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"Several studies have already been published in order to better understand the behaviour of interfaces. Different experimental methods, including direct shear tests, simple shear test, and tortional ring test, and also various constitutive models were presented to modelize the behaviour of the interface. These studies revealed that the main factors that affect the behaviour of the interface include the roughness of the interface, the soil mineralogy, the soil density, and the normal stress applied. This work was therefore directed primarily to better understand the overall behaviour of the interface and the influence of these factors in a monotonic and cyclical solicitation. Through the simulation of a direct shear test at constant normal stress (CNL) in FLAC 5.0, several typical behaviours, including degradation of shearing resistance and contractancydilatancy, have been observed and modelled. At first, the law of Mohr-Coulomb and its correspondent failure criterion have been implemented. Then several models have been proposed to model more precisely the behaviour. Finally, two cyclicals laws, the law of Ramberg-Osgood law and Byrne, originally developed for the soil, have been implemented in this model. This study has verified the consistency of the results and has determined whether the injection of such laws is sufficient to modelize the behaviour of the interface under cyclic loading. "

"Tujuan dari penelitian ini adalah untuk menguji pengaruh pembebanan statis dan siklik terhadap perilaku mobilitas siklik pasir jenuh. Serangkaian uji monotonic simple shear dan cyclic simple shear tak terdrainase yang terkonsolidasi dilakukan pada berbagai kondisi tegangan vertikal efektif, kepadatan relatif, dan beban siklik untuk menginvestigasi jenis kegagalan. Rasio ketahanan siklik digunakan untuk menilai kekuatan siklik. Hasilnya menunjukkan bahwa uji MSS menunjukkan respon perilaku non-flow yang tidak terdrainase yang ditandai dengan strain hardening yang berkelanjutan. Analisis stress path menunjukkan bahwa tanah menunjukkan mobilitas siklik, meskipun dengan kapasitas deformasi yang terbatas. Untuk respons siklik, dapat diamati bahwa peningkatan tegangan efektif vertikal selalu mengakibatkan penurunan ketahanan siklik, terlepas dari apakah kriteria regangan atau kriteria tegangan likuifaksi yang digunakan. Sebaliknya, peningkatan kepadatan relatif akan menghasilkan peningkatan resistensi siklik. Dampak dari tegangan vertikal efektif terbukti lebih nyata dibandingkan dengan dampak dari kepadatan relatif dan CSR. Kriteria tegangan secara konsisten menghasilkan estimasi yang lebih tinggi terhadap kecenderungan likuifaksi pada pasir akibat akumulasi tekanan pori pada kondisi tidak terdrainase. Jumlah siklus mempengaruhi nilai shear modulus dan damping ratio. Tegangan vertikal efektif tidak signifikan mempegaruhi shear modulus dan tidak berpengaruh terhadap damping ratio. Kepadatan relatif tidak signifikan terhadap shear modulus dan damping ratio, sedangkan CSR signifikan terhadap pengaruh nilai shear modulus dan damping ratio. Degradasi shear modulus dan peningkatan damping ratio terbesar pada saat terjadi siklus yang memicu likuifaksi

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The objective of this study is to examine the influence of static and cyclic loading on the cyclic mobility behavior of saturated sand. A series of consolidated undrained monotonic and cyclic simple shear tests were conducted under varying conditions of effective vertical stress, relative density, and cyclic load to ascertain the types of failure. The cyclic resistance ratio was employed to assess the cyclic strength. The result revealed that the MSS test demonstrated a non-flow undrained response characterized by sustained strain hardening. Analysis of the effective stress paths suggested that the soil displayed cyclical mobility, albeit with restricted capacity for deformation. For the cyclic response, it can be observed that an increase in the vertical effective stress invariably results in a reduction in the cyclic resistance, irrespective of whether the strain criterion or the stress criterion of liquefaction is employed. Conversely, an increase in the relative density will result in an increase in the cyclic resistance. The impact of effective vertical stress is demonstrably more pronounced than that of relative density and CSR. The stress criterion consistently yields a higher estimation of the tendency towards liquefaction in sand due to the accumulation of pore pressure in the undrained state. The number of cycles has an impact on the shear modulus and damping ratio. The effective vertical stress has no significant effect on the shear modulus and has no effect on the damping ratio. The relative density has no significant effect on the shear modulus and damping ratio, while the CSR exerts a notable influence on the values of these properties. The deterioration of the shear modulus and the enhancement of the damping ratio were most pronounced during the liquefaction-inducing cycle.     "

"ABSTRACTThe definition, purposes and applications of Damage Mechanics, which is relatively newly developed, is introduced and reviewed. Initially and mostly, Damage Mechanics relates to metal materials. The appearance of micro cracks due to the application of external load and their propagations cause damage to the material. This paper discusses and reviews Damage Mechanics when applied to concrete. A mathematical model of concrete subjected to tension using Continuum Damage Mechanics Theory proposed by Jean Lemaitre and Jacky Mazars in. 1982 is presented. This initial model, which is called Scalar Damage Model, even relatively simple in the formulation but gives quite good result to model the concrete in tension. This can be seen from the comparison between the numerical and experimental results done by them at laboratory in Cachan, France. Application of the initial model to analysis of reinforced concrete beam of three-point flexion subjected to monotonic loading is presented and evaluated. By using the initial model, the damage evolution, stress evolution and flexural rigidity evolution of the observed beams can be reviewed. The possibility of the application of the initial model to analysis of reinforced concrete beam in three-point flexion subjected to cyclic loading is also reviewed."

"This book explains the hypoplastic modelling framework. It is divided into two parts, the first of which is devoted to principles of hypoplasticity. First, the basic features of soils mechanical behaviour are introduced, namely non-linearity and asymptotic properties. These features are then incorporated into simple one-dimensional hypoplastic equations for compression and shear. Subsequently, a hypoplastic equivalent of the Modified Cam-Clay model is developed in 2D space using stress and strain invariants to demonstrate key similarities and differences between elasto-plastic and hypoplastic formulations. Lastly, the mathematical structure of hypoplastic models is explained by tracing their historical development, from the early trial-and-error models to more recent approaches. In turn, Part II introduces specific hypoplastic models for soils. First, two reference models for sand and clay are defined. After summarising their mathematical formulations, calibration procedures are described and discussed. Subsequently, more advanced modelling approaches are covered: the intergranular strain concept incorporating the effects of small strain stiffness and cyclic loading, viscohypoplasticity for predicting rate effects, soil structure to represent structured and bonded materials and soil anisotropy. The book concludes with a description of partial saturation and thermal effects: topics that are increasingly important to the disciplines of energy and environmental geotechnics.Selecting a constitutive model and its parameters is often the most important and yet challenging part of any numerical analysis in geotechnical engineering. Hypoplasticity involves a specific class of soil constitutive models, which are described in detail here. The book offers an essential resource, both for model users who need a more advanced model for their geotechnical calculations and are mainly interested in parameter calibration procedures, and for model developers who are seeking a comprehensive understanding of the mathematical structure of hypoplasticity."

"Geografis Indonesia berlokasi pada kawasan Ring of Fire yang  membuat Indonesia menjadi salah satu negara yang sangat rawan terhadap gempa. Sambungan pondasi dengan pile cap  termasuk bagian yang rawan rusak ketika terjadi gempa. Melihat hal tersebut dan masih jarangnya penelitian terkait perilaku spun pile yang tersambung ke pile cap, maka dilakukan penelitian tersebut pada studi ini. Studi numerik kinerja spun pile D1200 akibat pembebanan monotonic pada tanah soft clay bertujuan untuk melihat perilaku dari spun pile yang tersambung pada pile cap dengan basis kondisi di pelabuhan. Studi dilakukan dengan 2 tahap yaitu studi validasi dan studi parametrik

Studi parametrik pada penelitian ini dilakukan untuk menjawab rumusan masalah dan tujuan penelitian. Studi parametrik dilakukan dengan variasi rasio tulangan longitudinal beton pengisi spun pile, kuat geser tanah, panjang free standing, dan besar gaya aksial. Permodelan pada studi ini menggunakan software Lpile dan SAP2000. Software Lpile ditujukan untuk memodelkan kurva p-y tanah yang digunakan sebagai model tanah nonlinier pada SAP2000. Permodelan SAP2000 dilakukan dengan pembebanan pushover dan permodelan penampang dengan section designer.

Hasil permodelan pada studi ini dianalisis dengan melihat kapasitas penampang, kurva load-displacement, daktilitas, dan proses terbentuknya sendi plastis. Hasil studi menunjukkan bahwa penambahan beton pengisi spun pile akan menambah kapasitas penampang. Penambahan rasio tulangan beton pengisi, semakin besar kuat geser tanah, dan semakin besar gaya aksial menunjukkan peningkatan pada kekuatan dan kekakuan struktur. Namun, pada penambahan panjang free standing menunjukkan penurunan kekuatan dan kekakuan struktur.

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Geographically, Indonesia is located in the Ring of Fire area which makes Indonesia become one of the countries most prone to earthquakes. The connection of pile-pile cap is prone to damage when earthquakes occur. Refer to that things dan there are only a few study about behavior of connection spun pile-pile cap, the research was carried out in this study. Numerical Study Of Spun Pile D1200 Performance Due To Monotonic Loading In Soft Clay Soil aims to see the behavior of spun pile-pile cap connection which refer to a port condition. The study was conducted in 2 stage, there are validation studies and parametric studies.

Parametric study in this research is aim to answer the problem formulation and  research objectives. Parametric Studies are carried out with variations in the ratio of longitudinal reinforcement of spun pile infill, soil shear strength, free standing length, and axial load. On this study, the structure modelling used Lpile and SAP2000. Lpile was used to get p-y curves of the soil that will use to nonlinier soil modelling on SAP2000. SAP2000 modeling carried out with pushover loading and using section designer to model the spun pile section.

The results of this study analize was analyzed with strength capacity, load-displacement curves, ductility, and the process of plastic hinge. The results showed that the addition of concrete infill will increase the strength capacity of spun pile. The addition of reinforcement ratio of concrete infill, the greater soil shear strength and axial load showed an increase in structural strength and stiffness. However, the addition of the length of free standing shows a decrease in structural strength and stiffness."

"ABSTRAKPada tahun 2017, Kementrian PUPR melakukan revisi peta gempa yang meliputi pembaharuan sumber sumber gempa baru. Akibat meningkatnya potensi gempa, maka terjadi peningkatan seismic demand dalam perancangan bangunan tahan gempa. Perancangan bangunan tahan gempa sering menggunakan konsep performance based design (PBD). Konsep PBD mengijinkan terjadinya kerusakan pada bangungan melalui mekanisme sendi plastis. Konsep PBD belum dapat diaplikasikan pada struktur bawah, karena sulit untuk direparasi. PBD dapat dipelajari melalui analisa pushover, yaitu dengan membebani struktur secara lateral sampai struktur tersebut mengalami kegagalan. Penelitian ini memodelkan spun pile berdiameter 450 dan 600 mm produksi dari salah satu BUMN di Indonesia. Spun pile tertanam dalam tanah kohesif berjenis soft clay sedalam 20 m. Koneksi antara spun pile dengan pile cap dianggap kaku, sehingga dimodelkan sebagai jepit. Ujung dari pile menumpu pada tanah keras yang dimodelkan sebagai sendi. Tanah dimodelkan sebagai nonlinear spring yang menambah kekakuan pada struktur. Pemodelan dilakukan dengan menggunakan SAP2000 V21. Tujuan dari penelitian ini adalah mencari kekuatan, daktilitas, dan proses terbentuknya sendi plastis. Terdapat tiga buah parameter yang diujikan untuk mendapatkan gambaran kapasitas spun pile. Pertama, dilakukan variasi luas tulangan pada beton pengisi spun pile. Kemudian, kekakuan tanah dibedakan berdasarkan nilai undrained shear strength. Selanjutnya, parameter yang diuji adalah efek beban aksial yang berbeda. Hasil dari penelitian menunjukkan bahwa penambahan pada ketiga parameter tersebut meningkatkan kekuatan pile secara keseluruhan sebesar 2-13%. Disisi lain, nilai daktilitas meningkat seiring dengan penambahan tulangan beton pengisi sebesar 2-15% , namun berkurang 2-10% pada penambahan kekakuan tanah dan beban aksial.

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ABSTRACT

In 2017, the Ministry of Public Works and Housing revised the earthquake map which included renewing of new earthquake sources. Seismic demands in the design of earthquake resistant buildings increase due to the increased potential of the earthquake. The design of earthquake resistant buildings often uses the concept of performance based design (PBD). The PBD concept allows damage to buildings through plastic hinge mechanism. The PBD concept cannot yet be applied to the lower structure, because its complications in repair. PBD can be studied through pushover analysis, by applicating lateral load until the structure fails.This research investigates 450 and 600 mm diameter spun pile produced by one of the state-owned corporation in Indonesia. The spun pile is embedded in cohesive soil of soft clay type as deep as 20 m. The connection between the spun pile and the pile cap is a rigid connection, so it is modeled as fix. The pile tip rests on hard soil which is modeled as pin. The soil is modeled as nonlinear springs which adds rigidity to the structure. Modeling is done using SAP2000 V21. The purpose of this research is to observe the capacity, ductility, and formation of plastic hinge. There are three parameters tested in this study to obtain the capacity of pile. First, a variation of spun pile infilled concrete reinforcement area. Then, the stiffness of the soil which varies by the value of undrained shear strength. Furthermore, the parameters tested are different axial load effects.The results of this study indicate that increasing the three parameters resulted in raising overall pile strength by 2-13%. On the other hand, the ductility value increases with the addition of reinforced concrete reinforcement by 2-15%, but decreases by 2-10% with the increase of soil stiffness and axial load."

"Skripsi ini membahas perilaku respon struktur terhadap pembebanan dinamik multi-eksitasi. Penelitian ini dilakukan melalui permodelan struktur dengan menggunakan program analisis struktur SAP2000. Analisis yang dilakukan adalah mempelajari perilaku respon struktur portal tiga dimensi di bawah pengaruh pembebanan multi-eksitasi akibat getaran mesin. Parameter yang disimulasikan adalah posisi beban, arah eksitasi beban, frekuensi getar beban, massa mesin, dan properti isolator. Melalui penelitian ini, faktor utama beban multi-eksitasi dapat dipelajari sehingga nantinya dapat menjadi acuan dalam proses penyederhanaan analisis struktural terhadap beban multi-eksitasi.

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The focus of this study is the structure responses behaviour under multi-excitation loading. This research was conducted through structural modelling using SAP2000 structural analysis program. The analysis conducted was to learn about the behaviour of three-dimensional frame structure responses under multiexcitation loading due to vibrations from machineries. Parameters simulated in this research are loading position, loading direction, loading frequency, mass of the machine, and isolator properties. Through this research, main factors of multiexcitation loading can be investigated so they can be implemented as a reference in the structural analysis simplification under multi-excitation loading."