Print ISSN: 1992-7428

Online ISSN: 2706-686X

Volume 4, Issue 7

Volume 4, Issue 7, Winter and Spring 2007, Page 1-140


ESTIMATION OF HYPERBOLIC STRESS-STRAIN PARAMETERS FOR GYPSEOUS SOILS

Ahmed Helal; Ahmed H. Abdul-kareem

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 1-15
DOI: 10.37650/ijce.2007.39358

The hyperbolic model is a simple stress-strain relationship based on the
concept of incrementally nonlinear elastic behavior. The hyperbolic stress-strain
relationship was developed for use in finite element analysis of stresses and
movements in earth masses. To estimate hyperbolic parameter values required for
nonlinear finite element analysis, data used from the triaxial compression tests for
the gypseous soils exposed to the effect of drying and wetting cycles carried out by
(Mohammed, 1993). From these data, the parameters (C, φ, K, n, Rf), which are
required by Duncan-Chang model, 1970 can obtained for analyses of dams,
excavations and various types of soil-structure interaction problems.
In addition, it can be found that the primary loading modulus, K, the
exponent number, n, and the failure ratio, Rf, have random values during rewetting
cycles for CU and UU triaxial compression tests

EFFECT OF CUT-BACK MC-60 ON PERMEABILITY AND COMPRESSIBILITY OF A GYPSEOUS SOIL

Muayad A. Ahmed Al-Sharrad

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 16-26
DOI: 10.37650/ijce.2007.14194

ABSTRACT A study of the effect of cutback MC-60 on the permeability and compressibility characteristics of sandy gypseous soil is presented. Series of laboratory tests are carried out including classification, compaction, and conventional oedometer tests as well as a new test named compressibility- permeability leaching test. Test results shows that the superlative enhancement in compressibility and permeability and thereby in collapsibility occurred with 7% additive.

ANALYSIS OF STONE COLUMN IN SOFT SOIL BY FINITE ELEMENTS METHODS

Ahmed A. Al Hity

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 27-41
DOI: 10.37650/ijce.2007.39370

This paper includes an analysis to asses the behavior of stone columns using the finite
element method and to provide bases and information helping geotechnical engineers to
design foundations resting on weak soils reinforced with stone column.
The axisymmetric quadrilateral element is adopted in the finite element
program to simulate the soft soil and the stone column while the one-dimensional
element is used to simulate the soft soil and the stone column-soil interface. The
nonlinear inelastic stress-dependent model is used to simulate the behavior of the soil
and the interface throughout the incremental loading stages adopting nonlinear
parameters obtained from triaxial and direct shear stress.
The analysis is carried first on a selected basic problem, to clarify the nonlinear
of the column, in which a selected geometry, boundary condition, and material
properties for both soil and interface as chosen.
The rest of the analysis is grouped into the effect of some of the parameters
concerning the geometry of the stone column and the material of column and adjacent
soil are investigated.
It was found that the increase in stone column length and in relative stiffness
of stone column material to soil play an important role in increasing ultimate capacity
of the stone column and in reducing settlements.

GROUNDWATER INVESTIGATION IN THE PIEDMONT ZONE OF HIMALAYAN FOOTHILL REGION, INDIA, USING ELECTRICAL RESISTIVITY TECHNIQUES

Asmat Ramzi abdulgafor; Mufid alhadithi

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 42-52
DOI: 10.37650/ijce.2007.39378

Electrical resistivity, observations well and lithological data are used for the
groundwater investigation in the piedmont zone Ratmau –Pathri Rao watershed in
Haridawre Districted of Uttaranchal India, The analysis of the resistivity data in the
light of known lithology indicates that two aquifer (shallow and deep) are generally
present in the area
The resistivity of aquifers are generally varies in wide range. This is due to the
presence of different size of ranges of grains condition consisting of fine sand and
gravel (pebble) in the Tarai zone which further grade to coarser material (Boulder in
the Bhabhar zone)

EVALUATION OF DYNAMIC PROPERTIES OF HIGH PERFORMANCE STEEL-FIBER CONCRETE BY USING NON-DESTRUCTIVE TESTS

Khalid Battal Najim

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 53-70
DOI: 10.37650/ijce.2007.14198

Abstract: The presented investigation studies the effect of steel fiber content on the dynamic properties of High Performance Steel Fiber Concrete by using non-destructive testes; Vibration tests (Electrodynamics tests) were used to obtain the dynamic modulus of elasticity, dynamic shear modulus (modulus of rigidity), damping capacity, and dynamic Poisson‘s ratio. The results demonstrated in general an improvement in dynamic properties, which were tested for example, the percentage increasing in compressive strength relative to the reference concrete were 2.5%, 6.6%, 5.8% for High Performance Concrete (HPC) with 0.5%, 1%, and 1.5% steel fiber by volume of concrete respectively.

GEOMETRIC NONLINEAR ANALYSIS OF STRUCTURES WITH NON-PRISMATIC MEMBERS RETSING ON ELASTIC FOUNDATION

Ahmed T. Al-Ejbari; Hamid. A. Faris; Ibrahim. A. Al-Jumaily

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 71-98
DOI: 10.37650/ijce.2007.14196

Abstract In this study, a theoretical analysis is presented to estimate the in-plane large displacement elastic stability behavior of structures having non-prismatic members of linearly and nonlinearly varying sections resting on elastic foundation (Winkler type) and subjected to static loads applied at joints only. The analysis adopts the beam-column approach and models the structural members as beam-column elements resting on distributed springs. The formulation of beam-column element is based on Euler approach allowing for the influence of the axial force on bending stiffness. Changes in member chord length due to axial deformation and flexural bowing are taken into account. The stability and bowing functions are estimated using methods of finite differences and finite segments. Also, approximate results have been obtained by using approximate stability and bowing functions of linearly and nonlinearly tapered members resting on elastic foundation. A computer program has been coded in QB language to carry out the proposed analysis of structures with prismatic or non-prismatic members of linearly and nonlinearly varying sections resting on elastic foundation. As a result of this study; the only difference between the analysis of non-prismatic members resting on elastic foundation and those which are not, when adopting the beam-column approach, is represented in the stability and bowing functions, and this is reflected directly on the tangent stiffness matrix.

Control Planning of Time, Cost and Quality for Fast Track Projects

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 99-119
DOI: 10.37650/ijce.2007.14197

الخلاصةان العناصر الرئيسية لغرض انجاز المشروع الإنشائي بأسلوب التنفيذ المتسارع هي الوقت والكلفة والجودة بحيث يكون ذا منفعة وضمن مدة محددة ومناسبة .إن نجاح المشروع يهم صاحب العمل إضافة إلى كل من الفريق الاستشاري والفريق التنفيذي . يهدف هذا البحث إلى تطوير مقترحات أساسية وعملية للسيطرة على آليات التخطيط العام للمشروع باستخدام التنفيذ المتسارع إضافة إلى الخطط التفصيلية للسيطرة على عامل الوقت بالتزامن مع السيطرة على العاملين الأساسيين الآخرين وهما كلفة المشروع وجودة الأعمال المنفذة، وذلك لغرض تلافي السلبيات و منع الانحرافات التي تسبب تأخير تنفيذ المشروع في الوقت المناسب. ولغرض تحقيق هدف البحث فقد تم إجراء العديد من المقابلات الشخصية مع عينة منتخبة من ذوي الخبرة بالمشاريع الإنشائية التي تنفذ بأسلوب التنفيذ المتسارع ومن الذين يعملون في القطاعين الحكومي والخاص وأخيرا تم استخلاص عدد من الاستنتاجات والتوصيات التي تقدم نظرة جدية وشاملة لجميع الأنشطة والأعمال التي تحيط بالمشروع وتأثيرها على الوقت والكلفة والجودة لغرض التحسين المستمر لمشاريع التنفيذ المتسارع الإنشائية.

THE EFFECT OF ADDITION OF STEEL FIBERS ON COMPRESSIVE AND TENSILE STRENGTHS OF STRUCTURAL LIGHTWEIGHT CONCRETE MADE OF BROKEN BRICKS

Mahmoud Kh. Mohammed

Iraqi Journal of Civil Engineering, 2007, Volume 4, Issue 7, Pages 120-140
DOI: 10.37650/ijce.2007.14195

Abstract This research studies the effect of adding steel fiber in two percentage 0.5% and 1% by volume on plain structural lightweight concrete (SLWC) produced by using crushed bricks as coarse lightweight aggregates (LWA) in a lightweight concrete mix designed according to ACI committee 211-2-82 with mix proportion 1:1.12 :3.35 by volume .The wc equal to 0.5 and cement content 550 kgm3. Different tests where performed for fresh and hardened SLWC such slump test ,fresh and hardened unit weight ,compressive strength and two indirect tests of tensile strength (splitting tensile and flexural strength). The results demonstrated that the effect of addition of steel fiber was more pronounced on the tensile strength of SLWC than the compressive strength of such concrete .The maximum increase of compressive ,splitting tensile and flexural strengths at 28-days were 38.8,77.12 and 111.2 % in the SLWC containing 1% fiber. On the other hand the rate of strength gain between 3 and 28 days was constant on compressive strength of plain concrete and that containing steel fiber while this rate was clearly increase on tensile strength especially flexural strength.