Advanced Materials Research Vols. 671-674

Abstract: Because the coal mine derrick technology needs, to be in from the original winch system of backward 10m based on a new set of new ground winch system, resulting in the original derrick structure stress state change. By using SAP2000 finite element software, the establishment of three-dimensional finite element model, the dynamic characteristics and technological transformation and bar stress were analyzed, for the coal mine derrick technological transformation to provide certain reference.

Abstract: The air added mss have important influence on film modal. Based on the commercial finite element (FE) package ABAQUS, a numerical procedure for membrane mode analysis was set up and used to analyze a square film modal. The membrane pre-stress can be introduced through temperature load . The equilibrium shape of the space film was obtained through a geometrical nonlinear step .The dry and wet mode of the film structure was calculated and analyzed by means of the Lanczos method. The added mass above each vibration region is equal to the uniformly distributed air with height of 0.65l. The rectangular plane film test revealed the validity of the finite element simulation on the membrane structure base frequency. The film structure with edge cable is a rational structure form. The proposed analysis method and conclusion on the film structure modal analysis has the reference value.

Abstract: Fiber reinforced polymer rebars have advantages of light weight, high tensile strength and excellent corrosion resistance. However, researches showed that [1-2], the low elastic modulus of FRP rebar resulting in a larger deflection than steel reinforced concrete beam in equivalent condition. Therefore, it is crucial to control the deflections in serviceability limit states. Three GFRP reinforced concrete beams were tested with four-point bending, deducing the cracking moment formula of the FRP reinforced beam. Then, Bischoff model is adopted to calculate the deflection, and reaching a good agreement with the experimental results. We recommend Bischoff model to evaluate the immediate deflections.

Abstract: Retrofitting and reinforcement project of a historic hotel building are introduced in article. The method of increasing new concrete frame structure in original structure interior and the original exterior wall considered as a retaining structure was adopted in the retrofitting and reinforcement project. The structure subjecting to the force was clear and the reinforcement construction process was relatively simple after the retrofitting and reinforcement. Design and construction of the structure strengthened are according to the existing code completely and can ensure the safety and the seismic performance of the structure.

Abstract: Concrete-filled FRP tubes (CFFTs) have received significant research attention over the last two decades. However, the experimental studies on the behavior of CFFTs filled with high- and ultra high-strength concretes (HSC and UHSC) remain very limited. This paper presents the results of an experimental study on the compressive behavior of circular HSC- and UHSC-filled fiber reinforced polymer (FRP) tubes (HSCFFTs and UHSCFFTs). A total of 24 aramid fiber made CFFTs were tested under uniaxial compression to investigate the influences of concrete strength, amount of confinement and manufacturing method of FRP tubes. The influence of tube manufacturing method was investigated with specimens manufactured with either automated filament winding or manual wet lay-up techniques. In this paper the experimentally recorded stress-strain relationships are presented graphically and key experimental outcomes discussed. The results indicate that the manufacturing method of the FRP tubes significantly influence the compressive behavior of CFFTs.

Abstract: Existing experimental studies showed that the reinforced concrete (RC) beams strengthened with prestressed carbon fiber-reinforced polymer (CFRP) plates had two possible flexural failure modes (including the compression failure and tension failure) according to the CFRP reinforcement ratio. Theoretical formulas based on the compatibility of strains and equilibrium of forces were presented to predict the nominal flexural strength of strengthened beams under the two failure modes, respectively. It can provide a reference for engineering application of strengthening design.

Abstract: Eight reinforced concrete beams (six externally reinforced and two contrast beams) were tested under the primary or secondary load experiment. According to the test results, the existing formulas and specifications were applied to make calculations on reinforced beams. Besides, comparisons were made between test and calculation value, the differences were pointed out and improvement measures were proposed. Comparisons were made between test and calculation value on normal section flexural bearing capacity of reinforced concrete beams strengthened by externally prestressed transverse tensioning method and they are in good agreement.

Abstract: H shape steel strut, which is the most commonly used material in traditional braced wall system (TBWS), has some disadvantage such as narrow strut spacing and cost ineffectiveness. Therefore, a newly retaining wall system with pre-stressed (PS) wale and square pipe struts is developed for widening strut spacing and saving construction costs. In this study, three cases, which are changed from TBWS with H shape steel strut to retaining wall system with PS wale and square pipe struts, are compared construction costs and constructability. This results reveal that construction costs is decreased by 46.9% on average and constructability is improved by decreasing the amount of material and widening the strut spacing.

Abstract: With the increased demand for high-rise and long-span structures, high strength with high performance steels have been utilized for these kind of structures. For the grade 800MPa high performance steel, although it was included in Korean Standard as high strength steel(HSA 800), however the HSA 800 steel was excluded in Korean Building Code-Structures due to the rack of research results for the structural behaviors of members fabricated with HSA 800 steel. Therefore, this paper describes basic study for the design specification of structural members using HSA 800 high performance steel. For this purpose, welded H-shaped stub column specimens with various width-to-thickness ratios were designed and tested in order to investigate the buckling behaviors and ultimate compressive strength.

Abstract: The field inspection and safety assessment of a transmission angle tower are actively carried out in this study. The field measurement and inspection are firstly introduced and then the structural model is constructed based on finite element approach with the aiding of commercial package ANSYS. The equation of motion of the transmission tower-line system is established for numerical analysis. The gravity, base settlement and dynamic wind loading are applied on the tower to examine the structural responses. The deformation and stresses distribution of the transmission angle tower are computed to explore the damage reasons. The made observations indicate that the peak stresses of some members are large than the permitted yielding stresses of steel material. The damage event is induced by coupling loading effects