Applied Mechanics and Materials Vols. 638-640

Abstract: The safety of a reinforced concrete frame building with cracks on a large area of its wall was investigated by using numerical analysis and field tests. The cracks were caused by the roof additional equipments. The layout of the roof additional equipments was measured to determine their additional loads. The width and depth of existing cracks was also measured. The static strength analysis based on the finite element technique is used to evaluate the influence of the additional loads on structural strength. The research results show the unreasonable supports of additional loads and the insufficient stiffness of secondary beams are the main reasons for causing cracks on the wall, and a reinforcement and repair thought for the building is proposed.

Abstract: The purpose of this study is to investigate shear performance of RC beams strengthened with combined CFRP and steel plates. Fourteen beams were tested to shear failure under simply supported four-point loading conditions. The variables of this investigation included strengthening technique, shear span to depth ratio, percentage of CFRP, percentage of steel plate, CFRP and steel plate orientation, CFRP and steel plate wrapping type. The results show that the simultaneous application of CFRP sheets and steel plate greatly increases the shear resistance of RC beams. The steel plates improve the bond behavior of CFRP sheets. A design formula is proposed to calculate the shear resistance of the beams strengthened with combined CFRP sheets and steel plates. The predictions agree well with the test results.

Abstract: A new type buckling restrained brace ensuring to work under different levels of earthquakes is analyzed in this paper. The brace is simplified by LINK elements of SAP2000. The skeleton curve of the mode is clarified. Three specimens with different slot widths are designed to evaluate the simplified model used in the software SAP2000. The evaluation work is accomplished through the software ABAQUS. The force mechanism, the hysteretic model and proposed reasonable scopes of slot widths are grasped. The numerical simulation work proves that the new type buckling restrained brace performs excellently.

Abstract: The main research methods to predict and research wind loads on buildings at home and abroad include wind tunnel tests, field measurement and numerical simulation. However, the wind tunnel tests and field measurement require big funds, long cycle and complicated measurement. Moreover, numerical simulation technology is quite mature. In this paper, based on fluid dynamics software CFD and criteria Reynolds k-ε turbulence model, wind field of the village flat roof with parapet is studied using the numerical simulation technology. Furthermore, the wind pressure data in different wind angles are processed and analyzed. The results show that wind angle has a significant impact on the wind pressure and its distribution. When the wind angle is 0 °, the air pressure-fluctuation in each node of the roof is small, and the pressure coefficient is steady between -1.50 and -2.00. When the wind angle is 45 °, the air pressure fluctuation in each node of the roof is large, and the pressure coefficient fluctuates between -0.8 and -3.0. When the wind angle is 90 °, the wind pressure-fluctuation in each node of the roof is equal to the fluctuation between 0 ° and 45 °wind direction angle, and the wind pressure coefficient fluctuates between -0.7 and -1.7. When incoming flow is along the asymmetric axis, the wind pressure-fluctuation is large, and the wind pressure is greater than that in the large negative pressure zone which is along the symmetry axis, which can bring serious damage on the roof.

Abstract: With the development of construction technology and construction equipment, now almost all industrial and civil buildings are changing to frame structure. As a result of the differences in floor height, span and the thickness of the cast-in-place floor slab, so the frame column and beam stress is different. When the stress exceeds a certain limit, then it will result in the problem of “strong beam weak column”, and this affects the quality of the buildings, thus how to solve the strong beam weak column caused by the cast-in-place floor slab becomes very meaningful.

Abstract: Different from the Euler beam and Timoshenko beam, the spatial fine beam model considers some effects such as shear displacement, the additional axial displacement produced by lateral bending and the additional transverse displacement induced by reduced stiffness due to transverse shear deformation. In this paper the internal force formula of the spatial fine beam model, applying to Vector Form Intrinsic Finite Element (VFIFE) analysis, are derived and corresponding programs are developed. A spatial cantilever beam and a space frame are analyzed and the load-displacement curves are compared using different beam element models. The results show that when the depth-span ratio is relatively small, the load-displacement curves nearly have no difference. When the depth-span ratio becomes larger, the yield load gotten by the fine beam model is significantly smaller than that obtained by the Euler beam and Timoshenko beam. Therefore, when the deep beam is analyzed, the shear displacement, the additional axial displacement and the additional transverse displacement caused by stiffness reduction can’t be ignored. The spatial fine beam model proposed in this paper has good accuracy in the analysis of deep beam.

Abstract: The types of assembly floor slab member and the present development situation of assembly floor slab standardization at home and abroad is presented in the article, as well as assembly floor slab layout schemes and its advantage and disadvantage is presented, and the assembly floor slab standardization scheme is proposed to promote the application of assembly floor slab in steel frame structures.

Abstract: The fresh-old concrete bonding interface is the key to designing assembled monolithic water-distributing beam of mechanical draft cooling tower. Force mechanism analysis indicated the loading-failure process was closely related to the development of cracks, which, combined with moist circumstance, aggravated corrosion. So the interface must be controlled in uncracked. In the critical condition, aggregate interlock of concrete and dowel action of reinforcement composed the shear strength of interface. Affected by the combined impact of shear force and moment, main rebar is under a state of complex stress, the principal stress of which can be calculated by the forth strength theory. Toutilize the rebar completely, the length of rebar in cast-in-site part should abide by the anchorage length.

Abstract: Based on the push-out test of the improved PBL shear connector, a finite element modal was established. In the FEA software of ANSYS, element type of Solid65 was adopted to simulate concrete; element type of Solid45 was adopted to simulate perforated rebar and steel plate, and element type of Conta173 and element type of Targe170 were adopted to simulate the interaction between perforated rebar and concrete, corrugated perforated plates and concrete. From the calculation of finite element modal, carrying capacity of the shear connector and the relative slip between steel plate and concrete were got. By comparing, the result of experiment is well with the result of calculation. Furthermore, the finite element modal is used to simulate mechianial properties of double row holes PBL shear connector. From the result of calculation, it can be concluded that the carrying capacity of double row holes shear connector is higher than the single row hole shear connector.

Abstract: In order to study and improve shear-shear deformation hysteresis model of reinforced concrete shear walls, experiment of reinforced concrete shear walls was conducted. Based on experimental data, shear-shear deformation relationship is deduced and shear-shear deformation hysteresis curves are obtained. The existing shear-shear deformation hysteresis models of reinforced concrete walls are discussed and improved, and the calculated shear-shear deformation hysteresis curves with the modified model fit well with experimental results.