Kazıklı temeller ve kazıklı temellerin bilgisayar programları ile hesabı

Abstract

Kasıklar en qenel anlamıylaüzerindeki yapınıff yük­lerini daha derinlerdeki taşıma aücü daha yüksek olan semin veya kaya tabakasına aktarmak için kullanılan; in­ce. usun yapı elemanlarıdır- Kasıklar ayrıca; şevlerin sağlamlaştırılmasında, kaldırma kuvvetler inin-ve yatay semin etkilerinin karşılanmasında limanlar ve köprü ayakları gibi su içinde yapılan yapılarda ve polplans perde yapımında da kullanılmaktadır*Kasıklar ve kazıklı temeller hakkında bilgiler ile- kazıklı temellerin hesabı için yapılmış bilgisayar prog­ramların incelendiği bu tez, yedi ana bölümden oluşmak­tadır «Birinci Bölümde; tezin kapsamı ve amaci verilmiştir.İkinci ve üçüncü bolümde; kasık çeşitleri ve bunların incelenmesi ile kasik tipinin seçimine ait bilgiler veri 1mistir -Dördüncü bölümde; kazıklı temellerin yatay yük altındaki davranışları incelenmiştir. Besinci bölümde; kazıklı temellerin düşey yükleme haline ait bilgiler mevcuttur-Altıncı bolümde; kazıklı temeller, grup kazık olarak incelenmiş kasıkların qrup içindeki davranışları ele alinmiştir.Yedinci bölymde; Matris metodu < sonlu elemenler > kullanılarak hazırlanmış yatay yüklü, düşey yüklü kasık ve grup kazık programları ile ilgili açıklamalar verilmiştir. Ekler bölümünde; Bilgisayar programları ve çıktıları ile sayısal uygulamalar verilmiştir.

The purpose of the main Function of piles is to transfer the load to lower levels in the ground, which are caable o-f sustaining the load with an adeguate -Factor o-f safety and without setting at the working load by an amount detrimental to the structure that they support.The piles Caryy the loads mainly in axial compression but there are numerous examples where piles may be required to Caryy uplift loads when used to support tall structures subjected to overturning Forces from winds or waves.Piles are used when the subsurface canditions are not suitable for the use of spread footings and mats, or build these last in the position where they should be located if the piles were not piles canbe classified with respect to different criterions. They can be devided in terms of their function as; Friction piles, End-bearing piles, Compactions piles, Anchor piles In order to categorize the various types of piles and their method of installation, a simple division into; Driven, Driven and cast in-situ, Bored, Screwed Piles is often employed. Some codes and researchers places piles in there categorious as folows; Large-displacement piles, Smal1-displacement piles, Non-displacement piles. Piles according to material used in their installation can be classified as; Timber piles Concrete piles, Stel piles.Differen kinds of piles have been discussed. In addition to the factors of safety and econa/ny, before choosing what kind of pile will be used in design, aduantages and disadvan­tages of differentkinsd of piles should be used in design, aduantages and disadvantages of different kinds of piles should be considered.After getting some defailed and compared information about types of piles, taking decisions for choosing the types of piles, which will be applied for foundation, can be so easy.Computation methods of pile loads can be divided i-n three group, which isexplained in the first part of this study. These are; Dynamic formulas, Statik formulas, load test The fourth and fifth parts are lateral loaded pile and vertical loaded pile Lateral loaded pile are commly anlyzed by the P-Y analy­sis. P-Y relation ship for a given soil must be obtained from an instrumented lateral load test. The results of an alterna- tif procedureto P-Y method for the elastoplastic analysis of laterally loaded piles are presented with P-y method in fourth part. This analysis is based on the boudary element method and assume knowledge of the shear strength profile of the soil.In the fifth part, axially loaded piles are examined thiS" part is concerned with the evaluation of pile strees and de­formations under axial or working loads.The method of analysis can be used for partially or fully embedded piles, with or without a batter. The part of a pile embedded in the ground will Caryy part of the vertical load by shear transfer along the shaft to the adjacant soil, and remainder of the load the will becarried by point. The stress conditions around a driven pile is very complex after driving. This applies both to the total and effective stress condition. There fore, it is quite impossible to Caryy out a rational short, term analysis, of the bearing capacity of driven friction piles only long term bearing capacity of friction piles can be subjected to rational analysis.In the fifth Dart, QIS0 piles are examined«when we wont Timber piles, Concrete piles, Stel piles.Differen kinds of piles have been discussed. In addition to the factors of safety and econa/ny, before choosing what kind of pile will be used in design, aduantages and disadvan­tages of differentkinsd of piles should be used in design, aduantages and disadvantages of different kinds of piles should be considered. After getting some defailed and compared information about types of piles, taking decisions for choosing the types of piles, which will be applied for foundation, can be so easy.Computation methods of pile loads can be divided i-n three group, which isexplained in the first part of this study. These are;Dynamic formulas, Statik formulas load testi.The fourth and fifth parts are lateral loaded pile and vertical loaded pile Lateral loaded pile are commly anlyzed by the P-Y analy­sis. P-Y relation ship for a given soil must be obtained from an instrumented lateral load test. The results of an alterna- tif procedureto P-Y method for the elastoplastic analysis of laterally loaded piles are presented with P-y method in fourth part. This analysis is based on the boudary element method and assume knowledge of the shear strength profile of the soil.In the fifth part, axially loaded piles are examined thiS" part is concerned with the evaluation of pile strees and de­formations under axial or working loads.The method of analysis can be used for partially or fully embedded piles, with or without a batter. The part of a pile embedded in the ground will Caryy part of the vertical load by shear transfer along the shaft to the adjacant soil, and remainder of the load the will becarried by point. The stress conditions around a driven pile is very complex after driving. This applies both to the total and effective stress condition. There fore, it is quite impossible to Caryy out a rational short, term analysis, of the bearing capacity of driven friction piles only long term bearing capacity of friction piles can be subjected to rational analysis.In the fifth Dart, QIS0 piles are examined«when we wont The individuol piles for axial loads to Dlannmg, we must know the properties of the individuol piles. For examole, Ne­gative Skin Friction must he obtained for the individuol pi­les .Negative Skin Friction can be developed from:A cohesive fill placed over a chosionless soil deposit.; the fill develops shear resistance between the soil and pile from lateral pressore/flow affects and drogs the pile downward as the fill consolidates.A cohesionless fill placed over a compressible, cohesive deposit. In this case there will be some downdrag in the fill zone, but the principal downdrag will occur in the zone of consoli dat ion.Bowering of the groundwater table with resultinq ground subs i dence.Pile-driving Cand-load-test> operations which produce ne­gative stress in the upper shaft when the load is released and the pile shaft expands upward.After that, we can say; negative skin friction is a downward force acting on the piles due to relative mowement between the piles and surrounding compressible soil.These frictional forces drag the pile downward, thereby increasing the load transferred to the stratum beneath the pile tip. The amount of this load may be fairly large and may cause freg- vent hasmful settlements.In the sixth paort, broup piles are examined.In qeneral, the following rules may be followed as far as the grouD-oction of pile groups is considired;a) The piles driven in to coarse granular soils couse compaction of soils. As a conseqvence, the value of pile ef- ficieney is equal to or laraer than unity. Therefore, there will be no qroupaction reduction in piles in grouos driven into coarse granular deposits,Group-oction can also be neglected for piles driven in to clay.Group-oction will not be considered for piles drivon into stiff clay underlying a shoft lo yer.Pile foundations may also cause settlements and a seff lement anlysis of a pile foundation should be made if soil conditions reqvire.The ofter important things about the pile groups is thatp pile cap desing.In general, pile caps are supposted by notless than three piles in order to maintain stability. The piles are em­bedded in the pile cap an amount usually specified in the co­des. Embedment is at least 150 mm in the cap and the main rein forcing bars are placed at a clear distance of 75 mmaboue the pile cut-off elevation. This means that the effective deptti af a pile cap is generally about 250 mm less th-nn the total thickness of the pile cap.The edec distance of the exterior piles are also speci fied in the codes, and it is generally reguired that the exterior piles should have at least soomm distance from the edge of concrete for relatively small diameter piles.Also, in the sixth part results of an exensive series of computations for group settlement and deflection ratios for both a homegenous soil moss and a Gibson. Soil, are presen­ted, To reduce the volume of results, attention has been ge­nerally conflicted to piles that are either pinned to the pile cap (. no moment developed at pile heads ) or that are fixed in to a massive cap so that the pile headscan be consi­dered as fixed < no rotation ). For these condition, the group settlement, lateral deflection, and rotation can be simply real ted to the response of a single pile.If the center of a pile top is 150 mm or more outside the section were the diagonal shear stress is to be checked, the entire reaction of the pile should be assumed effective in producing shear on the section.The reaction from any pile located 150 mm or more inside the section, probaly contributes very little to the shear. Hence, the reaction moy be considered as zero. For indermedi- ate positions, a stroigth—1ine interpolation is comml used.to planning the location of a number of piles in agroup, we should consider so much thigs, and these are in the sixth part. The importont point about group is, the group settle­ment, lateral deflection and rotation can be simply realted to the response o-f a single pile. Because, the piles are eit­her pinned to the pile cap or that are fixed into a massive cap so, the pile heads can be considered as fixed.The main purpose of this study is a computer programme which to computepile foundation.The computer programmerr which are menu programme, late­ral pile, static pile and group pile were composed and provi­ded to run together each other in harmonious.By the menu programme, datas and data files are prepared by asking questions on the screen of the computer for input the information of the piles of the soils.The lateral pile programme modified by finite element method. This computer program can be used to compute internal forces and pile displacements for a laterally loaded pile with head free to rotate and translate and for either a nodal moment or lateral force, or both - solutions of this programme are bonding moments shear strength, soil recetion and element deflection, Cl, C2, C3, C4 that are called the cofficient of the stifness matrix of the group piles are written in a file namend C DAT.The vertical loaded pile programme, lateral vertical load and moment can be applied together. This programme also user finite element metod and it can be used for partially or fully, embedded piles, with or without a batter.Matrix solution for any two-dimensional general solution for any two-dimensional pile loading with three degrees of freedom.This program may oscillate if the pile is too long ( overdesigned ) for the given load, when the load is -fixed or if pile loads are small and ponitx is specified unless the convergence criterion is relaxed. Convergence can be improved by making a trial run, observing the point deflectionm then running the problem with a revised pontx valve.solutions of this programme are moments, vertical forces soil reactions and element deflections, in addition C5 coffi- ent will be written in C .... DAT file, for group piles.The group piles computer programme compute the individu- al-pile forces and diplaneements of pile group of any confi­guration and any a number of piles. The pile group loading can be general, but the cap must be rigid.It is not necassary that pile tops be at equal elevation in other words, X,Y,Z, coordinates any read for each piles may be of unequal length.After solutions this programme, the vertical loaded pile programme should be run again todesign the piles.