Papers by Keyword: Reinforcement

Abstract: In recent years, using the hydraulic mud fill to carry out the reclamation construction actions has been an acceptable way to settle the contradiction between the scanty lands with the rapid industrial development in coastal regions. How to improve the ultra-soft foundation made of fresh hydraulic mud fill efficiently has been the crucial issue. This paper presents three reinforcement techniques in reclamation projects, and the applications are briefly introduced.

Abstract: In this paper, the effect of different enwrapping methods on the mechanical behaviour of short timber columns were presented and analysed.Five timber columns reinforced by CFRP and AFRP with two enwrapping forms (hoop and spiral) were tested under the axial compressive.The failure mechanism of specimens, the load-displacement relationship and the load-strain relationship were analyzed. Test results showed that the reinforcement with FRP can obviously improve the compressive bearing capacity of the columns and the highest improve ratio is 57.5%. The compressive stress of specimens reinfoced with hooped FRP sheets is much higher than the ones with spiral method. And the lateral deformations of reinforced specimen is greatly constrained by FRP. In addition, the knags of the wood will affect the mechanical behavior of columns on a large extent.

Abstract: Basing on the reinforcement of a practical project, which is a reinforced concrete multi-span cantilever girder bridge, by changing section properties to improve the bearing capacity and seismic performance of the bridge. Then, a finite element model is established and solved by using the subspace iteration method, the frequency and vibration type is compared that of the bridge before and after reinforcement, the effectiveness of the new method on the structural dynamic characteristic is verified at the same time. Then, the seismic response of the bridge is calculated and analyzed by using the response spectrum method, which can provide method for reinforcement of similar bridge.

Abstract: Combined with the actual project that Rehabilitation and Strengthening of cleaning workshop at Longfeng refinery, three structural schemes of platforms are provided in this paper, and finally steel girder-diagonal brace scheme is selected through comparative analysis. Load, material and selection of section size for platform structural members are given. Deformation and internal force of structure are obtained by theory and PKPM analysis, the reasonableness that the member section is selected is verified. Connection design and specific structural measures are given, and finally the reinforcement design and checking for the carbon fiber of the original frame column is carried out, and these can provide reference for similar Retrofitting Project.

Abstract: The present work focuses mainly on the uses of silane coupling agents in chloroprene rubber (CR) reinforced with precipitated silica (PSi). Grafting of organoalkoxysilane onto surfaces of PSi was conducted, and the characteristics of surface-modified PSi were determined by BET technique, light-scattering particle size analysis, DRIFT and ²⁹Si NMR spectroscopy. The 3 types of silane coupling agents used in this work were as follows: 3-aminopropyl triethoxysilane (APTES), 3-chloropropyl triethoxysilane (CPTES) and bis (3-triethoxysilylpropyl) tetrasulfide (TESPT). Processability of compounds and mechanical properties of vulcanizates were then investigated, and compared for the effectiveness of silane coupling agents used in property enhancement. The results reveal that the silane type affects not only the compound processability, but also the vulcanizate mechanical properties. Among 3 silanes, the CPTES and TESPT are capable of reducing the filler-filler interaction to greater extent than the APTES, leading to superior compound processability. Moreover, the amino and mercapto groups of APTES and TESPT, respectively, significantly enhance the mechanical properties of CR vulcanizate more effectively than the chloro groups of CPTES. This might be ascribed to the combined effects of enhanced rubber-filler interaction and improved filler dispersion.

Abstract: This work studied the antibacterial performance and mechanical properties of natural rubber (NR) compound reinforced with commercial silica at various silica loadings form 0, 20, 40 and 60 parts per hundred rubber (phr). 2-Hydroxypropyl-3-Piperazinyl-Quinoline carboxylic acid Methacrylate (HPQM) based Neusilin at loadings of 0, 3 and 5 phr were used as anti-bacterial agent against Escherichaia coli (E.coli) ATCC 25923 and Staphylococcus aureus (S.aureus) ATCC 25922. The antibacterial performance was reported as a clear zone radius by diffusion test and a percentage reduction of bacteria by Plate-Count-Agar (PCA) method. The results suggested that the increasing silica loading in the NR vulcanizates improved the tensile modulus and hardness, but decreased elongation which had optimal tensile strength at 20 phr of silica. Additionally, the HPQM based Neusilin did not affect the mechanical properties of the rubber vulcanizates. The antibacterial results showed that the inhibition zone radius and the percentage reduction increased with increasing HPQM based Neusilin, but decreased with silica filler content. The antibacterial efficacy was inversely related to the reinforcement level of the NR vulcanizates by the silica. The percentage reduction of bacteria of NR compound filled with 5 phr of HPQM based Neusilin achieved 99.9%.

Abstract: The flexural properties in terms of ductility of laminated brittle composites have been studied experimentally in the laboratory. Test specimens consisting of variable layers of mesh were prepared and tested under third point loadings. It was observed that the brittle matrix altered it properties and behaved as the ductile matrix even with small amount of ductile materials. The causes of the change in the properties have been clarified by analyzing the experiment data. The experimental results were verified by the theoretical formulation. The formulation showed that the flexural modulus of the entire section of brittle composites obtained by section analysis is equal to the modulus of ductile layers plus a factor of the difference of modulus of ductile and brittle layers. This factor is third order of ductile layer causing flexural properties in brittle composite even with 10% of ductile materials.

Abstract: Taking a flyover as the background, this paper compares two reinforcement scheme, and ultimately chooses the paste carbon fiber polymer method to reinforce the bridge. It calculates and analyzes the structure before and after the reinforcement, then compares the stress state , shear load-carrying capacity and flexural capacity. At last ,it evaluates the effect of the paste carbon fiber polymer method and puts forward some suggestions.

Abstract: In this study, an attempt has been made to develop electroless Ni-P-ZrO₂ nanocomposite coatings on mild steel substrate where the reinforced nanosized ZrO₂ particles were prepared by mechanical milling using high energy planetary ball mill. An alkaline bath was used with a suspension of ZrO₂ particles (4 g/L) for the synthesis of Ni-P-ZrO₂ composite coating. The surface morphology, size range and phase analysis of as-prepared ZrO₂ particles were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and the properties of the coatings such as hardness and wear (ball-on-disc) were investigated and compared with Ni-P deposits. The results showed that as-prepared ZrO₂ particles exhibit irregular shaped and size ranges from 14 to 17nm. After heat treatment (400°C,1h), the microhardness and wear resistance of the coatings are significantly improved. The Ni-P-ZrO₂ nanocomposite coatings exhibit enhanced wear resistance over NiP coating.

Abstract: The influence of excavation on surrounding buildings has been studied widely,but there was little attention to its reliability of reinforcement. In this paper, which was based on an excavation project of a security housing in Tianjin, about fourty thousand square meters, numerical analysis on wire poles were carried out by using finite element software Plaxis2D,and the comparative analysis is made with monitoring results.The results show that,when there is no reinforcement, foundation pit excavation will cause the displacement of wire poles more than allowed; after reinforcement, the numerical results of wire poles displacement conform to the requirements,monitoring data also shows that the wire poles displacement is in the allowable range. Results indicate that the reinforcement can improve the soil deformation effectively, and the design method is reliable.