Advanced Materials Research Vols. 255-260

Abstract: To study further the bearing capacity of square steel tube columns filled with steel reinforced concrete, several broken modes were divided based on the changing of neutral axial. Bearing capacity computation formula was deduced by stirrup method. Amplified coefficient of eccentricity was regressed based on computed results of nonlinear program, and mid-long columns capacity was deduced. Input the computation formula into Excel, capacity was calculated by exhaustion the compression zone depth of concrete. Calculation results were agreed well with the tested ones.

Abstract: A large number of non-dispersible underwater concrete materials will be extensively used in works which span over rivers and sea, so it is important to study the performance of non-dispersible under water concrete structures. Non-dispersible underwater concrete is the concrete mixing with special additives-anti-washout admixture, which is a kind of water-soluble polymers with long-chain structure and strong absorption capacity. In the present paper, the axial and eccentric compression performance of non-dispersible underwater concrete columns were experimentally investigated. The failure modes and loading capacity of the columns of non-dispersible underwater concrete were mainly discussed. The experimental results showed that the compression performance of non-dispersible underwater reinforced concrete columns and the common reinforced ones are similar in some aspects.

Abstract: In order to ensure the safety of the staff and the property of our laboratory, and guarantee the ship/bridge crash test conducted safely and smoothly, we adopt the safety monitoring system to supervise the whole ship/bridge crash testing laboratory and to be early warning, under the background of special application of ship/bridge crash testing laboratory. According to the actual site of crash testing laboratory, we choose the most suitable technology and operating principle to satisfy the request of ship/bridge crash testing laboratory. At the case that we do not need to increase the number of camera excessively, we can achieve the maximum coverage of the field of view by choosing the multi-function camera and designing the layout of it, and we will take advantage of the broadcasting alarm system to reach the purpose of keeping the safety of our laboratory. The results of actual application show that the staffs in the monitoring room can take the whole laboratory under their controls if we make use of this kind of safety monitoring system of ship/bridge crash testing laboratory, and we can fully protect the safety of the staff and the property of our laboratory. For the pretty good stableness and capacity of resisting disturbance, the system can greatly satisfy the request of keeping safety and early alarm.

Abstract: Mechanical properties of CFT column and steel beam joint with inner stiffening ring was analyzed by using FEA program ANSYS. Simultaneity, using correlative theory of circular beam, stress distributing rule of stiffening ring was induced. The multi-dimensions joint is different from the annular plane in bidirectional. Not only the turn of beam-annular stress concentration, but also lied on the oblique angle, smaller of the angle easier to form the biggest stress area. Thickness of stiffening ring can impact on load absorption of enforced plane. Results of FEA are valuable methods for design of stiffening ring.

Abstract: Yield Point Spectra (YPS) are used to indicate the influence of P-∆ effects on the lateral strengths of structures with constant ductility demands. The intensity of P-∆ effects is represented by an index, called the effective height, h_eff . Both the yield displacement and the effective height are stable parameters, even when the structure shows nonlinear behavior. The strength ratio, n, is defined as the ratio of lateral strength associated with P-∆ effect at the peak displacement and the total strength developed at the peak displacement response. In this paper by Ploting strength ratio(n) vs. yield displacement , the influence of P-∆ effects has been verified.

Abstract: Progressive collapse refers to a phenomenon in which a local damage of a primary structural element leads to the failure of partial or whole structural system. To investigate the progressive collapse of structures, nonlinear dynamic procedure leads to more accurate results than static procedures. Nonlinear dynamic procedure is very complicated and the evaluation or validation of its results may be very time-consuming. Therefore using simplified methods are very important. This paper presents a simplified and accurate analysis procedure for progressive collapse analysis of steel structures. The proposed method results show to have good agreement with nonlinear dynamic analysis results. Also, the capacity curve obtained from dividing the accumulated area under the nonlinear static load-displacement curve by the corresponding displacement of the column-removed point is used to predict the progressive collapse resistance of the column-removed structure.

Abstract: This paper gets the column-end moment amplification factors of the concrete frame in the seismic zones of intensity seven and eight, by using the software CANNY and the method of pushover. The results show that when considering the casting slab, the reinforced concrete frame can develop a strong column and weak beam yielding mechanism when the column moment amplification factor adopts 1.4 for seven intensity area and 1.2 for eight intensity zone, preventing the development of collapse.

Abstract: Transfer structures in recent years have been well used in building structures. In this paper a new type of beam transfer structure with haunching braces is presented. Push-over analysis on an example structure against the new reinforced concrete transfer frame with haunching braces is conducted. The development feature of the plastic deformation of the structure and the responses of the acceleration and displacement during elasto-plastic stage of the structure are discussed. The seismic performance of the structure is evalated using Capacity Spectrum Method. The results show that the height of the section of the transfer beam with haunching braces should be selected between 1/10~1/8 of span, combined with the position of haunching braces and the upper loading. The seismic performance point of the example structure firstly appears at the ends of ordinary frame beams, indicating that proper design can ensure seismic safety of the transfer structure. It can provide reference for engineering practice.

Abstract: This paper presents an analysis in attachment spacing of tower cranes. Both the support spacing under the rigid support and the flexible support are obtained for this purpose. For deriving the rigid support spacing, differential equation is used. The principle is used for calculating the support spacing, which the extended segment has the same Euler critical force with the independent segment. The flexible support distance is obtained by setting the integrated stiffness matrix zero, which is equivalent to structural instability. The order of the overall stiffness matrix is big when the tower crane is attached many times. In order to calculate more convenient for solving the matrix determinant, a transfer matrix method is adopted. To verify the influence of the flexibility caused by the support device, an example is carried out by both rigid and flexible support situations for this purpose, and the support spacing is computed numerically. Numerical results for the support distances of a tower crane will be presented and discussed.

Abstract: The behavior of materials under repeated loading has been examined, but extended studies are more and more needed especially for damaged reinforced structures such as bridges, where high-cycle fatigue phenomena and corrosion can be significant. In the present paper, a theoretical model based on fatigue performance of materials and stress analysis for cross-section is proposed in order to analyze the fatigue damage of corroded reinforced concrete beams under repeated loads. Further, fatigue life is predicted by applying this method, and the method is evaluated by test results.