scholarly journals Natural Hazards - Impacts, Adjustments and Resilience

2020 ◽  
Author(s):  
Bhushan Mohan Raisinghani
Keyword(s):  
Local Level ◽  
Design Tools ◽  
High Grade ◽  
Design Codes ◽  
Framed Structures ◽  
Analysis And Design ◽  
Proper Design ◽  
Construction Type ◽  
Rc Framed Structures ◽  
Section Analysis

Reinforced concrete is a global material, the utilization of which has no limits. India is a country that uses mostly RC framed structures as the routine building construction type. The building is made of inter-connecting elements in horizontal and vertical directions. To showcase the effectiveness of high grade of concrete and confining reinforcement much research has been carried out till date from 1980s. However, in design of structures we do not consider the effect of confining reinforcement in resisting stress in any member element. Various tools have been developed to find the capacity of member at element level to resist forces. For performance-based design of buildings, it is necessary to evaluate the performance at individual local level and at global levels. In this study, the effect of available tools (for section analysis) and design codes for member limit calculation is demonstrated and structure is evaluated for the threshold limits given in ASCE-41. It is observed that the code designed members are sufficient to resist lateral earthquake forces effectively for the estimated hazards if proper design tools are employed.

scholarly journals Effect of Unreinforced Masonry Infill Walls on Seismic Performance of Reinforced Concrete Framed Structures

2017 ◽  
Vol 11 (1) ◽  
pp. 919-931 ◽  
Author(s):  
Mohamed M. Abdelaziz ◽  
Mohamed S. Gomaa ◽  
Hany El-Ghazaly
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Unreinforced Masonry ◽  
Shear Forces ◽  
Infill Walls ◽  
Framed Structures ◽  
Masonry Infill ◽  
Analysis And Design ◽  
Masonry Infill Walls ◽  
Rc Framed Structures

Introduction:Unreinforced Masonry infill walls (URM) are commonly used in the Reinforced Concrete (RC) framed structures as interiors and exteriors partition walls. Although they usually are not considered in the structural analysis and design, their influence on the seismic performance of the framed structures is significant. A common practice in the modern and old RC buildings is to remove the URM walls in the lower stories for commercial reasons; garages, storages, shopsetc.Methods:In the present work, the effect of the URM walls on seismic performance of the RC framed structure will be studied. For that, three groups of 2-D three-bay framed structures, which are fully and partially infilled with the URM walls, will be studied. These groups are classified as three stories, six stories, and nine stories RC framed structures representing low, medium and, high rise buildings; respectively. In each group, different infill panels' configuration will be studied in order to simulate the cases of ignoring or considering the stiffness and strength of the URM. Double-strut nonlinear cyclic model for masonry panels has been utilized in order to account for the structural action of the URM walls. Pushover analysis is adopted for the evaluation of the seismic response of the frames considering the material inelasticity and the geometric nonlinearity in the analysis.Results and Conclusion:Some selected numerical simulation results in terms of base shear forces, lateral deflections, and inter-story drift ratios are obtained for all the considered configurations and presented in comparative way. The regular distribution of the infill walls can improve the framed structure performance. However, omitting the infill from the ground story leads to soft story phenomena as the columns in this story are more vulnerable due to the shear forces acting on them.

Structural System of Safe House against Tornado and Earthquakes

2013 ◽  
Vol 594-595 ◽  
pp. 449-454 ◽  
Author(s):  
Mohammad Rezaeian Pakizeh ◽  
Abdul Kadir Marsono ◽  
Masine M. Tap
Keyword(s):  
Braced Frames ◽  
Load Path ◽  
Natural Period ◽  
Infill Walls ◽  
Framed Structures ◽  
Analysis And Design ◽  
New Type ◽  
Safe House ◽  
Rc Framed Structures ◽  
Inertia Forces

Every year earthquakes, tornadoes and other extreme windstorm cause fatalities or even kill people, devastate and millions of dollars worth of property. The likelihood that a tornado will strike building is a matter of probability. The study describes the analysis and design, the engineering process the new type of tornado safe room (Fig. 1) according to the FEMA guidance. It also evaluates the effects of in-fill frames and the linear response of reinforced concrete braced frames and comparison with frames with shear wall. The main conclusion drawn from this study is to elaborate that the masonry in-fills, are strongly influence the structural seismic response and contribute to the overall stiffness and can decrease drifts and displacements. Infill walls have significant role in the strength and ductility of RC framed structures and should be considered in both analysis and design globally. These walls make the structure significantly stiffer, and reduce the natural period of the structure. Locally, infill walls changed the load path, the distribution of forces between different elements of the structure, and the change the demand of forces on their adjacent elements of the bounding frame. Due to the high relative stiffness of the infill frames, they act as the main lateral load-resisting system and attract larger portions of the earthquake and tornado induced inertia forces.

Evolution of seismic design codes of highway bridges in Chile

2021 ◽  
pp. 875529302098801
Author(s):  
José Wilches ◽  
Hernán Santa Maria ◽  
Roberto Leon ◽  
Rafael Riddell ◽  
Matías Hube ◽  
...  
Keyword(s):  
Seismic Design ◽  
Failure Modes ◽  
Highway Bridges ◽  
Design Codes ◽  
Seismic Codes ◽  
Analysis And Design ◽  
Residual Displacements ◽  
Shear Keys ◽  
Maule Earthquake ◽  
2010 Maule Earthquake

Chile, as a country with a long history of strong seismicity, has a record of both a constant upgrading of its seismic design codes and structural systems, particularly for bridges, as a result of major earthquakes. Recent earthquakes in Chile have produced extensive damage to highway bridges, such as deck collapses, large transverse residual displacements, yielding and failure of shear keys, and unseating of the main girders, demonstrating that bridges are highly vulnerable structures. Much of this damage can be attributed to construction problems and poor detailing guidelines in design codes. After the 2010 Maule earthquake, new structural design criteria were incorporated for the seismic design of bridges in Chile. The most significant change was that a site coefficient was included for the estimation of the seismic design forces in the shear keys, seismic bars, and diaphragms. This article first traces the historical development of earthquakes and construction systems in Chile to provide a context for the evolution of Chilean seismic codes. It then describes the seismic performance of highway bridges during the 2010 Maule earthquake, including the description of the main failure modes observed in bridges. Finally, this article provides a comparison of the Chilean bridge seismic code against the Japanese and United States codes, considering that these codes have a great influence on the seismic codes for Chilean bridges. The article demonstrates that bridge design and construction practices in Chile have evolved substantially in their requirements for the analysis and design of structural elements, such as in the definition of the seismic hazard to be considered, tending toward more conservative approaches in an effort to improve structural performance and reliability for Chilean bridges.

Graphical Spreadsheets as Convenient Tools for Turbomachinery Education

2001 ◽  
Author(s):  
Timothy F. Miller
Keyword(s):  
Software Package ◽  
Design Tool ◽  
Design Tools ◽  
Primary Reason ◽  
Educational Design ◽  
Analysis And Design ◽  
Radial Pump ◽  
And Function ◽  
Design Aspect ◽  
Spreadsheet Software

An unfortunate aspect of engineering education in general, and turbomachinery education in specific, has been the difficulty of incorporating the design aspect of instruction with the time-consuming components that make up theoretical instruction. The primary reason for this difficulty is the extremely limited time (typically three months) allocated to teach turbomachinery as a senior-level quarter or semester technical elective. It is desirable to develop an educational design tool that can be simultaneously exercised by a student to perform various design tasks and function as a means of theoretical instruction. Such a tool can permit the students both greater depth and breadth of exposure and may be subsequently used by the students in their future capacity as professional engineers. In this paper, this tool is illustrated by several applications of a commercial “graphical spreadsheet” software package (MathCAD, though others such as Mathmatica and Macsyma are appropriate as well). Some graphical spreadsheet design tools are presented, and these tools are applied to the analysis and design of a radial pump, centrifugal compressor, and radial-inflow turbine.

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