Advanced Materials Research Vols. 255-260

Abstract: Problems regarding the combined axial force and bending moment for the behaviour of semi-rigid steel joints under service loading have been recognized in recent studies. As an extended research on the cyclic behaviour of a bolted endplate joint, this study is performed relating to the contribution of column axial force on the cyclic behaviour of the joint. Using finite element analysis, the deteriorations of the joint performance have been evaluated. The preliminary parametric study of the joint is conducted with the consideration of flexibility of the column flange. The column axial force was observed to significantly influence the joint behaviour when the bending of the column flange dominates the failure modes. The reductions of moment resistance predicted by numerical analysis have been compared with codified suggestions. Comments have been made for further consideration of the influence of column axial load in seismic design of bolted endplate joints.

Abstract: Based on the experiment of timber circular columns made of pine and fir confined by carbon-aramid hybrid FRP (HFRP) sheets under axial compression, the failure modes, axial bearing capacities, peak compression strains were analyzed. The results showed that: Compared to the unconfined specimens, the axial bearing capacities and peak compression strains of the specimens confined by HFRP sheets were all improved. Axial bearing capacities of pine and fir specimens improved 6.6％～16.8％ and 5.0％～16.9％,respectively. Peak compression strains of pine and fir specimens improved 8.9％～60.2％ and 11.5％～56.8％, respectively.

Abstract: Based on the experiment of timber rectangle beams made of pine and fir reinforced with CFRP/AFRP hybrid FRP (HFRP) sheets. The failure modes and bending bearing capacity and load-deflection curves and strain distribution at mid-span section were analyzed. The results showed that: Comparing with the specimens without being reinforced by HFRP, there is certain improvement in bending bearing capacity and stiffness of the specimens reinforced with HFRP respectively. Bending bearing capacity of the pine specimens improve 18.1%~62.0% and bending bearing capacity of the fir specimens improve 7.7%~29.7%. Stiffness of the pine specimens improve 13%~21%, and stiffness of the fir specimens improve 6%~10%. Based on the experimental data, the computing formulas of bending bearing capacity of timber rectangle beams made of pine and fir reinforced with HFRP were presented.

Abstract: Short-pier shear wall structure design in a high building was introduced in this paper, the author explored how to dispose various styles short-pier shear wall structure, the author expound practical application of conception design in short-pier shear wall structure design.

Abstract: Employing twisted forms in tall buildings is a relatively new architectural phenomenon, as are the cases with the Chicago Spire and Shanghai Tower. These super-tall buildings employ outrigger structures as their primary lateral load resisting systems. This paper presents structural performance of outrigger structures employed for twisted towers. Twisted tall buildings of different twisted rates are designed with outrigger structures. Two cases are studied comparatively. The first case uses spirally slanted perimeter mega-columns in response to the twisted building form. The second case uses vertical mega-columns, set back from the building perimeter, and cantilevered floor slabs from the column lines. The comparative structural efficiency of these cases is presented.

Abstract: This paper presented an experimental study on piezoelectric impedance based prestress force monitoring for prestressed concrete (PSC) beam. The low cost piezoceramic (PZT) patch was attached at the beam firstly and different levels of prestress force were applied to the tendons. The electro-mechanical impedance (EMI) spectra of surface bonded PZT patch were then collected using an impedance analyzer by sweeping the frequency. The statistical index RMSD is then adopted to quantify the variation of EMI spectra due to the variation of prestress force. The relationship between the prestress force and the RMSD index is established. The results show that the EMI technique is a practical and reliable nondestructive test method for prestress force monitoring.

Abstract: As a new type of resist lateral force structure, short-pier shear wall structure has been widely used in high-rise and super-tall residential construction. However, at present, there isn’t a specifically targeted short-leg walls structure design and construction technical regulations both at home and abroad, which led to the architectural engineering design and construction market turmoil. By the prophase research of the short-leg walls structure seismic performance, and a great deal of experiments, combine with the latest research results at home and abroad, adopt the limit state design method based on probability theory, the paper clarifies the definition of short-leg walls, and analyzes the calculation method of section load-carrying capacity for earthquake combination and no-earthquake combination, which has certain directive significance and engineering application for the design and construction of high-rise residential buildings.

Abstract: The water seepage of underground structure is the serious problem in the construction engineering, and becomes one of the most harm in current infrastructure with the huge potential safety hazard and economic loss. The electro-osmosis technology is once widely used in the fields of soft ground stabilization of rock engineering, the biological pharmacy and the oil production engineering in China. This paper referred experiences of overseas, combined electric pulse signal and the electro-osmosis technology to reduce seepage of the underground structure, and solved underground structure water seepage problems. The paper comprehensively analyzed the research status of the technology at home and abroad and its feasibility in theory, also introduced the general implementation methods of projects, and carried on the comparison of the pulse electro-osmosis technology and the traditional moisture-proof technology in application.

Abstract: Corrosion of reinforcement can significantly affect the bond strength between the steel bar and the surrounding concrete thus greatly reducing the load bearing capacity of the concrete structure. In this paper, a simple analytical model is proposed to evaluate the maximum bond strength of corroded concrete with varying rebar diameters and concrete cover thickness. Predicted results compared well with experimental test data.

Abstract: There are many existing architectural structures that need reinforcement because of low construction quality, absurd design, inappropriate use, accidental natural disaster and building function change etc. Since there are several possible reinforcement schemes available to one structure, choosing the optimal scheme becomes a crucial problem that a designer must face. The optimization of reinforcement schemes needs considering not only quantitative factors like construction cost and period, but also qualitative index, which is difficult to quantize, such as durability and construction difficulty degree. Therefore, scheme selection is a representative multi-index semi-structural problem. This poses considerable difficulty to designers and is complicated to regulate because of the subjective randomness. In this paper, fuzzy multi-index half-structural theory is applied to the selection of building reinforcement schemes. By determining relative membership degree matrix and objective weight matrix of each index, superior degree of each scheme to decision is decided; objective index and designers’ experience are combined effectively, and then optimal reinforcement scheme can be obtained. The results reveal that the calculate results are well consistent with those of test, and have great computational accuracy.