scholarly journals Design and Static-Performance Evaluation of Concrete-Filled-Tube Rock Shed Structure

2020 ◽  
Vol 20 (5) ◽  
pp. 165-173
Author(s):  
Juho Lee ◽  
Hyeoung-Deok Lee ◽  
Jong-Keol Song ◽  
Jiho Moon
Keyword(s):  
Performance Evaluation ◽  
Debris Flow ◽  
Static Analysis ◽  
Static Load ◽  
The Road ◽  
Equivalent Static Load ◽  
Static Performance ◽  
New Type ◽  
Cut Slopes ◽  
Rockfall Protection

Rockfall protection facilities are necessary to reduce damages from rockfall or debris flow on roads near steep cut slopes. In Korea, rockfall protection fences and rock sheds are widely utilized for rockfall protection facilities. The rock shed is made of reinforced concrete or steel in the shape of a tunnel, and it is used for protecting the road from massive rockfall (up to 3,000 kJ of rockfall energy). In this study, a new type of rock shed comprising a Concrete-Filled-Tube (CFT) was designed. First, the proposed CFT rock shed could resist up to 3,000 kJ rockfall energy. Next, the performance of the CFT was verified through static analysis in which the 3,000 kJ rockfall energy was considered as the equivalent static load.

Sublimation of composite ice and its influence on performance of ice shells

2021 ◽  
Vol 36 (1) ◽  
pp. 67-77
Author(s):  
Yue Wu ◽  
Junkai Huang ◽  
Jiafeng Chen
Keyword(s):  
Numerical Simulation ◽  
Shell Structure ◽  
Composite Shell ◽  
Engineering Practice ◽  
Sublimation Rate ◽  
Long Span ◽  
Static Performance ◽  
New Type ◽  
Ice Sublimation ◽  
Composite Shell Structure

The long-span ice composite shell structure is a new type of ice and snow structure developed in recent years. The engineering practice of ice composite shell shows that sublimation is one of the important reasons for its damage and even collapse. In this paper, we firstly supplemented the existing H-K equation and obtained the revised ice sublimation equation through indoor evaporative plate experiment considering the influence of admixtures and wind speed. Afterwards, combining the simulations of solar radiation and CFD, the numerical simulation of sublimation distribution on the surface of were realized by programming in Grasshopper platform. During sublimation, the thickness of the ice composite shell decreases by 0.38 mm every 10 days and the sublimation rate on the sunny side was 1.7 times that on the shady side. Finally, the static performance and stability of the sublimated ice composite spherical shell were analyzed. After 70 days of sublimation, the thickness of the ice composite shell structure becomes thinner and uneven, which leads its sensitivity to external load increases.

Determination of seismic design forces by equivalent static load method

2003 ◽  
Vol 30 (2) ◽  
pp. 287-307 ◽  
Author(s):  
JagMohan Humar ◽  
Mohamed A Mahgoub
Keyword(s):  
Seismic Design ◽  
Static Load ◽  
Base Shear ◽  
Uniform Hazard Spectra ◽  
Uniform Hazard Spectrum ◽  
Higher Mode Effects ◽  
Mode Effects ◽  
Equivalent Static Load ◽  
Adjustment Factors ◽  
Mode Vibration

In the proposed 2005 edition of the National Building Code of Canada (NBCC), the seismic hazard will be represented by uniform hazard spectra corresponding to a 2% probability of being exceeded in 50 years. The seismic design base shear for use in an equivalent static load method of design will be obtained from the uniform hazard spectrum for the site corresponding to the first mode period of the building. Because this procedure ignores the effect of higher modes, the base shear so derived must be suitably adjusted. A procedure for deriving the base shear adjustment factors for different types of structural systems is described and the adjustment factor values proposed for the 2005 NBCC are presented. The adjusted base shear will be distributed across the height of the building in accordance with the provisions in the current version of the code. Since the code-specified distribution is primarily based on the first mode vibration shape, it leads to an overestimation of the overturning moments, which should therefore be suitably adjusted. Adjustment factors that must be applied to the overturning moments at the base and across the height are derived for different structural shapes, and the empirical values for use in the 2005 NBCC are presented.Key words: uniform hazard spectrum, seismic design base shear, equivalent static load procedure, higher mode effects, base shear adjustment factors, distribution of base shear, overturning moment adjustment factors.

The structural optimization of roadheader conical picks based on fatigue life

2018 ◽  
Vol 09 (02) ◽  
pp. 1850013 ◽  
Author(s):  
Zhenguo Lu ◽  
Lirong Wan ◽  
Qingliang Zeng ◽  
Xin Zhang ◽  
Kuidong Gao
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Static Analysis ◽  
Element Model ◽  
Cutting Resistance ◽  
Strength Failure ◽  
New Type ◽  
Conical Picks ◽  
Fatigue Life Analysis ◽  
The Finite Element Model

Conical picks are the key cutting components used on roadheaders, and they are replaced frequently because of the bad working conditions. Picks did not meet the fatigue life when they were damaged by abrasion, so the pick fatigue life and strength are excessive. In the paper, in order to reduce the abrasion and save the materials, structure optimization was carried out. For static analysis and fatigue life prediction, the simulation program was proposed based on mathematical models to obtain the cutting resistance. Furthermore, the finite element models for static analysis and fatigue life analysis were proposed. The results indicated that fatigue life damage and strength failure of the cutting pick would never happen. Subsequently, the initial optimization model and the finite element model of picks were developed. According to the optimized results, a new type of pick was developed based on the working and installing conditions of the traditional pick. Finally, the previous analysis methods used for traditional methods were carried out again for the new type picks. The results show that new type of pick can satisfy the strength and fatigue life requirements.

Application of a combined and automated monitoring and early warning system for debris flows at the Dawinbach

2021 ◽  
Author(s):  
Tobias Schöffl ◽  
Richard Koschuch ◽  
Philipp Jocham ◽  
Johannes Hübl
Keyword(s):  
Debris Flow ◽  
Early Warning ◽  
Pulse Compression ◽  
Mitigation Measures ◽  
Heavy Rainfall Event ◽  
Monitoring Site ◽  
Traffic Lights ◽  
The Road ◽  
Pulse Compression Radar ◽  
Monitoring And Early Warning

<p>After a heavy rainfall event on August 31<sup>st</sup>, 2019, a debris flow at the Dawinbach in the municipality of Strengen (Tyrol, Austria) caused a blockage of the culvert below the provincial road B-316 and deposition in the residential area. The debris deposition raised up to 2 to 3 meters on the road and led to property damage to real estate. The total volume of the debris flow was approximately 15 000 cubic meters.</p><p>In order to control a further debris flow of this magnitude, the Austrian Service of Torrent and Avalanche Control started to construct mitigation measures. They include a channel relocation in order to significantly increase the channel crosssection. Hence the construction company STRABAG is also relocating the provincial road bridge.</p><p>Since the risk for this road section and for the workers on site is particularly high during the construction period, a combined monitoring and early warning concept was developed and implemented by the BOKU, Vienna and the company IBTP Koschuch.</p><p>The monitoring site consisting of a pulse compression radar and a pull rope system was installed 800m upstream from the fan. The combination of the two sensors now results in three major advantages.</p><ul><li>At sensor level, the system operates redundantly.</li> <li>A more reliable differentiation between increased discharge or debris flow is given.</li> <li>In the event of a false alarm, the system provides easier diagnosis and assignment of the fault.</li> </ul><p>Two events of increased runoff occurred during the deployment period. Both were successfully detected by the pulse compression radar. Here, the first event was used for threshold validation of the radar unit. Thus, an alarm could already be sent out automatically for the second one. The road is controlled by an integrated light signal system consisting of three traffic lights. A siren near the construction site can warn workers of an impending event by means of an acoustic signal. The reaction time after the alarm has been triggered is between 75 and 150 seconds, depending on the speed of the debris flow. The responsible authorities are informed by sending an SMS chain, which includes details about the type of process and the type of the activated triggering system.</p>

scholarly journals Optimization of Performance Evaluation of Urban Road Pavement

2021 ◽  
Vol 283 ◽  
pp. 02033
Author(s):  
Ziyi Zhang ◽  
Yu Sun ◽  
Han Xu ◽  
Qiyun Zhu
Keyword(s):  
Performance Evaluation ◽  
Evaluation Model ◽  
Vital Role ◽  
Set Pair Analysis ◽  
Road Maintenance ◽  
Entropy Weight ◽  
Urban Road ◽  
The Road ◽  
Road Pavement ◽  
Pair Analysis

In recent years, urbanization has developed rapidly, and urban road play a vital role as the premise. Due to the good effectiveness of asphalt pavement, which is more popular in urban road, and road maintenance demands are also increasing. In order to make the maintenance work appropriate, accurate pavement performance evaluation is the premise. This paper collects the data of a road pavement condition in Shanghai and calculates the sub-indexes of each section. We use the entropy weight method to obtain the influence degree of each sub-index. Then we use the revised set pair analysis to construct the comprehensive performance evaluation model of urban road pavement. The analysis shows that compared with the standard method and the set pair analysis, the revised model is more objective, in line with the actual use of the road.

scholarly journals Erratum: “Experimental study on dynamic and static performance of a new type of pressure-absorbing energy bolt system” [AIP Adv. 11, 075124 (2021)]

AIP Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 099901
Author(s):  
Yi Zhang ◽  
Qiyu Chen ◽  
Wei Zhang ◽  
Zhiying Lu ◽  
Youbao Ma ◽  
...  
Keyword(s):  
Experimental Study ◽  
Static Performance ◽  
New Type

scholarly journals FEATURES OF MODELING THE DRIVE UNIT OF THE MIXER WITH BIDIRECTIONAL ROTATIONAL IMPACT ON THE MATERIAL

2020 ◽  
pp. 101-107
Author(s):  
K. Yudin ◽  
A. Pogosbekov
Keyword(s):  
Static Analysis ◽  
Frequency Converter ◽  
Practical Implementation ◽  
Belt Drive ◽  
Unit Operation ◽  
The Finite Element Method ◽  
Drive Unit ◽  
Mixing Chamber ◽  
New Type ◽  
Selection Of

Periodical mixers are considered. The expediency of developing a new type of mixer is presented. Features of the material movement in the mixer allow to speak about the presence of elements of a gyroscopic effect. The mixing chamber is rotated by means of belt, chain and conical transmission. The resulting complex spatial movement of material particles can be controlled by a frequency Converter and the selection of appropriate gears or using a belt drive. An algorithm for modeling the drive unit of a mixer with a bidirectional rotational effect on the material is presented. The features of the drive unit and its components are considered. The task is to build a model of deformation of the drive unit of the mixer. The finite element method (FEM) for the drive unit of the mixer is used. Machine experiments are performed that implement fatigue calculations of the drive unit with a study in the SolidWorks Simulation environment. The results of static analysis of the drive unit operation in determining the deformation, static analysis of the drive unit operation in determining the voltage with varying torque are obtained. A variant of static analysis is presented when using a belt drive instead of a gear drive. The practical implementation of the mixer drive unit in metal is shown. Conclusions on modeling are made.

scholarly journals Numerical Simulation of Dynamic Response and Evaluation of Flexural Damage of RC Columns under Horizontal Impact Load

2021 ◽  
Vol 11 (23) ◽  
pp. 11223
Author(s):  
Bin Hu ◽  
Jian Cai ◽  
Jiabin Ye
Keyword(s):  
Static Load ◽  
Impact Load ◽  
Bending Moment ◽  
Internal Force ◽  
Displacement Curve ◽  
Fe Model ◽  
Damage State ◽  
Rc Columns ◽  
Equivalent Static Load ◽  
The Impact

By using the ABAQUS finite element (FE) model, which has been verified by experiments, the deformation and internal force changes of RC columns during the impact process are investigated, and a parametric analysis is conducted under different impact kinetic energies Ek. According to the development path of the bottom bending moment-column top displacement curve under impact, the member is in a slight damage state when the curve rebounds before reaching the peak and in a moderate or severe damage state when the curve exceeds the peak, in which case the specific damage state of the member needs to be determined by examining whether there is a secondary descending stage in the curve. Accordingly, a qualitative method for evaluating the bending failure of RC column members under impact is obtained. In addition, the damage state of RC columns under impact can also be quantitatively evaluated by the ratio of the equivalent static load Feq and the ultimate static load-bearing capacity Fsu.

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