasets, insufficient training, overfitting, and other influences. More experimental data are needed to enhance the current database to effectively apply ML in more applications for FRPs under different loading and environmental conditions. The paper ends by suggesting future research directions in this field.