Advanced Materials Research Vols. 446-449

Abstract: The underwater structure of power house is major structure under the dynamic loads of unit. The vibration problem is very common in operation. So the structures should have sufficient stiffness to resist dynamic loads of unit. This paper establishes three-dimensional finite element models with finite element analysis software—ANSYS. Dynamic characteristics of the power house and dynamic responses of structure under earthquake are analyzed. The results of the computation show that fluid-solid coupling may be ignored when studying dynamic characteristics of structures of the underground power house.

Abstract: With the development of economy, the area of construction grows fast, the use of mass concrete basic of the high-rise and large building also becomes normal. So the cracking control of mass concrete has become an important topic nowadays. In this paper, the mechanism of the cracking and the methods to control the cracking will be studied. And then the stress and temperature field of the basic platform of the national stadium in the mass concrete curing period will be studied by infinite element method. After that, results of the infinite element method will be compared with the results of monitoring. At last, we can come to a conclusion that the cracking of the mass concrete can be controlled in reasonable limits by some measures.

Abstract: The aim of this paper is to present a practical yet simplified method in the second-order analysis of semirigid connected steel frames. Based on the principle of new shear force distribution method, by taking partial frame as an analytical subassembly model and using a rotation spring which has variable bending stiffness to model flexibility of beam-column connection, this paper derives a simplified non-iterative inner force and lateral deflection computation formula considering P-Delta effects on semirigid connected steel frames. The numerical examples show that semirigid of beam-column connections obviously increases the horizontal displacement and P-Delta effect on the steel frame. Therefore the influences of semirigid connection should been considered in second-order analysis of building steel frame. The presented method is not only relatively practical and easily applicable to manual computation but also has a rather high accuracy, and can be used by the engineers in preliminary design for semirigid connected steel frames.

Abstract: The mechanics principle of setting strengthened storey to control the horizontal displacement in super high-rise structure was analyzed, several super high-rise frame tube structure models were established and the maximum peak displacement as well as storey displacement of the structure under the horizontal earthquake load were analyzed via the finite element program; Utilizing controlling structural horizontal displacement as a judge objective, the appropriate setting number of strengthened storey and optimization location were obtained; eventually, the methods on improving the lateral stiffness via setting beam type strengthened storey in super high-rise frame tube structure were put forward. The obtained conclusions are capable to be a reference for designers.

Abstract: Based on the structural characteristics that the distribution of mass and stiffness is symmetrical in staggered truss structure, the load-carrying performance of staggered truss structure is equivalent to a pressure-bend combinational strut in this paper. By analyzing the relationship among curvatures , bending moments and shear forces of the pressure-bend combinational strut, the balance differential equations of the pressure-bend combinational strut is erected. Based on Runge-Kutta method, the lateral iteration equation derived by considering the influence of the second-order effects is derived. This paper analyzes the lateral displacements of floors of the staggered truss structure examples considering second-order effects or not, and gives a comparative analysis with the existing finite element software Ansys. The results show that the calculation method of second-order effects proposed in this paper has a good precision.

Abstract: Concrete beam reinforced with FRP plate has many advantages—high bearing capacity, light weight, fast construction progress, corrosion resistance, etc. The collaborative work between FRP and concrete is achieved through the binder, so the interface of them is the weak link. Under external loads, the interface of FRP-concrete will emerge inevitable internal force redistribution, and the FRP plate is a kind of resin material and its physical and mechanical properties will change with temperature and time. In this paper, using energy method, the differential equations of interfacial shear, meanwhile considering temperature and creep effect of FRP plate strengthening concrete beams were established. And the calculating formulas of interfacial shear under different loads were given.

Abstract: Steel portal frame is easy to build,but the connection styles of end-plate have greater influence on the structure. In this paper, The formula about initial stiffness of end-plate connections has been given.The essay uses ANSYS to analyze the initial stiffness of end-plate connections. Several factors have also been analyzed about the stiffness.The conclusion is that the form of end-plate, thickness, bolt diameter all affect the structural deflections.But these reasons couldn’t change the integral moment of the structure.

Abstract: Today, the structures constituted by different materials, increase more and more, especially the lower part is concrete, the upper is steel. For this type of structural system, modal damping matrix is non-diagonal matrix, the earthquake response equation is coupled on the modal damping matrix, the modal coupling of the non-proportional damping system leads to the traditional real modal analysis methods not be directly applied. For such structure, the changes of the damping ratio are analyzed in this article. Finally, the equivalent damping ratio of Shenzhen Airport is obtained using the energy theory.

Abstract: Based on the contrast analysis of loads provided in foreign and China standards, analysis and discussion are mentioned about the definition and estimation of dynamic wind pressures for multi-span greenhouse structural design in details. Meanwhile, taking advantage of past experience in greenhouse structural design a practical method which can be used in greenhouse design was given for wind loads. Under the present conditions, it is relative safety in calculation wind loads according to Load code for the design of building structures (GB 50009-2001), yet it is unnecessary to make modification of statistical reappearing factor in calculation wind load-dynamic pressure when considering the coefficients of wind pressure depending on height and the gust factor according to Greenhouse structure design load (GB/T 18622-2002).

Abstract: Abstract: The fly ash and coal gangue were used as main raw materials to roast solid insulating brick.Lower than solid clay brick (300 °C) which belongs to low temperature roasting , roasting time cycle is 24 h ,the ratio of fly ash and coal gangue is 60% :35%. the B7 admixing expanded pearlite compressive strength is 30.25 MPa . Strength reach general clay brick MU30 high-class level .Thermal coefficient of conduction is 0.4 W/(m.K), lower than general clay brick thermal coefficient of conduction 0.78 W/(m.K); In addition , B7 XRD pattern has evident quartz、mullite diffraction character peak and TGA-DTA pattern between 900°C~1200°C, following temperature rise, green body heat-absorbing , begin melt 、glass reduction .The result is high in strengths . SEM scanning show : after being roasted in 950°C , globular solid glass bead 、pearlitic drusy pearlite 、flocculation aluminosilicate phase and so on , raw materials particle interstices were filled with viscous hyaline, so that B7 turned out high strengths . Acidproof、alkaliproof、freezing test and strengths results show: the lasting quality of solid insulating brick was best.