scholarly journals Serviceability analysis of piled foundations supporting tall structures

2021 ◽  
Author(s):  
Maria Iovino ◽  
Raffaele Di Laora ◽  
Luca de Sanctis
Keyword(s):  
Coupling Effect ◽  
Pile Group ◽  
Mathematical Framework ◽  
Moment Capacity ◽  
Tall Structures ◽  
Pile Interaction ◽  
Elevated Water ◽  
The Moment ◽  
Water Tanks ◽  
Piled Foundations

AbstractPile foundations supporting tall structures, such as wind turbines, chimneys, silos, elevated water tanks or bridge piers, are subjected during their life span to remarkably eccentric loads. These may lead to significant rotations which, however, cannot exceed the limiting values corresponding to the safe operation of the structure. A physically motivated mathematical framework aimed at the prediction of the serviceability performance of such kind of structures is herein presented and discussed. Piles are idealized as uniaxial nonlinear elements characterized by two yielding loads, one in compression and one in uplift, while pile-to-pile interaction effects are modeled by means of superposition, through an approximate solution. The axial load–moment capacity of the pile group is preliminary determined from a recent closed form, exact solution based on upper and lower bound theorems, allowing the analysis to be performed under load control. The model is capable of accounting for the dependence of the moment–rotation response from the dead load of the structure and the ‘coupling effect’ between generalized loads and displacements. The prediction performance of the proposed calculation method is validated against both numerical and experimental benchmarks. Finally, a parametric study allowed to assess the importance of pile-to-pile interaction on the foundation response under eccentric loads.

Experimental study of interaction and coupling effects in pile groups subjected to torsion

2008 ◽  
Vol 45 (7) ◽  
pp. 1006-1017 ◽  
Author(s):  
L. G. Kong ◽  
L. M. Zhang
Keyword(s):  
Coupling Effect ◽  
Pile Group ◽  
Test Results ◽  
Pile Groups ◽  
Coupling Effects ◽  
Lateral Resistance ◽  
Torsional Resistance ◽  
Pile Interaction ◽  
Group Configuration ◽  
Centrifuge Model Tests

Piles in a pile group subjected to torsion simultaneously mobilize lateral and torsional resistances. Hence, complicated pile–soil–pile interaction effects and load deformation coupling effects occur in the pile group. In this study, a series of centrifuge model tests were carried out to investigate these effects in three-diameter spaced 1 × 2, 2 × 2, and 3 × 3 pile groups subjected to torsion in both loose and dense sands. The test results showed that the effect of horizontal movement of a pile on lateral behaviors of its adjacent piles is significant in 3 × 3 pile groups and such effect varies with group configuration and pile position. The p-multiplier concept can be used to quantify the effect and values for the p-multiplier are suggested. The effect of lateral movement of a pile on the torsional resistances of its adjacent piles and the effect of torsional movement of a pile on the lateral resistances of its adjacent piles were found to be minor in these tests. For an individual pile in a pile group subjected to torsion, the mobilized lateral resistance was found to substantially increase the torsional resistance of the pile. Such a coupling effect is quantified by a coupling coefficient, β, which describes the contribution of subgrade reaction to the increase of torsional shear resistance.

scholarly journals Examining the horizontal displacement of diaphragm wall embraced by strut affected by piled foundations adjacent to urban deep excavations

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Alireza Darvishpour ◽  
Amirmohammad Amiri ◽  
Asadollah Ranjbar
Keyword(s):  
Horizontal Displacement ◽  
Pile Group ◽  
The Other ◽  
Diaphragm Wall ◽  
Horizontal Distance ◽  
Two Dimensional ◽  
Deep Excavations ◽  
Adjacent Structures ◽  
The Moment ◽  
Piled Foundations

Utilizing the piled foundation is extremely important and applicable in the civil and geotechnical engineering due to the improvementin the bearing capacity. Employing urban deep excavations, on the other hand, is inevitable and examining the effect of the pile groupis significantly vital due to the nearness of adjacent structures. In this research, the effect of the pile group foundation on the diaphragm wall embraced with struts in urban deep excavations is examined using two-dimensional numerical modeling. The resultsobtained from modeling show that the horizontal distance between the foundation and the excavation edge and also the pile lengthcan significantly affect the horizontal displacement of the wall and the moment diagram imposed on the wall, so that the effect ofthe foundation on the wall is considerably reduced for the distance greater than a certain value.

scholarly journals Development of Rocking Isolation for Response Mitigation of Elevated Water Tanks under Seismic and Wind Hazards

2020 ◽  
Vol 2020 ◽  
pp. 1-26
Author(s):  
Hassan Alemzadeh ◽  
Hamzeh Shakib ◽  
Mohammad Khanmohammadi
Keyword(s):  
Equations Of Motion ◽  
Water Supply Systems ◽  
Base System ◽  
Tall Structures ◽  
First Case ◽  
Wind Hazards ◽  
Fixed Base ◽  
Tank System ◽  
Elevated Water ◽  
Water Tanks

Elevated water tanks are categorized as strategic components of water supply systems in modern urban management. Past earthquake events have revealed the high vulnerability of these structures. This paper investigates the development of rocking isolation (RI) to these structures as a response mitigation technique. Using an analytical approach, a dynamic model is developed for two isolation cases: (1) at the pedestal base and (2) under the tank. The model incorporates a simplified analogy for simulating the liquid-tank system which is modified for a tank under rocking motions. Based on the dynamics of rocking structures, the equations of motion, impact, and uplift transitions are derived. Then, free vibration and seismic response history analyses are carried out on a sample structure. Discussions are made on the effect of RI on the dynamic and seismic responses of the pedestal and components of the liquid-tank system. Effects of various RI cases, pedestal heights, and tank filling levels are studied for a group of structures excited by an ensemble of ground motions. Considering that the system may be vulnerable to other lateral loadings, the combined effects of seismic and wind hazards are also studied. The wind loads are assumed to act statically and simultaneously with the seismic excitations. Results show that the first case of RI decreases the acceleration demands of mid-rise and tall structures, thus lowering the structural demands to 50% of the fixed-base system. However, the second case of RI has almost no effect on the performance of the system, upgrading only the response of mid-rise structures. Both RI cases also aggravate the wave oscillations and increase the freeboard requirements. Finally, while the combined seismic and wind hazards have almost no effect on the operational performances, the force demands of the structures are increased by 10%.

Flexural Resistance of Steel-Coconut Shell Concrete-Steel Composite Beam with Normal and J-Hook Shear Studs

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Lakshmi Thangasamy ◽  
◽  
Gunasekaran Kandasamy ◽  
Keyword(s):  
Concrete Strength ◽  
Steel Plates ◽  
Coconut Shell ◽  
Core Material ◽  
River Sand ◽  
Concrete Core ◽  
Conventional Concrete ◽  
Moment Capacity ◽  
The Moment ◽  
Core Concrete

Many researches on double skin sandwich having top and bottom steel plates and in between concrete core called as steel-concrete-steel (SCS) were carried out by them on this SCS type using with different materials. Yet, use of coconut shell concrete (CSC) as a core material on this SCS form construction and their results are very limited. Study investigated to use j-hook shear studs under flexure in the concept of steel-concrete-steel (SCS) in which the core concrete was CSC. To compare the results of CSC, the conventional concrete (CC) was also considered. To study the effect of quarry dust (QD) in its place of river sand (RS) was also taken. Hence four different mixes two without QD and two with QD both in CC and CSC was considered. The problem statement is to examine about partial and fully composite, moment capacity, deflection and ductility properties of CSC used SCS form of construction. Core concrete strength and the j-hook shear studs used are influences the moment carrying capacity of the SCS beams. Use of QD in its place of RS enhances the strength of concrete produced. Deflections predicted theoretically were compared with experimental results. The SCS beams showed good ductility behavior.

scholarly journals Elevated Water Tank

2019 ◽  
Vol 8 (12S2) ◽  
pp. 271-276
Keyword(s):  
Water Treatment ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Water Tank ◽  
Elevated Water ◽  
Water Tanks ◽  
The Way

Water tanks are the capacity booths for putting away water. Raised water tanks are built to be able to deliver required head with the purpose that the water will movement affected by gravity the development exercise of water tanks is as antique as enlightened guy. The water tanks project has an firstrate want as it serves ingesting water for amazing populace from exceptional metropolitan urban groups to the little population dwelling in cities and towns. The smaller than ordinary project is led for a time of 15 days to have total all the way right down to earth information on unique tactics and issues appeared within the field. An change issue like construction factors, layout Parameters, information of Formwork, information of aid, process of Water treatment Plant and Execution had been controlled over the span of our smaller than regular undertaking."improved water tanks" via raising water tank, the enlargement upward push makes a conveyance strain at the tank outlet. The profile of water tanks begins offevolved with the utility parameters, consequently the type of materials applied and the form of water tank become directed by way of approach of those factors: 1. Vicinity of the water tank (inner, out of doors, over the floor or underground). 2. Volume of water tank need to preserve. 3. What the water may be utilized for? Four. Temperature of territory wherein might be located away, fear for solidifying. Five. Weight required conveying water. 6. How the water to be conveys to the water tank. 7. Wind and quake plan contemplations allow water tanks to endure seismic and excessive wind occasions

scholarly journals Flexural Behavior of Steel Beam Strengthening by Prestressing Strands

2018 ◽  
Vol 7 (4.20) ◽  
pp. 572
Author(s):  
Dr. Mohammed M. Rasheed ◽  
Mr. Ali F. Atshan ◽  
Mr. Kamal Sh. Mahmoud
Keyword(s):  
Reference Beam ◽  
Flexural Behavior ◽  
Radius Of Curvature ◽  
Steel Beams ◽  
Steel Beam ◽  
Bottom Flange ◽  
Moment Capacity ◽  
External Prestressing ◽  
Prestressing Strands ◽  
The Moment

Seven simply supported steel beams were tested to explain the effect of strengthening by external prestressing strands. All of the beams have the same steel section, clear span length and the strengthening samples which implemented by two external prestressing strands. The tested beams are divided into two categories according to existing of external prestressing strands, the first category consists of one steel beam as a reference, while, the second group deals with steel beams strengthening by external prestressing strands and consists of six steel beams divided according to the eccentricity location of prestressing strand with jacking stress (815 MPa). From experimental results, it was found that the moment curvature curves behavior for the tested beams are stiffer and with less ductility than the reference beams and the ultimate moment capacity is increased with increasing the eccentricity location. While, the maximum radius of curvature at bottom flange decreases with increasing the eccentricity location as compare with the reference beam.   

Database of rocking shallow foundation performance: Slow-cyclic and monotonic loading

2020 ◽  
Vol 36 (3) ◽  
pp. 1585-1606 ◽  
Author(s):  
Manouchehr Hakhamaneshi ◽  
Bruce L. Kutter ◽  
Andreas G. Gavras ◽  
Sivapalan Gajan ◽  
Angelos Tsatsis ◽  
...  
Keyword(s):  
Monotonic Loading ◽  
Testing Equipment ◽  
Shallow Foundation ◽  
Moment Capacity ◽  
Wide Range ◽  
Supporting Soil ◽  
Rocking Foundations ◽  
System Properties ◽  
The Moment ◽  
Cyclic Loading Tests

Many physical model tests have examined the performance of rocking foundations during cyclic and seismic loading. These tests varied in model size, testing equipment, superstructure properties, footing shape, supporting soil environment, and loading protocol. “FoRCy, Foundation Rocking database of Cyclic and Monotonic Loading” is a new database (published at https://datacenterhub.org/ ), summarizing the results of monotonic and slow-cyclic loading tests of rocking foundations. The database consists of columns identifying testing equipment and facility, soil, superstructure, and system properties, as well as loading protocol and results. The database contains 456 records (rows), each one being unique in either model configuration or loading amplitude. To illustrate its value, this article shows correlations between (1) settlement, rotation, and factor of safety with respect to bearing capacity and (2) moment and cumulative rotation for shallow footings. Data indicate that the rotation required to mobilize the moment capacity is surprisingly constant (about 0.01 radians) for a wide range of experiments.

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