Advanced Materials Research Vol. 680

Abstract: The beam-column joint is a crucial zone in a reinforced concrete moment resisting frame. It is subjected to large forces during severe ground shaking, and its behaviour has a significant influence on the response of the structure. In the present study, two half-scaled cast-in-situ beam-column subassemblies (i) without slab and (ii) with slab, with reinforcement detailing as per ACI 318-63 (1963) provisions are constructed. The beam-column joints are comprehensively instrumented and tested under static displacement controlled cyclic loading. This paper explains the contribution of the floor slab, especially in “Tension flange” on the overall cyclic behaviour of the subassembly, and the experimental results of horizontal joint shear stress are discussed, and compared with the ACI 352R-02 provisions.

Abstract: The grouping pile foundation is widely used in the construction of bridge over sea and its scale of construction is generally dominated by the wave force on the pile groups. Because of the presence of the slab, not only the incident wave but also the diffraction wave should be considered in calculating wave loads on pile groups. The diffraction from a submerged circular cylinder representing the slab was taken as an example, and wave loads on piles in the diffraction wave field were calculated by using Morison formula. Results show that the effect of slab decreases with the increase of incident wave number. Changing laws of different piles in the pile-group foundation varied with the submerged depth. Wave loads at the meeting-wave side of slab is larger than the back side of that. And the presence of slab caused the deflexion of inline force. The grouping piles coefficient can be taken as 0.7.

Abstract: As the industrial development brings the structures growth, the consumption of the natural aggregate is increasing annually. On the other hand, the amount of the potential aggregate is decreasing with the huge amount of construction waste from the concrete demolition. The annual total amount of natural aggregate consumption estimated 370million tons. And the experts are concerned about the depletion of aggregate which is presumed to be exhausted in 20 years, considering the annual consumption, which is approximately 250million(m³) in construction industry. Along with this issues, the government promotes to use recycled coarse aggregate from the construction waste in consideration of social, economic and environmental aspects. In conclusion, the purpose of this study is to promote to use of recycled coarse aggregate as a future substitute resource and to increase awareness of it as well. This study conducts the experiments by comparing high-strength concrete for the substitution of chosen two companies.

Abstract: Recently, many structures which were built about 30 years ago are watched by reconstruction. Demolished concrete is occurred in the process and these quantity increase about 10% more than the preceding year. Although the government have promoted to use recycled coarse aggregate, many registered architects have not use it, because natural aggregate is still cheaper than recycled coarse aggregate's price and they have question about quality of recycled coarse aggregate. In addition, there are no grounds to rely upon compressive strength and ultrasonic pulse velocity method of recycled coarse aggregate when it is used to high strength concrete. In this paper, bases will be adduced to verify applicative possibility of estimation of compressive strength of high-strength concrete with recycled aggregate using ultrasonic pulse velocity method. For this, compressive strength and ultrasonic pulse velocity method tests of 240 high strength concrete specimens with recycled coarse aggregate were performed, and the high strength concrete specimens were tested within the limits such as compressive strength and ultrasonic pulse velocity

Abstract: Recently, many structures which were built about 30 years ago are watched by reconstruction. Demolished concrete is occurred in the process and these quantity increase about 10% more than the preceding year. Fortunately, recycled aggregates are produced from demolished concrete, whereas the recycled aggregates are not used often because there are not many researches which have been verified by experts or researchers about strength when reinforced concrete is made with recycled aggregates. In this paper, high strength reinforced concrete is valued with potential applications and check change of strength when it made by recycled aggregates. For this, flexural tests of 4 high strength reinforced concrete beams with recycled aggregates were performed, and the high strength reinforced concrete beams were tested within the limits such as compressive strength, flexural strength, ductility, strain, and curvature. The current test data were examined in terms of flexural strength, along with the data from previously tested reinforced concrete beams with recycled aggregates.

Abstract: In order to validate the seismic performance of reinforced concrete grid-mesh frame wall , four grid frame walls in half size is made with different height-width ratios and different grid forms in the paper. Two of them are filling with cast-in-place plaster as filling material. According to the experimental results of these four walls subjected to horizontal reciprocating loads, we know that the grid-mesh frame wall's breaking form are in stages and multiple modes, and the main influencing factors are height-width ratio and grid form, what's more, with cast-in-place plaster as fill material, could not only improve the level of the wall bearing capacity and stiffness, but also improve the ductility and seismic energy dissipation capacity.

Abstract: As one of the most important road performances of concrete, the frost-resistance has a direct effect on the working life of the road. The performance can be improved by adding admixture. The research is based on the interior experiments. The frost-resistance experiment is carried out through the different proportion to compare the concrete test-pieces of different cement dosage. Thus, they can analyze the changes of the frost-resistance between ordinary concrete and the one which added air-entraining agent. As a result, it can be known how the air-entraining agent affects the frost-resistance of the concrete.

Abstract: The embedded large-diameter cylinder had been widely used in coastal engineering since it could be embedded into ground directly without excavation. A 3D elastic-plastic finite element model has been established to analyze the distribution and development of the friction resistance on large-diameter cylinder under the wave load. The results show that the development of friction on different areas of the cylinder is unsynchronized. The friction resistance first developed on the outer surface of the structure, after that, the inner friction began to develop. Only in certain areas the firction resistance can achieve ultimate value at the ultimate state.

Abstract: Stainless steel has been utilized on structural members of building due to significant characteristics in its superior corrosion resistance, durability, aesthetic appeal etc. Recently, structural behaviors and curling effect in single shear bolted connection fabricated with thin-walled plane plates have been studied by T.S. Kim. In this paper, finite element analysis (FEA) has been conducted based on the existing test result of channel bolted connections in austenitic stainless steel. The validation of numerical approach was verified to predict the structural behaviors such as fracture mode, ultimate strength and curling occurrence of bolted connections. Curling (out-of- plane deformation) also occurred in the connections with a long end distance like bolted connections assembled with plane plates. The curling caused the ultimate strength reduction and ultimate strength reduction caused by curling has been estimated quantitatively through the comparison of FEA results of FE models with free edge and restrained curling. Additional parametric analysis for FE models with extended variables has been performed. Therefore, the ultimate strengths were compared with current design strengths and reasonable strength formulae for connections with no curling effect were proposed.

Abstract: Experimental studies for single shear bolted connection of cold-formed ferritic stainless steel fastened with two bolts (2×1 bolt array) and 3.0 mm thick plate has been performed by T.S. Kim etc. End distances parallel to the direction of applied force were considered as the main variables of specimens. Curling (out of plane deformation) was observed in bolted connection with 60mm end distance and it caused abrupt strength reduction. The purpose of this paper is to compare the analysis results with test results and investigate the curling influence on ultimate strength through numerical modelling. FE models with restrained curling were also simulated for strength comparison with the curled specimen. Therefore, the validation of finite element(FE) analysis in predicting ultimate strength and curling behaviour was verified and the strength reduction ratio by the curling was estimated.