lateral loads
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2022 ◽  
Vol 142 ◽  
pp. 104564
Author(s):  
Lubao Luan ◽  
Lei Gao ◽  
George Kouretzis ◽  
Xuanming Ding ◽  
Hongyu Qin ◽  
...  

Author(s):  
Bayi Bage

Abstract: In India, about 50-60% of the total area is vulnerable to the seismic activity. Earthquakes are the vibrations or the motion of the ground due to release of energy. The vibrations or ground motion are the important factors to analyze and design, the earthquake resistant structure. So, to reduce the impact of earthquake different efforts has been done in this field. Basically, earthquake exerts lateral as well as vertical forces so to dissipate those forces and the vibration in system earthquake resistant structure has been design. The design of earthquake resistant structures depends on providing stiffness, strength and inelastic deformation which withstand the earthquake forces. As the height of the structure increases the lateral loads acted on the structure increases and decrease in the stiffness, so to counteract those shear walls and different damping devices has been used. Keywords: IS Code 1892-Part-1:2016; U - Section, Z- Section, H-Section, T-Section


Author(s):  
S. P. Kotecha

Damping performs essential function in format of earthquake resistant structures, which lower the change of the shape when they are subjected to lateral loads or earthquake. In the existing study fluid viscous dampers (FVD) are used to consider the response of RCC buildings on sloping ground. The important challenge of a structure is to endure the lateral loads and switch them to the foundation and to control the story displacement. In order to make structure earthquake resistant, (FVD) have been used. The building is modeled in ETAB 2018 and modeled with different location of FVD. After the study results show building with fluid viscous dampers (FVD) at diagonal bracing shows better performance.


2022 ◽  
Vol 11 ◽  
Author(s):  
Thanh Tu Ha ◽  
Florian M. Thieringer ◽  
Martin Bammerlin ◽  
Dominik Cordier

Biopsies of brain tissue are sampled and examined to establish a diagnosis and to plan further treatment, e.g. for brain tumors. The neurosurgical procedure of sampling brain tissue for histologic examination is still a relatively invasive procedure that carries several disadvantages. The “proof of concept”-objective of this study is to answer the question if laser technology might be a potential tool to make brain biopsies less invasive, faster and safer. Laser technology might carry the opportunity to miniaturize the necessary burr hole and also to angulate the burr hole much more tangential in relation to the bone surface in order to take biopsies from brain regions that are usually only difficult and hazardous to access. We examined if it is possible to miniaturize the hole in the skull bone to such a high extent that potentially the laser-created canal itself may guide the biopsy needle with sufficient accuracy. The 2-dimensional, i.e. radial tolerance of the tip of biopsy needles inserted in these canals was measured under defined lateral loads which mimic mechanical forces applied by a surgeon. The canals through the skull bones were planned in angles of 90° (perpendicular) and 45° relative to the bone surface. We created a total of 33 holes with an Er : YAG laser in human skull bones. We could demonstrate that the achievable radial tolerance concerning the guidance of a biopsy needle by a laser created bone canal is within the range of the actual accuracy of a usual navigated device if the canal is at least 4 mm in length. Lateral mechanical loads applied to the biopsy needle had only minor impact on the measurable radial tolerance. Furthermore, in contrast to mechanical drilling systems, laser technology enables the creation of bone canals in pointed angles to the skull bone surface. The latter opens the perspective to sample biopsies in brain areas that are usually not or only hazardous to access.


2022 ◽  
Vol 961 (1) ◽  
pp. 012063
Author(s):  
Taha K. Mahdi ◽  
Mohammed. A. Al-Neami ◽  
Falah H. Rahil

Abstract Increasing the cross-sectional area of piles leads to an increase in the lateral bearing resistance and reduces displacements near ground level. This increase compensates for the reduction in soil stiffness at the seabed level. Installing wings near the mudline level is one approach for increasing the area of the pile in mudline level. This research paper discusses a number of small-scale laboratory models and FEM models to study the benefit of adding wings on the variation of bearing capacity of laterally pile loaded embedded in sandy soil. To determine the advantages of adding wings to the pile, four embedded ratios (4, 6, 8, 10) were used to model both flexible and rigid pile types with various wing numbers and dimensions. The results revealed that adding wings to the pile improves lateral load resistance and greatly reduces lateral deflection. So, to achieve better resistance, wings must be linked with the pile shaft perpendicular to the lateral load applied nearer the top of the pile head. Increasing the number of wings results in a large increase in lateral pile capacity. The ultimate lateral applied load is proportional to the rise in relative density at the same (L/D) ratio.


2022 ◽  
Vol 961 (1) ◽  
pp. 012033
Author(s):  
Ahmed S. Ali ◽  
Nahla M. Salim ◽  
Husam H. Baqir

Abstract Piles with helices are a kind of foundation that is capable of withstanding compression, tension, and lateral loads. However, for almost 25 years, this kind of Pile was widely used across the world. Its behaviour is unpredictable and terrifying, especially in Iraq. The present study analysed this kind of Pile using the finite element method. It was recommended that the helical pile geometry be modeled by numerical model technique and the computer program Plaxis 3D. The plaxis 3D software is a well-known geotechnical engineering tool that numerically analyses soil and simulates experimental work in terms of curve matching and outcomes. Furthermore, an analysis of variables was conducted. The primary variable research investigates the influence of the number of helices and the tapered helix distance under static and cyclic load. The final finding is that the more helices in a pile, the smaller the displacement (or amplitude) in comparison to one helix under the effect of uplift static and cyclic load. As a result that the effect of helix number on soil behaviour is more than the effect of changing the distances between helix.


Author(s):  
Harsh Joshi

Abstract: Due to sloping land and high seismically active zones, designing and construction of multistory buildings in hilly regions is always a challenge for structural engineers. This review paper focuses to establish a review study on the Possible Types of building frame configuration in the hilly region and he behavior of Such building frames under seismic loading conditions, and (3) The recent research and developments to make such frames less vulnerable to earthquakes. This paper concludes that the dynamics characteristics of such buildings are significantly different in both horizontal and vertical directions, resulting in the center of mass and center of stiffness having eccentricity at point of action and not vertically aligned for different floors. When such frames are subjected to lateral loads, due to eccentricity it generates torsion in the frame. Most of the studies agree that the buildings resting on slanting ground have higher displacement and base shear compared to buildings resting on plain ground and the shorter column attracts more forces and undergoes damage when subjected to earthquake. Keywords: Building frame configuration, Seismic behavior, Dynamic characteristics, Response spectrum analysis, time history analysis.


Author(s):  
Megha Bhatt ◽  
◽  
Sandip A. Vasanwala ◽  

Reinforced concrete chimneys are tall industrial structures specially used in power plants to expel waste gases at high enough elevation. Based on the study of various literature available for the subject, various geometrical, material, and loading parameters to be followed to prepare the test specimens are presented in this paper so that the test specimen represents the behaviour of the actual RC chimney. The special construction process required to be followed is described in this paper along with the various analytical checks to be performed before the actual application of lateral loads on test specimens. Different design standards give different design recommendations mainly in terms of the stress-strain curve of concrete and steel. So, various experimental tests performed by applying the lateral load on specially designed and casted test specimens which represents the actual chimney in the field helps the researchers to compare the various design standards and helps the industry to opt for the same.


Author(s):  
Yue Liang ◽  
Rifeng Xia ◽  
Zeyu Liu ◽  
Chen Ma ◽  
Hongjie Zhang ◽  
...  

In the waterway construction projects of the upper streams of the Yangtze River, crushed mudstone particles are widely used to backfill the foundations of the rock-socketed concrete-filled steel tube (RSCFST) pile. The mudstone particles are prone to being crushed, which influences the mechanical properties of the soil and the interface between the soil and the steel cased on the RSCFST pile. The crushing of the particles will be aggravated by reciprocating shear of the interface when the pile experiences repeating lateral loads. The reciprocating shear of the interface may, therefore, weaken the bearing capacity of the pile. In this study, we develop a new apparatus to study the mechanical properties of the steel–soil interface under a reciprocating shear condition. With this apparatus, a set of large-scale direct shear experiments are carried out with two different boundary conditions, that is, a constant stress boundary and a constant stiffness boundary, respectively. Comparative experiments and parallel experiments are carried out to study the physical properties of steel–mudstone particle interface and the stability of the apparatus. Parallel experiments show that the instrument has good stability. The comparative experiment results also reveal the differences of the shear behaviors of the interface under two conditions. Analysis of the experiment results shows that the normal stiffness condition is closer to the real boundary condition when the soil–steel interface is cyclically sheared. The particle crushing and the attenuation of normal stress is the main reason causing the degrading of the interface.


CivilEng ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 1-20
Author(s):  
Vidya Subhash Chavan ◽  
Shen-En Chen ◽  
Navanit Sri Shanmugam ◽  
Wenwu Tang ◽  
John Diemer ◽  
...  

This paper examines the scour problems related to piers-on-bank bridges resulting from frequently flooded and/or constricted waterways. While local scour problems for bridge piers in riverine channels have been addressed extensively in the literature, there have been few studies addressing piers-on-bank scour scenarios. A comprehensive three-dimensional finite element analysis using the element removal (ER) technique has been performed on a recently constructed bridge with an observable scour problem on multiple piers. The analysis is further extended to study the effect of “combined scour” or extensive erosion of soil between adjacent piles. Three different loading cases were considered in the study, and the results demonstrated that the effects of local and combined scours on bridge drilled shaft foundations can be significant under the combined actions of axial, lateral loads and bending moments. Specifically, the most critical case of combined scour is when maximum moment effect is applied to the piers. The results of this study show that the interaction of soil displacement fields between adjacent piles should be investigated for bridge crossings with piers-on-bank, with a high risk of flooding during the moderate-to-low probability of the occurrence of precipitation events, as they can increase the pile head displacements and the bending moments in the soil and result in the early failure of bridges.


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