Publications

Fibre-reinforced polymer strengthening and fibre Bragg grating–based monitoring of reinforced concrete cantilever slabs with insufficient anchorage length of steel bars

Reinforced concrete cantilever slabs are among structures that are most likely to develop structural integrity problems, as they are statically determinate and often exposed to the outdoor environment. This article presents an experimental study on the strengthening of reinforced concrete cantilever slabs where the anchorage of the top steel reinforcing bars into the adjacent wall was insufficient. The experimental study involved the use of a fibre-reinforced polymer strengthening system and fibre Bragg grating sensors for strain monitoring. The fibre-reinforced polymer strengthening system consisted of glass fibre–reinforced polymer sheets and glass fibre–reinforced polymer spike anchors which connected the glass fibre–reinforced polymer sheets to the adjacent concrete wall. The test results showed that the fibre-reinforced polymer strengthening system was effective in improving the load-carrying capacity of reinforced concrete cantilever slabs and the fibre Bragg grating sensors worked efficiently and reliably for strain monitoring. The debonding in glass fibre–reinforced polymer sheet/glass fibre–reinforced polymer anchor-to-concrete bonded joints was found to be a progressive process associated with an increasing load. The fibre-reinforced polymer strengthening system examined in this study is thus a potential ductile solution for deficient cantilever slabs.

Improving efflorescence resistance of metakaolin-based geopolymer via magnesium incorporation

FRP-Confined concrete-encased cross-shaped steel columns: Effects of key parameters

Hybrid double-skin tubular columns with a large rupture strain FRP outer tube: Stub column tests

PREDICTION OF PEELING FAILURE OF REINFORCED CONCRETE BEAMS WITH EXTERNALLY BONDED STEEL PLATES.

Keywords SOUTH BANK UNIVERSITY, LOUGHBOROUGH TECHNOLOGY UNIVERSITY CONCRETE, REINFORCED, BEAMS, FAILURES, PEELING, PREDICTION, PLATES, STEEL, BONDED, EXTERNALLY, PREMATURE, GLUING, SOFFITS, MODELS, MECHANISMS, TESTS, CRITICAL, AXIAL, TENSILE, STRESS, LOADS, CRACKS, STRENGTHENING, ANISOTROPIC, REINFORCEMENT, UPPER BOUNDS, LOWER BOUNDS, ULTIMATE, CAPACITY, MODES, THEORY, STRESS, SHEAR, FLEXURAL, ONE WAY, BONDING, STRAIN, BENDING, SECTIONS, CROSS SECTIONS... Show All

The melting potential of various ash components generated from coal combustion: Indicated by the circularity of individual particles using CCSEM technology

Development and Verification of Severe Accident Simulation Capability for a NPP Simulator

It is reflected in the severe accident in Fukushima Daiichi that the emergency capacity of nuclear power plant needs to be enhanced. A nuclear plant simulator that can model the severe accident is the most effective means to promote this capacity. Until now, there is not a simulator which can model the severe accident in China. In order to enhance the emergency capacity in China, we focus on developing a full scope simulator that can model the severe accident and verify it in this study. The development of severe accident simulation system mainly includes three steps. Firstly, the integral severe accident code MELCOR is transplanted to the simulation platform. Secondly, the interface program must be developed to switch calculating code from RELAP5 code to MELCOR code automatically when meeting the severe accident conditions because the RELAP5 code can only simulate the nuclear power plant normal operation state and design basis accident but the severe accident. So RELAP5 code will be stopped when severe accident conditions happen and the current nuclear power plant state parameters of it should be transported to MELCOR code, and MELCOR code will run. Finally, the CPR1000 nuclear power plant MELCOR model is developed to analyze the nuclear power plant behavior in severe accident. After the three steps, the severe accident simulation system is tested by a scenario that is initiated by the station black out with reactor cooling pump seal leakage, HHSI, LHSI and auxiliary feed water system do not work. The simulation result is verified by qualitative analysis and comparison with the results in severe accident analysis report of the same NPP. More severe accident scenarios initiated by LBLOCA, MBLOCA, SBLOCA, SBO, ATWS, SGTR, MSLB will be tested in the future. The results show that the severe accident simulation system can model the severe accident correctly; it meets the demand of emergency capacity promotion.

Compressive behaviour of UHPC-filled square high-strength steel tube stub columns under eccentric loading

Design of a two-stage cryopump with hydrogen-helium separation capability for fusion reactor application

Iron Transformation and Ash Fusibility during Coal Combustion in Air and O₂/CO₂ Medium

Little work has been performed on the transformation of iron and ash fusibility during oxy-coal combustion, which is of great significance to assessing ash deposition propensity. A high-iron bituminous coal was burnt at 1300 °C in a laboratory drop-tube furnace under four conditions: (1) 21 vol % O2/79 vol % N2 (air-firing), (2) 21 vol % O2/79 vol % CO2 (oxy-firing), (3) 27 vol % O2/73 vol % CO2 (oxy-firing), and (4) 32 vol % O2/68 vol % CO2 (oxy-firing). The bulk ash samples were subjected to X-ray fluorescence and Mössbauer spectroscopic analyses. The effects of changing from air combustion to O2/CO2 combustion and the effects of varying the O2 level in O2/CO2 combustion on iron transformation and ash fusibility were investigated. The results show that varying the combustion condition has insignificant effects on the elemental composition of coal ashes but has appreciable effects on the relative proportions of iron combustion products that were identified as hematite, magnetite, and Fe–glass phases. This indicates that speciation analysis is as important as bulk analysis for thorough ash characterization. Replacing N2 in air with CO2 results in a higher content of hematite but a lower content of magnetite. Increasing the O2 level in O2/CO2 combustion increases the formation of hematite but decreases the formation of magnetite. In contrast, the amount of Fe–glass phases remains almost unchanged. An appreciable fraction (about 8% Fe) of hematite/magnetite seems to crystallize out of the molten glass phases during combustion, and it is not significantly affected by changing combustion conditions. The fusion temperatures of the oxy-fired ashes are higher than those of the air-fired ash and increase with the inlet O2 level. A positive correlation between the hematite content and the ash fusion temperatures is observed.

The Influence of Pore Distribution of Coal Char in the Char Fragmentation and Included Minerals Partitioning: A Percolation Modeling

The processes of char fragmentation, including mineral partitioning and particulate matter (PM) formation during dense and porous char combustion, were observed by a site percolation model. This model simulated the diffusion-controlled regime of char combustion, and the size distributions of included minerals in typical bituminous coal were determined by the computer-controlled scanning electron microscope (CCSEM), and the data were put into the char matrix randomly. The model presents the influence of initial pore distribution on char oxidation and fragmentation, the impact of the char conversion process on the extent of fragmentation, the change of ash distributions with the char conversion, and the particulate matters (PM) size distribution, which is derived from the consequence of the competition between char fragmentation and included minerals partitioning and coalescence. The results indicate that with increasing initial char porosity (φ), the number of large size pores increases but the number of pores decreases, which leads to open pores increasing, close pores decreasing, and the surface reaction area increasing. While φ ≥ 0.4, char fragmentation obviously occurs during the stage in which the rates of char conversion are 0.4–0.6, and it looks as though the maximum value of fragmentation will transfer to an earlier conversion stage if it has a larger φ. The enhanced φ shows a positive effect on the increase in the number and concentration of PM < 10 μm (nominally aerodynamic diameter), this is attributed to char fragments more drastically, and the probability of mineral coalescence reduces a lot.

Optimization studies of various coal-conversion systems: coal dissolution phenomena. Interim report, April-December 1978

An investigation of the bituminous coal dissolution phenomena has been undertaken in order to develop information which would be useful in the design and scale-up considerations for a commercial liquefaction plant. The experimental data of this study were derived from pilot plants using various coal liquefaction processes. The data were analyzed in order to better understand the phenomena which occur in the preheater and reactor sections during the liquefaction of coal. Two different stages were found to exist in the coal dissolution reactions. In the initial stage of coal dissolution, a first-order reaction scheme is proposed, whereby coal undergoes a fast thermal reaction producing preasphaltene as the predominant product. Conversion for this reaction is calculated based on the amount of pyridine solubles formed. The rate coefficient for this stage is found to follow an Arrhenius type temperature dependence with an activation energy of 48 approx. 55 Kcal/g-mole. In the second stage of coal dissolution, a slower first-order rate expression is proposed in which the preasphaltene is converted to benzene solubles with subsequent rehydrogenation of the coal-derived solvent. A semi-empirical correlation for the dissolution rate coefficient in the second stage reaction is presented, which reasonably accounts for the effects of temperature, hydrogen partial pressure and of particular importance - reactor hydrodynamics. However, the rate coefficient was found to be practically independent of coal particle size. Finally, the rate of hydrogen absorption during coal dissolution is modeled by assuming that the gas and liquid phases are in equilibrium at the interface. The overall gas absorption coefficient was found to be a function of superficial gas velocity.

Concrete-encased steel columns confined with large rupture strain FRP composites: Axial compression tests

Biochar as the effective adsorbent to combustion gaseous pollutants: Preparation, activation, functionalization and the adsorption mechanisms

Development of an in-situ SEOP 3He neutron spin filter for magnetic imaging techniques

The water splitting cycle for hydrogen production at photo-induced oxygen vacancies using solar energy: experiments and DFT calculation on pure and metal-doped CeO₂

Water splitting driven by photo-induced oxygen vacancies for H 2 production was proved to be facile on metal doped CeO 2 .

Seismic retrofit of RC frames through beam-end weakening in conjunction with FRP strengthening

The strong column/weak beam requirement is now widely accepted in the design of reinforced concrete (RC) frames to achieve good seismic performance. However, many existing RC frames violate this requirement as they were designed according to inadequate design codes (generally previous codes). In particular, RC frames designed according to the previous Chinese codes for seismic design are likely to violate this requirement as the contribution of a cast-in-place floor slab in tension is not included in assessing the moment capacity of the beam in negative bending. This paper proposes three promising beam weakening techniques in combination with FRP strengthening to achieve this strong column/weak beam hierarchy and presents the preliminary results of an ongoing study into the effectiveness of and design procedures for the proposed techniques. Disciplines Engineering | Science and Technology Studies Publication Details Teng, J. G., Zhang, S. S., Jing, D. H., Nie, X. F. & Chen, G. M. (2013). Seismic retrofit of RC frames through beam-end weakening in conjunction with FRP strengthening. In R. Al-mahaidi, S. T. Smith, Y. Bai & X. Zhao (Eds.), Proceedings of the 4th Asia-Pacific Conference on FRP in Structures (APFIS 2013) (pp. 1-8). Victoria, Australia: Swinburne University of Technology. This conference paper is available at Research Online: http://ro.uow.edu.au/eispapers/4957 SEISMIC RETROFIT OF RC FRAMES THROUGH BEAM-END WEAKENING IN CONJUNCTON WITH FRP STRENGTHENING J.G. Teng , S.S. Zhang , D.H. Jing , X.F. Nie 1 and G.M. Chen 3 1 Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, China. 2 School of Civil Engineering, Southeast University, China. School of Civil and Transportation Engineering, Guangdong University of Technology, China. Email: cejgteng@polyu.edu.hk ABSTRACT The strong column/weak beam requirement is now widely accepted in the design of reinforced concrete (RC) frames to achieve good seismic performance. However, many existing RC frames violate this requirement as they were designed according to inadequate design codes (generally previous codes). In particular, RC frames designed according to the previous Chinese codes for seismic design are likely to violate this requirement as the contribution of a cast-in-place floor slab in tension is not included in assessing the moment capacity of the beam in negative bending. This paper proposes three promising beam weakening techniques in combination with FRP strengthening to achieve this strong column/weak beam hierarchy and presents the preliminary results of an ongoing study into the effectiveness of and design procedures for the proposed techniques.The strong column/weak beam requirement is now widely accepted in the design of reinforced concrete (RC) frames to achieve good seismic performance. However, many existing RC frames violate this requirement as they were designed according to inadequate design codes (generally previous codes). In particular, RC frames designed according to the previous Chinese codes for seismic design are likely to violate this requirement as the contribution of a cast-in-place floor slab in tension is not included in assessing the moment capacity of the beam in negative bending. This paper proposes three promising beam weakening techniques in combination with FRP strengthening to achieve this strong column/weak beam hierarchy and presents the preliminary results of an ongoing study into the effectiveness of and design procedures for the proposed techniques.

Integrated water washing and carbonization pretreatment of typical herbaceous and woody biomass: Fuel properties, combustion behaviors, and techno-economic assessments