Applied Mechanics and Materials Vols. 94-96

Abstract: It has studied the influence of roughness, binder and freeze-thaw cycles on strength, durability and other characteristics of interface between new and old concrete in the progress of airport concrete pavement maintenance by doing tests in the conditions of normal temperature and freeze-thaw cycles.

Abstract: The static and crawl tests on the steel orthotropic deck of Xihoumen bridge were performed, which is to study the mechanical behavior and stress history curve of the construction details under traffic loading. The results of the tests reveal that, under the three-axle-weighted 30 t truck, the biggest value of longitudinal stress for the bottom of rib is 51.7MPa，the value of principal stress for the hole upper of diaphragm is 30.8MPa and transversal stress for the deck is 16.7MPa. the length of longitudinal influence line of transversal stress for the deck and vertical stress for the web of rib is about 7.2m. The influences of the principal stress for the opening upper of diaphragm and longitudinal stress for the bottom of rib are 5.4m and10.8m, respectively. Furthermore, the stress range and cycle times were analyzed by sluicing method. Under the condition of the craw tests, cycles of the key details that the stress range is larger than 5MPa for steel orthotropic deck are as follows: the longitudinal stress for the bottom of rib is three times and the biggest value of range is 60.1MPa: the transversal stress for the deck is three times and the biggest value of range is 26.8MPa: the vertical stress for the web of rib is four times and the biggest value of range is 16.1MPa: the principal stress for the hole upper of diaphragm is two times. Finally, Based on the results of dynamic test, and considering the specifications on impact coefficient by various countries, we suggest that impact coefficient shall be adopted in the calculation of fatigue of steel bridge deck; the joints on bridge deck 1+=1.75; for other parts, the calculation of each structure details of longitudinal ribs and deck, 1+=1.0; for calculating lateral girder (diaphragm) details, 1+=1.15.

Abstract: The aseismatic strengthening technique for masonry structure was researched in this paper. The seismic response of a L-type school building with and without isolation system were computed by using software SAP2000. The isolation system were made up of lead rubber bearings or combined Isolation system. The results showed that base-isolated strengthening can reduce not only the translational response but also the torsional response with earthquake. The combined Isolation system was more effetive in decreasing translational response than the lead rubber bearing, but inferior to in decreasing torsion response.

Abstract: This article studies the deformability of Fang Ren Glass Cloth in strengthening autoclaved fly ash brick masonry, based on the experiment of the mechanical behavior of specimens under single-direction loading. It also analyzes grid sticking method and the effect of U、L trim strips anchoring of specimens. One polymer mortar specimen and three strengthening specimens are used in the experiment. The results illustrates that the cracking load、ultimate load and deformability of strengthened masonry are higher than the un-strengthened one. The study has also shown that anchoring is important; the effect of strengthening is remarkable when anchored well.

Abstract: According to the experiment of 11 eccentrically compressed reinforced concrete columns and 1 comparative column under the monotonic loading, the bearing capacity，ductility，and the destruction mode of the columns before and after their consolidation have been compared and analyzed．The experimental results illustrates that external coherence of FRP could effectively enhance their bearing capacity and the improvements have relation to many aspects, such as the number of fiber layers, the category of fiber, approaches of how fiber sheet paste, the width of FRP and consolidation space and so on; the ductility of consolidation column mainly depends on how fabric pasted. Longitudinal pasting fiber sheets can greatly improve the bearing capacity of the column, but its ductility declined; the longitudinal-horizontal pasting fiber sheets can enhance column’s the bearing capacity and ductility and this brings about the best consolidation effects. Additionally, based on the analysis of experimental results, a formula for the bearing capacity of the normal section of the large eccentric loading reinforced concrete column consolidated with FRP sheets has been proposed, and the calculation results tally with the experimental results.

Abstract: Construction quality of epoxy-bonded steel plates is not easy to check for absence of inspection standard in situ. In this paper inspection methods of the critical evaluation factor-bond compactness of epoxy- bonded steel plates, hammer test based multi-level grids and infrared holography, are proposed by theory analysis ,specimen experiments and practical validation in engineering. In final he suggestion on the practical usage of these two methods are also presented.

Abstract: Fire-resistance performance experiments with static loading-fire are investigated about two carbon fiber sheet (CFS) shear strengthened reinforced concrete (RC) beams exposed to the ISO834 standard fire. Shear strengthened RC beams are wrapped with fire insulation material- thick painted fire retardant coatings. Relationship between measure points’ temperature and time are achieved. The results suggest that: the ratio of shear-span is the main factor to fire-resistance rating and failure modes of CFS shear strengthened RC beams in fire; shear-failure fire-resistance rating are increased by thickening fire insulation to shear strengthened RC beams. A computer program is developed to calculate the temperature fields of fire insulated concrete beams shear strengthened with CFS coated thick fireproof material. This program is validated comparing with experimental results. Researches can give a supplement to produce overall fire-resistance factors of CFS shear strengthened reinforced concrete beams at high temperatures.

Abstract: Aim at one tall building structure model, which is a nonlinear three-dimensional finite element model. ANSYS FEM software is used to set up the structure model, proceeding modal analysis on natural vibration period and vibration model; ANSYS FEM software is used to import El Centro and Taft acceleration time-travel curves, which are used in 7 degree film, proceeding elasto-plastic analysis, and compared with the result of PKPM software earthquake static effect, the layer displacement calculation results contrast between two software shows it is consistent, but contrary results occurs in ISDA. So for the similar project design auxiliary FEM analysis is needed; Seven degree rarely met earthquake acceleration time-travel data and larger seismic peak acceleration time-travel imported to research the plastic development.

Abstract: Global stability analysis cannot be ignored for large-span spatial steel structures. Beijing Jiangtai Winter Garden adopts hybrid structure with latticed shell and vertical cables, on which glass curtain wall is fixed. Therein the reticulated shell is composed of 9 spatial arches and other common frames, thus it can be seen as arch-reticulated shell hybrid structure. This paper analyzes the stability of one single arch structure which has the largest span in the whole structure, including buckling analyses and non-linear full range analyses. The results show that the stability of single arch meets requirements, and the nonlinearity has great influence on the stability of single arch structure. Besides, although the initial geometric imperfection has certain effect on the elastic structure, it has little effect on the elasto-plastic one.

Abstract: In this paper, the non-scallop welding joint as the research object is analyzed by ABAQUS software where the implicit analysis method is used to define the residual stress distributions. Based on the thermal analysis, the non-linear quasi-static analysis is also taken, and then the results are compared with the experimental results. The results demonstrated higher accuracy of the finished simulation.