Jun Wu Dai

Dynamic Response of Ceiling System with Light Steel Furring and Gypsum Board under Severe Earthquake

In order to make sure reliability of ceiling system according to the current code, response acceleration of ceiling suspension points are obtained by seismic model developed by ANSYS/LS-DYNA. Then the FE model of ceiling system according to the current code is also developed in ANSYS/LS-DYNA. The input acceleration is added on ceiling suspension point. The following features are obtained from ceiling system with light steel furring and gypsum board under severe earthquake. These are: 1 Many gypsum boards which are designed according to the current code are failed and drop down，that may result in casualties. 2 The furrings are failed and did not drop down, then may drop for higher peak acceleration. 3 The ceiling system according to the current code is not safe under severe earthquake.

Collapse-Resistance Measure for the Bottom Frame Structure under Earthquake

The bottom frame structure, with serious earthquake damage, occupies a large proportion in the houses collapsed in earthquakes. However, because it is economic and practical, it is still widely used. Based on the understanding of the seismic performance of bottom frame structure, this paper determines to study seismic measures of the bottom frame structure. The current seismic measures can be divided into two major categories: strengthening key components and avoiding key components, therefore this paper adopts the method of strengthening parts which are easy to collapse for reinforcement, under the premise of meeting the stiffness ratio between reasonable layers, adds wing wall to improve the capacity of resisting collapse of the structure and pinpoints the efficiency of adding wing wall in the capacity of resisting collapse through quantitative analysis. Although there are differences in the improvement of the capacity of resisting collapse under different seismic waves, adding wing walls reasonably can greatly improver the anti-collapse capacity of the structure..

Research Status for Nonstructural Components under Severe Earthquake

This paper introduces the seismic damage of nonstructural system under severe earthquake at home and abroad. Then seismic research on nonstructural system is little, and that does not match to severe damage, especially the nonstructural system cost high proportions of total price. Damage of nonstructural system has affected people in the life and property safety in the earthquake. Moreover, the paper pays more attention to ceiling system under seismic.

Seismic Damage of Suspended System in Lushan Earthquake

The seismic damage of nonstructural system is severely, and has affect escaped from building and rescue. Suspending system is the typical one of the nonstructural system. This paper investigated the seismic damage of suspending system in Lushan earthquake. Suspending system of many buildings are failure, especially for the hospital and gymnasium which is used for disadvantaged group and rescue. Moreover, design of suspending systerm is lack of industrial standards, so much attention should be paid.

Impact Response and Failure Mode for Single-Layer Geodesic Spherical Domes under Impact Load

Based on the ANSYS/LS-DYNA software, the analysis for the 40m span geodesic spherical domes under impact load is carried out. By changing the mass of impact object, impact velocity and impact location, the parametric analyses on the dynamic response of the structures under the impact loading are carried out. The three failure modes of the spherical domes are summed up: local dent of structure and global collapse of structure, Punch failure of structure. Then the characteristics of the dynamic response of the structure with different failure mode, such as the impact course, impact load, speed of nodes, displacement of nodes, and stress of bars, are investigated. It is further improvement of failure mode for single-layer reticulated dome under impact.

Ambient Vibration Test on Earthquake Damaged R/C Building Structures

Reinforcement concrete (R/C) structure is constructed and developed very rapidly in recent 30 years with the economic increasing not only in metropolitan cities but also in wide rural areas of China. It’s famous for its’ easy construction and high load bearing capacity. But in recent large earthquakes, more and more different type of severe damages about R/C structures have been observed due to either unreasonable design or extra-high ground shaking intensity exceeding the design level mostly. In the field investigation for the 2010 Yushu Ms7.1 earthquake of China, six RC frame buildings, were investigated and tested by means of the ambient vibration test method. Both of the test results of the natural frequency for each building as well as its’ damage pattern were described and briefly analyzed in this paper. The investigation results provide reference data for nonlinear numerical analysis and retrofitting of RC frame building structures.

Seismic Damage Analysis for Multi-Story Masonry Building with R. C. Frames on Ground Floor

Multi-story Masonry Building with R. C. Frames on Ground Floor (Framed-Ground Floor Structure for short) which has serious seismic damage and high collapsed rate, is the unreasonable structure system. However, the structure system not be abolished for economic reason. Collapse types of that are divided into collapse of ground floor, collapse of transition layer, global collapse. And seismic damage is also serious for frame column and shear wall. Experiences are obtained from above seismic damage, and the following aspects should be taken into account in the future. 1. The shear wall can be increased to improve stiffness of weak layer. And designer should try to arrange the walls equably. 2. In order to avoid stiffness mutation, stiffness ratio between ground frame and transition layer can be adjusted. 3. Collapse resistant design of Framed-Ground Floor Structures should be emphasized.

Failure Modes for Single-Layer Reticulated Domes under Oblique Impact

FE models of both the single-layer Kiewitt-8 reticulated domes with a span of 60m and the cylindrical impactor were developed incorporating ANSYS/LS-DYNA. Afterward, fourteen groups impact are simulated by changing the impact position or impacted angle on reticulated dome, and impact velocity and mass of impactor are changed for each group impact. On the basis of large numbers of numerical simulations, characteristics of dynamic response for reticulated dome under impact are shown. And four failure modes (Members slightly damaged, Local collapse of dome, Global collapse of dome, Members shear failed) are presented for single-layer Kiewitt-8 reticulated dome under diverse impact. The distributing of failure modes for the fourteen types impact are different from each other, and the adverse position and angle are summrized.

GB ASME & RCCM Analysis of Piping Design Camparison about Class 2 Components

Three primary nuclear technique of RCCM, ASME and the GB50267-97 code of China, have the similar classification of nuclear facility in nuclear power plant, including the code class and security class. The class 2 pressure pipeline design clauses in the 3 codes are similar, but are not identical. The earthquake input and the clauses about the class 2 pressure pipeline are compared. The results show that, when use the alternative damping values for response spectra analysis, GB and ASME are somewhat safer than RCCM in level B criteria, RCCM is somewhat safer than GB and ASME in level D criteria. In class 2 piping design code, RCCM stress assessment focuses more on the pressure, the GB and ASME is more focuses on considering the weight and occasional loads, in the lower pressure and the same stress intensification factor conditions, GB and ASME criteria are conservative than RCCM.

Cost Estimation Method of Post-Earthquake Rehabilitation of Power System

Power system related to the peoples livelihood is an important lifeline and its rapid post-earthquake rehabilitation and reconstruction is particularly important. Considering the importance of power system, cost estimation method of post-earthquake rehabilitation of power system is proposed. Based on the direct economic losses of power system, post-earthquake rehabilitation cost is given by index of the post-earthquake adjustment factor which is put forward according to post-earthquake rehabilitation cost and direct economic losses of power system in “5.12” Wenchuan earthquake. Cost estimation method of post-earthquake rehabilitation of power system could provide good suggestions for post-earthquake rehabilitation work.