Applied Mechanics and Materials Vols. 638-640

Abstract: In Northeast China, brick-wood building is widely distributed, but due to the absence of the seismic code, there are many differences between structure and construction technology in different regions .That makes the seismic capacity is uneven. Therefore, we chose the typical brick-wood building in the Northeast as the object of study. Based on seismic data in QianGuo earthquake, using numerical simulation technique to analyze the earthquake damage and failure mechanism of brick-wood building, explores the causes of seismic damage. On this basis, we proposed the new seismic reinforcement technology measures, by comparison has gone through a transformation of a typical brick-wood building aseismic capacity significantly better than the prototype. Meanwhile, this research helps to understand the seismic performance of brick-wood buildings in the Northeast, and to develop appropriate policies on disaster for the region is of great significance.

Abstract: A single bent structure of PHC pile wharf was taken as the research object. A finite element model was established and studied by pushover analysis along the transverse direction by SAP2000. The parameter conversion relationship between response spectrum of ATC-40 and of Chinese codes was studied. Seismic performance evaluation of the wharf structure is conducted. The conclusion is that the single pile yield order of the PHC pile wharf is from the bottom to the top. The wharf structure meets the seismic capacity requirements on condition of frequent earthquake of 7 degree, but needs appropriate reinforcement on condition of rare earthquake of 7 degree.

Abstract: Focusing on a complicated metro station with shallow depth, its three-dimensional calculation model was established, which includes not only the main station structure, but also includes the subsidiary structure such as the entrances and detailed structures such as the holes in the floor. The Davidenkov model was employed to simulate the nonlinear characteristics of the soil. The three-dimensional nonlinear seismic responses were analyzed. it can be shown from the calculation that: (1) the metro station structure can satisfy the demand under given seismic motion; (2) it is more important for structural concept design and structural measures design than the strength and deformation design for complicated underground structures.

Abstract: To protect Chinese ancient buildings, tou-kung (bracket sets) in the Forbidden City in Beijing were taken as example to study their aseismic constitution problems and strengthening methods by survey as well as analysis methods. According to constitution characters and mechanical performances of these tou-kungs, their typical aseismic constitution problems were summed up, causes for the problems were discussed, and strengthening advices were proposed. Results show that typical aseismic constitution problems of these tou-kungs include decay, crack, deflection, slack and disengage of parts and so on; main causes relate not only to constitution, construction and bearing performances of bracket sets, but also material properties of wood; besides, effectively strengthening methods for these tou-kungs include reassembling, gluing, iron components connection and so on.

Abstract: Buckling-restrained braces (BRBs) and self-centering buckling-restrained braces (SC-BRBs) have been verified as novel energy dissipation bracing systems. This paper conducted a comparative investigation on the seismic-resisting performance of a Benchmark steel frame with these two types of bracing systems using the finite element analysis software OpenSEES. The analysis demonstrated that, in the equal-strength design principle, the SC-BRB frame results in weaker energy dissipation, bigger story drifts, and more evenly distributed story drifts along the building height compared to BRB frame. The residual deformations of SC-BRB frame under strong earthquakes are significantly smaller than the pure frame as well as BRB frame, but the maximum axial bracing force and floor accelerations are increased significantly for SC-BRB frame.

Abstract: A new type of joint between Concrete-filled Square Steel Tube columns and steel beam is proposed in this paper, and the seismic behavior of this type of joint under low-reversed cyclic loading experiment is researched. Ductility behavior, dissipation of seismic energy of this joint under horizontal, repeat load are analyzed. The experimental results showed that all specimens have good ductility and energy dissipation capacity. The story angle drift ductility ratios are μ=3.23~3.63, and the equivalent viscous damping coefficients are he=0.25~0.35,which meet the needs of the code for seismic design of building.

Abstract: The chloride-induced corrosion of steel bars is focused in this study which is one of the major causes of deterioration of RC bridges under marine environments. The steel corrosion usually causes cracking and spalling of the concrete cover due to the expansion of corrosion products. Structural distress due to loss of bond or reduction of the cross-sectional area can be caused with time. A girder bridge exposed to the marine environment is studied to present the fragility curves variance in time in this study. The damage states of the bridge are determined to five stages by using the maximum displacement ductility. The proposed method will be useful to evaluate the seismic performance of new or existing bridges considering steel rebar corrosion.

Abstract: The seismic behavior factor of moment resisting steel frame-steel plate shear wall under two different horizontal loading patterns was investigated according to the maximum inter-story drift ratio reaching 1/50. It could be achieved with the same calculated standard as the foreign codes and the determined behavior factor was compared with foreign research results. The method using the software SAP2000 to calculate seismic behavior factor according to the maximum inter-story drift ratio reaching 1/50 was presented and the specific example was used to elaborate the operating process. The seismic behavior factor R, the overstrength factor R_Ω and the ductility reduction factor R_μ of 10-storey 3-span steel frame-steel plate shear wall under the inverted triangle load are respectively 6.07, 2.96 and 2.05. while they are respectively 7.2, 3.37 and 2.13 under the uniform load. Finally, it can be concluded that the economic and reasonable design goals are achieved for this structure.

Abstract: The reinforcement of a r.c. building for social housing has been achieved by using Steel-Concrete Composite (SCC) walls at the ground floor, preceded by temporary brick pillars for structural deficiency to vertical loads, due to the poor load capacity of the r.c. columns. The SCC walls have been realized first by placing steel columns on both sides of the existing pillars and, after removal of the temporary brick piers, by merging the steel columns in the cast of the new walls. The top of the walls has been connected to the upper floor in order to ensure the diffusion of the seismic forces. Foundations have been reinforced to support the seismic base shear.

Abstract: Side-strengthened reinforced concrete or precast prestressed concrete beam for inadequate seismic performance is proposed in this paper. The factors are simulated by ABAQUS software for the impact of seismic performance, which are difference of material strength grade, initial load and the order of prestressing and pretightening. The strengthening technology can improve the seismic performance of side-strengthened beam. The meterials with different strength grades which used for beams give full play to their role. The initial load has little effect on the seismic performance. The way of prestressing after pretightening plays a favorable effect for the seismic performance. The simulation results can accurately reflect the impact of these factors on the side-strengthened beam.