Modal Analysis and Vibration Control of Benfield Frame

There is a low frequency and great amplitude on Benfield frame of Jianfeng chemical plant. With finite element modal, the reasons and mechanism of the vibration on Benfield frame are analyzed and confirmed. And a method of vibration control about the main vibration resource (100V10) is proposed to reduce the amplitude of Benfield frame vibration.     

Simulation of Evacuating Buffer in High-rise Building Fires

Buffer zone set between aisle and anteroom is proposed to improve the traditional mode of pressurizes mechanic smoke extraction. Fire Dynamic Simulation is used to simulate the model of high-rise fire. Eight models are set and analyzed, in which the smoke temperature distribution and concentration distribution are compared, and the best parameters is worked out. The result shows, when exhaust smoke volume is constant, the velocity of air curtain is as low as possible; when the volume of air curtain is constant, the smoke volume is as low as better. Based on the comparison, it is found that the smoke removal efficiency of mode 4 is the best one, which is about 74.06%. The evacuating buffer not only can let smoke out timely, but also can guarantee safe personnel evacuation.     

Simplified Calculation on Across-Wind Response of Tapered High-rise Structures with Circular Section

Now it is complex to calculate across-wind response of tapered high-rise structures with circular section abroad and its research at home is inadequate.Based on random vibration theory and across-wind force spectrum proposed by B.J.Vickery,a simplified formula on maximum across-wind response of tapered high-rise structures with circular section is achieved in this paper.With respect to engineering calculation,the results obtained by simplified method corresponds with those obtained by standard method based on the theory of random vibration well,but the prediction values by approximate method proposed by B.J.Vickery are smaller.     

The Research of Dynamic Characteristic with GPS under Ambient Excitation for High-rise Building

Based on GPS technology,this paper studies the dynamic characteristic under ambient excitation of major blocks of Chongqing University and analyze excitation data and verifies the excitation scheme.The result of research indicates that the building vibration frequency can be obtained accurately and quickly to monitor dynamic characteristic of buildings under ambient excitation with GPS.It provides reference for structural design of high-rise building and basis of correcting error of construction accurately.     

Stability Analysis of Rock Cave Ground under High-rise Buildings

This paper presents an all-side study on one successful engineering project, the Chongqing Zhourong Plaza, twenty floors high with two air raids caves just cross under it. The study includes geological investigation, rock mass parameters choice, elastic-plastic rock mass failure criteria, calculation with finite element method, results analyses, conclusions on stability analyses and construction suggestions.     

Numerical Simulation for Fire Smoke Flow in a High-rise Building with Patio Space

Characteristics of smoke flow and fire spread in a patio space of a high-rise building were studied to investigate their influences on fire compartment and safety evacuation.Fire development model was established and fire scenarios were designed to simulate fire and smoke spread by CFD software numerically based on concepts of fire performance-based design in a high-rise building with double patio space,whose height are 74.65 m and 55.95 m,respectively.Simulation results show that in all fire scenarios,performance targets for safety evacuation for people in each floor was satisfied,if smoke was extracted naturally using the patio space.Hang walls mounted in corridors around the patio space prevent smoke flowing out smoothly,shorten the coming of the risk time and increase fire danger.Using chimney effect,it is preferred to adopt natural smoke exhaust method in a high-rise building with patio space.     

Wind Vibration Analysis on the Large -span Curtain Wall

The large-span structure requires wind vibration analysis when computing the wind load;however,the formula in current code on wind vibration coefficient can hardly be applied in large-span structure,making its computation difficult and troublesome.This paper makes wind vibration analysis on the large-span curtain wall combined with certain engineering background in the methods of both time domain and frequency domain,and then the derived results are compared.The analytical results demonstrate identical distribution and contiguous numerical value of wind vibration coefficient concluded from the two varied methods;furthermore,even if the method in time domain is higher in computational complexity,more data on the response of structure under wind can be obtained,which provides reference for the theoretical analysis and engineering design.     

Analysis of Vibration Experiment for Pedal-motor

Based on the analysis of experimental model, the vibrating experiment was made for the frame and engine of motorcycle in order to find the resonance frequency of the frame. Then the effect of engine exciting on the body vibration was analyzed, so that the mode frequency avoids the range of engine rotation speed. The experiment results show that the vibration of the saddle in vertical direction and the handlebar are caused by the resonance, while the vibrations of the other two directions of saddle and the pedal are the result of the transmission of engine energy. In order to decrease the transmission of the engine energy to pedals, we can change the stiff welding between the pedals and the frame of the motorcycle into the elastic link. Furthermore, to avoid the resonance of the frame in vertical direction, besides increase the stiffness of the frame, we can reduce the stiffness of the frame under the condition of having sufficient intensity, so that the nature frequency of the frame is reduced below the operating speed of the motorcycle engine.     

RC Frame Component's Stiffness Reduction Factor Considering Non-elastic Characteristics

The simplified method, in which second-order elasticity analysis having undergone stiffness reduction is employed to research into sway frames' second order effect, has begun to be accepted by Chinese Standard. In the proper ascertainment of the value of stiffness reduction factor considering non-elastic characteristic, it is advisable to properly choose the checking computation method of the stiffness reduction on the basis of a comprehensive analysis of RC frame. Combined with a contrastive analysis of the present schemes in USA and New Zealand, a scheme to ascertain the RC frames component's stiffness reduction is proposed for the revision of the Chinese Standard.     

Seismic Performance of Regular RC Frame with Specially Shaped Columns

According to the code and technical regulation,an irregular RC frame with specially shaped columns has been designed,which situated at the area of fortification intensity 8. Subsequently,the nonlinear dynamic analysis has been carried out for the structure by inputting ground motions in two directions. After summing up the calculation results,this paper has examined seismic performance of the structure under the rare seismic actions and given a primary evaluation on the structure to see if it could achieve the predetermined anti-seismic aims. It indicates that the structure designed according to the codes can achieve the predetermined anti-seismic aim under the rare earthquake.     

Discussion on the Characteristics of Smoke Movement and Smoke Control Methods in a Shaft of High-Rise Building

Characteristics of smoke movement and smoke control in a shaft is a serious issue that closely related to the fire safety of high-rise building. This paper talks about the studies on the characteristics of smoke movement in a shaft of high-rise building from three aspects: the factors which influence smoke movement in a shaft, the distribution of smoke parameters and the upward velocity of smoke flow. Smoke control methods which are commonly used and the problems in engineering practice are summarized. Some methods thoughts are given to improve the efficiency of smoke control.     

The Mode and Vibration Response of the Double Involute Gear

From the mathematical model of the double involute gear teeth surface at any corner position,we establish the model of the double involute gear with high precision and parameter in Pro/E,analyze and calculate the influence of natural frequency by the parameter of the double involute gear,analyze the frequency respond elementary.The conclusions reflect the gear's performance of dynamics,and provide the librate characteristic data for the design of double involute gear.     

Research of Expert System for High-rise Buildings Foundation Scheme

In this paper, the factors influencing the foundation scheme of high-rise buildings are analyzed. In accordance with the complex hierarchical structure and the uncertainty of foundation scheme, a knowledge base of hierarchical structure is set up and an inexact reasoning is realized. Then, the expert system for high-rise buildings foundation scheme (TBFES) is built on the knowledge base with the expert system tool CLIPS.     

A Study on Characteristics of Elasto_Plastic DisplacementResponse of Structures Under Seismic Action

The characteristics of elasto-plastic displacement response of structures subjected to different types of ground motions are studied and generalized in this paper.     

Application of GPS Technology in High-rise Building Axis Monitoring

In order to meet the modern construction demand,in this paper,with the project where the GPS technology used to monitor the axis of main teaching building of Chongqing University(verticality),the application of this technology is expounded.The result indicates,in high-rise construction,it is a kind of effective method to use GPS to control the axis.