scholarly journals Seismic Base Isolators For A Silo Supporting Structure

2015 ◽  
Vol 11 (2) ◽  
pp. 1-9
Author(s):  
Daniel Bîtcă ◽  
Emilian Ursu ◽  
Paul Ioan
Keyword(s):  
Cross Sections ◽  
Seismic Action ◽  
Material Consumption ◽  
Ground Acceleration ◽  
Supporting Structure ◽  
Maltese Cross ◽  
Small Intensity ◽  
The Cost ◽  
Seismic Area ◽  
Base Isolators

Abstract A 3000 tones capacity silo, located in a seismic area with ground acceleration ag = 0,20g and TC =1,0s, was designed in a classical solution The supporting structure has an octagonal shape in planview, and columns with “Maltese cross sections”. The main lateral resisting system is made up of centric bracings with cross-section class I. The technological project has required two silos and the solution was to support them on a common raft foundation. The stresses and strains due the seismic action led to material consumption that exceeded the agreed budget. In order to reduce the costs, two versions of isolator positions were studied: base isolators (at the connection between infrastructure and superstructure) and at the silo’s bearing level on the supporting structure. A number of eight vertical seismic isolators were used and in order to limit the horizontal displacements due to wind action and for small intensity earthquakes special devices were introduced Comparing the state of stresses and deformations and also the cost analysis regarding the positioning of the isolators, the second solution was chosen as the most feasible.

scholarly journals Case Study of a Heavily Damaged Building during the 2016 MW 7.8 Ecuador Earthquake: Directionality Effects in Seismic Actions and Damage Assessment

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 74
Author(s):  
Luis A. Pinzón ◽  
Luis G. Pujades ◽  
Irving Medranda ◽  
Rodrigo E. Alva
Keyword(s):  
Damage Assessment ◽  
Strong Motion ◽  
Response Spectra ◽  
Seismic Action ◽  
Damage State ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Capacity Curves ◽  
Building Orientation

In this work, the directionality effects during the MW 7.8 earthquake, which occurred in Muisne (Ecuador) on 16 April 2016, were analyzed under two perspectives. The first one deals with the influence of these effects on seismic intensity measures (IMs), while the second refers to the assessment of the expected damage of a specific building located in Manta city, Ecuador, as a function of its azimuthal orientation. The records of strong motion in 21 accelerometric stations were used to analyze directionality in seismic actions. At the closest station to the epicenter (RRup = 20 km), the peak ground acceleration was 1380 cm/s2 (EW component of the APED station). A detailed study of the response spectra ratifies the importance of directionality and confirms the need to consider these effects in seismic hazard studies. Differences between IMs values that consider the directionality and those obtained from the as-recorded accelerograms are significant and they agree with studies carried out in other regions. Concerning the variation of the expected damage with respect to the building orientation, a reinforced concrete building, which was seriously affected by the earthquake, was taken as a case study. For this analysis, the accelerograms recorded at a nearby station and detailed structural documentation were used. The ETABS software was used for the structural analysis. Modal and pushover analyses were performed, obtaining capacity curves and capacity spectra in the two main axes of the building. Two advanced methods for damage assessment were used to obtain fragility and mean damage state curves. The performance points were obtained through the linear equivalent approximation. This allows estimation and analysis of the expected mean damage state and the probability of complete damage as functions of the building orientation. Results show that the actual probability of complete damage is close to 60%. This fact is mainly due to the greater severity of the seismic action in one of the two main axes of the building. The results are in accordance with the damage produced by the earthquake in the building and confirm the need to consider the directionality effects in damage and seismic risk assessments.

Research the Utilization Rate of Aluminum Alloy Material

2014 ◽  
Vol 595 ◽  
pp. 79-82
Author(s):  
De Ying Sun
Keyword(s):  
Aluminum Alloy ◽  
Complex Structure ◽  
Unit Cost ◽  
High Strength ◽  
Alloy Sheet ◽  
Machining Process ◽  
Utilization Rate ◽  
Material Consumption ◽  
The Individual ◽  
The Cost

There are many parts in aerospace fixing device, the 7075 - t351 brand aluminum alloy is a commonly used material of these parts [2].The material has high strength, good toughness, wear resistance and resistance to spalling corrosion resistance and other characteristics; After the machining deformation, comprehensive mechanical processing performance is good [1]. As a result, the materials are widely used in aerospace equipment. Smaller wall thickness, complex structure, multiple azimuth need processing, is the characteristics of these parts, make the individual parts machining material consumption is larger, increase the cost of the material consumption. In this paper, through the analysis of part structure and machining process, adopt to layout method, in order to improve the utilization rate of aluminum alloy sheet metal, reduce the unit cost.

Analysis and Demonstrative Application of a Base Isolation/Supplemental Damping Technology

2008 ◽  
Vol 24 (3) ◽  
pp. 775-793 ◽  
Author(s):  
Stefano Sorace ◽  
Gloria Terenzi
Keyword(s):  
Base Isolation ◽  
Numerical Models ◽  
Ground Acceleration ◽  
Fixed Base ◽  
Supplemental Damping ◽  
And Performance ◽  
High Damping Rubber ◽  
Design Earthquake ◽  
Rubber Bearings ◽  
The Cost

As a concluding step of several studies on a special base isolation/supplemental damping system, where pressurized fluid viscous spring-dampers are coupled to steel-Teflon sliders, the system was applied for the first time to a demonstrative strategic building in Italy. A final experimental campaign was developed to assess the interference of the dissipative actions of the two component devices. The campaign confirmed the linear additive combination implicitly assumed in relevant numerical models. The design and performance evaluation analyses performed on the building showed that maximum base displacements were only just below 45 mm, for the basic design earthquake level. As a result, very simple joints for all the facilities were used. For the same earthquake level, reduction factors of 2.48 and 2.12 on the superstructure response accelerations were obtained for the two main directions in plan as compared to peak ground acceleration. Low base displacement values, and a totally elastic superstructure response also emerged for the maximum earthquake level considered, as well as for the most demanding Italian historical near-fault ground motions introduced as inputs in the final verification analyses. The cost of the building structure resulted to be around 10% lower than the cost of a fixed-base traditional design, as well as of a base isolated structure incorporating high damping rubber bearings.

Extreme Modal Combinations for Pushover Analysis of RC Buildings

2013 ◽  
Vol 553 ◽  
pp. 117-124
Author(s):  
Ante Mihanović ◽  
Boris Trogrlić ◽  
Ivan Balić
Keyword(s):  
Limit State ◽  
Pushover Analysis ◽  
Mode Shapes ◽  
Eurocode 8 ◽  
Elastic Model ◽  
Seismic Action ◽  
Target Displacement ◽  
Ground Acceleration ◽  
Higher Modes ◽  
Practical Procedure

The pushover method is a practical procedure for comprehensive nonlinear analysis of structures subjected to seismic action. Application of this method, in accordance with the Eurocode 8 rules and due to engineering simplicity, favours application utilizing the first mode. The aim of the presented research in this paper was to find the influence of multi modal combinations in assessing the bearing capacity of reinforced concrete (RC) frames and walls. This paper presents a procedure in which the most extreme state is defined by the lowest ground acceleration caused by a predetermined shape of an elastic spectrum. The extreme bearing value is obtained by the envelope principle. Mode shapes and period sizes are determined on a linear elastic model while the limit state of the load bearing system is evaluated in a nonlinear state of structures. Results of the analysis show that influences of higher modes are significantly higher and that the safety/reliability, indicated by the criteria for the target displacement, in accordance with Eurocode 8 (Annex B), is not achieved. Inclusion of higher modes, in some presented examples, decreases the peak ground acceleration by more than two times, which is significantly less favourable than the target displacement criteria.

Bison Jump Location is Primarily Predicted by Minimizing Visibility at the Wold Site, Johnson County, Wyoming

2016 ◽  
Vol 81 (4) ◽  
pp. 752-763 ◽  
Author(s):  
Brigid S. Grund ◽  
Spencer R. Pelton ◽  
Todd A. Surovell ◽  
Neffra A. Matthews ◽  
Tommy A. Noble
Keyword(s):  
Great Plains ◽  
Cross Sections ◽  
Steep Slope ◽  
Bison Bison ◽  
Visibility Analysis ◽  
Johnson County ◽  
Cost Paths ◽  
The Cost ◽  
Least Cost Paths

The Wold Bison Jump (48JO966) is a communal bison (Bison bison) hunting site in Johnson County, Wyoming. It likely represents a single kill event precipitated by Great Plains foragers between A.D. 1433 and 1643. Operating the jump required that prehistoric hunters drive stampeding bison up a steep slope in order to position them within a V-shaped drive line configured to funnel them toward a cliff. Using iterative models of least cost paths, topographic cross-sections, and visibility analysis, we test which landscape-embedded variables are optimized at the jump site as compared to other potential localities across the study area. We find that this site’s placement is primarily explained by minimizing the distance at which the cliff face is visible and secondarily by minimizing the cost of slope and curvature routes ascending into the drive lines. Our procedure could hypothetically be used to predict optimal jump locations on similar landscapes.

scholarly journals Effect of Column Dimensions on Seismic Behavior of Multi-Storey Buildings

2020 ◽  
Vol 9 (12) ◽  
pp. 193-195
Keyword(s):  
Cross Sections ◽  
Seismic Behavior ◽  
Seismic Action ◽  
Lateral Loads ◽  
Base Shear ◽  
Structural Mechanism ◽  
Rc Frames ◽  
Seismic Force ◽  
Nonlinear Static ◽  
Storey Building

This study aims at considering the effect of columns size on the seismic performance of reinforced concrete structures, in this article, three RC frames with different columns sizes have been analyzed. The five-storey building is analyzed for seismic force by Choosing three different type column cross-sections of the structural mechanism. i.e. (60x45) cm, (550x45) cm and (50x40). To assess the behavior of multi-storey building under seismic action Nonlinear static analyses for lateral loads were performed by using standard package SAP2000 software. The comparison of these frames for various earthquake response parameters like stiffness and base shear with roof displacement was executed. It is observed that the seismic efficiency in frame 1 of column dimensions(60x45) cm was significantly large with small displacements and The results are well-illustrated in this article.

Gun Barrel Refurbishing Using a Shrink-Fitted Autofrettaged Liner

2018 ◽  
Vol 140 (2) ◽  
Author(s):  
J. Perry ◽  
M. Perl
Keyword(s):  
Cross Sections ◽  
Cost Effective ◽  
Von Mises Stress ◽  
Maximum Pressure ◽  
Internal Diameter ◽  
Original Performance ◽  
Gun Barrel ◽  
Von Mises ◽  
Von Mises Stresses ◽  
The Cost

During the firing of guns, the barrel undergoes two major damaging processes: wear of its inner surface and internal cracking. Barrel's are condemned based on either the increase of their internal diameter due to wear or the severity of their internal cracking. The cost of replacing such a damaged gun barrel runs in the tenth of thousands of U.S.$. Therefore, cost effective methods are sought for restoring such gun barrels. In the present analysis, a new method is proposed for refurbishing vintage gun barrels by machining their inner damaged layer and replacing it by an intact, autofrettaged, shrink-fit liner that will restore the barrel to its original performance. The design of the shrink-fitted liner is based on two design principles. First, the von-Mises residual stress distribution through the thickness of the barrel at each of its cross sections along the inserted liner should be at least equal in magnitude to von Mises stress, which prevailed in the original barrel. Second, once the maximum pressure is applied to the compound barrel, the von-Mises stresses at the inner surfaces of the liner machined barrel should be equal to their respective yield stresses. The preliminary results demonstrate the ability of this process to mend such barrels and bringing them back to their initial safe maximum pressure (SMP) and their intact conditions, rather than condemn them. Furthermore, from the authors' experience, based on a preliminary rough estimate, such an alternative seems to be cost effective.

scholarly journals Choice of the Optimum Cross-Sections for 20–110–330 kV Overhead Lines Under Market Conditions / 20–110–330 Kv Gaisvadu Līniju Optimālo Šķērsgriezumu Izvēle Tirgus Apstākļos

2012 ◽  
Vol 49 (6-I) ◽  
pp. 13-22 ◽  
Author(s):  
S. Guseva ◽  
L. Petrichenko
Keyword(s):  
Cross Sections ◽  
Practical Application ◽  
Market Conditions ◽  
Market Prices ◽  
Overhead Lines ◽  
Modified Method ◽  
Discrete Character ◽  
Line Cross ◽  
Electrical Materials ◽  
The Cost

Abstract Approach is proposed to the choice of overhead line cross-sections that would be optimal under market conditions. For this purpose, in the design practice and at network reconstruction two methods exist: of the economic current density, and of the economic intervals. As of now, none of them works properly, since the cost of electrical materials, of building and construction as well as the total investments in a line are determined by the market prices. Therefore, a modified economic intervals’ method has been developed that can work under market conditions. The method allows also considering the discrete character of standard cross-sections for the lines and concrete technical and technically-economic parameters. For practical application of the proposed method, universal economic nomograms for 20-110-330 kV overhead lines have been calculated and constructed. In the paper, a user interface is proposed for realization of the modified method in Matlab environment.

Cycle Considerations for Tactical Fighters in the Early 1990’s

1982 ◽  
Author(s):  
H. D. Snyder
Keyword(s):  
Cross Sections ◽  
Fighter Aircraft ◽  
Significant Parameter ◽  
Operation And Maintenance ◽  
Radar Cross Sections ◽  
And Performance ◽  
The Cost ◽  
Engine Cycle

The requirements for tactical fighter aircraft in the early nineties will call for improved maneuverability from current fighters, as well as shorter takeoff and landing distances, reduced radar cross-sections and IR signatures, and supersonic persistence. Also, the cost of procurement, operation and maintenance of the engine (LCC) will be a significant parameter in determining the type and performance of the next fighter engine. Each of the above requirements has an effect on the engine cycle to be chosen for the next fighter engine. The sum of these effects should result in a specific engine cycle which best answers all of the aircraft needs, but the effects of these requirements tend toward diverse cycles. This paper addresses these issues and presents a comparison of cycles that meet the anticipated requirements for tactical fighter aircraft in the early nineties. The paper also compares the usage of such aircraft in peacetime training to the design mission in combat.

Study of High-Quality Concrete Properties for Roadway Surfaces

2019 ◽  
Vol 974 ◽  
pp. 477-481
Author(s):  
O.V. Kazlitina ◽  
E.S. Glagolev ◽  
A.S. Milkina ◽  
S.A. Kazlitin
Keyword(s):  
Building Materials ◽  
Systematic Approach ◽  
Road Construction ◽  
Fiber Reinforced Concrete ◽  
Concrete Pavements ◽  
Material Consumption ◽  
Cement Concrete ◽  
Concrete Properties ◽  
The Cost ◽  
High Degree

Currently, the device of cement concrete pavements is still less popular than the asphalt covering. In the construction of roads, great attention should be paid to the widespread use of new, efficient building materials and products of improved quality, with a high degree of prefabrication, ensuring an increase in the level of industrialism, a reduction in material consumption and the cost of road construction. The experience of research, design and devices allows a systematic approach to the design appointment, the choice of materials and technologies for the device of cement concrete roads. The device of cement concrete web of fiber-reinforced concrete is one of the promising areas in the construction complex.

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