Applied Mechanics and Materials Vols. 166-169

Abstract: Based on the experiment results of five plain steel plate-light weight concrete hollow deck specimens, the design methods of the composite decks which mainly including the calculation method of the bearing capacity and calculation method of the flexural rigidity were introduced. In the paper, the bearing capacity and flexural rigidity of the composite at two orthogonal directions, which including the direction parallel to the pipes and the direction perpendicular to the pipes, were both introduced. The calculation results of the bearing capacity and middle-span deflection were in good agreement with those of the experimental results, and in the return calculation methods were verified. Therefore, the design methods and calculation methods were useful to the design of this new type composite deck.

Abstract: A simplified finite element model for analysis of the Layered steel fiber beams with the concrete damaged plasticity model has been presented. The numerical simulation of load-deflection curve of layered steel fiber reinforced concrete beam under three-point loads is performed using ABAQUS. The results of simulation are generally in conformance with the experiment. The results of numerical simulation show that layered steel fiber has little contribution to the elastic capacity of concrete beam. But it can improve the ultimate bearing capacity of concrete beam obviously. The bending collapse style of layered steel fiber reinforced concrete beam is different from plain concrete beam evidently with obvious ductile characteristic.

Abstract: The chemistry check-ups were reviewed in the first maintenance of 600 MW supercritical once-through boiler units in Henan. Several problems were found: (1) high rates of scaling on the waterwall and economizer; (2) high rates of salt deposition on the turbine blades; (3) the formation of salt deposits on blades were complicated; (4) corrosion of low pressure turbine blades in period of maintenance was a universal phenomenon; (5) FAC (flow-accelerated corrosion) were most frequent in HP heaters and HP drain lines in most fossil plants. The reasons have been analyzed and the suggestions have been provided.

Abstract: Abstract：Combined isolation system is combined with rubber bearings which provide resilience forces and sliding isolated bearings which provide damp. According to the rule of axial forces redistributing between two kinds of bearings under earthquake, a calculating method considering the vertical force redistribute of isolation layer was given. With this method, the results of an example show that axial force will transfer from rubber bearings to sliding isolated bearings along with the horizontal displacement of isolation layer. The bigger the displacement is the more axial force transfers. So the axial-forces redistribution is a self-adjustable performance of the system, and also is an advantage for the system.

Abstract: Retrofit using FRP materials for strengthening reinforced concrete member is widely applied, as this method is advantageous in terms of workability and performance guarantee. But in External Bonded Retrofit (EBR) methods, bond capacity, which is the most important part of FRP retrofit, frequently lowers. As an improved method, Near-Surface-Mounted Retrofit (NSMR) method was developed to secure absolute bond capacity in performance required from an epoxy adhesive between FRP Plates and concrete. This paper deals with the experimental result about the bond capacity of EBR and NSMR method and the effects of shear keys in NSMR. As a result, NSMR methods showed more increasing in bond strength than EBR methods. In addition, given that maximum strength increased as shear keys became more distant from a loading direction, the effects of these shear keys raised.

Abstract: The damage mechanism and causes of the shaft lining structures are introduced, and the advantages and disadvantages of some current shaft lining structures are analyzed. The prospects of steel plate-high strength concrete composite shaft lining structure are proposed in this paper.

Abstract: According to lots of documents previously studied, a seismic design method is put forward based on displacement for steel moment frame. This method is established in condition that the yield displacement of steel frame can be determined by its geometrical dimension; then the objective displacement (ultimate displacement) can be determined in light of performance level of the structure, and the corresponding coefficient of ductility can be obtained. Thereafter, the design base shear of steel frame structure can be calculated by the use of reduced elastic spectrum. Thus, the design of stiffness and capacity can be conducted on steel frame structure. The analysis of case study indicates that the displacement-based seismic design method addressed herein is of reasonable safety and reliability, and of operational convenience, which can still realize the seismic design of steel frame structure at different performance levels.

Abstract: Abstract: In order to study static strength of doubler plate reinforced circular hollow section (CHS) K-joints, experimental and numerical studies conducted by the authors. The effects of parameters Δ (the ratio between the length of doubler plate and the diameter of the brace) and α (the width of the doubler plate) on CHS K-joints subjected to bending load have been investigated and reported by the authors. It is found that the ultimate strength of a CHS K-joints reinforced with appropriately proportioned doubler plates can be up to 2 ratio to its un-reinforced counterpart. Reasonable geometric parameters of the doubler plate can make the chord, brace and doubler plate work together to bear the external bending load. The width and length parameter of the doubler plate, however, have no effect on the stiffness of the reinforced K-joints.

Abstract: At present, according to Code for Design of Steel Structures（GB50017—2003）,for axially loaded column with plated column base, the column bases are considered as hinged supports, but possess actually remarkable rotational restraint. The effective length of columns can be decreased when the constraint function of plated column base is considered in calculation. The calculation of effective length factor of columns is usually according to the approximate formula which is deduced by the rotational stiffness. Axially loaded column plated column base models were established with the finite element software, the effective length factor of columns was obtained by the method which can avoid calculating rotational stiffness of plated column bases, the influence factors on the rotational restraint of axially loaded column plated column base, such as the base plate thickness, the diameter of anchors, the column section size were also analyzed in this paper.

Abstract: Using the model test systems self-designed, the deformation characteristics such as displacement and bending moment of cast-in-situ concrete pipe piles under lateral load were studied, the nonlinear characteristics of pile top horizontal displacement and the maximum bending moment variation with load were also analyzed by fitting the measured data. Further, the main factors such as pile length, pile diameter that affect the deformation characteristics significantly were also analyzed. The results show that the relationship between horizontal displacement of pile top and load is nonlinear hyperbolic, but the relationship of maximum bending moment and load is power function. All results can provide a reference for related pile projects.