Advanced Materials Research Vols. 255-260

Abstract: Two different specimens of hollow composite columns with perforated ribs, one is the column with double steel skin and the other is with single steel skin, were designed for imposing axial compression test. The tests indicated that both of the columns have a good bearing capacity and the column with double steel skin has a comparatively better bearing capacity than the one with single steel skin. Then comparisons between tests and finite element analysis (FEA) were preceded, which showed that not only the load-displacement relationship of the columns, but also a reasonable failure mode can be simulated by the finite element analysis.

Abstract: An orthogonal experiment of sixteen frame column underpinning joints was introduced, experiment was designed by a normal table of “five-factor and four-level”, five factors referred to ratio of shear-span of moving beam, ratio of underpinning beam stirrup steel bar, underpinning beam longitudinal steel bar parameter, concrete strength, and planted reinforcement, in addition every factor had four experiment datum. Then, the underpinning joint stress mechanism and failure mode was determined, based on the experiment the conclusion was drawn that the ratio of shear-span of moving beam was the key factor to the joint failure mode; and the failure course was divided two stages which were before and after interface punching slip by theoretical analysis, for the phase before interface punching slip a space and plane “tension-bar-arch” mechanical model was presented for the underpinning joint, then mechanic analysis was put into the models, and two series theoretical calculation correlations for this underpinning joint were obtained, by comparison with the test result one model and one formula was choose, this theoretical results were agreement with experiments results.

Abstract: In order to evaluate and predict the behaviors of concrete structures under the normal atmospheric conditions, a new similarity experimental method is presented which can evaluate the field performance of reinforced concrete (RC) structures by measuring the structure in the artificial accelerated environment. The causes of concrete structural damage and the social harm caused by the RC structural durability failure were analyzed. The current status of concrete carbonation was described. The method establishes the similarity-relationship of performance changing between the field and the accelerated environmental conditions by contrasting and analyzing the behaviors changing under both environments, and realizes the effective and exact estimate to the field structures from the indoor accelerated experiments. It brings forward a new way of thinking to test the RC structures under the atmospheric conditions.

Abstract: A current development trend of the industrial equipment is ultra-large scale. The construction, transportation, and installation of these equipments require ultra-large tonnage lifting equipments. At present, domestic ultra-large tonnage lifting equipments, particularly for special purpose are still immature, unable to meet requirements of the lifting of ultra-large structures. Based on the need of ultra-large steel structures (offshore oil platforms) lifting, using strength theory and finite element analysis, a continuous lifting mechanism for the lifting of ultra-large structures was designed in this article. The continuous lifting mechanism consists of two parts: the mechanical support structures which was designed in this article, and the hydraulic system. The main characteristics of the mechanism are: the framing truss structure assures large height lifting; and the accumulated of synchronous blocks achieves large height lifting.

Abstract: In this paper, a non-destructive analytical method was proposed to predict the serviceability of corroded RC structure from corrosion cracking. Two models of corroded reinforced concrete were proposed to take into account the influence of corrosion pattern. Based on a three-phase model linking corrosion cracking and reinforcement corrosion and the transfer length, the models allowed quantification of the effect of the steel cross-section loss and the deterioration of the steel-concrete bond. Using a macro-element FEM analysis, the serviceability models were performed on a corroded beam stored in a chloride environment under sustain loading to predict the deflection of mid-pan under service load and compare with the experimental results.

Abstract: Comparative analyses of twenty-eight finite element structures with filler walls were established to study dynamic characteristics of RC frame structures under seismic waves. The results of these analyses show that filler walls have little influence on vibration modes of the structure. But as a result of soft storey in the bottom of building caused by reduction of the filler walls, vibration modes have a great influence. As the stiffness of filler wall decrease, the stiffness of soft storey decrease shapely, vibration mode curve becomes much smoother. Considering the filler wall has influence on the vibration periods of framework, the reduction factor of 0.7 should be taken. The influence of filler wall to the value of lateral drift and storey displacement angle of frame can not be ignored. The main effect factors to the dynamic characteristics of framework are included quantity, location, material of the fill wall and the selection of seismic waves.

Abstract: The layered construction technique is the common method of large steel structures in the non-slide construction. In process of the former three-tier construction, the structure is prone to forming large deformation because of great span, large weight of interlayer equipments and other various factors. In this article, to obtain high dimensional accuracy and good deformation control data, the positions of temporary support points of the 3M201 that is a module of large steel structure in a project are optimized successfully with the ANSYS optimization of finite element.

Abstract: The changing ratio of modal curvature is proposed for damage recognition, and its ability of damage localization and damage quantitative has been studied in this paper. For testing the effect of damage recognition, two research parameters, the different section rigidity and the scope of damages, are included. And changing rules of the index with structure rigidity, constraints, and structure supporting system have been studied at the same time. The numerical analysis results indicated: The relation of linear increase exists between the changing ratio of modal curvature and the extent of damage, the changing slope of the index is bigger with the increase of damage extent; The boundary condition and the structure supporting system will affect the value of index; In the view of one special structure, case study should be carried to establish the relationship between value of index and the extent of damage.

Abstract: Knowledge of the economic and social effects of aging, deterioration and extreme events on civil infrastructure have been accompanied by recognition of the need for advanced structural health monitoring and damage detection tools. In this paper the time-delay neural networks (TDNNs) have been implemented in detecting the damage in bridge structure using vibration signature analysis. A simulation study has been carried out for the incomplete measurement data. It has been observed that TDNNs have performed better than traditional neural networks in this application and the arithmetic of the TDNNs is simple.

Abstract: Based on 5 test specimen of steel-high strength concrete composite beam, This paper analyzes test results, researches on mechanical properties of steel-high strength concrete composite beams, load-deformation properties, performance of the interface slip and strain of the midspan across-section of beams, Study on the performance of the steel-high strength concrete composite beams.