Advanced Materials Research Vols. 163-167

Abstract: “Castellated beam” is a name commonly used for type of expanded beam. Castellated beams combine beauty, versatility, economy in steel design. These are fabricated from standard rolled section and are engineered to save time of construction, enabling saving in steel and reducing building costs. These are mainly designed to reduce weight and at the same time increase the efficiency in structural performance. The principal advantage of castellation is the increase in vertical bending stiffness castellated beams have proved to be efficient for moderately loaded longer spans where the Design is controlled by moment capacity or deflection. In this paper a steel beam is selected and Finite Element Analysis is done for constant loading and support condition by using ANSYS software. The deflection pattern at the center of castellated beam is studied for different parametric conditions by changing depth of hexagon to the depth of web ratio and also by changing the position of hexagon along the length of the beam. A comparison is done for various conditions.

Abstract: U-section steel-encased concrete composite beams is the new type composite beam.This kind of composite beam takes thick steel plate as bottom plate and thinner cold-formed thin-walled steel as web which are connected through a u-shaped section by welding, and then concrete are poured in the u-shaped. In this paper an experimental study was conducted on six full size simple supported U-section steel-encased concrete composite beams.The relationships of the load-deflection curves of the composite beams were obtained. From the experimental results,the variation laws of deflection are analysed,and three defletion formulas are analysed and compared. Based on actual code. A theoretical formula is proposed for defletion. The results of theoretical formula are proved to be in good agreement with the experimental results.

Abstract: For typical tubular T-joint, the common failure generally occurs near the weld toe on the chord surface due to the fact that the stiffness of the chord in radial direction is much smaller than that of the brace in axial direction. In this paper, the static strength of tubular T-joints is improved by filling concrete into the chord. The finite element method is used to investigate the improving effeciency of the static strength for tubular T-joints with filling concrete in the chord under axial compression and tension. Firstly, 6 T-joint models were analyzed to prove that filling concrete in the chord is effective to increase the static strength and the stiffness of T-joints with hollow section. Afterwards, based on the analyzing mechanism for CFCT T-joint under axial compression and tension, the different performances under axial compression and tension between circle hollow tubular T-joint and CFCT T-joint were clarified, and the different failure modes for tubular T-joints with hollow section and CFCT T-joints were compared and analyzed.

Abstract: The steel box girder is widely used benefited from the high torsional and bending rgigidity, good entirety, light weight, better appearance and good stability. Using 6 quality control method, the problem diagnosis and quality control are made to the steel box girder’s making critical process such as assembly and jointing in the New Hi-Tech Zone of Xi'an’ s Arterial road 4# bridge , so as to meet the quality requirements.

Abstract: The prestressed steel beam is regarded as a composite system of beam and cables, and the interaction of the two parts is fully considered. The variational method is used to derive the equations for calculating the tension increment of external cables and deflection of steel beam under applied loadings. A model test of prestressed steel beam is used to verify the calculation results.

Abstract: In this paper, the properties of CF (carbon fiber) reinforced HPC (high performance concrete) containing LP (limestone powder) have been studied including its compressive strength, flexural strength, chloride ion permeation resistance, wearability and acid rain resistance. The results show that flexural strength, acid rain resistance and wearability of CF reinforced HPC containing LP are all better than those of LP HPC without CF, moreover, its flexural strength at 7days and 28days are both larger than 10MPa. While the short-term compressive strength and resistance to chloride ion permeation are decreased by introducing CF. Also the results indicate that CF reinforced HPC containing LP suits to be used as road pavement materials in abundant acid rain area.

Abstract: The mechanics performance of reinforced concrete members subjected to axial compression, bending, shear and torque is very complex. Several calculation models have been established to estimate the torsional capacity of combined torsion members; however, the calculation results of different models have a great variation. In this paper, variable-angle space truss model is adopted to analyze the mechanics performance of reinforced concrete members subjected to combined torsion. With respect to various shapes of specimens, various load modes, and various strength of concrete, a unity equation about torsional capacity of combined torsional member is obtained. Based on the unity equation, the torsional capacity of 59 combined torsional specimens is calculated. In contrast with the equation of ACI and the code of China, the torsional capacity calculated by the unity equation agrees well with the results of experiment and much better than the results of ACI code and China code. It is concluded that the unity equation can provide valuable reference for calculation and design of combined torsion members.

Abstract: The long concrete bedding cushions are more vulnerable to cracking than the dam concrete, even the cushion is much shorter than the dam block, especially those constructed in hot season and the off period lasts long. The cracking mechanism of such cushion is studied and presented in this paper. There are several reasons contribute to the cracks of bedding cushion, but the thermal stress is the main factor. The temperature distribution is always unevenly during the construction period of bedding cushion. During the long off period, temperature drop in local high temperature zone, temperature fluctuation and temperature difference between inside and surface are the main factors causing cracks for bedding cushion without proper thermal control measures. Some thermal control measures are always used in practical engineering, but it can not always effectively prevent bedding cushion from cracking. Reasonable water pipes cooling measure, which can prevent local high temperature at the early age of construction, and effective heat preservation measures in cold season, which can reduce temperature difference between inside and surface and temperature fluctuation, are necessary to prevent cracking. One bedding cushion of concrete dam is numerically stimulated by 3D FEM, and effective temperature control measure is proposed in this paper.

Abstract: Based on the principle of minimum potential energy, the interface slips in concrete filled square steel tubular column is calculated. According to the study of bond-slip behaviors of steel reinforced concrete and steel tube concrete, a pull-out mechanics model of concrete filled square steel tubular column has been built. The slip displacement on the interface of steel and concrete of the column along the embedment length is derived by the principle of minimum potential energy. The calculation results show that the slip curves have the basic characteristics of quadratic curves distribute. The results can be used to describe the interface slips between steel and concrete under complicated loads.

Abstract: Wall and tie column shear strength of every floor in masonry buildings as indicators of earthquake-resistant capacity, the evaluation criteria of the indicators was obtained based on the earthquake damage analysis on the 72 multi-storey masonry buildings in Dujiangyan and Hanwang areas. Based on these tests, a rapid seismic evaluation method of masonry buildings was proposed, this method can assess the degree of earthquake damage for the masonry structure under the level of seismic intensity directly. The application of the method is introduced by analyzing the earthquake damage of a masonry building in Wenchuan earthquake. The results show that the method can evaluate the aseismic performance for masonry buildings, and can assess the degree of earthquake damage additionally.